Bio 140 Exam 1

Vocab

Adaptive Radiation

A period of unusually rapid evolutionary diversification in which natural selection accelerates the rate of speciation within a group, with new species adapted for specific niches

Allopatric Speciation

Describes populations that are geographically separated from each other

Artificial Selection

A form of directional selection similar to natural selection, but with selection done intentionally by humans, usually with a specific goal in mind, such as increased milk yield in cattle

Biological Species Concept

Species are groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups; most widely used and accepted definition of a species, but cannot be applied to asexual organisms

Bottleneck

An extreme, usually temporary, reduction in population size that may result in marked loss of genetic diversity and, in the process, genetic drift

Co-Speciation

A process in which 2 groups of organisms speciate in response to each other and at the same time, producing matching phylogenies

Convergent Evolution

The independent development of similar features or traits in unrelated or distantly related species

Directional Selection

A form of selection that results in a shift of the mean value of a trait in a population over time

Disruptive Selection

A form of selection that operates in favor of extremes and against intermediate forms, selecting against the mean

Ecological Species Concept

The concept that there is a one-to-one correspondence between a species and its niche

Endosymbiosis

A symbiosis in which one partner is inside the other one and they grow like that: ex mitochondria and chloroplasts

Eukaryote

An organism who’s cell that have a true nucleus

Founder Effect

A type of genetic drift that occurs when only a few individuals establish a new population

Gene Flow

The movement of alleles from one population to another through interbreeding between members of each population

Gene Pool

All the alleles present in all individuals in a population or species

Genetic Drift

A random change in the frequency of an allele due to the statistical effects of finite population size

Germ-Line Mutation

A mutation that occurs in eggs and sperm or in the cells that give rise to these reproductive cells and therefore is passed onto the next generation

Hardy-Weinburg Equilibrium

A state in which allele and genotype frequencies do not change over time, implying the absence of evolutionary forces; also specifies a mathematical relationship between allele frequencies and genotype frequencies

Morphospecies Concept

The idea that members of the same species usually look like each other more than like other species

Niche

A complete description of the role a species plays in its environment, and of its requirements, both abiotic and biotic

Phylogenetic Species Concept

The idea that members of a species all share a common ancestry and a common fate

Sexual Selection

A form of selection that promotes traits that increase an individuals access to reproductive opportunities

Somatic Mutation

A mutation that occurs only in somatic cells; cannot be passed down

Species

A group of individuals that can exchange genetic material through interbreeding to produce fertile offspring

Stabilizing Selection

A form of selection that selects against extremes and therefore maintains the status quo

Symbiont

An organism that lives in closely evolved association with another species (ex: bees and flowers)

Sympatric

Describes populations that are in the same geographic location

Vicariance

The process in which a geographic barrier arises within a single population, separating it into 2 or more isolated populations that are isolated from each other