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44 Cards in this Set
- Front
- Back
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what is homology? ex |
similarity among species due to the inheritance of a trait from a single common ancestor. ex: whales and hummingbirds (vertebraes) |
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evolution of beak depth in Daphine major ground finches is an ex of |
direct observation; change through time |
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what is the phylogenic relationship between galapagos |
how species/group of related species change over time, beak size and shape |
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what is modern synthesis |
reformulation of the theory of evolution |
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6 evidence for evolution |
direct observation of change through time, homology (cellular), embryologic similarities, vestigal characters, convergence, sub-opt design |
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which is the best explanation for vestigal organs? |
feature is useless, no longer serves purpose so it evolves to be smaller, human coccyx
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what is convergence? ex |
trait that keeps being observed in species. ex: dolphins and whales have different form but same function
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what is sub-optimal design? ex |
jury rigged design. ex: convergent evolution of a thumb in pandas, not actually a thumb but paws
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what are may's 5 theories of darwinian evolution? |
1. evolution per se-lineages change over time 2. N.S.- darwin's mechanism of species 3. Mult of species- one species can give rise to 2 or more new species 4. C.D.- organisms share common ancestors 5. Gradualism- evolution happens slowly over gradual time |
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what happens if a trait in question is heritable |
the modes of selection will decrease genetic variation in the population, too. eventually, the genetic variation in any trait related to fitness will be eliminated, pop reaches equilibrium at mean value of trait, mean fitness of pop changes
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what would have to happen to a change of land mammal to aquatic mammal |
locomotion, hearing, balance, water intake
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what are the 5 facts |
1. population naturally tends to increase without limit (resources will diminish)
2. pop are subject to limiting factors, lack of resources tend to limit pop growth (space, time, predators) 3. pop do not grow exponentially for extended periods, limit to pop growth 4. individuals in a pop vary in morphology, behavior and physiology 5. some of this variation is heritable |
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evodots; 3 things required for natural selection |
1. variance 2. heritability 2. visibility |
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do individuals evolve? why/why not |
no. phenomenon in populations, individuals can have adaptations for better fitness |
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how did the drought change the characteristics in medium ground finch pop |
rain went from 30mm to 24mm, the average beak depth among pop increased, less smaller seeds and more larger seeds |
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what trait did the Grants think were most common |
beak depth |
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why are samples used |
impossible to collect info for entire population, more in depth study with sample rather than pop, minimize expenses without sacrificing accuracy
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trait of characteristics of an organism that increases an organisms fitness opposed to others of its species |
adaptation
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what are the techniques for measuring heritable variation? what do they mean |
1. heritability of a trait- fraction of total var in trait due to var of genes 2. phenotypic var-total var in a trait 3. genotypic var- var due to genes 4. environment var- var due to genes 5. broad-sense var |
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does natural selection act on genotypes or phenotypes |
phenotypes. evo consists of changes in allele frequencies |
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3 modes of selection and examples |
1. directional- fitness consistency increase or decrease with the value of a trait, mean goes larger 2. stabilizing- does not alter avg value of trait in pop 3. disruptive- large decrease of pop in middle, everything changes, does not alt avg, increase amount of var |
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why does the pop change and not change |
individuals do not change coats. but they produce offsprings whose coats on avg look like mom and dad, but the pop does change as cold arithmetic. mice make babies, traits persist to next gen, others fail and traits vanish |
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what are 2 components of genetic var |
additive- additive effects of genes dominance- gene interactions with dominance |
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the ability of an individual to survive and reproduce the environment |
darwainian fitness |
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how does natural selection lead to evolutionary change |
when individuals with certain characteristics have a greater survival/reproductive rate than other individuals in a pop and pass these inheritable genetic characteristics to their offspring |
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2 inferences |
1. not all individuals in pop survive to reproduce 2. survival and reproductive success are not random |
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what is natural selection, ex |
organisms better adapted to their environment tend to survive and produce more offspring. ex: brown vs sand mice |
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facts of logistic growth |
pop increases at first, growths slows as population increases, when pop size is constant the pop will stay the same because of new births |
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what is linear vs exponential growth |
linear- growth by constant amount per time (paycheck) exponential- growth by constant percent per time (interest on bank account) |
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the proportion of the variation observed in a population that is due to variance in genes, varies between 0 and 1 |
heritability |
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ex of artificial selection |
pigeons (tail feathers-desirable trait) |
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darwins 4 postulates |
1. there is variation among individuals 2. variations among individuals are passed from parents to offspring 3. some individuals are more successful at surviving and reproducing than others 4. survival and reproduction of individuals are not random |
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why is artificial selection a useful took to look at during natural selection |
breeders produce next generations with desirable traits shown in parents. in next gen the desirable trait will have a higher proportion |
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what were the 3 serious problems with the theory of evolution |
variation- knew nothing of mutations inheritance- knew nothing of genetics time- nuclear fusion was not discovered |
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which individuals tend to survive |
individuals with higher variation |
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surviving and reproducing; ______ what changes is; ________ |
individuals, population |
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gradual change in a population |
darwainian evolution |
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a process that results in descent with modification or evolution |
natural selection |
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what is embrological sim? ex: |
sim and diff among vertebrae embryos at diff stages of development. ex: chicken and human |
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vestigal characteristics, ex |
functionless, remains of a trait that is small, inherited from common ancestors. ex: human coccyx |
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what is a gene |
stretch of DNS that codes for a type of protein that has a function in the organism |
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what is an allele |
1 or 2 or more alt. forms of a gene that arise by mutation and found at same place on a chromosome |
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homozygous vs heterozygous |
homo-same alleles for a trait, pure hetero- diff alles, not pure |
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dominant vs recessive |
dom- stronger pheno rec- weaker pheno |
