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33 Cards in this Set
- Front
- Back
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What is biological evolution? |
a change in the genetic composition of a population that occurs across generations |
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what evolves? |
populations involve NOT individuals |
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what changes when something evolves? |
the proportions of genes in a gene pool |
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what is a gene pool? |
the total of all the genes in all the individuals of the population. Changes take place across generations |
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Since humans change.. do they undergo evolution? |
humans undergo development and metamorphosis, not evolution. |
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how long does it take for evolution to occur? |
shortest possible time in one generation. For evolutions of species/families usually 100s or 1000s of generations |
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what changes when a population undergoes evolution? |
the frequency of alleles change- even if it is a small change in frequency |
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what can cause evolution to happen? |
Mutation, migration/gene flow, random genetic drift |
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what is mutation? |
ultimate source of genetic variation |
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what is migration/gene flow? |
when a few individuals from one population interbreed with another population- introducing genes into a population |
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what is random genetic drift? |
accidental events involving very small population shifts the frequencies of genes (volcanic eruption on a small population) |
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what must be present in a population in order for it to evolve? |
genetic variation and phenotypic variation |
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what is genetic variation? |
different forms of alleles- usually results in phenotypic variation |
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what is phenotypic variation? |
must be genetically based |
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what is the evolutionary theory? |
it is an organizing principle of science- not a hypothesis |
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what is the theory of common descent? |
all life on Earth is descended from one ancestral population |
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difference between micro and macro evolution |
micro- small changes in frequencies of genes in a population- takes millions of years
macro- evolution of new species, families and other major groups |
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what is the static earth hypothesis? |
that the physical and biological nature of Earth remains unchanged over time |
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this hypothesis is based on two things |
the scala nature and the great chain of being |
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what is the scala nature? |
levels of fixed life forms |
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what is the great chain of being? |
earth has to remain just as god created it- that means nature is unchanged |
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what is the principle of stratigraphy? |
positioning of fossils- different layers |
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what is the theory of uniformity? |
geological processes are continually changing the Earth |
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what is believed through the Lamackian evolution? |
it is an inartistic drive toward perfection - acquisition of characters through use and disuse - inheritance of acquired characteristics |
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what is an example of Lamackian evolution? |
the mud skipper uses its fins to move from puddle to puddle- eventually muscles become stronger |
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according to the theory of common descent, is their a common ancestor to all life on earth? |
Yes. assuming that simple life only arose once from non-life |
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who do humans share ancestors with? |
all- orangatans, gorillas, chimps, bonobos |
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what is homology? |
refers to similarities among species or function that results from shared ancestry- same # of bones. same function |
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what is the static model? |
species arise separately and do not change over time |
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what is transformation model? |
species arise separately but change over time to adapt to changing environment |
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what is the separate types model? |
species change over time, new species can arise, derive from a common ancestor |
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what are vestigial structures |
those who appear to have greatly reduced function compared to similar structures in other species- no longer function as they once did |
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what is the theory of island biogeography? |
distribution of organisms on Earth, especially on land- islands nearest to mainland |
