Ap Bio unit 1 terms

Evolution

Evolution

changes in the heritable traits of a population of organisms as successive generations replace one another.

Fitness

an organism's ability to pass its genetic material to its offspring

Adaptation

any heritable trait that helps an organism survive and reproduce in its environment.

Phylogeny

the evolutionary history of a kind of organism

Homologous Structures

an organ, system, or body part that shares a common ancestry in multiple organisms

Analogous Structures

features of different species that are similar in function but not necessarily in structure and which do not derive from a common ancestral feature

Embryology

The study of the development of an organism from the fertilization of the egg to the formation of the embryo, focusing on the cellular and molecular processes that guide growth and differentiation.

Vestigial Structures

features of an organism that are considered to have lost much or all of their original function through evolution

Molecular Homologies

similarities between species on the molecular level; ex: DNA/Amino acid sequences

Convergent Evolution

occurs when organisms that aren't closely related evolve similar features or behaviors, often as solutions to the same problems

Divergent Evolution

represents the evolutionary pattern in which species sharing a common ancestry become more distinct due to differential selection pressure which gradually leads to speciation over an evolutionary time period

Natural Selection

the process whereby organisms better adapted to their environment tend to survive and produce more offspring.

Artificial Selection

an evolutionary process in which humans consciously select for or against particular features in organisms

Genetic Drift

the change in frequency of an existing gene variant in the population due to random chance

Mutation

Any change in the DNA sequence of a cell

Founder effect

type of genetic phenomenon that occurs when a small group of individuals establishes a new population, leading to reduced genetic variation and potential differences in allele frequencies compared to the original population.

Bottleneck effect

type of genetic phenomenon that occurs when a population's size is significantly reduced for at least one generation, leading to a loss of genetic diversity. This reduction can result from events such as natural disasters, habitat loss, or human activities, causing the surviving population to have a limited gene pool.

Sexual Selection

mechanism of evolution in which members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex

Gene Flow

any movement of individuals, and/or the genetic material they carry, from one population to another

Prezygotic barrier

a mechanism that blocks reproduction from taking place

Postzygotic barrier

a mechanism that reduces the viability or reproductive capacity of hybrid offspring

Speciation

the formation of new and distinct species in the course of evolution

Allopatric speciation

speciation that occurs when biological populations of the same species become isolated due to geographical changes

Sympatric speciation

the splitting of an ancestral species into two or more reproductively isolated groups without geographical isolation of those groups.

Hardy-Weinberg Equilibrium

the genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors.

Directional Selection

the change in a phenotype or genotype of a population in one direction away from the mean (average) in a particular environment over time.

Disruptive Selection

a specific type of natural selection that actively selects against the intermediate in a population, favoring both extremes of the spectrum

Stabilizing Selection

form of natural selection wherein individuals with moderate or average phenotypes are more fit (more likely to survive and reproduce)