Biology Chapters 13-15

Galápagos Islands

A volcanic archipelago located approximately 900 km off the coast of South America.

Darwin's observations

Darwin noted unique wildlife on the Galápagos Islands, including blue-footed boobies, giant tortoises, marine iguanas, and diverse finch species.

Natural selection

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

Adaptive radiation

The rapid evolution of many species from a common ancestor, often following a significant environmental change.

Microevolution

Small changes in allele frequencies in a population over generations.

Stabilizing selection

A type of natural selection that favors average traits and reduces variation.

Directional selection

A type of natural selection that favors one extreme phenotype, leading to a shift in population traits.

Disruptive selection

A type of natural selection that favors both extreme phenotypes, potentially leading to speciation.

Species

Groups of organisms that can interbreed and produce fertile offspring.

Hybrid zones

Regions where different species meet and interbreed, with outcomes including reinforcement, fusion, or stability.

Biological species concept

A definition of species based on the ability to interbreed and produce fertile offspring.

Common ancestor

The shared ancestor from which multiple species descend.

Gene pool

The total set of genes (and their alleles) in a population.

Hardy-Weinberg principle

The principle stating that allele frequencies in a population remain constant in the absence of evolutionary influences.

Fossils

Preserved remains or traces of organisms from the past, providing evidence of evolutionary history.

Homologous structures

Body parts that share a common ancestry but may have different functions.

Analogous structures

Body parts that perform similar functions but do not share a common evolutionary origin.

Convergent evolution

The process where unrelated species evolve similar traits due to similar environmental pressures.

Plate tectonics

The theory that explains the movement of Earth's plates, affecting geographic and evolutionary processes.

Extinction events

Mass loss of species occurring at specific points in Earth's history, significantly impacting biodiversity.

Evolutionary trees

Diagrams that depict the relationships between species, showing lines of descent and common ancestry.

Genetic drift

Random changes in allele frequencies in a population, particularly significant in small populations.

Gene flow

The transfer of genetic variation from one population to another.

Speciation

The process through which new species arise.

Adaptive radiation examples

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

Molecular systematics

The use of molecular data (DNA, RNA) to study the relationships and evolution of species.

Shared derived character

A trait that is unique to a particular group of organisms, indicating a common ancestry.

Gene duplication

A molecular event that results in the presence of two or more copies of a gene in the genome.

Macroevolution

Large-scale evolutionary changes that occur over long time periods, typically above the species level.

Short-term evolution example

Antibiotic resistance in bacteria as a result of rapid natural selection.

Punctuated equilibrium

The theory that species remain unchanged for long periods and then undergo rapid changes.

Sympatric speciation

The process of speciation that occurs in populations that live in the same geographic area.

Allopatric speciation

The formation of new species due to geographical isolation.

Evolutionary evidence types

Evidence for evolution comes from the fossil record, biogeography, comparative anatomy, and molecular biology.

Mutation significance

Mutations introduce new genetic variation into a population, which can lead to evolutionary changes.

DNA similarities

The molecular evidence suggesting relationships among species based on genetic material.