zoolongyy (evolution)

Evolution

The change in inherited traits and allele frequencies of a biological population over successive generations.

Charles Darwin

English naturalist who formulated the theory of evolution through natural selection after observing diverse species on his global voyage.

Key study organisms of Charles Darwin

Galápagos finches, giant tortoises, and barnacles.

Jean-Baptiste Lamarck

Early biologist who proposed the hypothesis of inheritance of acquired characteristics and the principle of use and disuse.

Lamarck's hypothesis of use and disuse

The proposal that body parts modified or developed through use or disuse during an organism's lifetime are directly inherited by its offspring (e.g., giraffes stretching necks).

HMS Beagle voyage

Five-year survey expedition around the world, particularly South America and the Galápagos Islands, providing the primary field evidence for Darwin's theories.

Fossil evidence observed by Darwin in South America

Extinct giant mammals in Argentina that closely resembled extant species in the same geographic region.

Adaptive radiation

The rapid evolutionary diversification of a single ancestral species into multiple distinct forms, each adapted to exploit a specific ecological niche.

Adaptive trait vs. maladaptive trait

An adaptive trait increases an individual's evolutionary fitness in a specific environment, whereas a maladaptive trait decreases fitness.

Natural selection

The differential survival and reproduction of individuals due to differences in heritable phenotypic traits.

Four fundamental principles of natural selection

Variation, overproduction of offspring, competition for limited resources, and differential reproductive success (inheritance).

Alfred Russel Wallace

British naturalist who independently formulated the theory of evolution by natural selection and co-published the discovery with Darwin.

Microevolution vs. macroevolution

Microevolution involves small-scale changes in allele frequencies within a population across generations, while macroevolution refers to large-scale evolutionary changes at or above the species level over geological time.

Biogeography

The scientific study of the spatial distribution of biological organisms and ecosystems across geographic space and through geological time.

Analogous structures

Body parts in different species that perform a similar function but evolved independently from different ancestral origins (e.g., bird wings and insect wings).

Homologous structures

Anatomical features derived from a common ancestor that may perform different functions in descendant species (e.g., a human arm and a whale flipper).

Gene pool

The aggregate of all alleles across all gene loci present in an interbreeding population at a given time.

Genetic drift vs. gene flow

Genetic drift refers to random fluctuations in allele frequencies due to chance events, whereas gene flow is the transfer of genetic material between populations via migration.

Three primary modes of natural selection

Directional selection (favors one extreme phenotype), stabilizing selection (favors intermediate phenotypes), and disruptive selection (favors both extreme phenotypes).

Modes of speciation (allopatric, sympatric, parapatric)

Allopatric involves geographic isolation; sympatric occurs within the same geographic range without physical isolation; parapatric occurs in adjacent populations with a shared border.