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Population Genetics & Evolution (Population Genetics (gene pool=total…
Population Genetics & Evolution
Evolution=gradual conversion of one species into one or more species
extremely slow process
Natural Selection=mutations causing new alleles or new genes to make organisms more adapted or less adapted then organisms without that mutation to their environment
detrimental allele or gene=individual does not contribute its genes to the population growth
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:black_flag:
beneficial allele or gene=individual contributes its genes to the population growth :check:
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Population Genetics
population genetics=genetics of individuals of a species
crossing over increases genetic diversity
gene pool=total # of alleles in all the sex cells of all individuals of a population :
Factors that Cause the Gene Pool to Change
mutation
existing alleles decrease in frequency
new alleles increase in frequency
Accidents
:fire:
organisms cannot adapt to them
droughts
floods
hailstorms
fires/volcanic eruption
affects the well-adapted and not well-adapted
artificial selection
process where humans change the allele frequency of a gene pool
breeding crop plants
breeding domestic animals
natural selection
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two conditions must occur for it to happen
offspring must keep being produced
progeny must differ from each other in their types of alleles
there is no planning, intention, purpose, or voluntary decision
sexual reproduction alone does not change the gene pool of a population
Situations in which Natural Selection Does Not Operate :no_entry:
when individuals in a population are identical
lack of competition
Multiple Selection Pressures
multiple factors affect plants at the same time :
some alleles can be advantageous at some points but disadvantageous at other times
if an allele is beneficial depends on environment
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when an environment changes, an alleles beneficialness can change
Rates of Evolution
some species have not evolved into new species even though they're millions of years old :!!:
loss of a disadvantageous structure can occur very quickly
Speciation
evolution causing a new species to evolve=speciation
