Chapter 14
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
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Population
group of individuals of the same species living the same area and interbreeding
Gene pool
total collection of genes in a population at any one time
Change in relative frequencies of alleles in a population over generations =
evolution
____ _____ is the basis of evolution
genetic variation
Mendel discovered the
heredity processes required for natural selection
What increase genetic variation in a population
mutations and sexual reproduction
Many characters result from..
the combined effect of several genes
Not all variation in populations is..
heritable
Mutation
random change in the nucleotide sequence of DNA
Duplication of genes or small pieces of DNA by meiosis may lead to
new genes
Mutations rarely _____ the adaptation of an individual to its environment
improve
Only mutations in ___ can be inherited by offspring
gametes
Mutations in multicellular organisms..
do not significantly affect genetic variation
Mutations is prokaryoytes quickly generate
genetic variation
Sexual reproduction
most genetic variation results from unique combination of alleles each individual inherits
Gametes of same individual vary significantly in
genetic make up
Mircoevolution
genetic change in a population over time
Individuels dont evolve..
populations evolve over generations
Mutations are the origin of all new…
genes and alleles
3 main causes of evolutionary change are
• natural selection • genetic drift • gene flow
Natural selection
if individuals differ ion their survival reproductive success, natural selection will alter allele frequencies
Genetic drift
a change in the gene pool of a population due to chance
In small population chance event may lead to..
l.oss of genetic diversity
Bottleneck effect leads to a
a loss of genetic diversity when a population is greatly reduced