Chapter 23 The Evolution Of Populations Flashcards
Adaptation
Natural selection improves the match between an organism and environment
Microevolution
Small scale, a change in allele frequencies in a population over generations
Genetic variation
Diff among ind in the composition of their genes or other DNA sequences
Mutation
A change in the nucleotide sequence of an organisms DNA
Population
A group of ind of the same species that live in the same area and interbreed, producing fertile offspring
Gene pool
Consists of all copies of every type of allele at every locus in all members of the pop
Conditions for hardy weinberg =
no mutations, random mating, no natural selection, extremely large pop size, and no gene flow
natural selectionq
individuals in a population exhibit variations in their heritbale traits and those with traits that are better suited to their environment tend to produce more offspring than those with traits that are not a well suited
adaptive evolution
evolution that results in a better match between organisms and their environmnent
genetic drift
chance events that can cause allele frequencies to fluctuate unpredictably from one generation to the next, especially in small pops
the founder effect
when a few individuals become isolated from a large population, this smaller group may estabilish a new pop whose gene pool differs from the source pop
the bottleneck effect
a suddne reduction in pop size due to a change in the environment
gene flow
the transfer of alleles in to or out of a pop due to the movement of fertile ind or their gametes
relative fitness
the contribution an ind makes to the gene pool of the next gen, relative to the contributions of other individuals.
directional selection
favors on extreme of phenotype
