BIO CHP 17
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What is the smallest unit that evolves?
the variant forms in which genes exist
- no more than 2 for a given gene
- -one from the mother
- -one from the father
The sum total of alleles in a given population
Basis of evolution is...
a change in the frequency of allels in a gene pool
a change of allele frequencies within a population over a relatively short period of time.
these changes in alleele frequencies can said to have evolved
What are the 5 agents of micro-evolution?
- -gene flow
- -genetic drift
- -sexual selection
- -natural selection
Permanent alteration in an organism's DNA
Some mutations are heritable, meaning they can be passed on from one generation to the next.
Movement of genes from one population to another
through migration: movement of individuals from one population into the territory of another
chance alternation of allele frequencies in a population
- has greatest effects on small populations
- -bottleneck effect
- -the founder effect
form of natural selection that can affect the frequency of alleles in a gene pool
occurs when differences in reproductive success arise becuse of differential success in mating
- Some individuals more successful than others in surviving
- -and hence reproducing
- -owing to traits that better adapt them to their environment
- the phrase "survival of the fittest" is misleading
- -implies that evolution works to produce generally superior being who would be successful competitors in any environment
- only has to do with relative reprouctive success of individuals in a given environment at a given time.
What are the three modes of natural selction?
Stabilizing, directional, diruptive
- most common
- moves a given character in a population toward intermediate forms and hence tends to preserve the status quo
moves a given character toward one of its extreme forms
- moves a given character toward two extreme forms
- (rarest form)
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