Exam 1 ISU Bsc 101 Wodika (part 3 - chapteres 13,14)

binary fission

a type of asexual reproduction in which one parental cell divides into two. how bacteria reproduces.

population

a group of organisms of the same species living together in the same geographic area.

gene transfer

The process by which bacteria can exchange segments of DNA between them.

evolution

Change in allele frequencies in a population over time.

fitness

The relative ability of an organism to survive and reproduce in a particular environment.

natural selection

The greater survival and reproduction of individuals with certain traits in a particular environment that leads to a change in allele frequencies in a population over time.

adaptation

The process by which populations become better suited to their environment as a result of natural selection.

directional selection

A type of natural selection in which organisms with phenotypes at one end of a spectrum are favored by the environment.

stabilizing selection

A type of natural selection in which organisms near the middle of the phenotypic range of variation are favored by the environment.

diversifying selection

A type of natural selection in which organisms with phenotypes at both extremes of the phenotypic range are favored by the environment.

population genetics

The study of the genetic makeup of populations and how the genetic composition of a population changes.

gene pool

The total collection of alleles in a population.

allele frequency

The relative proportion of an allele in a population.

nonadaptive evolution

Any change in allele frequencies that does not by itself lead a population to become more adapted to its environment; the mechanisms of nonadaptive evolution are mutation, genetic drift, and gene flow.

genetic drift

Random changes in the allele frequencies of a population between generations; tends to have more dramatic effects in smaller populations than in larger ones.

founder effect

A type of genetic drift in which a small number of individuals leaves one population and establishes a new population, resulting in lower genetic diversity than in the original population.

bottleneck effect

A type of genetic drift in which a population is suddenly reduced to a small number of individuals, and alleles are lost from the population.

gene flow

The movement of alleles from one population to another, which may increase the genetic diversity of a population.

biological species concept

The definition of a species as a group whose members can interbreed to produce fertile offspring.

reproductive isolation

Mechanisms that prevent mating (and therefore gene flow) between members of different species.

speciation

The genetic divergence of populations, leading over time to reproductive isolation and the formation of new species.