Term
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Definition
| the mechanism of evolution, species drift apart |
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Term
| Formal Definition of natural selection |
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Definition
| "Species with advantageous traits are more likely to pass those traits on to their offspring" |
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Term
| what are the three pillars of Darwin's theory that must be true for Natural Selection to function? |
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Definition
1. Variations between individuals
2. Non-random differences in survival and thus fertility, and all organisms must produce more offspring than will survive
3. variation must be heritable |
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Term
| define homology and provide 2 examples |
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Definition
| similarities in body parts between species, a good example is mammalian forelimbs and bee's antenna, which are modified limbs |
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Term
| there are nine different bodies of evidence for evolution that we discussed in class |
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Definition
1. paleontology
2. extinct species and groups
3. transitonal fossils that link the past and the present. Example: fossils that show whale-like creatures with hind legs
4. vestigal organs
5. homologous groups
6. inefficient design
7. similarity in embryonic development
8. concordant phylogenies
9. biogeography: related species on isolated islands |
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Term
| name, don't define the 5 sub-theory's Darwin's theory |
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Definition
1. evolution
2. common descent
3. gradualism
4. population speciation
5. natural selection |
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Term
| define the pillar of darwin's theory that is common descent |
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Definition
| common descent is the idea that all life is related in one giant tree |
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Term
| define the pillar of darwin's theory that is gradualism |
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Definition
| gradualism is the idea that differences between organisms evolve by many many small steps through intermediary forms |
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Term
| define the pillar of darwin's theory that is population speciation |
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Definition
| evolution occurs by changes in the PROPORTION of individuals within a certain population that differ by one or more trait |
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Term
| what drives populational speciation? what exactly is it that changes as populations split? |
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Definition
| what changes is the PROPORTION of individuals who have certain traits |
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Term
| define the pillar of darwin's theory that is natural selection |
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Definition
| changes amongst individuals in populations (not species) over time is responsible for evolution |
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Term
| all traits/phenotypes have these two components |
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Definition
| all traits/phenotype have an environmental and heritable component |
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Term
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Definition
| the amount of variance in a trait that is due to genotypic differences |
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Term
| do all traits have the same proportion of variance due to genotype and environment? |
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Definition
| no, different traits have different levels of heritability |
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Term
| name the three types of selection: |
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Definition
1. stabalizing selection
2. directional selection
3. disruptive selection |
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Term
| Natural selections acts upon ___ while evolution acts upon ____ |
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Definition
| natural selections works upon phenotypes whereas evolution works upon gene frequency |
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Term
| what isn't immediately explained by natural selection and requires a new way of looking at selection? |
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Definition
| exaggerated sexual characteristics that don't benefit survival aren't immediately explained by natural selection, but are exaplained by sexual selection |
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Term
| difference in parental investment in offspring can be broken down into these two halves |
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Definition
1. gametes. Males have small, mobile gametes that they can/want to shot everywhere and don't care where they end up. Females have large, immobile gametes and must find the right male gametes
2. parental care. males aren't as motivated to look after their offspring if they can have many offspring. females can only have so many and must look after the ones she creates |
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Term
| basic difference between "male fitness" and "female fitness" |
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Definition
1. male fitness: sperm is cheap, mates are hard to find.
2. female fitness: eggs are expensive, mates are easy to find |
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Term
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Definition
| males competing with other males for mates |
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Term
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Definition
| female competition over males |
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Term
| what are two ways males compete? |
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Definition
the two ways males compete are:
1. physical contest
2. signaling |
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Term
| why do males compete? what variation drives them to compete over females? |
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Definition
| variation in number of offspring drives males to compete: if they do well, they can reproduce many many times |
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Term
| sexual selection in iguanas is an example of what |
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Definition
| large body size for males is very helpful b/c physical domination wins them a lot of mates. However, large body size is very bad during starvation times. Sexual and natural selection are antagonistic, they work against each other |
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Term
| what is an example of the alternative mating technique of "sneakers" |
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Definition
| Blue Gills are an example an a species that involves "sneakers." The large male fish build nests, females come to nests to lay eggs, and sneaker males with female-looking bodies sneak in to the nests to inseminate the eggs before the large males can |
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Term
| three consequences of sexual selection |
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Definition
1. dimorphism: very different body types between males and females
2. sperm competition
3. differences between parental care between sexes |
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Term
| what is an example of a mating process that is similar to sperm competition itself? |
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Definition
| honeybee mating, where males chase queen as she flies away, the first to catch her sticks his mating plug in her, this kills the male and the plug pumps semen into the queen |
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Term
| how do many males "enforce" polygamy in the wild? |
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Definition
| polygamous mating system can result when males inseminate females and then follow them around to make sure they don't mate again |
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Term
| orb-web spiders are are an example of what? |
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Definition
| orb-web spiders are an example of sexual cannabalism, when the female eats the male there is a better chance of insemination. 60% of males don't survive mating |
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Term
| what is an example of sexual role reversal? |
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Definition
| an example of sexual role reversal is giant water bugs, where eggs are laid on the back of the male, and he airates them to protect them from fungi. Males invest more in offspring, and females compete over males |
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Term
| how does site of fertilization relate to relate to parental care? |
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Definition
| when fertilization is internal, females remain with offspring. when fertilization is external, males remain with offspring. |
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Term
| how are the costs of choosing a mate generally different between the two sexes? |
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Definition
| in general, the cost for choosing a bad mate is higher for females than males, so females have to more picky |
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Term
| what 4 things do females gain by choosing a "good" mate? |
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Definition
1. good parenting
2. resources
3. parasiteless sex (safe sex)
4. "good" genes |
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Term
| two examples of "good parenting" in the animal world. |
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Definition
1: Turns. During courtship, if males bring food back to the nest it is a good sign for females
2: insects. They bring "nuptial gifts" of prey snagged from spider webs to impress females |
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Term
| good gene hypothesis says that females are looking for two things related to genes: |
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Definition
1. exaggerated male characteristics
2. good genetic qualities for children |
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Term
| 2 requirements of good gene hypothesis |
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Definition
1. there must be a physical indicator of the trait
2. the trait must be heritable |
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Term
| "good gene" selection leads to what? |
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Definition
| good gene selection leads to exaggerated male characteristics |
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Term
| potential problem with females making their choices based on "good genes" |
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Definition
| if all females mate with males with the most exaggerated sex characteristics, it reduces genetic variability, which is bad for populations as a whole |
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Term
| how can "good genes" work alongside natural selection? |
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Definition
| if the physical trait that the "good gene" codes for is also an indicator of fitness, like long tails in birds is correlated with fewer parasites |
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Term
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Definition
| females hide ovulation to keep males around longer |
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Term
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Definition
| when an individual's fitness is reduced for the overall good of the colony/population |
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Term
____ are the vehicles for evolution, not ____
(this is an exaplanation for altruism) |
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Definition
| genes are the vehicles for altruism, not individuals |
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Term
| use genes to explain when altruism is evolutionarily favorable |
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Definition
| evolution favors traits that help that COPY of the gene that codes for them be passed on, even if it's not through that specific induviudal |
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Term
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Definition
| inclusive fitness says that fitness has two halves: direct (genotype) and indirect (altruism and other things) |
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Term
| equation to see if altruism helps a gene be passed on |
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Definition
if the following is true, the altruism helps the gene be passed on:
(cost to helper)<(relatedness)*(benefit to receiver) |
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Term
| does a gene that helps all other organisms equally have an altruisitic benefit? |
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Definition
| no, for genes to be helped by altruism they must help family more than they help strangers. this is the relatedness part of the equation |
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Term
a very eusocial situation would be where
____ cost of eusocial gene to carrier
____ relatedness of organisms helping one another
____ benefit of eusocial gene to other |
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Definition
a very eusocial situation would be one where
1. low cost of eusocial gene to the carrier
2. high relatedness of the organisms
3. high benefit of eusocial gene to organisms |
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Term
| largest group of eusocial insects |
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Definition
| the largest group of eusocial insects are the group that contains bees, wasps, and ants, called hymenoptera |
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Term
| 2 things about naked mole rat colonies |
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Definition
1. highley inbred
2. queen controls the colony with violence |
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Term
| white-fronted bee eaters: what are they an example of? |
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Definition
| they are an example of altruism, they all help feed the young together, and they are more likley to feed the young of those from their natal nest |
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Term
| phenotype is due to these four things |
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Definition
1. genotype
2. developmental history
3. current pattern of use and disuse
4. environmental conditions |
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Term
| cross-fostering experiment |
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Definition
| when you put two organisms with similar/same genotypes in different enviornments. compare to common garden experiment |
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Term
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Definition
| when you raise organisms with different genotypes in the same environment. compare to cross-fostering experiment |
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Term
| example of environmental effect on phenotype in humans |
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Definition
| lack of sunlight can cause nearsightedness |
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Term
| genes don't cause outcomes, they only ______ |
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Definition
| genes don't cause outcomes, they only make certain outcomes possible |
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Term
| what part of the cell cycle causes genetic variation? |
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Definition
| meiosis is the part of the cell cycle that "causes" genetic variation |
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Term
| other than mieosis, ____ in DNA directly causes genetic variation |
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Definition
| mutations in DNA cause genetic variation |
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Term
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Definition
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Term
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Definition
| replaces regular codon with stop codon |
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Term
| mutations that change gene expression create a new ____ |
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Definition
| mutations that change gene expression create a new phenotype |
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Term
| mutations in coding regions of DNA are generally what? |
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Definition
| mutations in coding regions of DNA are generally fatal |
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Term
| mutations that don't have an effect on phenotype aren't _____ |
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Definition
| mutations that don't have an effect on phenotype aren't subject to natural selection |
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Term
| quantitative vs. qualitative traits |
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Definition
| qualtitative traits have discrete, simple genotypic-phenotypic relationships, like mendel's peas. quantative genes are genes that aren't like that |
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Term
| population genetics looks at _____ |
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Definition
| populations genetics looks at allilic frequenices across a population |
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Term
| for hardy-weinburg conditions to be met, what three things must be true? |
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Definition
| 1. no gene flow 2. no selection 3. no mutation |
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Term
| there are ___ allele(s) in a halpoid system, when two haploids come together to make a zygote there are ___ alleles |
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Definition
| haploid systems have one allele, when they come together in a zygote you get a full genotype with 2 alleles and a full genotype |
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Term
| under perfect H-W conditions, how long should autosomal (non-somatic) chromosomes take to reach equilibrium? |
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Definition
| with no natural or sexual selection or gene flow or anything, it autosomal chromosomes can hypothetically reach H-W equilibrium in one generation |
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Term
| why do most organisms who display the phenotype for lethal genetic diseases have parents who show no symptoms? |
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Definition
| those genetic diseases are recessive, so the parents are heterozygous and display no symptoms. |
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Term
| under H-W equilibrium, some recessive phenotypes are very very rare, what is the consequence of this we discussed? |
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Definition
| the consequence is healthy parents who are heterozygous for some recessive deadly genetic disease and have children with that deadly disease |
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Term
| name 5 conditions that "violate" H-w |
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Definition
1. non-random mating
2. inbreeding
3. genetic drift
4. heterozygous advantage
5. frequency |
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Term
| two examples of the effects on inbreeding |
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Definition
1. louisana panthers have had their populations severely diminished and they are very inbred.
2. inbreeding causes albanism rates to shoot up |
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Term
| true or false: genetic drift is due to N.S. |
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Definition
| genetic drift isn't due to N.S., it is due to sampling error |
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Term
| what effect can genetic drift have on small populations? |
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Definition
| randomness can cause variance in small populations and you can even lose alleles |
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Term
| 2 examples of the founder effect |
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Definition
1. galapagos islands
2. many amish people have six fingers |
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Term
| genetic drift makes a bigger difference in a small or big population? |
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Definition
| genetic drift has a good chance of causing a large change in a small population |
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Term
| genetic drift in large populations |
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Definition
| genetic drift in large populations can amount to many small changes adding up over time, as there is no force pushing the population back to normal |
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Term
| example of heterozygous advantage |
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Definition
| being heterozygous for the gene for sickle-cell anemia helps your chances of survival against malaria |
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Term
| define frequency dependent selection and give an example |
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Definition
| frequency dependent selection is when a rarer phenotype is favored simply because it is rarer. an example is the predatory swimming dude with a lopsided mouth that only attacks from one direction, the ones that attack the way most fish aren't looking have an advantage |
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Term
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Definition
| when an normally diploid organism only has one allele at a certain gene |
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Term
| define heterogametic and give an example |
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Definition
| heterogametic is when sex chromosomes are different, an example is XY in human males |
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Term
| eye color in fruit flies is an example of this |
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Definition
| eye color in fruit flies is an example of sex-linked inheritance |
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Term
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Definition
| genetic variation due to changes in chromosomes |
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Term
| when do transposable elements effect genetic variaiton |
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Definition
| transposable elements only effect genetic variation when they change coding regions of DNA |
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Term
| plasmid's role in genetic varition |
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Definition
| plasmids replicate seperatly from the rest of bacterial DNA and are passed from bacteria to bacteria, a plasmid can introduce new genetic information to a new bacteria it enters |
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Term
| what element of genetic variation can double the amount of some protein being made? |
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Definition
| gene duplication can lead to doubling of a certain protein being made |
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Term
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Definition
| duplication of entire genome |
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Term
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Definition
| anagensis is evolutionary change over a long period of time |
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Term
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Definition
| cladogenesis when two species diverge from one |
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Term
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Definition
| a polytypic species is a species that varies in phenotype across a large area |
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Term
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Definition
| allopatric populations are populations of one species that live in different areas |
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Term
| three ways to classify species |
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Definition
1. biological species concept- all about whether organisms can breed
2. morphological species concept- classifies species by species that look the same
3. phylogenetic species concept- says that groups that are on independent evolutionary trajectories are different species |
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Term
| what is strange about the engatina salamander? |
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Definition
| the engatina salamander is in california and changes genotypically and phenotypically across a gradient, some places neighboring populations are too different to breed with one another but both those populations can breed with a third, "middle" population |
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Term
| how does speciation start? |
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Definition
| speciation starts as a genotypic cluster of organsisms begins to fill a certain niche |
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Term
| after two genotypic clusters of a population occupy different niches, what can occur that furthers the process of speciation? |
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Definition
| when hybrid offspring between the two cluster aren't viable, then speciation is occuring and the two clusters may develop into different species |
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Term
| three types of speciation |
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Definition
1. allopatric speciation
2. parapatric speciation
3. homoploid (hybrid) speciation |
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Term
| define allopatric speciation |
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Definition
| allopatric speciation is speciaiton due to to physical separation of two populations |
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Term
| after allopatric speciation, the ____ ____ is common, because of the genetic makeup of the new population |
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Definition
| after allopatric speciation, the founder effect is common because the new population has a relatively small population size, which skews the genetic makeup of the new population |
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Term
| example of allopatric speciation |
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Definition
| wright whales are seperated by the equator, and the coccopods on the whales are geographically isolated too |
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Term
| define parapatric speciation |
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Definition
| parapatric speciation is speciation across an environmental gradient |
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Term
| give an example of parapatric speciation |
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Definition
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Term
| what term did we discuss that is "instant speciation"? |
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Definition
| polyploidy changes the genetic makeup of an organism so much it is "istant speciation" |
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Term
| define homoploid speciation |
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Definition
| homoploid speciation is when a hybrid offspring with parents of two different species is more fit than either parent |
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Term
| give an example of homoploid speciation |
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Definition
| butterflies are an example of homoploid speciation |
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Term
| 5 prezygotic reproductive isolating mechanisms |
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Definition
1. spatial isolation
2. temporal isolation
3. mechanical isolation
4. gametic isolation
5. behavioral isolation |
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