Term
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Definition
The knowledge of future events, any amount of prior planning.
Evolution has no degree if teleology and happens due to random events shaping the strength and direction of selection upon the genotype and preferential genotypic mutations and variations in a population |
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Term
| Where did Darwin find his initial ideas for the process of natural selection? |
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Definition
| Reading Malthus' 'Population' about the struggle for existence where he created the though process behind the favourable variations would tend to be preserved in a population and then the unfavourable ones would be destroyed |
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Term
| What prevents organisms from populating at too large a value and taking over the world? |
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Definition
| Competition for resources, habitat, space which all act as limiting factors and variables. Resources are finite and therefore do not support infinite growth. This results in variable r values and then the a habitat carrying capacity |
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Term
| What must be remembered when discussing evolution of organisms and the planet? |
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Definition
Time available in evolutionary history is absolutely vast, evolution is not a fast process but the generations that have passed in the millions and billions of years have allowed this intelligent and rather adapted life.
More generations = more possibilities for evolutionary pathways and adaptationary change. (Evolution will still most probably follow the easiest pathway when trying to understand phylogenies ever) |
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Term
| What were the reasons Maria explained as the reasons Darwin could move forward? |
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Definition
1 - Struggle for existence
2 - Variation amongst individuals
3 - Geology (seeing that all these geological structures were made so time must be in vast quantity for evolution)
4 - Adaptations seen in nature for specific habitats and niches
5 - Biogeography of different species in similar places with very similar adaptations but differing morphologies and then very similar species in morphology and adaptations in different places but the niches will be of similarity in the two different places
6 - Wallace, Wallace's line, Wallacea, just an all round G, saw these similarities in the species either side of wallet line but importantly saw the distinctions too! |
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Term
| What are the three requirements for a a population to undergo natural selection? |
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Definition
A - Trait under selection must have a degree of variation in the population
B - A consistent relationship must exist between the trait under selection and fitness (be it fecundity, mating, fertilising ability, fertility or survivorship
C - A consistent relationship for the trait under selection between the the parent and the offspring, which is at least partially independent of common environmental effects |
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Term
| What will happen to a trait that has a good heritability in population as a result of natural selection |
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Definition
| The trait frequency distribution will differ among age classes of individuals in different life-history stage, beyond was expected by ontogeny If the population is not at equilibrium, the trait distribution of all offspring in the population will be predictably different from that in the parents, beyond what would be expected from just the natural variation amongst individuals in pop and the consistent difference in trait value between parent and offspring |
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Term
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Definition
| This is the development of an organism in its lifetime, traits will differ throughout an organisms life time and this is to be understood so we are able to detect variation in the traits that exceeds the change created by ontogeny to detect a selection gradient |
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Term
| How do you measure heritability? |
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Definition
| Plot the graph of parent traits vs offspring traits and then work out the gradient of the line. This value = the h^2 value |
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Term
| What type of density dependent selection is mimicry? |
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Definition
Positive because the more of you that share the distastefulness, especially with the shared morph/colouration/mimicry, the larger the span of protection
A rare morph will have lower fitness in an area where another morph is common because there will be a much higher negative association towards the common due to the positive density dependent selection |
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Term
| What selection does standard morph/colouration mimicry often protect against and get effected by? |
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Definition
| Predation selection. The more inconspicuous/protected the animal, the less it will be predated upon so it pays to be an accurate mimic. (Often this is not true as in the hoverfly guest lecture in EvoBeh but this is for another time) |
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Term
| Famous mimicry positive density dependent experiment? |
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Definition
| Two differing colourations of Heliconius species pattern and then measure relative fitness in each other one's habitat. The rarer individual had a lower fitness in the habitat of the more common morph, for obvious mimic protection ring reasons |
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Term
| Famous crypsis example of non-random evolution? |
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Definition
| Peppered moth morphs, pre and post industrial evolution. First Biston betularia carbonaria seen in 1892 and had high fitness with continued 14% selective advantage over the Biston betularia typica |
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Term
| What is one directional selection called? |
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Definition
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Term
| What is stabilising selection selecting against? |
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Definition
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Term
| What is disruptive selection selecting against? |
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Definition
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Term
| What is correlational selection? |
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Definition
This is a mode of selection that will favour certain combinations of traits. E.g. fitness will be highest when one trait is at a certain level ONLY/ESPECIALLY when the correlated trait is also at a certain specific level.
[image] |
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Term
| What are interlinking phenotypes? |
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Definition
| This is very similar to correlational selection on phenotypes and is where there are different combinations of varying levels of traits that will create the highest individual fitness. May even be when a certain phenotype is replaced by another but this will effect selection as the high fitness combinations are the the ones that will most likely become more common in a population |
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Term
| What is pseudo selection? |
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Definition
| This is when it appears that a certain trait is being selected upon but intact the trait is correlated to the REAL trait being selected one and because of this correlation, the correlated trait falsely appears to be predated on |
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Term
| How do you work out the selection differential and what is shown as? |
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Definition
S = the difference in trait means before and after selection
Measure the trait mean in the before population and find the difference between that and the trait mean after the selection action, this can be the difference between means of two different generations |
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Term
| How do you work out the intensity of selection of a trait and how is it denoted? |
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Definition
| Work out the selection differential and then divide it by the standard deviation of the population trait recordings after selection = i |
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Term
| How do you work out the selection gradient and how is this denoted? |
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Definition
| ß = Find the relationship between the trait and then show a measurable fitness component such as number of chicks fledged and then plot this on a graph and work to the gradient of the line. Like heritability for a trait/fitness relationship |
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Term
| What is countervailing selection? |
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Definition
This is the idea that selection of a trait at one life stage will be effected by the selection of the trait at a different life stage
E.g. is the personality selection in great tits in bearing young. for 1 yr old birds, the fitness is greaser with extreme personality pairings and then past that, an intermediate offspring, disassortative mate pairing gains the most fitness |
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Term
| What is fluctuating selection? |
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Definition
| This is the idea that different traits will provide different fitness benefits at different points in world time and possibly generations. It is often environmentally dependent and the trait will be useful in some stage son environment but not so much in others |
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Term
| What are correlated characteristics? |
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Definition
These are traits that are linked and will influence each other correlated traits fitness benefits or costs. this means measuring the influence of each trait becomes very hard to assess because each trait becomes a variable for measurement of that trait.
Must be tested with a multiple regression assessment and must include statistical error
Can be experimentally tested to a degree with artificial manipulation and control of these other variables but its still not exactly perfect science. It easier with flowers than it is with animals as well |
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Term
| Whats trait circular distribution? |
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Definition
[image]
Is used to display the correlated traits before and after selection. The oval shape is showing the the traits are correlated. This can be confusing as in this case it is pseudoselection on weight because the selection is on height and then indirect acts on weight also due to the correlation |
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Term
| How do you work out the relative fitness of an individual in a certain respect and how is it denoted? |
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Definition
RELATIVE fitness is worked out by dividing the individuals trait 'score' by the the population average trait 'score'.
It is represented as a w |
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Term
| What is the breeders equation? |
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Definition
| R = h2 x S R - Response to selection transmission of within-generational changes to the next generation h^2 = heritability (proportion of variance that is genetically based) S = selection differential (amount of phenotypic variation that exists between a population before and after selection) |
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Term
| How do you estimate a trait mean for the next generation? |
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Definition
| Add on the Response to Selection (R) on to the trait mean of the population before selection and it will give you a good mean of trait in a population after selection |
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Term
| What is often considered the paradox of selection? |
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Definition
Traits that relate very strongly to fitness should contain little to no variation however this variation still persists and often in high quantities in populations.
There is a trend that shows that more variance in more trivial fitness traits but still not as little variance in the fitness traits as predicted |
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Term
| What is the difference between genetic and non-genetic polymorphism? |
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Definition
Genetic polymorphism is the variable polymorphisms that are most common like hair colour, feather colouration and sex.
Non-genetic polymorphism is when the variation is controlled by external factors. External factors may trigger a genetic element but the control is still external. Example is when environmental predatory risk will initiate some morphic transition such as a sideways development in a barnacle or back spines in the daphnia.
Prefatory risk triggered polymorphism will often pose some trade-off such as reduced fecundity but the increase survival with the heightened predator presence means that the fitness levels out |
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Term
| What is the coefficient of variation and how is it denoted? |
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Definition
It is for working out variation in traits with continuous variation
CV = Standard deviation of trait ÷ mean of the trait values |
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Term
| How much variation does the coefficient of variation have in value? |
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Definition
The coefficient of variation will be really very small in traits where there is determinate growth and the traits are selected for a specific accurate size such as a bird bill.
Traits for determinate growth creatures can be small, birds traits vary around 2-4%
Traits for indeterminate growth creatures can have more variable CV such as in fish where the CV will have a large range depending on the variation within population which will dependent on a lot of external resource and predation factors |
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Term
| What are the terms for traits controlled by different numbers of genes? |
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Definition
Monogenic - 1 gene (categorical)
Oligogenic - A few genes (e.g. blood type)
Polygenic - Many genes (quantitative/continuous) |
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Term
| What is the Partition of Variance and who came up with it? |
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Definition
Fisher, R. A.
VP = VA + VG + VE
VP = Variance in phenotypes amongst individuals
VA = Additive genetic variance (simple genetic effects coming into play)
VG = Variance in non-additive genetic effects (dominance and epistasis)
VE = Variance in non-genetic effects such as environmental and developmental variance |
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Term
| What is the estimate for heritability of continuous traits? |
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Definition
h2 is often low but preeeeetty much never 0 for continuous traits
h2 morphology > h2 physiology and behaviour > h2 life history
HOWEVER, Many life history traits were found to have a higher heritability than the morphology |
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Term
| What is h2 in term of inherited variance? |
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Definition
h2 = Additive Variance ÷ Phenotypic Variance
Phenotypic Variance = Additive Variance + Variation Response
Variation Response = Genetic Variance + Environmental Variance |
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Term
| What are the basic points for the maintenance of variation in traits? |
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Definition
Mutation-Selection Balance
Balance of Selective Forces
-Heterosis (heterozygote advantage)
-Fluctuating Frequency Dependent Selection
-Antagonistic Pleiotropy
-Genotype via Environmental Interaction |
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Term
| Which Diseases are good Heterosis examples? |
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Definition
Sickle Cell anaemia where crossing of two strains/two alleles gives protective advantage over Malaria
PRNP129 heterozygote gives protection over Kaur Disease which is the one you get from the eating brain cannibalism in New Guinea |
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Term
| What is Antagonistic Pleiotropy? |
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Definition
This is the mechanism that explains how some genetic individuals will have a higher fitness in different areas.
An otherwise lower fitness allele genotype may have higher fecundity than others and therefore due to this heightened aspect of fitness it shows some evolutionary advantage to persist in population |
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Term
| What are the reasons for a lack of evolutionary response to selection? |
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Definition
Biased heritability estimates (experimental or study bias)
Countervailing Selection (different traits give have different fitness at different life stages)
Fluctuating Selection (Strength and direction of selection will differ in space and time)
Genetic constraints
Selection only on one environmental component
Environmental deterioration |
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Term
| What does biased heritability estimate mean? |
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Definition
| This is in regard to explaining why no evolution occurs in the presence of a direction of selection. It is the explanation that there is little to no actual heritable resemblance between parent and offspring |
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Term
| How do you work out the breeders equation for several traits? |
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Definition
R = Gß
Where:
R - Vector of Responses (change in the mean of each characteristic but in vector form)
ß - Directional selection gradient (The slop of linear regression of relative fitness on phenotypic values)
G - Additive Genetic Covariance Matrix
Will look like this...
[image]
Where if the traits are completely independent one another, the covariances would be 0!
This is to understand the effect of correlating genetic constraints |
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Term
| What is the "animal model" for phenotype? |
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Definition
[image]
This is to understand the variation in an individual that might occur |
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Term
| What is the difference between a tactic and a strategy? |
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Definition
Strategy is a plan to behave in different situations and the general way an organisms will go about it, temperament and such
Tactic is the behaviour used in a specific situation and the actual action taken in that situation |
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Term
| What are the basic values for the hawk vs dove game? |
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Definition
[image]
World revolves around the fact that a mixture of Hawks and Doves exist in the world and that tactics used are variable, solidly repeated tactics will lose fitness quickly as patterns can be predicted |
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Term
| When is being a hawk in the Dove-Hawk Game a stable ESS? |
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Definition
[image]
When 1÷2(V-C)>0 or when V>C
This means that when the benefits of winning will outweigh the cost of losing |
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Term
| In the Hawk-Dove Game, what happens when the V < C? |
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Definition
[image]
This means that the cost of losing is greater than the benefits of winning and therefore neither being a hawk or dove is an ESS. This means that a mixed strategy becomes the ESS |
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Term
| What are the three classes of reproductive strategies? |
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Definition
Alternative Strategies - Genetic polymorphism leading to equal fitnesses overall meaning there is no selection that removes any alternative strategy. This is uncommon.
Mixed Strategies - Equal fitnesses that will lead to individuals using different mating strategies fairly randomly, this is quite rare.
Conditional Strategies - The common form of mating strategy and means the mating strategy used is the one that fits in with the current life history status of the individual and possibly dominance status in a group |
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Term
| How do you draw out a competition matrix? |
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Definition
[image]
This is usually best for the examples where each strategy can be beaten another strategy but will beat another strategy |
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Term
| What is the good example for Rock Paper Scissors in real life? |
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Definition
This is the Side Blotched Lizard that will have three variable colourations Orange, Blue and Yellow. These Colours have different strategies associated with them too.
Orange - Aggressive and territorial
Blue - Less aggressive and smaller territories
Yellow - Sneak maters and non-territorial
Yellow < Blue < Orange < Yellow < Blue < Orange < Yellow...
Frequencies will cycle in a population due to frequency dependent selection |
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Term
| How can Long Tailed Tits be used to understand the Conditional mating strategies? |
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Definition
This is because the new parents are susceptible to predation and chicks can be eaten so it is a choice for an individual to try to pair off and have their own offspring or it may be in the their best interest to go and help their parents or siblings raise their offspring and increase the inclusive fitness. It is conditional on their choice and current living status which is often time of year dependent
The expected breeding success reduces massively between April and June and then the percent of individuals starting to build nests go es down and actual percent beginning to help relatives go up! |
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Term
| What explains the 50/50 sex ratio? |
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Definition
The rarer sex would realistically be able to gain more matings than the common one and so that sex would have higher RS and then once a balance has been met, the equal RS of the sexes would mean a very constant 50:50
Diploid species with sex determination controlled by the nucleus and the costs and benefits of being either sex is equal |
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Term
| What is the actual payoff and payment in the prisoners Dilemma matrix? |
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Definition
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Term
| What did Maria say was the most stable ESS in the prisoner's dilemma game? |
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Definition
Tit for Tat and Cooperate first!
Only remember the last move the opponent plays and therefore you will get a forgiving tactic and this will supposedly help out |
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Term
| What is a life history trait? |
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Definition
Its a life history trait if, holding all else equal, a correlation between the trait and fitness exists and remains
e.g. age at maturity, adult size, number and size of offspring |
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Term
| What is the reproductive value and how does it change through time? |
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Definition
This is the no. of offspring expected to be had in an individuals lifetime
Reproductive value appears to go up as the organism grows up and almost works like the inverse of mortality as when chance of mortality is high (young and very old), the reproductive value of an organism is at its lowest and highest when the organism is in best physical fitness with lowest chance of death.
ALSO depends on the rate at which the population is growing and declining |
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Term
| What's important about reproductive schedules? |
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Definition
| The early start to reproduction (early age of sexual maturity) is often a good thing as this means individuals can start contributing to the population growth quicker but also frequency and no. of offspring is essential as THIS will influence the rate of pop growth A LOT because of the way relationship with mortality and other possible variables |
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Term
| What is the Darwinian Demon? |
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Definition
| A hypothetical being that will start reproducing straight after birth, product infinite offspring and will live forever |
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Term
| What are the possible life history constraints? |
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Definition
Phylogenetic: Evolution cannot just happen over one generation, designed specifically to suit certain environment/niche so hard to deviate
Biomechanical: The physical constraints upon living beings, organisms require certain sizes of structures to function and most things bigger or smaller for them would not work
Developmental: The way in things develop will be the way they develop, they cannot form into another structure to perform a different function, there is determinate growth
Physiological: Principle of allocation (Investment into certain aspects of life history cannot be reversible so quickly and once the investment has been made, that is it |
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Term
| What is the most basic reproductive trade-off? |
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Definition
Semelparity vs Iteroparity
Semelparity = 'Big Bang' reproduction e.g. Onchorychus kisutch
Iteroparity = Steady life long reproduction |
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Term
| What is the house and the car problem? |
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Definition
This is the idea that people with nice houses must invest all money into house and get shit car and people with shit house must invest into nicer car!
This is not the case and the people with nice houses often have the nicer cars so in nature it is not just the individuals that invest more into foraging ability may just be a better quality individual and therefore can still invest more into territory control possibly are than one who solely invested into territory control as they are just a poor quality individual |
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Term
| How is the house and car problem displayed graphically with room for the quality of individual to play as well? |
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Definition
[image]
Yellow = Top Quality
Red = Lowest Quality
Most individuals will exist in the black triangle
The larger the variation in condition in a population however, the larger the black triangle will be! Large variation in condition will usually result in quite a small black triangle (called the allotment) |
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Term
| What does a real life reproductive tradeoff look like? |
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Definition
[image]
Small reef will save up their reproductive ability and invest in growth rate instead and then the already large reefs will invest in the reproduction as they have already reached a good size in growth |
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Term
| What does the basic model of predation selection on age of sexual maturity look like? |
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Definition
[image]
Survival drops when getting older because everyday you escape death, the chance of dying the next day increases. This is especially true for high predation and therefore optimal reproduction age is lower in organism which will live in areas of high predation
e.g. GUPPIES |
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Term
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Definition
| Questions why all organisms have not evolved to become semelparous as this annual or temporal semelparity resolves in the most effective means of population growth. HOWEVER, semelparity only really favours the individual if the chance of parent surviving is relatively small compared to offspring survival. When the chance of the parent living and being able to continue to to reproduce again is high and offspring is possibly lower, especially without the help of the parent (parental care) then the iteroparity will evolve |
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Term
| Does semelparity favour wetter or dryer site in plants? |
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Definition
| Semelparity favours dry sites because the conditions are much less predictable and seem very harsh so a large reproductive effort in a favourable wet patch in the averagely very dry conditions will leave the the best chance for lots of surviving offspring and allow them to successfully establish |
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Term
| What is the difference between extrinsic and intrinsic death? |
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Definition
Extrinsic death is the death from extrinsic factors such as predation and such
Intrinsic is dying from mutation in the body and disease and internal factors |
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Term
| What is antagonistic pleiotropy in regards to old age mutation accumulation? |
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Definition
The mutations that may favour early life and reproductive success will accumulate even with very negative effects later in life because the early reproductive success means i cannot be selected against and then the bad results later in life will lead to a high accumulation of shitty old age deaths!
This is why cancer and old age diseases persist and occur so commonly because there is no negative selection upon them |
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Term
| What does R. E. Ricklefs say are the reasons for senescence? |
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Definition
| Senescence occurs in organisms, especially in those with a low extrinsic mortality rate because the wear and tear of the body is too costly to repair and there is no selection against it and there is no genetic variation for the repair in old age away and therefore is no basis for any selection anyway |
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Term
| What is the alternative theory of mortality? |
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Definition
Mortality is supposedly a random chance in the standard theory.
Alternative theory says that mortality is not random and will effect the individuals who invest more into protection/immunity/evading death.
Couple of papers suggest early investment into immunity may lead to lower risk of disease and lower senescence later in life.
It is seen in Caenorhabditis remanei |
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Term
| What is the difference between competitive exclusion and character displacement? |
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Definition
Ver similar mechanisms in theory but Competitive Exclusion has a ecological standpoint and the Character Displacement has a evolutionary standpoint. Competitive Exclusion can lead to Character Displacement
CE - Superior competitor excludes inferior from some habitats (Gause, 1934)
CD - One species influences the evolution of resource use in another as a result of interspecific competition (Will usually be physically defined as a divergence of traits in the two competing species) |
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Term
| What are the assumptions of character displacement? |
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Definition
That there is 1:1 relationship with trait size and the resource in question (e.g. beak size and seed size)
Positive response to the resources in question |
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Term
| What is the good example of a beautiful show of positive response to resources? |
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Definition
| The Asellus aquaticus feeding on fungi and the success of this isopod is much greater when feeding on the more abundant fungi as they have evolved to respond better and utilise the common food stuff more than the rare shit |
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Term
| How is character displacement seen in sympatric relationships? |
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Definition
[image]
The traits are optimal when in exclusive allopatry but as soon as the sympatry occurs, co-existence causes trait divergence to be as optimal as it can be in the presence of a competing species |
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Term
| When is character displacement hard to detect? |
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Definition
| In the presence of phenotypic plasticity and intrinsic stored genotypic variance when trait divergence can occur through a simple genotype/phenotype change and then it leads to a seeming character displacement but by evolutionary definition, is not |
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Term
| What is reinforcement in regards to character displacement? |
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Definition
| This is the character displacement that occurs when two morphological species are in allopatry and go through a degree of morphological displacement in their reproductive traits and sexually signalling traits as to avid confusion in breeding with the wrong species |
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Term
| What is the criteria for character displacement? |
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Definition
1. Should 100% not be by chance
2. Differences seen in allopatry and sympatry should have genetic basis
3. Enhanced differences should be seen in the between sympatric species due to evolutionary shifts, rather than an inability of similar sized species being able to coexist
4. The trait divergence seen should be in accordance to the resources that are being shared
5. Sites of sympatry and allopatry should be not differ greatly in the conditions and resources available which may lead to other explanations for the divergence of species' traits
6. Evidence should be found to show that the similar phenotypes will compete for food |
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Term
| How many cases have been found (by 2000) that follow all 6 criteria for true character displacement? |
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Definition
61 overall
35 carnivores, 14 herbivores, 5 primary producers, 4 scavengers and 2 microbivore.
^^These skews in numbers may be the result of simple research study bias |
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Term
| What is trait overdispersion? |
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Definition
| This occurs in character displacement as a result of the traits diverging, usually in sympatry and then the traits of sympatric species are more different from each other than would be expected by chance when looking at the species trait means |
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Term
| What is apparent competition? |
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Definition
[image]
The prey becomes the downward selecting force rather than a resources being the upwards selecting force! In areas where a prey may cause negative selection of another prey type |
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Term
| What are theoretical approaches to understanding predator prey coevolutionary relationships? |
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Definition
1) 'Technology limited' - Meaning there is no cost to adaptation but the mutation/selection rate is limiting the possibilities for both predator and prey. Can achieve steady state of relationship or extinction if one exceeds the others rate
2) 'Tradeoffs' - Adaptations represent a cost and benefit balance and therefore the coevolutionary states of each show a balance that can tip depending on condition of individual or environmental condition |
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Term
| What did Abrams (2000) say about predator prey relationships? |
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Definition
| Investment by predator or prey into adaptations to increase one aspect of fitness will lead to a reduction in other aspects of fitness |
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Term
| What has been seen through the ages for the Encephalisation Quotient through the ages between predators and prey? |
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Definition
| There has alway been a larger brain for size in the predators/carnivores and as the time has gone through from the archaic orders to now, they have both become bigger with similar patterns being seen and recently the gap between predator and prey brains has got smaller |
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Term
| What was the toxin we looked at to discuss predator prey relationships with toxins and toxin resistance? |
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Definition
| TTX is the toxin produced in the newt that is predated on by the garter snakes and the areas with high newt density there is high toxin resistance but areas where other prey is eaten the toxin resistance is lower which suggests a tradeoff between toxin and something which is their speed apparently |
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Term
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Definition
| This is the signalling of unpalatability, it shows that the animal is nasty and is what a good proportion of mimicking is based on |
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Term
| What is parsimony in evolution? |
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Definition
| This is the idea that the evolution will usually take the simplest route of how things occurred because it is a mechanism that does not take the extravagant route of events in most cases, goes the the route with the least steps |
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Term
| What did Alatalo & Mappes (1996) find out about the evolutionary route of aposematism? |
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Definition
That the evolutionary route of aposematism was probably unpalatability initially and then an occurrence of gregariousness would lead to aposematism quickly although the aposematism can occur without gregariousness but solitary aposematic individuals will start off with disadvantage because of the non-cryptic colouration.
Then the mimics of the established gregarious aposematic species would not have to live in gregarious lifestyles as the warning colouration had already been established so they can have advantage off the back of the aposematic gregarious species |
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Term
| Once again, what is the difference between Mullerian and Batesian? |
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Definition
Mullerian = They're all rank (Mullered by the bad taste)
Batesian = Some are aite to eat |
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Term
| What is special about Opossums toxin resistance? |
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Definition
| Jansa & Voss (2011) found that they have highly variable regions for toxin resistance in the von Willebrand factor gene which will lead to much higher resistance to some snake toxins compared to other model mammal organisms because opossums are snake predators |
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Term
| What is the bacteria that resistance evolution is studied on? |
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Definition
Pseudomonas flurorescens resistance to the bacterial predator Bdellovibrio bacteriovirus
3 morphs
- Smooth Morph SM
- Fuzzy Spreader FS
- Wrinkly Spreaer WS (It's extinct now because it had terrible resistance)
SM is super resistant and is technology limited as the mutation rate is the speed it develops resistance and will develop resistance higher than the predator can develop efficiency so SM beats the B. bacteriovirus
FS is less resistant and as it becomes slightly more resistant it loses ability to utilise resources and its exponential growth rate reduces signifying a cost of adaptation and a tradeoff |
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Term
| What is the optimal virulence of a parasite? |
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Definition
| It is the optimal amount of damage it will do to its host, it must be enough so that the host struggles to rid the parasitic burden but not enough to kill it as the parasite requires the host to live |
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Term
| What happened to the virulence of Myxomatosis? |
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Definition
They took the most violent strain from south america in 1940s and then as the decades went by in France, Australia and England, the strain become less virulent as it evolved not to kill the host so quickly as this was not beneficial for the parasite.
The English strain became 50% deadly and then stopped evolving at that, compared to the Aus and Fra strains which became 50-25% deadly! Possibly due to the English having Flea vector and Aus/Fra having Mosquito vector |
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Term
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Definition
Equation for the Parasitic Intrinsic Reproductive Rate.
Parasite wants this value to be as large as possible as it is the mean number of new cases/infected individuals will occur from ONE infected individual.
[image] |
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Term
| What is the relationship between virulence and both recovery rate of host and intrinsic parasite reproductive rate? |
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Definition
[image]
As virulence increases, the recovery rate decreases for the host. There is also different ways in which parasites act so the two lines show two differing effects but they both have an optimal virulence to maximise the Ro value |
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Term
| What is usually more virulent, vector borne or directly transmitted parasites? |
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Definition
Vector borne are, the vector is not infected so will do the transmitting itself whereas if directly transmitted, the parasite cannot reduce the health of the host too much as the host still needs to have a high activity rate to go about and spread the parasite
Waterborne parasites are also extreeemely virulent because they have an active transmission method and therefore will not have to keep the host alive as once it dies they will often be able to leave and float to another host. |
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Term
| What is vertical and horizontal transmission in parasites and what type of virulence they prefer? |
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Definition
Vertical = passes between generations of hosts, this will prefer higher virulence
Horizontal = transmitted between hosts in same generation and will prefer reduced virulence |
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Term
| What was a good evolutionary tradeoff we looked at with Parsnips? |
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Definition
Parsnip webworm, Depressaria radiella, is the parasite.
Pastinaca sativa is the parsnip plant and will produce furanocoumarins to poison and deter the webworm, however the level of toxins produced is in relation to the seeds produced, with the tradeoff being between reproductive value and resistance |
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Term
| Which bird is unparasitised by the cuckoo but will still recognise the intruders egg in an experiment? |
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Definition
| Starlings, they are intraspecific parasites themselves as they will attempt to put their eggs in other individual's nests in order to pass on the parental care duty |
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Term
| Which are the predominant species to get parasitised by the cuckoo? |
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Definition
| Reed Warbler, Dunnock (the worst at recognising parasite eggs), meadow pipit and the pied wagtail |
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Term
What is a hypothesised reason as to explain this...
[image] |
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Definition
| This is probably a ghost of parasitism past an these birds used to used by the cuckoo but then the individuals became wary and became savvy and were able to detect them so the cuckoo moved on to more naive hosts |
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Term
| How is egg mimicry able to occur in such specific manners in the cuckoo? |
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Definition
| The genes for the egg mimicry are in the female sex specific chromosome W, as the females are WZ and the males are just ZZ, so the males will romp around mating and the females will remain species specific with their egg mimicry |
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Term
| What is a resistance cycle? |
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Definition
This is the idea for the red queen hypothesis. The cycle continues for efficiency of infection and resistance against infection.
The idea that the present host genotype is the most susceptible even though it is selected resistance for the parasite but the parasite is selected specifically for that host genotype and past and future genotypes will be different and not be specifically selected for those genotypes. |
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Term
| What is prezygotic isolation? |
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Definition
Premating isolation, reasons as to why the two individuals could not mate like environmental barriers or even physical barriers
Animal e.g. two Pundamalia spp. (cichlid like fish) have different colouration and therefore do not display each others sexually selected preferences and therefore would not ever cross breed
Pant e.g. two Aquilegia spp. (orchid like flowers) would never be cross pollinated because one of the flowers is predominantly fed on by hawkmoth and therefore the pollinating species create the pre zygotic isolation |
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Term
| What are the two types of postmating/postzygotic isolations? |
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Definition
Intrinsic/genetic and Extrinsic/ecological
Intrinsic means that the offspring will become infertile and therefore not able to breed. Occurs in Heliconius melpomene and H. cydno as the hybrid females are sterile
Extrinsic means that the offspring individuals of the the two extrinsically isolated parents have much lower fitness and even if they are able to breed, they will be weeded out of the population and selected against due to significantly lower fitness, may be due to the lack of specificity to an environment due to hybridity e.g. in the two leaf subspecies of Neochlamisus bebbianae which are both specific to two different leaves, the hybrids are just worse on either leaf because they are less specific |
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Term
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Definition
" 'Allo, there's another species range over there!"
Allopatric is the division of a range into two, so remember the hello/'allo analogy I've wonderfully created here |
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Term
| What is the by-product mechanism of speciation and what animal organism did we look at? |
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Definition
It is the occurrence of a slight allopatric barrier and then followed by the divergence and then through this divergence of species, new preferences for mate choose or something comes along and reinforces the divergence.
For example, Gambusia species of fish became divided into two lakes, with high or low predation. In the high predation they evolved thicker tails for faster swimming from predators. This thick tail then developed into a sexually selected trait by female and then the mating of these two new species would not occur because the females have different mate choice preferences |
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Term
| What is the Dobzhansky-Muller Model? |
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Definition
[image]
Dobzhansky-Muler Model is the model that shows how genetic incompatibility evolves from the ancestral genotype and then the fixed genes cannot create a viable fertile offspring |
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Term
| What are the predictions of the ecological speciation model? |
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Definition
1 - Rate of reproductive isolation is correlated with the strength of the divergent selection
2 - Ecological speciation reduces hybrid fitness leading to extrinsic isolation
3 - Trait under divergent selection influences reproductive compatibility of the two potentially diverging new species
4 - Parallel evolution of mating incompatibility over similar environmental gradients |
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Term
| What led to the cichlids developing different colours in the African lakes? |
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Definition
Divergent selection model, the sexual selection favours different colour and then the divergence of colours occurred and then the speciation process began.
This was because the sympatric species were genetically closely related but the dissimilar in colours and preference and such so this must have been the case |
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Term
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Definition
Biology that looks at why the organisms are distributed where they are and for what reasonings. The idea of placental mammals and marsupials on either side of the Wallace's line when first seen by Wallace.
Marsupials split from the Eutherian placental mammals between the Jurassic an Cretaceous periods and then the divergence of their biogeography gave us the Wallace Line |
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Term
| When can a population be under natural selection? |
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Definition
a) When variation amongst individuals exists in the population in some tribute or trait (e.g. (Gerhardt, 1991) NA Treefrog species' males will create choruses and then the individuals will create different constant/static or pulsating/dynamic and calls to attract mates)
b) Consistent relationship must exists between the trait containing variation and an aspect of fitness (e.g. (Parker, 2002) Gallus gallus shows honest gene indicator with redder comb indicating higher gut health and possibly increased immune function. This shows the the link to mate choice preference and fitness)
c) Degree of heritability int he trait and therefore consistent relationships in trait between parent and offspring (e.g. (Grant & Boag, 1978) Geospiza fortis displays beak size heritability of around 0.68 and therefore subject to natural selection) |
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Term
| What example can be given to explain variation in a trait? |
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Definition
| (Gerhardt, 1991) NA Treefrog species' males will create choruses and then the individuals will create different pitches and calls to attract mates. There are calling males and silent satellite males (which will just grab nearby females (alternative mating strategy)) and these will display different mating outcomes. Also display pulsating or static constant calling in the calling males which will lead to different mating properties, with dominant frequencies being preferred. However with nearby species, a known/common conspecific call may be preferred as to know the actual call of the correct member of the same species rather than another) |
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Term
| What example can be given to show the constant link between fitness and trait variation the leads to differential mate success and therefore sexual selection and evolution? |
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Definition
| (Parker, 2002) Gallus gallus shows honest gene indicator with redder comb indicating higher gut health and possibly increased immune function. This shows the the link to mate choice preference and fitness) |
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Term
| What example can be given for the showing of heritability amongst traits? |
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Definition
| (Grant & Boag, 1978) Geospiza fortis displays beak size heritability of around 0.68 and therefore subject to natural selection and therefore not too high or too low and there is a link high link between parent and offspring trait size |
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Term
| What example can be given to strong nonrandom selection in severe conditions? |
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Definition
(Grant & Boag, 1981)
Drought on the Daphne major islands between 1975 and 1977 led to seed abundance reducing massively and the larger hard seeds being the only ones in any form of abundance and this led to the reduction in small beak sized individuals and the large beaked ground finches becoming more abundant and a real bottleneck in terms of the beak size genotypes and led to predominance of large beaked individuals on the island for the years afterwards |
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Term
| What is an example of Mullerian mimicry ring? |
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Definition
| (Marek & Bond, 2008) Appalachian millipedes which are blind and therefore will exhibit no real possibility of sexual selected colouration as they have lost their eyesight before the existence of this colouration mimicry was exhibited. The 7 species will differ in colours when they exists in large populations with no true co-occurence of a similar species, however in areas of high co-occurence, the abundance of mullein mimics is high and they are protected by this positive frequency dependent selection of aposematism |
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Term
| What is an example of the effectiveness of the protection from Mullerian mimicry? |
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Definition
(Mallet & Barton, 1989) Looked at the mullein mimicry of the species of butterfly Heliconius erato and H. melpomene.
Both are distasteful and intra-specially colour polymorphic. Each morph however of the species will have a mimic in the other species.
When different morphs were taken from their natural area and moved into new territory, they were predated upon in high rates because the predators did not recognise them as a noxious species |
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Term
| What is an example of disruptive AND stabilising selection? |
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Definition
(Miles, 2004) looks at sprint speed in lizards and four that the directional selection was towards increased stride length and burst speed, which was the most preferential fitness benefit due to increased survival over slower individuals, regardless of size.
Selection for initial velocity was concave up (DISRUPTIVE), hence juveniles with intermediate values for initial velocity had lower fitness and individuals with high and low initial velocity had higher fitness.
Conversely, selection for mean velocity was concave down (STABILISING), thus juveniles with intermediate values for mean velocity had higher survivorship
The faster overall lizards will also have generally warmer, more predated habitats due to higher ability to evade capture and have faster growth rates. |
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Term
| What is an example of monotonic directional selection? |
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Definition
|
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Term
|
Definition
Biology that looks at why the organisms are distributed where they are and for what reasonings. The idea of placental mammals and marsupials on either side of the Wallace's line when first seen by Wallace.
Marsupials split from the Eutherian placental mammals between the Jurassic an Cretaceous periods and then the divergence of their biogeography gave us the Wallace Line |
|
|
Term
| When can a population be under natural selection? |
|
Definition
a) When variation amongst individuals exists in the population in some tribute or trait (e.g. (Gerhardt, 1991) NA Treefrog species' males will create choruses and then the individuals will create different constant/static or pulsating/dynamic and calls to attract mates)
b) Consistent relationship must exists between the trait containing variation and an aspect of fitness (e.g. (Parker, 2002) Gallus gallus shows honest gene indicator with redder comb indicating higher gut health and possibly increased immune function. This shows the the link to mate choice preference and fitness)
c) Degree of heritability int he trait and therefore consistent relationships in trait between parent and offspring (e.g. (Grant & Boag, 1978) Geospiza fortis displays beak size heritability of around 0.68 and therefore subject to natural selection) |
|
|
Term
| What example can be given to explain variation in a trait? |
|
Definition
| (Gerhardt, 1991) NA Treefrog species' males will create choruses and then the individuals will create different pitches and calls to attract mates. There are calling males and silent satellite males (which will just grab nearby females (alternative mating strategy)) and these will display different mating outcomes. Also display pulsating or static constant calling in the calling males which will lead to different mating properties, with dominant frequencies being preferred. However with nearby species, a known/common conspecific call may be preferred as to know the actual call of the correct member of the same species rather than another) |
|
|
Term
| What example can be given to show the constant link between fitness and trait variation the leads to differential mate success and therefore sexual selection and evolution? |
|
Definition
| (Parker, 2002) Gallus gallus shows honest gene indicator with redder comb indicating higher gut health and possibly increased immune function. This shows the the link to mate choice preference and fitness) |
|
|
Term
| What example can be given for the showing of heritability amongst traits? |
|
Definition
| (Grant & Boag, 1978) Geospiza fortis displays beak size heritability of around 0.68 and therefore subject to natural selection and therefore not too high or too low and there is a link high link between parent and offspring trait size |
|
|
Term
| What example can be given to strong nonrandom selection in severe conditions? |
|
Definition
(Grant & Boag, 1981)
Drought on the Daphne major islands between 1975 and 1977 led to seed abundance reducing massively and the larger hard seeds being the only ones in any form of abundance and this led to the reduction in small beak sized individuals and the large beaked ground finches becoming more abundant and a real bottleneck in terms of the beak size genotypes and led to predominance of large beaked individuals on the island for the years afterwards |
|
|
Term
| What is an example of Mullerian mimicry ring? |
|
Definition
| (Marek & Bond, 2008) Appalachian millipedes which are blind and therefore will exhibit no real possibility of sexual selected colouration as they have lost their eyesight before the existence of this colouration mimicry was exhibited. The 7 species will differ in colours when they exists in large populations with no true co-occurence of a similar species, however in areas of high co-occurence, the abundance of mullein mimics is high and they are protected by this positive frequency dependent selection of aposematism |
|
|
Term
| What is an example of the effectiveness of the protection from Mullerian mimicry? |
|
Definition
(Mallet & Barton, 1989) Looked at the mullein mimicry of the species of butterfly Heliconius erato and H. melpomene.
Both are distasteful and intra-specially colour polymorphic. Each morph however of the species will have a mimic in the other species.
When different morphs were taken from their natural area and moved into new territory, they were predated upon in high rates because the predators did not recognise them as a noxious species |
|
|
Term
| What is an example of disruptive AND stabilising selection? |
|
Definition
(Miles, 2004) looks at sprint speed in lizards and four that the directional selection was towards increased stride length and burst speed, which was the most preferential fitness benefit due to increased survival over slower individuals, regardless of size.
Selection for initial velocity was concave up (DISRUPTIVE), hence juveniles with intermediate values for initial velocity had lower fitness and individuals with high and low initial fitness had higher fitness.
Conversely, selection for mean velocity was concave down (STABILISING), thus juveniles with intermediate values for mean velocity had higher survivorship
The faster overall lizards will also have generally warmer, more predated habitats due to higher ability to evade capture and have faster growth rates. |
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Term
| What is an example of monotonic directional selection? |
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Definition
| (Berenbaum et al., 1990) looked at the significance of the selection for the intensity and concentration of Furanocoumarins in the Pastinaca sativa plant which aided the protection from the Depressaria radiella in a RQH evolutionary arms race. The direction of selection was from the parasite feeding on the plant and then the direction of selection on toxicity resistance in the parsnip moth also exists |
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Term
| What is an example whereby the strength of sexual selection for higher fitness is stronger than that of the survival selection for viability to reproduce? |
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Definition
| (Brittnacher, 1991) looked at Drosophila and found that the strength of selection for the males to have high virility was higher than that of any other selected component by chance and even on aspects of organisms fitness that would be linked to increased survival, indicating that the sexual virility is the most important aspect of the organism fitness |
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Term
| What is an example of correlational selection? |
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Definition
(Ennui & Fleming, 2000) looked at Salmo salar (Atlantic Salmon) and looked at the selection on egg size and brood size and found that the mothers would sacrifice the egg size (and therefore survival) for a larger brood size. This however is still required to be in balance as both are selected traits that lead to the survival and fitness of the reproductive success and offspring survival of the mother.
The selection for optimum egg size in regard to brood size also is an occurrence in highly fecund organisms with large ranges in brood sizes. The optimum value for selection was based upon the parents RS rather than offspring survival |
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Term
| What is an example of countervailing selection? |
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Definition
| (Both et al., 2005;Dingemanse et al., 2004) looked at the assortative and disassortative mate pairings of the Great tits (Parus major) and their mate preference at young and old ages. At young ages, the assortative mate pairings of both extremes of personality types (bold and shy) create fledglings with the highest fitness and highest offspring survival is obtained. At older ages, the mate pairings become disassortative and the pairs use one bold to look for new territory and and resources and one shy to look after young in the nest. This stops complete disruptive or stabling selection on personality types in the great tit population |
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Term
| What is a good example of fluctuating selection? |
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Definition
| (Wong et al., 2009) looked at the fluctuating sexual selection year to year to in the Sand Goby and found that the preference for male mate size and the amount of nest cover changed every year which led to individuals varying in size year to year also. Female's individual size did have an impact on their mate preference for male size, length and nest cover however this did not appear to change wholly year to year but the mean sizes of males that gained successful copulations in the different years varied significantly. This may have something to do with the water conditions and resource availability to do with the chance of offspring success if the individuals are of different sizes. |
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Term
| What is a good example of understanding correlated characteristics and determining indirect selection? |
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Definition
| (Rymer et al., 2010) looked at a particular Iris that is pollinated by hawkmoth and then looked at the selected traits that were preferentially pollinated by the hawkmoths which is what are sexually selected traits in flowering plants. The tube length was the tested variable and was experimentally manipulated and the scent was omitted form the study. The study looked at tube length and plant height, finding direct selection on tube length and that assortative mating occurred at low pop density and random mating at high pop density which would lead to stabilising selection at high pop density and loss of rare morphs of the tube lengths with plant height having little to do with it and is a pseudo-selected trait. However the scent that is a key part of the hawkmoth attrition varies greatly from different morphs of the plant and may exhibit some form of indirect selection on the tube length specifically due to the correlated trait of the scent-tube length |
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Term
| What is a good example of changing and maintaining variation in selected characteristics in species populations? |
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Definition
(Imai et al., 2016) looked at the difference and variation in Front, Middle and Hind leg lengths in closed Ant populations with extremely limited to no gene flow. Strongest selection was show for the hind leg tibia (HLT), which if cut off, effected the walking speed by 48% and thus higher than other limb loss impacts and therefore most important for manoeuvrability. The variation in this HLT amongst populations was negligible, all exhibiting presumably close to optimal HLT size/length as any other reduces work performance dramatically and any mutations are quickly removed from the population.
The Hind Tarsia Spur Length (HTSL) and low selection on this part and therefore showed that there was little functional use of a specific size of this spur and therefore within and between populations, the spur length displayed large variation. |
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Term
| What is an example of a non genetic polymorphism? |
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Definition
| (Black, 1993) looked at the predator-induced neck spines in the Daphnia pulex when a Notonetca is around. There is a tradeoff exhibited in this as the spines use sufficient energy and reduce the lifespan of the individual however they provide protection from the predator and therefore will increase immediate survival. This is a showing of phenotypic plasticity and therefore is an ability stored in all Daphnia individuals |
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Term
| What are the theories for maintaining the variation of traits in a population? |
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Definition
Theory 1: Mutation-selection balance
Theory 2: Fluctuating selection
Theory 3: Tradeoffs
Theory 4: Non-additive genetic variation
Theory 5: Sexually antagonistic selection
Theory 6: Frequency Dependent Selection
Theory 7: Antagonistic Pleiotropy
Theory 8: Overdominance (What Maria calls 'heterosis') |
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Term
| What is an example of Overdominance (what Maria calls heterosis) maintaining variation in in genetics in a population? |
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Definition
(Semel et al., 2006) looked at the introgression of domestic tomato lines compared to wild tomato which is supposedly fairly distantly related at this point, and found that the introgression lines of the domestic tomato had higher reproductive fitness due to over dominance and heterosis and there was no evidence for over dominance in the non-productive traits. The overdominace of such traits had been selected for in artificial selection for higher yields by farmers.
Experiment looked at the high numbers of QTL for reproductive and non-reproductive traits and found that the QTLs for reproductive traits showed commonly a mix of two alleles in a heterozygous state being most superior |
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Term
| What is the difference between negative and positive frequency dependent selection? |
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Definition
Negative = When the rare morph has higher fitness advantage (e.g. (Lively, 2009) looked at the RGH for the coevolution of rare and common host genotypes change in presence and absence of parasite in the new zealand mud snail and its trematode parasite)
Positive = When the common morph has the highest fitness (e.g. (Borer, 2010) looked at leaf beetles and the Mulleiran mimicry of them and showed a textbook wild example of this with common colour morphs linked to the current aposematism in the specific environment showed odds of week long survival increasing by 167% which is good. The variable community composition is then used to understand th variable common colour morph in the different community which will be shaped on what colours put off the predominant predators in that community) |
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Term
| What is a really good example of antagonistic pleiotropy? |
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Definition
| (Lambeth, 2007) looked at the antagonistically pleiotropic actions of ROS which are produced in the mitochondria and also by Nox enzymes which are used for empirical functions such as innate immunity and biochemical reactions such as the production and release of the thread hormone. The production of these ROS leads to irreversible and accumulative molecular damage to cells and DNA. Higher rates of these enzymes and such may lead to higher fitness when required but the increased production of ROS leads to the increased senescence of cells, proteins and DNA and therefore the increased damage of the ageing process and earlier death also due to the much increased chance of chronic diseases from damaged tissue such as lung fibrosis and cancer. |
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Term
| What is a tasty little example of genotype x environmental interactions that allows the persistence of genetic diversity and variation? |
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Definition
| (Paulesu et al, 2010) looked at the relationship between the genes that cause dyslexia and prevalence in different countries. It was just to show that some environments, the certain issues are not even issues. Single genetic controlled issue is not even regarded a problem in Italy because the the language is far more phonetic and closely match when spoken and read whereas in England it is considered far more of a problem because of the different environment |
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Term
| What are examples of non-additive genetic variation that provide the material for maintaining genetic variation in a population? |
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Definition
(Dantzer et al., 2013) looked at the maternal effects of red squirrels having an effect on the fitness of their offspring, using measures of brood size and the resources in the year before. The maternal effects where but being able to have an impact of the individual young fitness because they were able to gain more food and have a faster growth rate when lower brood sizes as higher percentage of the gathered food was able to to be fed to them. This is also linked to the house and car problem and can be contrasted to the brood size and offspring fitness findings in the Atlantic Salmon.
Can also talk about the epistasis in an individual and possibly phenotypic plasticity in changing environments and individuals with larger capabilities to change with larger range of phenotypic plasticity may be fitter in larger range of environments. |
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Term
| What is an example of fluctuating selection in the Copepod daphnia? |
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Definition
| Hairston & Dillon 1990) looked at the the changing timings of the egg laying which is highly dependent on the light conditions and therefore environmental production which can change with the different sea temperatures year to year which will change the fish (daphnia predators) population sizes. Changing timings of the egg laying is caused by the changing time to switch to diapause which will lead to differential offspring success due to higher or lower predation |
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Term
| What are the ways in which we can explain the lack of response to selection? |
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Definition
Biased heritability estimates
Countervailing Selection
Fluctuating Selection
Genetic Constraints
Selection only on Environmental Component
Environmental Deterioration |
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Term
| What is an example of a genetically controlled phenotypic dimorphism in males that leads to alternative mating strategies? |
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Definition
(Lank et al., 1995) looked at the Philomachus pugnax that contains genetically controlled by a single-locus, two-allele autosomal genetic polymorphism, which creates the three morphs:
Independent - display dark colouration and territorial behaviour
Satellite - Light colouration and no territory with wandering behaviour
Female morph - displays female plumage and uses sneak mating when the other two morphs are showing lekking behaviour |
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Term
| What is a good example of mixed mating strategies found in wild populations? |
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Definition
(Lubin et al., 2009) looked at the preference to either mate with distantly or close related individuals in the Date Stone Beetle. In closed systems, the females would take longer to mate with closely related individuals than to distantly related individuals showing a preference for outbreeding and therefore putting the large rates of inbreeding in the wild down to the lack of available distantly related mates.
The mixed mating strategy in this case was to the mixture between inbreeding and outbreeding and this was maintained by the assurance of mate in inbreeding as the mates are all around and available but the females will hold out in wild populations for a long time to wait for possibility of migrating male for higher fitness outbreeding scenario |
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Term
| What is a good example of a conditional mating strategy in a wild population? |
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Definition
(Huffed et al., 2010) looked at the Algae Octopus and observed the male-male aggression and male-female aggression. Often the larger males are the most aggressive and will win the male-male fights and therefore have higher reproductive success in the bouts. These males will then have a higher resource holding potential.
Different levels of aggression between males were found when competing for females that would be temporally guarded by another male that would be more accessible than the alternative adjacently guarded females which occupied dens that were within an arms reach of the guarding male. Significantly larger males were the adjacent guiding males and gained the most time copulating with females
Male-Female aggression was looked at also to understand the differing levels of aggressive behaviour between them and found the size not to be the key factor and there was evidence of large males fleeing from smaller females as during the male-female fights there was more chance of higher injury because aggression was much higher because of the resources they would be fighting over |
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Term
| What is a good example of cyclic alternative mating strategies being dominant in the population? |
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Definition
(Sinervo & Lively, 1996) looked at side blotched lizards nd found that the males have three different morphs, yellow, orange and blue.
Orange - aggressive & territorial
Blue - less aggressive & small territories
Yellow - sneakers & non-territorial
These will fluctuate in the population as being the most successful tactic meaning there is no true ESS.
[image] |
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Term
| What is an example of the conditional mating strategy in birds? |
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Definition
(MacColl & Hatchwell, 2002) looked at the choice Long Tailed Tit individuals make when creating a nest in the breeding season. Due to possible egg loss and predation of young, individuals can switch to become helpers for other nests if their own nest is lost, therefore still gaining inclusive fitness by aiding the raising of relatives nest. The survival rate of offspring to breeding age is higher in nest with helpers than those without.
The rates of failed nesters either choosing to re-nest or become helpers also changes through the season as the deeper in spring you go, the lower the chances of actually being successful in re-nesting become.
[image] |
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Term
| What is a good example of a alternate mating strategy controlled by genes? |
|
Definition
| (Taylor et al., 2016) looked at the supergene control of the three male morphs of the Philomachus pugnax and the corresponding mating behaviour. 1) Territorial Male. Dark in colouration and highly territorial and aggressive, represents around 90% of the populations and contains no supergene control and is WT in reference to the other morphs 2) Satellite Male. Light in colouration, not territorial,low aggression and will move between the dark males territories performing mate attractive signals and performances and gaining mates this way. Represents around 10-20% of the population and is genetically controlled by an inverted supergene of around 100 genes that control the ontogeny of the individual. 3) Faeder Male. permanently mimics a female and will steal copulations from sneak mating. Represent around >1% of the population and is also controlled by a similar supergene. Due to the inversion of the supergenes, these are unable to recombinate and are staple in the population |
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Term
| What is an example of a life-history tradeoff in Primates? |
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Definition
(Thompson, 2016) looked at Wild Chimpanzees and found a tradeoff between offspring growth and reproductive rates which acts as a quantity-quality tradeoff for the chimpanzees.
Chpanzees with high levels of resources tend to favour the faster rate of reproduction which aligns with the house and car problem as they are able to deal with the high reproductive rate and still maternally invest a high amount due to their good condition, the balance still occurs in chimpanzee mothers though and will tend to stay in this sort of bracket...
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Term
| What is an example of a tradeoff between current and future reproductive investment? |
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Definition
| (Morano, 2013) looked at the Cervus elaphus mothers who were far less likely to fall pregnant in a consecutive year of reproducing due to their investment into the current fawn. It did not effect future level of survival but on the reproductive value and success in the subsequent year. This shows that the frequency of the rutting season is not the level set for an individuals reproductive success. |
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Term
| What is an example of the house and car problem in birds? |
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Definition
(Mann, 1988) looks at Little Penguins and used experimental manipulation of their clutch sizes to understand why and how most birds will produce and fledge a maximum of two eggs in a season whereas a rare few are able to produce and fledge 3.
They had control nests and experimentally manipulated 1,2 and 3 eggs in a nest. The experimentally enlarged clutch sizes showed reduced fledgling success rates and therefore show the life history trait of laying 2 eggs is an evolutionary balance of maximum successful fledglings in a year |
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Term
| What is an example of Semelparity in mammals? |
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Definition
(Lopes, 2015) looked at the Agile Gracille Mouse Opossum and shows a large male die-off after reproduction which is possibly due to a large energetic cost of male-male competition for mates due to a sex-ratio skew towards males meaning competition for mates is large. There is also a post-weaning senescence of the females when the young are ready for independence showing evidence for non-overlapping generations.
Semelparity comes from the large brood size and early independence from the offspring working in synergy with low annual survival rates of the marsupial species that leads it to beneficial semelparity |
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Term
| What is an example species in the same taxa that display difference n reproductive life-history traits? |
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Definition
(Young, 1990)
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Comes from the good condition of the environment and the amount the individual has to invest into resources.
In dryer site they will live by a much slower and more determined life history, which leads to little activity until the conditions become good enough to gather the resources for a semelparous reproduction |
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Term
| What is a life-history trait nice to humans that involves reproductive trade-off and reduced senescence and is an example of effective post-reproductive selection? |
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Definition
(Herndon et al, 2010) talks about the grandmother effect with a selection for life after stopping reproduction in humans because the females who have stopped reproducing are able to increase the reproductive fitness of their offspring by helping them with the raising of their offspring and allowing the daughters to reproduce again and maximise their reproductive success. Herndon also speaks about the significant lack of cognitive degradation in humans and continued social cognition function in old age due to the grandmother effect and that the older individuals benefit their offspring more when they are more capable and able to provide good social care that will increase offspring success and the continued reproductive effort of the the grandmother's daughter. Chimpanzees can reproduce all the way until they die which is around the age of 60 and show significantly higher rates of cognitive function degradation compared to homo sapiens. (Hawkes 2016) modelled the idea of the grandmother effect evolving into an ancestral-ape population and with the fitness benefits that it would give the reproducing individual, with 1% of women living past beyond their fertility it would lead to a 40% by the end of their model, showing a selection upon this grandmother parental care trait.
The reduced mental cognition degradation is an exception that proves the rule for lower genetic and cellular repair in old age as in other primates which do not display the same grandmother use in old age display higher rates of cognitive degradation because there is less selection it |
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Term
| What is an example of a tradeoff that effects survival in both short and long term? |
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Definition
(Lüning, 1992) looked at the Daphnia pulled and then in and out of the presence of two predators, one feeding on small daphnia and one feeding on large.
Presence of the midge larvae, the Daphnia will produce large neck spines with several teeth and then the reduces chance of being predated on but increases investment of resources and earlier chance of mortality
In presence of Notonecta, the Daphnia will produce more and smaller clones of itself in asexual reproduction and lead to reduced size and earlier maturity at lower instars |
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Term
| What is an example of the classic view of 'extrinsic mortality rates reducing intrinsic lifespan' being reversed by condition dependence? |
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Definition
(Chen, 2012) looked at the Caenorhabditis and found that high random extrinsic mortality led to a largely reduced intrinsic mortality rate.
HOWEVER, in high levels of condition-dependent mortality, even with a higher random mortality rate, the intrinsic mortality rate increased which leads to a belief of high environmental condition can reverse the classic prediction if the mortality rate is based upon the intrinsic condition which is largely based upon the presence of a good condition environment |
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Term
| What is the example we looked at to describe the classic relationship between the high random extrinsic mortality rates effecting the intrinsic mortality rates? |
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Definition
| (Ricklef, 1998) looked at the effect of mortality rates on the captive bird population and found a significant relationship between increasing mortality rate and the increasing rate of senescence and found that in birds with low extrinsic mortality, the captive birds were mostly dying from the senescence which is due to the reduced genetic variation for the repair in old age because it is passed the point of selection through reproduction |
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Term
| What is the reference for competitive exclusion? |
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Definition
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Term
| What is an example of competitive exclusion in action in birds (trick bird wording here some careful haha lol) |
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Definition
(Hargis et al., 2000) found: In poultry, infection with Salmonella Gallinarum were extremely large and throughout the late 20th century was an issue until its irradiation through testing and slaughtering infected poultry. The redaiccation of the S. Gallinarum led to the rapid increase of S. Enteritidis which was weaker and displayed a lower transmission rate between poultry. It was then found that the Gallinarum form competitively excluded the Enteritidis form in the early 20th century and therefore monopolised the poultry Salmonella infections.
This is hypothesised to be likely due to the higher specificity of the Gallinarum which had no other animal reservoir whereas the Enteritidis was able to infect and live in other animal populations possibly meaning it was more of a generalist |
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Term
| What is an example of Character Displacement in sympatric evolution? |
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Definition
| (Rice et al., 2009) looked at the Spadefoot Toad tadpoles. The competition is between co-existing Spea multiplicata and Spea bombifrons. The competition is over prey resource use. Both species in allopatry will both preferentially produce a larger proportion of carnivorous morphs in the tadpoles as the carnivorous morphs are significantly more successful than the omnivorous morphs! However, parallel character displacement evolution has been shown in multiple sympatric habitats that the S. multiplicata will produce a significantly skewed number of omnivores in the sympatric habitats compared to the allopatric environments because the S. bombifrons are able to produce competitively superior carnivores |
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Term
| What is an example of a paper that discusses the character convergence in sympatry? |
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Definition
(Fox et al., 2008) discusses the idea that character displacement will only occur in sympatry when the competition for a certain resource is not imperative for survival and there is a substitutable alternative for one or both of the species in sympatry.
In species that are competing for an essential resource, the competitive selection increases and leads to increased convergence of traits to increase individuals chance of nutrient recruitment.
This is is especially true in many plant species in close proximity that will show larger competitive selective forces for the capture of non substitutable resources such as nitrogen and phosphorous (Tilman, 2007) |
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Term
| What is an example of Reinforcement in Anurans? |
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Definition
(Rice, 2014) looked at the Spadefoot toads in both allopatry and sympatry and the female preference for the mating calls of conspecifics and individuals from other species.
Using female individuals for the Spea multiplicta and Spea bombifrons they looked at the mate call preference.
S. multiplicata individuals from the sympatric areas showed much preference for the conspecific call and the call was slightly reduced call rate to the call when found in the allopatry. The individuals from the allopatric areas showed a slight preference for the higher call rate which was an exaggerated call rate which would be not found coming from the S. multiplicata males due to physiological constraints.
S. bombifrons showed a steady call rate and did not diverge from their allopatric call rate because they were physiologically constrained from getting any faster.
The character displacement exists for increased reproductive isolation reinforcement and ALSO is an example of pre-zygotic isolation behaviour in the two toad species. |
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Term
| What is an example of the rapid evolution of character displacement two competing species? |
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Definition
(Grant & Grant, 2006) looked at the competing species Geospiza fortis and Geospiza magnirostris.
In 2005 there was a large drought and led to the genetic bottleneck of both species in the island population.
Both species feed of Tribulus seeds and the lack of abundance led to the starvation of many of the individuals and increased competition for other food resources. G. magnirostris is about twice the size of the G. fortis and in the presence of the drought, selection for the G. fortis was towards smaller beak size and led to the character displacement from their larger beaked relatives only 30 years previous.
The drought in 1977 led to a selection of larger beaked individuals gaining the highest level of fitness but this was before the G. magnirostris had been introduced and therefore show evidence for character displacement as the beak selection acted in the opposite direction with the competing larger species. |
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Term
| What is an example of trait over-dispersion? |
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Definition
| (Rabosky, 2007) looked at the Ctenotus genus of lizard in Australia and found that there body size had become an over-dispersed trait quality in the local scale which was attributed to the partitioning of the local environment and food availability |
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Term
| What is an easier way to understand the two prey and one predator apparent competition model and how each of the prey will influence each other? |
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Definition
(Mogul, 2010) looked at this idea with invading prey species.
If the resident system is comprised of one prey and one predator and then a invading prey enters the system it can destabilise it completely or can lead to a stabilisation.
A stabilised revised model will occur if the invading species has a lower adapted defence to the predator than the resident prey, then the resident prey can afford to drop its level of defences as selection will ease off and then there will be a stable predator-2 prey model
If the resident prey has a defence similar to invading prey and then the resident prey can begin to evolve to become more adapted to the predator and then act as a superior competitor of the resident prey and the destabilise the relationship due to destabilising the population dynamics |
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Term
| What is the good encephalisation quotient paper for predator prey relationships? |
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Definition
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Term
| What is a good example of a predator-prey coevolution in snakes? |
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Definition
(Holding et al., 2016) looked at the North Pacific Rattlesnake and the North American Ground Squirrel which shows large resistance to the snakes toxin but the Rattlesnake acts as the antagonist in the interaction and is ahead in the phenotypic matching coevolution of toxin and toxin-resistance.
Co-evolution is locally specialised and follows a mosaic distribution over the entire regional area. This is shown by independent evolutionary coldspots, where one of the species occurs without the other and traits in coevolution can be tested to see any difference from that of an individual where both are found and in the ground squirrel and pacific rattlesnake there were found to be a single occurring species individual was significantly divergent from the individuals in coevolutionary arms races. |
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Term
| How did Fisher hypothesise Aposematism evolved? |
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Definition
He believed that in the unpalatable organisms, the gregarious behaviour evolved first and then the warning colouration came after this grouping behaviour to increase predator awareness of unpalatability
HOWEVER this is only ever truly required with truly naïve predators and were the initial bright warning colouration makes the prey conspicuous and will be an easier spotted target for the predator. Therefore in Heliconius butterflies for example in Mullerian mimicry, the predators are already wary of bright colouration meaning unpalatability and therefore not require much re-learnign about a new aposematic species and so there is no need for gregariousness!
Initial origin of aposematism will have generally required a gregarious synergy to increase the rate of predator learning so that the colouration confers an advantage and the prey is not killed before it is able to pass on any aposematic warning genotype to offspring. |
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Term
| What is a good example of aposematism? |
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Definition
This is warning colouration to advertise unpalatability or toxicity.
(Rojas et al., 2013) looked at Female colouration/aposematism in the sexually dichromatic species of Dyeing Dart Frog. The females display colouration as a warning of unpalatability and noxiousness.
The dichromatism comes from stronger selection for mate colouration as they are the species that carries and deposits the eggs, and due to high levels of larval cannibalism, the faster the frog gets to the egg laying tree-fall gap spots, the more successful their offspring will be, so the brighter the males are, the quicker parasites will learn of their unpalatability and will avoid preying upon them. The aposematism works in synergy with the birth migration they perform, as apposed to the females which just have the selection of aposematism and so are duller in colour.
(Summers et al., 2001) looked at the evolution of aposematism in poison dart frogs and found that the most likely scenario was that the warning colouration evolved in tandem with the toxicity and that this colouration became more vivid as the frogs became more noxious |
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Term
| What is the best simple example of coevolution of changing and escaping host-predator relationship? |
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Definition
The Asclepia host plant and the Tetraopes beetles which both develop higher toxicity and toxic resistance from the initial common ancestor to now, with new speciations occurring with larger toxicity and then the beetle will speciate and have a new level of toxicity resistance to deal with the new level of toxicity form the newly speciated host Asclepia.
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Term
| What is a good example of a changing Batesian mimicry model in response to model populational change? |
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Definition
Ackari et al., 2014) looked at the Batesian mimic the Scarlet King Snake which models from the noxious Coral Snake.
The Coral snake went locally extinct due to extirpation in the North Californian Sandhills and after this local extinction, the Kingsnake individuals had a mean rise in the accuracy of their mimicking. This is due to the gradual reduction in population and eventual extinction of the model which means that the protective noxious aposematic ring that protects the mimic is reducing with the disappearance of the noxious model and therefore any non-accurate mimics will be more readily predated upon. Therefore mean level of accuracy of the mimics has increased. This will likely only occur for a few more generations until the predators hunt the Scarlet Kingsnakes to local extinction as without the Batesian mimicry protection they will not be protected |
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Term
| What is an example of an invading parasite displaying increased virulence to the host? |
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Definition
(Graaf et al., 2011) looked at the trypanosome parasite C. bombi and the Fungi parasite Nosema bombi which are both extremely prevalent in commercially reared bumble bees in NA. Both parasites are transferred via horizontal transmission and due to the commercial process of rearing bumble bees it allows the virulence of the parasite to increase due to the lesser strength of selection for parasite defence due to the commercially increased breeding rate and therefore when the commercial bumble bees escape the commercial greenhouse crops, the parasites can be horizontally transferred to wild populations and display higher levels of virulence to the naïve wild hosts
This is also a real worry because the horizontally transmitted parasites will favour high virulence because they do not require a host to survive until reproduction to pass on the parasite to a new host
Nosema bombi is a sporophore and therefore provides active transmission this way |
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Term
| What is myxomatosis and why talk about it? |
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Definition
Myxomatosis is a virus that is used to explain the use of virulence. Evolved in SA and then the most virulent strain was taken from labs and introduced in Australia for the control of the rabbit populations. Originally mortality was in 4 days and then the resistance grew through strong force of selection and in just 6 years it had reduced from 100% mortality to 25% mortality.
The virulence drops because the of a coevolution of the virus and the rabbits. The rabbits develop selection through the strength of resistance selection and the virus develops a lower virulence to increase chance of reinfection by keeping the animal alive for longer to increase chance of vector passing the virus on.
Aus and Fra = Mosquito
Eng = Flea |
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Term
| What do vector-borne viruses display higher virulence than the directly transmitted (especially vertically transmitted)? |
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Definition
| This is because the vector borne viruses do not need to display any real life-prolonging tactics as the vector is usually able to transmit the virus from the infected individual quickly and the virus can often live inside the intermediate host. Such as in malaria where it can live inside the Anopheles mosquito and the virulence can be extremely high |
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Term
| What is the tradeoff hypothesis in parasitic virulence? |
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Definition
This is the new hypothesis for understand the virulence of the parasites that is believed to explain most parasitic virulence and not the avirulence hypothesis.
(Hurford, 2009) describes the ideas behind it and it is represented by this equation
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Term
| What is the Avirulent hypothesis in parasitic virulence? |
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Definition
| This is the idea that all parasitic virulences should evolve to become less virulent and just display a detrimental effect on the host to prevent resistance and recovery. This allows the parasite to continue the possibly symbiotic relationship it has with the host and continue feeding. This was then taken over by the Tradeoff hypothesis |
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Term
| What is a good paper to explain water-borne parasites/bacteria? |
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Definition
(Ewald, 1991) looks at the evolution of virulence in gastrointestinal bacteria causing diarrhoea and the increased tendency for high virulence because of the increased efficient transmission mechanism of the body and immunopathological response the body shows to the presence of the gastrointestinal bacteria.
Gastrointestinal bacteria caused 8-15 million deaths annually between 1970-1990 due to the transmission via the cultural vector of, generally speaking, contaminated drinking water but can include infected bed sheets and clothing which will be washed into the contaminated drinking water so the host virulence is also not constrained by immobilising the host as indirect transmission of cultural vector can still occur form an immobilised host, like it can with an arthropod vector. Example include Vibrio cholorae. |
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Term
| What is an example of reduced virulence in vertically transmitted host? |
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Definition
(Montes, 2014) looked at the Cucumber Mosaic Virus and the host Arabidopsis thalania and found a largely reduced virulence in the the vertically transmitted virus by increasing the transmission and reducing the accumulation and virulence in the host plant, this was able to occur after only 5 generations. This did not occur in the horizontally transmitted virus. This also shows evidence for the transmission virulence tradeoff.
The Host also showed increased resistance in the vertically transmitted virus through continuous selection adaptations. |
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Term
| What is a good example of a resistance tradeoff in host parasite evolution in Water Fleas? |
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Definition
(Auld et al., 2013) looked at the tradeoff in Daphnia dentira host with the infecting yeast parasite M. bicuspidata between the resistance and fecundity of the individuals!
The tradeoff existed with a foraging variable as the more frequent foragers were the more fecund individual due to high condition but the high rate of foraging led to a higher exposure to the parasite in the food stuff and therefore were more susceptible to infection.
Therefore the trade-off exists as a foraging mediated tradeoff between resistance and fecundity! |
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Term
| What is a good example of plant poison and insect parasitism tradeoff? |
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Definition
| (Berenbaum, 1997) looked at the Depressaria radiella Parsnip Webworm parasite and the Host Pastinaca sativa Parsnip plant and found there was a tradeoff in the amount of Furanocoumarins that were being produced by the plant and the number of seeds the plant was producing, therefore exhibiting a tradeoff between host fecundity and parasite resistance |
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Term
| What is the most important thing to remember about the coevolutionary arms race displayed between mutualists and parasite-host? |
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Definition
Parasite-Host relationship is always antagonistic.
Mutualists such as pollinators and plants coevolve so that the process is often easier and more beneficial, with a preference for specificity for each other
Parasite-host relationships will continue with the Red Queen Hypothesis with one attempting to escape and the other following on behind attempting to continue parasitising the host |
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Term
| What is a very good example of evolutionary arms races in hot and cold spots between parasite and host? |
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Definition
(Jackson, 2008) looked at the Alcon Blue caterpillar (Parasite) and the Myrmica ant hosts.
The Caterpillar is able to mimic the cuticular hydrocarbons that the ants produce to identify group members and young.
The Caterpillar is able to have a repertoire of cuticular hydrocarbon forms and show regional and local specificity for different any colonies and species and it will release the cuticular hydrocarbons which are closely matched to local population of a certain Myrmica species. It is then carried to the ant nest due to the signalling and then fed by nursing ants, nursing can be preferential to the caterpillar, like seen in cuckoo chicks, because the caterpillar is able to release higher specificity of cuticular hydrocarbons to manipulate the hierarchy.
Coldspot = little evolutionary speed in the evolutionary arms races
Hotspot = rapid coevolutionary arms race direction
Coldspots occur in the M. ruginodis du to high migration of colonies and therefore increased geneflow and less specific hydrocarbon chemical signalling so unparasitised colonies were preventing the arms race direction.
Hotspots occurred in the M. rubra which displayed high specificity and no migration between colonies. This leads to continuous change of the cuticular hydrocarbon chemical makeup and thus leads to the arms race for the specificity of this signal.
The Alcon Blue Caterpillar can prove fatal for M. rubra ant colonies due to high virulence and therefore there is strong force of selection for resistance in the M. rubra hotspots and this could lead to the a dynamic shift of hosts to the cold spot M. ruginodis. |
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Term
| What is a good example of adaptations of parasitisms past? |
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Definition
(Davies & Brooke, 1989) looked at the suitable but unused possible hosts of the Cuckoo and how they were able to recognise the cuckoo's egg which may be a sign of still innate earning from adaptations to cuckoo egg recognition and removal in their evolutionary past and thus the cuckoo moves on to find a new suitable and naive host.
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Term
| What is an okay example of the red queen hypothesis to explain the paradox of sex and to make sense of the coevolution that is required from parasite and host coevolutionary relationships? |
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Definition
(Gibson et al., 2017) looked at the prevalence of P. antipodarum (a NZ freshwater snail) which has a sexual and asexual lineage. In stable and independent habitats, the asexual will out populate and outcompete the sexual lineage but in the presence of the microphallus parasite, the sexual lineage comprised 72% of the coexisting population.
This is predominantly to do with the RQH (van Valen, 1973)
The sexual reproduction leads to the increase in recombination and selection for a rare genotype that infers form of temporary resistance to the parasite until the parasite will also adapt to increase infection for the first rare and now more common genotype so the rare genotype only covers temporary resistance in a population and therefore the RQH exists |
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Term
| What is a good example of post-zygotic reproduction that preceded pre zygotic isolation? |
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Definition
(Rudolph et al., 2012) looked at two sister species of Killifish, one Euryhaline and one Freshwater.
Both of these species are prezygotically and postzygotically reproductively isolated.
They looked at the ecologically diverging populations of the Euryhaline species and found detrimental fitness of the f1 hybrids of the saltwater and freshwater populations. The species is not yet prezygotically reproductively isolated and still display the same mating behaviour and attractions however the allopatry of the populations is leading to speciation and possible divergence towards speciation
THIS IS POSSIBLY SYMPATRIC GENETIC POSTZYGOTIC ISOLATION |
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Term
| Whats an example of extrinsic post-zygotic reproduction isolation and how can it also be drilled in by intrinsic P-Z isolation? |
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Definition
(Rogers et al., 2006) looked at allopatric ecologically diverging populations of Dwarf and Normal Lake Whitefish.
They found that backcrossed hybrids with both parental lineages showed asynchronous emergence and transgressive segregation. This asynchronous emergence led to detrimental fitness due to lack of gregariousness and overall low clutch offspring fitness and transgressive segregation occurred meaning that the resulting phenotype was extremely environmentally context dependent and that in any unfavourable conditions, the transgressive genotype would be extremely unfavourable.
The two populations also showed a largely increased embryonic mortality rate (6x higher) in the backcrossed young than in either of the two independent species.
The two forms of post zygotic isolation led to a large isolation of the two populations and would likely ultimately lead to speciation of the Dwarf and Normal populations
THIS IS DUE TO ALLOPATRIC SEGREGATION |
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Term
| How do the levels of reproductive isolation required for speciation occur in different geographical layouts? |
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Definition
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Term
| What is a study to show how reinforcement is mainly a functional mechanism in sympatric species and why? |
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Definition
(Rundle and Schluter, 1998) looked at the willingness of stickleback female of one distinct morph (benthic) to mate with the other distinct morph (limnetic) when the morphs had evolved either allopatrically or sympatrically.
The morphs that have evolved symmetrically showed a much reduced willingness to mate with another morph due to the mechanism of reinforcement that led the morphs be able to distinguish the features of the conmorph male |
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Term
| What is important to remember about genetic drift? |
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Definition
It is a process by which much of the speciation will occur but it will pretty much always be working in synergy with another process, usually a process of directional selection (mate preference divergence or environmental changes/divides)
Random Genetic drift is unlikely to do anything significant by itself |
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Term
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Definition
This is an organism which has been created through hybridisation of species and contain multiple copies of each of its parents genome, thus making it polyploidal.
Not all hybrids will be polyploid and not all polyploids will be hybrids but an allopolyploid is both! |
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Term
| What is an example of a speciation via hybridisation and polyploidy? |
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Definition
| (Holloway et al., 2006) looked at the Gray Treefrog, Hyla versicolor which is a sexual tetrapolyploid and has evolved from hybridisation events of three ancestors, all asexual and diploid. The three hybridisation events led to to three forms of hybrid and then these hybrids interbred, the resulting species was a sexual tetraploid in the form of Hyla versicolor |
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Term
| What is an example of possible Dobzhansky-Muller model in action in species? |
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Definition
(Brideau et al., 2006) looked at the male hybrid lethality of Drosopholia melanogaster and D. simulans and found that there were functionally diverging genes in the population that led to male lethality in f1 hybrids and may indicate a function for the last resulting push in the divergence in the speciation.
Lethal Hybrid Rescue in D. simulans and Hybrid Male Rescue in D. melanogaster interact in the f1 hybrids to result in lethality of male hybrid progeny. |
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Term
| What is an example of ecological speciation leading to reduced environmental dependent hybrid fitness? |
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Definition
(Rundle, 2002) looked at f2 hybrid backcrosses between benthic and limnetic populations of stickleback and their growth rates in the the two environments that was causing this ecological divergence, the littoral zone (favoured by benthic) and open water (favoured by limnetic). Tested benthic, limnetic, backcross benthic and backcross limnetic in both environments and shows detrimental fitness that would cause competitive exclusion in the specific environmental context.
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Term
| What is an example of host shift leading to divergence of mate preference due to by-product of host shift? |
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Definition
(Cocroft, 2008) looked at the Enchenopa binotata treehopper which has an ancestral population on the host tree Eastern Redbud and then the novel population on the Water Ash.
Water has environment is preferential for a higher frequency mate cal |
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Term
| What is an example of the Founder effect an what is the mechanism that leads to speciation? |
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Definition
(Wessel et al., 2013) looked at the Hawaiin Cave Planthopper, O. polyphemus which was was found to have migrated to a relatively new sailed of Hawaii and then founder populations split off from the migrating population into various lava tube caves. These various founding populations have become established and have shown rapid diversification in morphology and have become various subspecies because of this, leading to rapid reproductive isolation.
This founding populations then followed by a rapid increase in the phenotypic diversity of the characteristics of these plant hoppers is likely fitting with Carson's (1971) Founder-Flush hypothesis which says that the rapid decrease in population and bottle neck is then aided by a flush and rapid increase of genetic variability, which in this system is aided by the large epigenetic variability that is was contained in the plant hopper's genome.
The mechanism is genetic drift which is caused by the founding effect |
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Term
| What is the reference for the founder effect? |
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Definition
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Term
| What is important to remember about genetic drift? |
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Definition
It is a process by which much of the speciation will occur but it will pretty much always be working in synergy with another process, usually a process of directional selection (mate preference divergence or environmental changes/divides)
Random Genetic drift is unlikely to do anything significant by itself |
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Term
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Definition
This is an organism which has been created through hybridisation of species and contain multiple copies of each of its parents genome, thus making it polyploidal.
Not all hybrids will be polyploid and not all polyploids will be hybrids but an allopolyploid is both! |
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Term
| What is an example of a speciation via hybridisation and polyploidy? |
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Definition
| (Holloway et al., 2006) looked at the Gray Treefrog, Hyla versicolor which is a sexual tetrapolyploid and has evolved from hybridisation events of three ancestors, all asexual and diploid. The three hybridisation events led to to three forms of hybrid and then these hybrids interbred, the resulting species was a sexual tetraploid in the form of Hyla versicolor |
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Term
| What is an example of possible Dobzhansky-Muller model in action in species? |
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Definition
(Brideau et al., 2006) looked at the male hybrid lethality of Drosopholia melanogaster and D. simulans and found that there were functionally diverging genes in the population that led to male lethality in f1 hybrids and may indicate a function for the last resulting push in the divergence in the speciation.
Lethal Hybrid Rescue in D. simulans and Hybrid Male Rescue in D. melanogaster interact in the f1 hybrids to result in lethality of male hybrid progeny. |
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Term
| What is an example of ecological speciation leading to reduced environmental dependent hybrid fitness? |
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Definition
(Rundle, 2002) looked at f2 hybrid backcrosses between benthic and limnetic populations of stickleback and their growth rates in the the two environments that was causing this ecological divergence, the littoral zone (favoured by benthic) and open water (favoured by limnetic). Tested benthic, limnetic, backcross benthic and backcross limnetic in both environments and shows detrimental fitness that would cause competitive exclusion in the specific environmental context.
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Term
| What is an example of host shift leading to divergence of mate preference due to by-product of host shift? |
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Definition
(Cocroft, 2008) looked at the Enchenopa binotata treehopper which has an ancestral population on the host tree Eastern Redbud and then the novel population on the Water Ash.
Water has environment is preferential for a higher frequency mate call as the sound is able to travel better in this environment due to more efficient signal transmission and therefore this has adapted as a pre zygotic reproductive mating isolation and even though still produce fertile offspring, the two populations rarely interbreed sue to differential mate call and mate call preference
This matches the three predictions from by-product mechanism that
1) male signals are habitat specific
2) female sensitivity is habitat specific
3) male signals match female sensitivity |
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Term
| What is an example of an organism undergoing parallel ecological divergence? |
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Definition
(Nosil et al., 2002) looked at the stick insect species, Timema cristinae, which has strong host-interaction relationships which will cause strong selection for morph type. This is often due to the crypts predator avoidance mechanism that T. cristinae enforces. It has resulted in ecologically divergent pairs of populations exhibiting greater levels of reproductive isolation than ecologically similar pairs of populations of similar age.
This is the criteria for parallel ecological divergence.
The two host plants are distributed in a parapatric mosaic pattern, meaning that the patches of common host plant will overlap with a territory of the other host plant and low level geneflow is found between the interacting Timema cristinae species host-specific populations
Evidence shows that the different populations using the same host plant do not form monophyletic groups and therefore must have evolved multiple times, however the genetic divergence between the different populations of same host plant individuals is the smaller than that of the different host plant species from the same population. |
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Term
| What is an example of parasitic and mutualism in one? |
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Definition
(Lunau, 2004) - Looked at the pollinating parasitic moth Greya politella and the flower L. parviflorum. This moth can passively pollinate the L. parviflorum and then will oviposit onto the carpels of the flower for the eggs to hatch and feed on the flower.
The decision for the seed capsule production or abortion then fell on the presence of the Greya politella parasitising the flower. This shows a strong mechanical selection for the phenotypic plasticity to produce or abort a seed capsule. Egg presence would lead to the abortion of the seed capsule as it would be wasted effort as it would be eaten.
However, in areas of abundance of non-parasitic copolliantors, the flowers showed no effect of the Greya politella parasitism as the majority of the flowers were generally pollinated by another means showing a lack of selection for the the effect of the parasitic moth and therefore there was no abortion seen from the flowers with egg presence which suggests lack of selection for the detection of egg presence due to normality of other pollinators |
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Term
| What is an example of a mutualistic coevolution? |
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Definition
(Jander and Herre, 2010) looked at the relationship between fig wasps and fig species. The Fig wasps will lay their eggs inside of the fig fruit where the male progeny will then bite open the seeds of the fig fruit and feed on them before mating with the female progeny. The females will then leave the fig fruit and carry pollen from the fruit and will pollinate other fig tree flowers.
Insect reproductive success increases with the number of progeny they create, however, with increased progeny, there will be more males that will eat all of the seeds so none can be pollinated.
The Fig trees that are actively pollinated by the wasps must also be producing the figs to keep the wasps surviving as the wasps relative fitness and offspring survival relies on the pollination of the fig plant so that the fruit is produced and it is a safe nutritious place for oviposition.
Therefore there is reproductive tradeoff for the Fig Wasp so that they produce an optimum level of eggs so that the maximum number of offspring are produced whilst still painting the pollinating ability and viable seeds for the fig tree so that future oviposition is possible.
This mechanism also prevents pollen free wasp cheats as if the fig species such as Ficus citrofolia will not tolerate pollen free cheats as the figs will not mature or fruit without the continued high level of active pollination and therefore the wasps will not be able to reproduce
Some fig trees such as Ficus maxima is predominantly pollinated passively and therefore can afford to have pollen free cheats inhabiting the fig. |
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