BIO182 EX2

Adaptation

A heritable trait that enhances an organism's survival and reproduction in its specific environment.

Allele Frequency

The proportion of a particular allele (variant of a gene) within a population.

Allopatric Speciation

The formation of new species through geographic isolation of populations, which prevents gene flow.

Analogous Structures

Features in different species that have similar functions but evolved independently and do not share a recent common ancestor.

Artificial Selection

The process by which humans intentionally breed organisms with desirable traits.

Behavioral Isolation

A prezygotic reproductive barrier based on differences in courtship rituals or other behaviors that prevent interbreeding between species.

Biological Fitness

An individual's ability to survive and produce viable, fertile offspring relative to other individuals in the population.

Bottleneck Effect

A form of genetic drift that occurs when a sudden reduction in population size leads to a loss of genetic diversity.

Clade

A group of organisms that includes a common ancestor and all of its descendants (a monophyletic group).

Cladistics

A method of classifying organisms into groups (clades) based on shared derived characteristics.

Cladogram

A branching diagram that illustrates the hypothesized evolutionary relationships between taxa.

Convergent Evolution

The independent evolution of similar traits in distantly related species due to adaptation to similar environments.

Directional Selection

A mode of natural selection that favors one extreme phenotype over other phenotypes.

Dispersal

A form of allopatric speciation where individuals colonize a new geographic area, leading to reproductive isolation.

Divergent Evolution

The process by which populations of a common ancestor evolve and accumulate differences.

Evolution

Change in the allele frequency of a population over time.

Fixation

The point at which an allele has a frequency of 100% in a population.

Founder Effect

A form of genetic drift that occurs when a new population is established by a small number of individuals.

Gametic Barrier

A prezygotic reproductive barrier where the eggs and sperm of different species are incompatible.

Gene Flow

The movement of alleles between populations due to migration of individuals.

Genetic Drift

Random fluctuations in allele frequencies from one generation to the next.

Gradualism

A model of speciation that proposes species diverge slowly and gradually over long periods.

Habitat Isolation

A prezygotic reproductive barrier where two species live in different habitats and rarely encounter each other.

Hardy-Weinberg Equilibrium

A principle stating that allele frequencies in a population will remain constant in the absence of evolutionary influences.

Homologous Structures

Features in different species that share a common underlying anatomical structure due to shared ancestry.

Hybrid Inviability

A postzygotic reproductive barrier where hybrid offspring fail to survive or develop.

Hybrid Zone

An area where closely related species interact and interbreed, forming hybrids.

Macroevolution

Evolutionary change on a large scale, encompassing the origin of new taxonomic groups.

Microevolution

Evolutionary change within a population, such as changes in allele frequencies.

Mutation

A permanent change in the DNA sequence of an organism.

Natural Selection

The differential survival and reproduction of individuals with certain heritable traits.

Nonrandom Mating

A pattern of mating in which individuals do not mate randomly.

Outgroup

A distantly related group of organisms used as a reference point when analyzing evolutionary relationships.

Parapatric Speciation

The formation of new species from adjacent populations that experience reduced gene flow.

Peripatric Speciation

A form of allopatric speciation where a small, isolated population diverges from the main population.

Phylogenetic Tree

A branching diagram that represents the evolutionary relationships among a set of organisms.

Phylogeny

The study of the evolutionary history and relatedness of organisms.

Polyphyletic Group

A grouping of organisms that does not include their most recent common ancestor.

Postzygotic Barriers

Reproductive isolation mechanisms that occur after the formation of a hybrid zygote.

Prezygotic Barriers

Reproductive isolation mechanisms that prevent mating or block fertilization between different species.

Punctuated Equilibrium

A model of speciation proposing rapid divergence followed by long periods of stasis.

Reinforcement

The process by which natural selection strengthens prezygotic barriers when hybrids have low fitness.

Reproductive Isolation

The inability of two populations to interbreed and produce viable offspring.

Sexual Selection

A form of natural selection in which individuals with certain inherited characteristics are more likely to obtain mates.

Sister Taxa

Two evolutionary lineages that share the most recent common ancestor.

Speciation

The process by which new biological species arise.

Stabilizing Selection

A mode of natural selection that favors intermediate phenotypes over extremes.

Sympatric Speciation

The formation of new species within the same geographic area, typically due to reproductive isolation mechanisms.

Taxon (plural: Taxa)

A unit of classification in biology, such as a species, genus, family, etc.

Temporal Isolation

A prezygotic reproductive barrier where two species breed during different times, preventing interbreeding.

Vicariance

A form of allopatric speciation where a geographic barrier divides a previously continuous population.