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19 Cards in this Set
- Front
- Back
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Natural Selection
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assumpations:
-more organisms are born than can survive -great variation among organisms -most effective variation will be present in next generation |
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descent with modification
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new forms arise and old one disappear. new forms arise through natural selection
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metapopulation model
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deals with islands ... small pockets not continuous with larger population and the addition of new alleles is slower.
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sexual selection
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involves the competition for mating. superimposed on natural selection.
-- sexual dimorphism - one sex is larger and controls the breeding |
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optimization
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organisms become more and more adapted for their environment ... will never be perfect though becuase of too many constraints and the limitation of alleles (only have certain alleles so will not have all alleles needed for perfection)
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Speciation
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sympatric versus allopatric. speciation can arise from drift/mutation/natural selection/coadaptation
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Reproductive isolating mechanisms:
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pre-zygotic and post-zygotic. pre are things that keep organisms from breeding (habitat, temporal/behavioral/mechanismal)
-post -> keep offspring from being fertile/surviving .. |
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hybridization
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two diff species give rise to one highly variable species but ... sometimes in F2 generation, the offspring will not be fertile/viable (hybrid breakdown)
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character displacement
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two organisms are more different when they are together than when they are seperated ... due to competition
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sympatric speciation
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species in the same area ..
can lead to polyploidy, sexual selection, and change in host imprinting ... |
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heterochromy
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certain genes act as controller genes ... turn on other genes and dictate how long they remain on ... explains how two species can have such similar DNA but look and act so differently ...
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Population Growth
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associated with natality, mortality, and age structure ... there are many factors that effect the rate of reproduction .. 1)only females get pregnant 2)age of 1st reproduction 3) reproductive period (semelparity vs. iteroparity) and 4) litter size
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Population Growth curves
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Type 1 .. most live a long time and die off at once
Type 2 .. constant # dying Type 3 .. constant fraction dying Type 4 .. many die young and then likely survive if survive |
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Stable environments ..
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in a stable enviroment, the R=1 .. meaning each ind. replaced by one individual (pop not growing or declining)
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Exponential Growth
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overlapping vs. non-overlapping generations (overlapping generations equation incorporate the log..)
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altruistic acts
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acts that are for the good of the species ... it can be ewxplained evolutionarily ... you want your genes to be propogated in the next generations so you do things that will help make that happen (ex. bees and turkeys; warning calls)
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Continental Drift
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Effects:
1)volcanic activity 2)climatic changes 3)mounntain formation(influences wind and climate patterns -> rain shadow) 4)latitudinal position 5)connectedness -> continuous land mass vs. broken up land mass... 6)glaciation - migration still occuring from the last glaciation |
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Community Delineation
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1)would similar communities share similar organisms??
2)continuity - how sharp are the boundaries between communities?? 3)distributional overlap 4)history - the effects of glaciation on species recolonization and movement 5)interactions - the more crosslinks withing a community, the more tightly connected a community is .. (ex: spuirrels that eat truffles. pine trees and fungi are dispersed through the squirrel not being able to digest the spores) |
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Variations in Life Forms
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The amounf of solar radiation/temperaure/precipitation effects the variations in life forms. (ex. leaf shape .. smaller leaves have advantage b/c more S.A. per volume .. sun leaves on top of trees are more lobed b/c more surface area
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