Chapter 23: Evolutionary Processes

Vocabulary practice flashcards covering key terms and concepts from Chapter 23 Evolutionary Processes.

Alleles

Different versions of genes (e.g., A, a).

Genotypes

The specific combination of alleles present in an organism (e.g., AA, Aa, aa).

Phenotypes

The observable physical or physiological traits of an organism.

Evolution

The change in the frequency of different alleles or traits in a population over time.

Mechanisms of Evolution

Processes that change allele or trait frequencies in a population over time, including natural selection, mutation, gene flow, and genetic drift.

Natural Selection

A process that changes the frequency of alleles in a population over time if those alleles influence survival and reproductive success in a particular environment.

Mutation

A random change in the DNA sequence that creates a new allele of a gene and alters allele frequencies in a population.

Beneficial Mutation

A mutation that allows individuals to produce more surviving offspring, thereby increasing fitness.

Deleterious Mutation

A bad mutation that lowers an organism's survival or reproduction, thereby decreasing fitness.

Neutral Mutation

A mutation that has no effect on an organism's fitness.

Gene Flow

The movement of alleles between existing populations when organisms (or reproductive propagules like pollen grains) migrate and reproduce, making populations more similar to each other.

Genetic Drift

Any change in allele frequency in a population due to random chance, caused by the random removal of organisms and their alleles from the breeding population.

Founder Effect

A form of genetic drift occurring when a small number of individuals move from a population to a new location and start a new population whose allele frequencies are determined solely by the colonizing individuals.

Bottleneck Effect

A form of genetic drift occurring when a large population experiences a sudden reduction in size due to events like natural disasters, drought, or disease, leading to decreased allele diversity.

Fitness

The ability of an organism to survive and produce surviving offspring in its environment.

Adaptation

A trait that increases an individual's fitness in a specific environment.

Allele Frequency

The relative proportion or presence of a specific allele in a population.

Population

A group of individuals of the same species living in the same geographic area that can interbreed.

Sampling Error

The random deviation from expected allele frequencies that occurs during the transfer of alleles from one generation to the next, driving genetic drift.

Speciation

The evolutionary process by which populations evolve to become distinct species.

Nonrandom Mating

Mating patterns in which individuals select mates based on specific genotypes, phenotypes, or relationships rather than at random.

Null Hypothesis

A baseline statistical proposition asserting that no effect, change, or evolution is occurring in a population.