Evolutionary Biology Lecture Notes

These flashcards cover key concepts in evolutionary biology, providing definitions and explanations of terms related to evolution, speciation, natural selection, genetic variation, and more.

Evolution

Change in allele frequencies in populations over time.

Natural Selection

The process that acts on phenotypes, affecting allele frequencies in a population.

Synapomorphy

A shared derived trait useful for defining evolutionary relationships.

Plesiomorphy

A retained ancestral trait that is not derived.

Convergent Evolution

The independent evolution of similar traits in separate lineages due to similar selective pressures.

Homologous Traits

Structures in different species that are similar due to shared ancestry.

Phylogenetics

The study of evolutionary relationships among biological entities.

Phylogeny

A branching diagram that depicts the evolutionary history of organisms.

Speciation

The evolutionary process by which new biological species arise.

Allopatric Speciation

Speciation that occurs when populations are geographically isolated.

Sympatric Speciation

Speciation that occurs without geographic isolation.

Microevolution

Small scale evolutionary changes within a population.

Macroevolution

Large scale evolutionary changes that occur over geologic time.

Extinction

The end of an organism, typically as a result of environmental changes or pressures.

Adaptive Radiation

The diversification of a group of organisms into forms filling different ecological niches.

Divergence

The process where two or more related species become more dissimilar.

Hybridization

The process of interbreeding between two different species.

Sexual Selection

A mode of natural selection where members of one biological sex choose mates of the other sex.

Genetic Drift

A mechanism of evolution that occurs by chance fluctuations in allele frequencies.

Gene Flow

The transfer of genetic variation from one population to another.

Hardy-Weinberg Equilibrium

A principle stating that allele and genotype frequencies in a population remain constant from generation to generation without evolutionary influences.

Drift

Random changes in allele frequencies in small populations.

Founder Effect

Loss of genetic variation when a small number of individuals establish a new population.

Bottleneck Effect

A sharp reduction in the size of a population due to environmental events or human activities.

Fitness

The ability of an organism to survive and reproduce in its environment.

Trait

A characteristic of an organism that is influenced by genetics.

Phenotype

The observable physical properties of an organism, which result from the genotype.

Allele

Different versions of a gene that may produce distinguishable traits.

Diploid

A cell or organism that has two sets of chromosomes.

Polygenic Trait

A trait influenced by multiple genes.

Pleiotropy

The ability of a single gene to influence multiple phenotypic traits.

Selection Pressure

An environmental factor that can influence which individuals survive and reproduce.

Heritability

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

Evo-Devo

The study of how evolutionary processes influence development.

Molecular Clock

A method used to estimate the time of evolutionary change based on molecular data.

Hox Genes

Genes that control the body plan of an embryo along the head-tail axis.

Morphology

The study of the form and structure of organisms.

Ecological Opportunity

The availability of unoccupied ecological niches that allows species to diversify.

Key Innovation

A new trait that allows a species to exploit resources in novel ways, leading to diversification.

Ecological Speciation

The process by which barriers to gene flow evolve as a result of ecological factors.

Conservation

The protection and preservation of biodiversity.

Extinction Rate

The rate at which species become extinct.

Species Diversity

The variety of different species present in an ecosystem.

Gene Pool

The complete set of genetic information within a population.

Adaptive Trait

A trait that enhances an organism's ability to survive and reproduce in its environment.

Inbreeding Depression

Reduced biological fitness in a population due to inbreeding.