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scientific method
basic idea Brough forth by the Greeks
catastrophism
a set of organisms was wiped out by catastrophe and another replaced them
uniformitarianism
the earth is very old and dynamic, things we see impacting the world today have always existed
doomsday
eventually humans will outstrip the resources in the world, populations push up against available resources
Charles Darwin's postulates
Ability of a population to expand is infinite, but the ability of the environment to support populations is always finite
Organisms within populations vary, and this variation affects ability of organisms to survive and reproduce
Variation is transmitted from parents to offspring
adaptation
a trait that enhances reproductive success (fitness)
Directional selection
occurs when individuals with traits on one side of the mean in their population survive better or reproduce more than those on the other
Stabilizing selection
a type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait value
individuals
Natural selection acts on
Hardy-Weinberg equilibrium
Under certain assumptions, both the frequencies of alleles as well as the frequencies of genotypes, will remain constant from generation to generation
forces of evolution
natural selection, mutation, genetic drift, gene flow
founder effect
the reduced genetic diversity which results when a population is descended from a small number of colonizing ancestors
Biological species concept
species are groups or organisms that naturally or potentially interbreed in nature and are reproductively isolated
Reproductive isolation
individuals from one group do not breed successfully with those from another group, prevents gene flow, maintains differences between groups
Allopatric
speciation occurring via geographic isolation
Sympatric
speciation occurring in the same geographic location
Convergent evolution
occurs when species occupy similar ecological niches and adapt in similar ways in response to similar selective pressures
Divergent evolution
what occurs when two groups of the same species evolve different traits within those groups in order to accommodate for differing environmental and social pressures
clumped
valuable patches, constant competition, dominance relationship
dispersed
low-value patches, scrambled competition, alliances
females
male fitness depends on
food
female fitness depends on
care, competition, cooperation
strategies to enhance reproductive success
intersexual selection
selection favors traits that make males more attractive to females
65 mya
primates enter the scene in Cenozoic
mosaic evolution
the occurrence, within a given population of organisms, of different rates of evolutionary change in various body structures and function
Bipedal H1
efficient way to travel on ground for apes
Bipedal H2
Good way to keep cool in open country
Bipedal H3
leaves hands free for carrying things
Bipedal H4
efficient for harvesting food from small trees
Bipedal H5
adaptation for locomotion on flexible branches
Note
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