population, community and ecosystem

historical factors

ecological factors -abiotic factors

-dispersal

-population growth

-habitat: niche and selection

-communities, gradients and succession

anthropogenic factors -biodiversity and disturbance

-natural resource management

-conservation

5-10 deg. celsius

-precipitation is even among the seasons (80-120cm/y)

-drop leaves to conserve water (an adaptation to winter drought)

-their photosynthetic capacity means fast growth (faster than conifers)

tropical>temperate deciduous>boreal

-caused by disturbance and climate

->less glacation disturbance, warmer winters, more variation in microclimate and habitats

->less resources in N. and winter is a disturbance as well

-the account of the present day distribution in terms of abiotic/biotic interactions

what is historical biogeography? (IN THE PAST)

endemic taxa are restricted to one geographic area

-old endemics heading towards extinction

-young ones recently evolving new habitats

-we cannot assume endemics originated in their current locations -> a species may disperse widely and then die out where it originated

species with distinctly separated geographic distributions

(Ex: similar fossils found along the coasts of Australia, Africa, S. Asia and S. america b.c. of the continental drift)

what is a continental drift?

-early biogeographers (Linnaeus) thought all organisms were created in one place

-thru 1800's biogeographers struggled w. long distance dispersal to explain disjuncts such as flightless birds

-1912 = continental drift proposed by alfred wegener

-the shape of the continents fit together like a puzzle

-distributions of organisms are difficult to explain if continents never moved

-mountain chains, rock strata, glacial deposits and fossils could be aligned

abiotic (physical) factors

dispersal

biotic factors

biological interactions

habitat selection

(ex: fires in grasslands, temp and climate, soil composition>nutrients, dispersal barriers, elevation barriers, prey/predators)

climate (temp, moisture)

soils (minerals, texture, acidity, nutrients)

geology (rock type, land formations)

light (sun, shade)

nutrients (nitrogen, potassium, phosphorus)

habitat

pollutants

-restrict access to resources (food, nutrients, habitat)

-limit physical tolerance (hot/cold, toxins)

-physical barriers (river, mountain, lake, ocean)

-field observation of actual range in distribution

-determine ecological tolerance

-correlation between environmental gradients and a sp. optimum range

-experiments

-light, shade, temp. and moisture?

-transplanted seedlings above the treeline (all died)

-transplanted some with shade cloth (survived 180m above treeline)

-underneath herbacceous canopy (shaded, competition for water)

-on bare soil (high light, not competition)

-on bare soil, surrounded by canopy (high light, competition for water)

-limiting factors: light (temp.)>water

-alpine tree lines increase w. a 3 deg. cel./yr increase in temp.

-sp. displacement (deciduous replacing boreal)

-grassland succession into warm dry forest (Douglas fir, jack pine)

-ecological processes will be affected (flooding regimes, landslides, fire cycles)

-wet land shrinkage

-habitat changes faster than organism dispersal or adaptation (bad!)

->Ex: tropical cloud forests will disappear (and their unique plants/animals)

fossil evidence for dispersal from pollen layers in a lake sediments

-> can reconstruct dispersal patterns

how do species disperse?

1.

how do species disperse?

2.

how do species disperse?

3.

ANIMAL-ASSISTED DISPERSAL: coconut crabs

-nutrient source (berries eaten by birds, seeds dispersed in droppings)

-hitchhikers (burrs)

-parasites use humans as habitat and as a dispersal vectors

how do species disperse?

4.

how do species disperse?

5.

how do species disperse?

6.

how do species disperse?

7.

-size (# of individuals)

-geographic distribution (spatial patterns of distribution)

-growth (increase or decrease in size)

-population density (#/area or #/vol)

spatial patterns of distribution

CLUMPED DISTRIBUTION

-young stay close to birthplace

-when resources are only available in patches

EX: the checkerspot butterfly is contained to patches tht contain the plats its larvae feed on

-plants: competition for light, water and nutrients

-animals: defence of space (territory)

EX: sea birds defending their nesting space

-the result of many factors interacting to influence where individuals settle and survive

Ex: cactus only grows in the shade of the nurse plant

-population size   N(_t+1) = N_t+B-D+I-E

-N_t – original population size

increase is immigration (I), Birth (B)

decrease is emigration (E), Death (D)

[image]

-resources (food/water)

-habitat/space

-tolerance to climate

-tolerance to toxic substances

-competition

-predation and disease

Population Regulation

DENSITY DEPENDENT

-regulation of a population by changes in per capita birth or death rates in response to density

EX: depletion of food supply accompanies growth; attraction of predators by high density populations; disease

-if per capita birth and death rates are unrelated to population

EX: rare extreme events (early freeze, tornado, flood)

**density independent factors can intensify density dependent regulators  (ex: a freeze diminished food/prey)

-yes, by regulating density dependent factors: limiting food supply, disease or prey abundance (ex. introducing predators or removing habitat)

-not by regulation density independent factors: not effective b.c. it allows the population to grow at the highest rate

HUMAN GROWTH RATE

[image]

Niche and selection

-range of tolerance

[image]

[image]

-tolerance range defines suitable habitat (potential range)

-a niche consists of all the factors necessary for a species existence in terms of time, space and required resources

[image][image]

-an increase in the suitable habitat type

-evolution of broad tolerances (generalist genotypes/phenotypic plasticity)

-have evolved diff. tolerance optima in diff. parts of their distribution (ecotypic differentiation)

-physiological acclimation to the abiotic environment

ex: roots grow deeper depending on water supply

-an evolutionary response to natural selection

-populations of the same species genetically adapted to diff. environmental conditions

experiment: grow all populations in a common environment and observe phenotype

evidence of adaptation: morphology of populations differ when grown in the same environment

-lack of genetic variation (don't have the genes!)

-tradeoffs >physiological tolerance to one factor results in lack of tolerance to another

>increased tolerance to one specific toxin is linked to reduced tolerance to other toxins (same w/ habitat)

-selected habitat is one where movement is minimal

EX: sowbugs passively select humid habitats over dry, movement is random but more rapid in dry habitats

ex: salmon returning to spawning grounds

anopheles>malaria mosquitoes...each species of mosquitoes is associated with a particular breeding habitat

learned or inherited?

starlings

-young birds born w. geo-positional system (when transplanted could not locate their winter range, instead they flew the same direction and distance as they would have from home to get to their range)

-old birds are less disrupted (learned)

-number of species

-trophic structure (plants, herbivores, carnivores)

-composition (abundance, dominance-diversity>the dominant species)

-yes, populations evolve to increase fitness (reduce -ve effects of competition)

-tolerance ranges differentiate to reduce interaction

-increased competitive ability

EX: beak depth determines the size of seeds finches can eat > when in competition the finches eat diff. seeds

-evidence: distance to island and number of species (closer to mainland means more species>dispersal!!)

-dispersal: density dependent colonization (rate or arrival of new species)

-extinction: density dependent competition

-distance to island (affects dispersal)

-island size (intensifies competition)

[image]

continents

-info slide

-continental reserve of species (older)

-species/are ratio is small (less competition)

-therefore less extinctions, woo woooo

islands

-info. slide

-no species reserve (newer)

-species/area ratio is large (more competition)

-more extinctions

other types of islands

-info. slide

-mountains, isolated lakes, parks, nature reserves, ecosystems, habitats (logs), clear-cut forests

-extreme fragmentation (more islands, more extinctions)

->has improved dramatically in recent years in central america

-"all living things on earth"

-embraces ecosystem complexity, all species variation and all genetic variation on Earth

-the variety and relative abundance of species

-must define the organism, ecosystem and area

species richness (S): the number of species per specified collection/sample area 

OR

specified numbe[image]r of individuals 

USUALLY levels off

-trying to save a species by saving all the species/factors (such as habitat) which it depends on

-expensive and time consuming

-unknown ecological relationships

-management regimes for one species may negativley impact others

-species cannot exist w/o habitat

establishing priorities for conservation

-info slide

-the best way to maintain species diversity is to set aside areas in which species and their habitats are protected

-high-priority areas for est. parks are reserves are regions of unusually high species richness 'hot spots' and endemism 

1.what is the general name for an organism that lives w/in the body or cells of another organism?

2.is this an ex. of an interaction?

1.Endosymbiosis

2. yes, biological interactions are the relationships between two species in an ecosystem, so this is a v.strong ex. of interaction

obligate species interactions>the relationship is necessary for the survival of at least one of the organisms involved

facultative>the relationship is beneficial but not essential for survival of the organisms

two types of ecological facilitation

a. COMMENSALISM

b. MUTUALISM

a. benefits one organism and the other organism is neither benefited nor harmed (ex: Remora living on sharks and eating their leftovers)

b. an interaction between two or more species, where species derive a mutual benefit (pollination)

types of ecological interactions

-info slide

a.     Competition occurs when resources are scarce (there must be a limited supply of at least one resource for competition to occur)

b.     Nearly all species share at least part of their diet and use of other resources with other species, but resource sharing influences the abundances and distributions of species only if individuals reduce the ability of others to access resources, either by interfering with their activities – interference competition – or by reducing the available resources – exploitation competition

a.     Yes!

b.     Ex. Marine iguanas vs. lava lizards (one exploits the water, the other the land), the finch example where finches have different beak sizes to fill a different niche (eating different sized seeds to reduce competition)

 What is the role of interactions between species in adaptive radiation, and the effects of both historical and deterministic factors in the outcome of evolution on islands?

a.     Adaptive radiation is the outcome of speciation and adaptation in the context of ecological opportunity. It begins with colonization of a species-poor environment. The abundant populations of these species now compete for resources, with selection favouring adaptations that reduce competition between species, including morphological divergence and resource specialization

a.     Evolutionary determinism in adaptive radiations would include species-for-species matching between independently evolving clades. Such precise evolutionary convergence is rare and is only accomplished among closely related clades diversifying in the same region, for which the starting conditions may be similar

a.     Some biologists believe contingencies of history are so great that evolutionary diversification almost always takes a unique and unpredictable course

b.     Predator–prey co-evolution, as well as competitive interactions, can have a role in driving adaptive radiation

c.     Sexual selection or even founder effects and genetic drift, can shape phenotypic divergence within a clade

What attributes make islands good focal points for evolutionary studies?

a.     Their small size, distinct boundaries, simplified biotas and the abundance and tameness of island inhabitants all make it easier to observe and interpret patterns of evolution.

b.     Groups of islands can function as replicates in which general evolutionary patterns can be distinguished from unique outcomes

c.     their relative youth and geographical isolation

a.     Most mainland settings, by contrast, are packed with species, their main burst of evolutionary diversification long over. Such filled communities offer relatively few ecological opportunities, and evolutionary diversification tends to produce small variations on already successful adaptive themes

b.     Many islands and archipelagos are distant from other land masses, and some have been isolated, with low rates of colonization, for long periods. This allows island biotas to diverge along their own evolutionary trajectories, independent of, and unconstrained by, evolutionary events unfolding elsewhere

What could happen if the distributions of closely related species expanded on old islands?

  What is the ‘island rule’ and why is it not accepted by all scientists?

the tendency -contested by some- for sm. mammals to become larger and for lg. mammals to become smaller

->reduced predation on islands might release animals from being either v.lg, to defend themselves against predators, or v.sm, to hide form predators. Intermediate body size also might be more favourable energetically, allowing the max. allocation of energy to growth and reproduction. According to this theory, election would push mammals in the direction of the optimum, intermediate, size, but this would be countered by competitive and predatory pressures that are stronger in more species-rich mainland settings.

-the ability to procreate

-creation of a new member of the species, similar/identical to parents

-a fundamental property of life

-acellular

-are not cells 

-do not consist of cells

-virus take over of living cell's machinery in order to reproduce/make copies

-once exhausted, cell wall is lysed and releases thousands of new viruses into surrounding extracellular space

-another type of viral reproduction in which the infected bacterium doesn't lyse

-harbours the viral nucleic acid in its genome and passes it along over many generations until conditions trigger a lytic cycle

-dividing unicellular organism

-reproduction of prokaryotes give rise to clones

Up to the blastocyst stage of development, ALL cells in a vertebrate embryo are totipotent. 

True/False?

If you separate totipotent cells genetically different individuals will develop.

True/False?

bone marrow and umbilical cord stem cells are totipotent.

T/F?

-involves activating certain genes in somatic cells that are normally repressed

-allowing the cells to revert to a primitive totipotent state

-they can now differentiate into any tissue in the body

-most imp. way bacteria recombine their genes 

-through interaction of genome of one cell w. a sample of genes (DNA fragment) from another cell

-segments of DNA that can be inserted either at a new location on the same chromosome or into another chromosome

-their insertion produces phenotypic effect by disrupting the genes into which they are inserted

1.PROphase- chromosome duplicate

2.METAphase - align at the middle of the cell

3.ANAphase - chromosomes seperate/division of nucleus

4.TELOphase - chromosomes reach opposite poles and nucleus reforms

1.PROphase - chromosomes pair up

2.METAphase - align at the middle of the cell

3.ANAphase - chromosomes seperate/division of nucleus

4.TELOphase - chromosomes reach opp. poles and nucleus reforms (2 daughter cells w/ diploid DNA)

5.PROphase 2 - nucleus disappears and chromosomes pair up

6. METAphase 2 - align at the middle of the cells

7.ANAphase 2 - chromosomes split

8.TELOphase 2 - cells split (4 daughter cells with haploid DNA)

YES, they certainly can :)!

-asexual spore and seed formation

-budding

-parthenogenesis

-asexual production of seeds

-ovules develop directly into seeds

-therefore seeds are genetically identical to parents and no fertilization is needed

Budding: outgrowth of a new cell from the surface of a parent cell; new cells differentiate before the buds break away from the parents.

T/F?

-the development of unfertilized eggs

-common in arthropods

-spontaneous mutation RARELy improves an organism's ability to adapt to environment

-random accumulation of mutations in 'spare' copies of genes results in production of new and useful gene products

-natural selection tends to perpetuate transmission of the mutated genes

-DNA from one bacterium genetically 'transforms' another type

-some prokaryotes pick up genes (DNA) from environment

(ex: from their dead neighbours whose DNA has leaked out into the environment - this 'new' DNA is incorporated into host chromosome, becoming part of that cell's genome)

-viruses can carry genes picked up from one cell into another

-thru repeated cycles of infection

(ex: genetic info. can be transduced into bacteria by using phages - a widely used technique in molec. bio)

(ex2: 'clone' genes, or force bacteria into making human/animal proteins, by infecting w/ viruses that don't kill the infected cells, new gene(s) can be inserted/propagated)

transformation and transduction are not associated with risks for disease in humans/animals.

T/F?

FALSE, they are a huge risk.

-antibiotic resistance may be transferred from one bacterium to another

-simultaneous infection of cells w. more than one virus may result in 'mixing' of viral genomes = highly infectious, but non-lethal virus suddenly becomes lethal (ex: BIRD fucking flu, shiit)

Fungi live by _____ nutrition.

fill in the blank

-used by fungi

-secrete digestive enzymes that break down lg. food molecules in environment

-absorb breakdown products thru plasma membranes of their cells

what is hyphae?

there are two subtypes of hyphae

1.SEPTATE

2.COENOCYTIC

1. hyphae that have septa

2. hyphae that lack septa but may contain hundreds of nuclei

-branching projections that push into living plant cells

-absorbing the nutrients w.in those cells

fungi reproduction

-info. slide bitch

-when hyphae of diff. mating types meet and fuse

-the production of haploid spores w.in sporangia

-the production of naked spores at the tips of hyphae; these spores are called conidia (powdery mildew)

-cell division by unicellular fungi; either a relatively equal division (fission) or an asymmetrical division in which a sm. daughter cell is produced (budding)

-simple breakage of the mycelium

when it comes to fungi, individuals of the same mating type can mate with one another.

T/F?

-associations of fungus with a cyanobacterium

-a unicellular phosyntheitc alga

OR BOTH

'imperfect fungi'

-fungi that have not yet been placed in any of the existing groups

-a clade

-includes: glomeromycetes, ascomycetes and basidiomycetes

FUNGI TYPES

1.chrytrids

FUNGI TYPES

2.zygomycetes

FUNGI TYPES

3.sporangiophores

FUNGI TYPES

4. zygosporangium

FUNGI TYPES

5. glomeromycetes

FUNGI TYPES

6. ascomycetes

FUNGI TYPES

7. asci

-contains sexually produced ascospores

-its the characteristic sexual reproductive structure of ascomycetes

FUNGI TYPES

8. basidomycetes

FUNGI TYPES

9. basidiocarps

-spectacular fruiting structures found among fungi

-mushrooms are an example

FUNGI TYPES

10. basidium 

-a swollen cell at the tip of a hypha

-characteristic sexual reproductive structure of the basidomycetes

-it's the site of nucleus fusion and meiosis

-this is very important!!

-can also do web tutorial that goes along with it, very useful :)

-occurs in the gonads (testes/ovaries)

-gametes produced from diploid (2n) germ cells within gonads

gametes are diff. sizes

-in many species the reproductive roles of male and female diverged

-few lg. female gametes, many sm. male

-selection has been for lgr sex cells b.c. >increasing zygote size increases survival

>larger gametes have more nutrients for zygote

-increasing male gamete # increases siring success

-reduces potential for conflict between cytoplasmic organelles in embryo >sperm doesn't contribute to the cytoplasm

gametogenesis has to be controlled to ensure that effort is put into reproduction ONLY when there is a realistic chance of success?

T/F?

HOROMONES

hypothalmus

GnRH

-gonadotrophin releasing hormone

HORMONES

pituitary

LH >lutenizing hormone

FSH >follicle stimulating hormone

HORMONES

ovaries

-Estradiol (an estrogen)

-progesterone (a progestin)

-inhibin (a peptide)

HORMONES 

testes

-testosterone (an androgen)

-inhibin

[image]-

[image]

-leydig cells in tissue between seminiferous tubules produce male sex hormone

-seminiferous tubules are target for FSH (specifically Sertoli cell), also produce inhibin

control of the testis is simple inhibitory feedback control.

T/F?

at puberty, hypothalamic GnRH release is turned off.

T/F?

False

-it must be turned on, increasing pituitary output of the 2 gonadotrophin hormones, LH and FSH

testosterone acts with ____ (another hormone), to stimulate spermatogenesis.

->fill in the blank

FSH

-as well as acting around the body to development of the male phenotype (male body type)

sertoli cells respond to ___ (hormone) by making inhibin, which feeds back to selectively inhibit pituitary ___ (hormone) secretion, so circulating ___ (hormone) is stabilized > ________ feedback.

FSH

FSH

FSH

negative

testosterone acts back on the _______ to inhibit release of ___(hormone). Circulating ___ (hormone) is stabilized >______ feedback.

pituitary

LH

LH

negative

-few, large

-many, small

the principle ovarian hormones are androgens.

T/F?

to make sure that if fertilized, pregnancy can occur successfully

-the brain, pituitary and reproductive tract must respond in an appropriately timed fashion to the hormonal signals from the ovary

true 

-hypothalamic GnRH release is turned on

the resultant rise in FSH stimulates a group of follicles to start developing.

T/F?

-estradiol

-inhibin

-FSH

>this produces a limiting situation in the ovary, so only the healthiest follicles survive the resultant "FSH starvation" (in lg. mammals this is used to limit ovarian development to single healthiest follicle each cycle)

several days of rising estradiol signals the development of immature follicles.

T/F?

-progesterone

-estradiol

>the cells in the corpus luteum have a short life if pregnancy doesn't occur (about 7 days in a woman)

pregnancy

>the new embryo secretes hormones that will stop the cells of the corpus luteum from dying

-regression of the uterus

>in primates, this results in the shedding of the lining of the uterus (menstruation)

-temp

-photoperiod

-pollination mechanisms

the regulation of processes (such as flowering) by changes in length of day/night

>the length of the dark period determines flowering

>even if one leaf is exposed to inductive conditions, a plant hormone (Florigen) travels to the entire plant, causing whole plant to change (therefore the leaves measure the dark period)

induction of flowering by low temps

>may require as many as 50 days of -2 to +12 deg. celsius

>some plants require both vernalization and long photoperiod to flower

-the quality of genes she recieves

-the resources he controls > indirect: gamete dispersal

>direct: food, shelter, territory

-amount of assistance he provides

what is an example of evolutionary pressure? 

elephant seals

>males est. territory

>dominant male takes 40-50 females as his mates and fights off intruders

>the dominant male remains on the beach throughout the whole mating season and cannot leave to eat - therefore he has to start the breeding season as the biggest and strongest or he won't survive

-in some societies, political or military dominance translated to reproductive success, leading to genetically inbred human populations

>Ex: king Niall of the nine hostages in ireland

>Ex2: descendants of Genghis Khan in the former Mongol empire

--in 2010, sperm banks found that 11% of parents found their children to have 10 or more siblings

--cryos international in Denmark ships the sperm of college students to over 40 countries

1.ENVIRONMENTAL - getting gametes from one place to another

2.SPERM-EGG RECOGNITION - acrosomal process

3.SPERM-EGG FUSION - membrane rises around sperm head, microvilli elongate around it (then the block to polyspermy occurs)

1.primordial follicles: egg is arrested in the prophase of meiosis 1

2.hormonal stimulation reinitiates meiosis

3.meiosis 1 completes at ovulation

4.meiosis 2 doesn't complete until fertilization

>this makes sure egg is not mature, so fertilization cannot occur until out of the ovary (the sperm cannot fertilize it until the egg is haploid)

>in anisogamous species, the extra chromosome sets are extruded as 'polar bodies' - small cells with little cytoplasm

[image]

external fertilization in plants includes what?

-air and water

...i dont really understand this?

-aqueous environment

-sperm are extremely susceptible to drying out

**works well for sessile organisms, not so well for mobile life forms

what is double fertilization?

angiosperms

know 38.1 in the text/online as well as this one:)!

[image]

-parallels the exploitation of terrestrial environments

[image]

amphibians

-info. slide

-the first animals to move to land

-must move back to and use water for external fertilization

-use behavioural adaptation to ensure reproductive success (clasping)

in animals, the male gametes can survive for a short time in the air or on dry surfaces.

T/F?

false, male gametes cannot survive ever for a short period of time!

-therefore, all fully terrestrial animals have adapted to use internal fertilization

ovulation can be cued to mating in some reptiles. 

T/F?

TRUE

-some reptiles and 'reflex ovulator' mammals

-the trigger for the ovulatory LH surge is the physical act of mating (ex: cats and rabbits)

- form of asexual reproduction found in females, where growth and development of embryos occurs without fertilization by a male

-female whiptail lizards take turns (depending on stage of ovarian cycle) acting the role of the male in reproductive behaviour to trigger ovulation

-first fully terrestrial animals

-even those that have returned to water still use land for reproduction (sea turtles!)

-must use internal fertilization -> shelled egg was formed!

-eggs must be penetrated by sperm before teh shell forms around the egg

-shelled egg requires internal fetrilization

1. first meiotic division and release of polar body just before ovulation

2. the second meiotic division begins - not complete until fertilization

3. sperm capacitation - occurs in reproductive tract - necessary for the acrosome enzymes to bore a hole in the egg to all fertilization

4.fertilization occurs in the fallopian tube

5. implantations - DAY 21! (a week after fertilization)

human chorionic gonadotrophin (like LH, is hard to metabolize), excreted in urine, produced by the embryo.

Know following diagram...

the corpus luteum maintains estradiol and testosterone levels throughout the pregnancy in primitive mammals (rats, mice, hamsters).

T/F?

False

estradiol and progesterone do this, not testosterone

in lg. mammals w/ long pregnancies, the corpus luteum cannot survive long enough.

T/F?

when the placenta takes over, it produces the same steroids - estrogen and progesterone - after the corpus luteum dies.

T/F?

in humans, the switch (when placenta takes over after corpus luteum dies) occurs around the end of the 4th trimester.

T/F?

false

it occurs around the first trimester, many miscarriages occur at this time if the placenta is unable to take over properly

an increased estrogen/progesterone ratio + increased placental corticotrophin releasing hormone.

T/F?

oxytocin

from the posterior pituitary

-increases uterine contraction further

-establishing a positive reinforcement cycle that can only be resolved by expulsion of the uterine contents (haha)

**positive feedback system

what are determinants of reproductive success? 

(4)

1.inbreeding avoidance

2.parental care >parenting cues

>kinship recognition (not mating w/ ur own offspring)

3.hybrid incompatibilities

>inbreeding results in increased rates of expression of recessive alleles, some of which may be harmful

>outbreeding generates new gene combinations/interactions resulting in hybrid vigour (a time honoured tradition among farmers -> peaches and cream corn!!)

**genetic diversity is important! (ex: cheetahs)