HONORS BIOLOGY — UNIT 5 VOCABULARY

Charles Darwin

Developed the theory of evolution by natural selection.

Evolution

Change in a species over time; descendants become different from their ancestors.

Adaptation

An inherited trait passed to offspring that helps organisms survive in their environment.

Adaptive Radiation

One species evolves into many descendant species that occupy different ecological niches.

Allele Frequency

The proportion of one allele compared with all alleles for that trait in the gene pool.

Analogous Structures

Body parts with similar functions but different structures.

Artificial Selection

Humans modify a species by breeding it for certain traits.

Behavioral Isolation

Populations are isolated because of differences in courtship or mating behaviors.

Biogeography

The study of the distribution of organisms around the world.

Bottleneck Effect

Genetic drift caused by an event that kills a large part of a population.

Catastrophism

The theory that natural disasters shape Earth’s landforms and cause extinctions.

Coevolution

Two or more species evolve in response to changes in each other.

Convergent Evolution

Unrelated species evolve similar characteristics because of similar environmental conditions.

Descent with Modification

Organisms pass inherited traits to offspring, and changes over generations cause differences.

Directional Selection

One extreme phenotype is selected over a more common phenotype.

Disruptive Selection

Two opposite, less common phenotypes are selected over the most common phenotype.

Divergent Evolution

Related species evolve into different species as they adapt to different environments.

Extinction

The elimination of a species from Earth.

Fitness

An organism’s ability to survive and have offspring compared with others in its population.

Fossil

A trace or preserved remain of an organism from the past.

Founder Effect

Genetic drift that occurs when a small number of individuals colonize a new area.

Gene Flow

The movement of alleles from one population to another.

Gene Pool

All the alleles found in all individuals of a population.

Genetic Drift

A change in allele frequencies due to chance, most common in small populations.

Geographic Isolation

Populations are isolated by physical barriers.

Gradualism

Changes in landforms result from slow changes over long periods of time.

Homologous Structures

Body parts with similar structures in different organisms but different functions.

Microevolution

A change in a population’s allele frequencies over a few generations.

Mutation

A change in a DNA sequence.

Natural Selection

Individuals with beneficial inherited adaptations produce more offspring than other individuals.

Population

All individuals of the same species living in the same area.

Punctuated Equilibrium

Speciation occurs rapidly, followed by long periods of little evolutionary change.

Reproductive Isolation

Populations can no longer mate successfully or produce viable, fertile offspring.

Species

Organisms that can breed with one another and produce fertile offspring.

Stabilizing Selection

The intermediate phenotype is selected over phenotypes at both extremes.

Temporal Isolation

Populations are isolated because they reproduce at different times.

Uniformitarianism

Geological processes that shape Earth have remained consistent throughout time.

Variation

Differences in physical traits among individuals in a group.

Vestigial Structures

Remnants of body parts that functioned in an earlier ancestor.