Evolution of Populations

Science

The rapid diversification of one species into several different species

Adaptive radiation

The rapid diversification of one species into several different species. Adaptive radiation. It's when a single species evolves into multiple new species to adapt to different environments or niches.

The process by which unrelated species develop similar traits in similar environments

Convergent evolution

The process by which unrelated species develop similar traits in similar environments. Convergent evolution. Convergent evolution is when different species independently evolve similar features because they live in similar environments.

A form of natural selection which favors an uncommon trait, leading to a genetic shift of the population

Directional selection

A form of natural selection which favors an uncommon trait, leading to a genetic shift of the population. Directional selection. It is when a specific trait becomes more common in a population because it gives an advantage for survival and reproduction.

Natural selection which favors two extreme forms of a trait over an intermediate form

Disruptive selection

Natural selection which favors two extreme forms of a trait over an intermediate form. Disruptive selection. Disruptive selection is when extreme traits are more advantageous than average traits, causing diverse variations in a population.

Random changes in allele frequency, which usually occurs in small populations

Genetic drift

Random changes in allele frequency, which usually occurs in small populations. Genetic drift. Genetic drift is a process where chance events cause certain traits to become more or less common in a population.

A state where allele frequencies remain the same

Genetic equilibrium

A state where allele frequencies remain the same. Genetic equilibrium. Genetic equilibrium is when the genetic makeup of a population does not change over time.

Reproductive isolation caused by physical barriers like rivers or mountains

Geographic isolation

Reproductive isolation caused by physical barriers like rivers or mountains. Geographic isolation. Geographic isolation occurs when physical barriers, such as rivers or mountains, prevent different groups of a species from interbreeding.

Occurs when two populations evolve to the point that they cannot interbreed to produce fertile offspring

Reproductive isolation

Occurs when two populations evolve to the point that they cannot interbreed to produce fertile offspring. Reproductive isolation is when different species cannot have babies together or their babies can't have babies.

The evolution of new species from an existing species

Speciation

The evolution of new species from an existing species. Speciation. Speciation is the process by which populations evolve to become distinct species.

Natural selection which favors average forms of a trait, these forms become more common

Stabilizing selection

Natural selection which favors average forms of a trait, these forms become more common. Stabilizing selection. Stabilizing selection is when the average traits in a population are favored and become more common, reducing variation.

The change in a species over time

Evolution

The change in a species over time. Evolution. It is the process by which living organisms develop and diversify from earlier forms through gradual changes over generations.

A decrease in genetic diversity caused by a sharp decline in population size

Bottleneck effect

A decrease in genetic diversity caused by a sharp decline in population size. Bottleneck effect. The bottleneck effect occurs when a population's size is drastically reduced, leading to a loss of genetic variation.

A change in the gene pool caused by a small population migrating to a new area

Founder effect

A change in the gene pool caused by a small population migrating to a new area. Founder effect. It occurs when a small group of individuals starts a new population, leading to reduced genetic diversity.

States that allele frequencies in a population are constant unless a factor causes change

Hardy Weinberg principle

States that allele frequencies in a population are constant unless a factor causes change. Hardy Weinberg principle. The Hardy-Weinberg principle explains how in a stable environment, the genetic makeup of a population remains constant over generations unless influenced by external factors.

States that evolution happens in short periods, separated by long periods of stability

Punctuated equilibrium

States that evolution happens in short periods, separated by long periods of stability. Punctuated equilibrium. It is a scientific theory suggesting that species evolve rapidly during brief periods of change, followed by long periods of little to no change.

Selection where certain traits improve mating success, and are passed on to offspring

Sexual selection

Selection where certain traits improve mating success, and are passed on to offspring. Sexual selection. It's a natural process where individuals with certain traits are more likely to find mates and reproduce.

The proportion of one allele of a gene compared to other alleles of the same gene

Allele frequency

The proportion of one allele of a gene compared to other alleles of the same gene. Allele frequency. Allele frequency is how common a specific version of a gene is in a population.

Isolation between populations due to differences in courtship or mating behavior

Behavioral isolation

Isolation between populations due to differences in courtship or mating behavior. Behavioral isolation. It's when different species or groups don't mate because they have unique courtship behaviors that aren't recognized by the other group.

Reproductive isolation between two populations where they reproduce at different times

Temporal isolation

Reproductive isolation between two populations where they reproduce at different times. Temporal isolation. Temporal isolation is when two populations cannot interbreed because they mate or are active at different times.