Honors Biology - Evolution (9th grade)

Species Are Fixed

The belief that species do not change over time.

Adaptations

Traits that increase an organism's chances of survival and reproduction in a particular environment.

Allele Frequency

The proportion of a particular allele among all allele copies in a population.

Analogous Structures

Structures in different species that perform the same function but do not have a common evolutionary origin.

Artificial Selection

Humans intentionally breed organisms with desirable traits.

Binomial Nomenclature

A system for naming species using two names: the genus and species (specific epithet).

Biogeography

Study of the geographic distribution of species.

Bottleneck Effect

A reduction in genetic diversity due to a drastic decrease in population size.

Catastrophism

The idea that Earth’s history has been shaped by sudden, short-lived, and violent events.

Cladogram

A diagram used to show the relationships among species based on shared traits.

Directional Selection

Natural selection that favors one extreme phenotype over others.

Disruptive Selection

Natural selection that favors both extreme phenotypes and eliminates intermediate phenotypes.

Evolution

A change in the genetic makeup of a population over time.

Fitness

The ability of an organism to survive and reproduce.

Fossils

Remains or traces of ancient organisms preserved in rocks.

Founder Effect

A reduction in genetic variation when a small group of individuals starts a new population.

Gene Flow

The transfer of genetic material between populations through migration or interbreeding.

Gene Pool

The total genetic diversity found within a population.

Genetic Drift

A random change in allele frequencies in a small population.

Genus

A classification category that ranks above species and below family.

Hardy-Weinberg Equilibrium

A model used to measure genetic changes in a population over time.

Heritability

The proportion of variation in a trait that can be attributed to genetic differences.

Homologous Structures

Structures that have a common evolutionary origin.

Hybridization

The process of breeding two different species to create hybrid offspring.

Inheritance of Acquired Characteristics

Lamarck’s discredited idea that traits acquired during an organism’s lifetime can be passed on to offspring.

Interspecific Variation

Variation between different species.

Intraspecific Variation

Variation within the same species.

Microevolution

Small-scale changes in allele frequencies in a population over time.

Migration

Movement of individuals between populations.

Mutation

A change in the DNA sequence.

Natural Selection

The process by which individuals with beneficial traits are more likely to survive and reproduce.

Normal Distribution

A bell-shaped curve that represents the distribution of traits in a population.

Paleontology

The study of fossils and ancient life forms.

Phenotype

The observable physical traits of an organism.

Population

A group of individuals of the same species living in the same area.

Recombination

The process during meiosis that shuffles genes and creates genetic variation.

Species

A group of organisms that can interbreed and produce fertile offspring.

Specific Epithet

The second part of a species name in binomial nomenclature, unique to each species within a genus.

Stabilizing Selection

Natural selection that favors the average phenotype and reduces variation.

Uniformitarianism

The idea that Earth’s features are shaped by continuous, uniform processes.

Variation

Differences in traits among individuals in a population.

Vestigial Structures

Structures that have lost their original function.

Carolus Linnaeus

Developed binomial nomenclature and classified organisms.

Georges de Buffon

Proposed that species change over time and may have common ancestors.

Erasmus Darwin

Suggested that life evolved from a common ancestor.

Jean Baptiste Lamarck

Proposed the idea of inheritance of acquired characteristics.

George Cuvier

Advocated for catastrophism and believed that extinction had occurred.

James Hutton

Proposed the idea of uniformitarianism, suggesting that geological processes occur gradually over time.

Charles Lyell

Supported Hutton’s ideas and applied them to the understanding of Earth's geological history.

Thomas Malthus

Proposed that populations grow exponentially, leading to competition for limited resources.

Alfred Russel Wallace

Developed a theory of evolution by natural selection similar to Darwin’s.

Darwin’s Observations

Variation exists within populations, and organisms produce more offspring than can survive.

Survival of the Fittest

Organisms with advantageous traits are more likely to survive and reproduce.

Common Descent

All species are related by common ancestry.

Darwin’s Theory of Evolution

Natural selection works on heritable traits, acting on individuals.