Chapter 20: Development of Evolutionary Thinking and Evolutionary Biology since Darwin

Vocabulary flashcards covering the key concepts, terms, and figures from the Evolutionary Biology lecture notes (Darwin, Lamarck, Beagle voyage, Modern Synthesis, and foundational ideas in evolutionary thinking).

Evolution

The change in heritable traits in populations over generations, leading to descent with modification.

Descent with modification

Darwin’s idea that all living things are related by common ancestry and have diversified over time through inherited variations.

Natural selection

The process by which heritable traits that improve survival or reproduction become more common in a population over generations.

Artificial selection

The human-driven selection of traits through breeding, contrasted with natural selection in nature.

Lamarckism (inheritance of acquired characteristics)

An early evolutionary theory proposing that traits acquired during life are passed to offspring; later unsupported by genetics.

Use and disuse

Lamarck’s idea that body parts grow with use and shrink with disuse, influencing evolution.

Uniformitarianism

Geological idea that present-day processes have operated the same way throughout Earth’s history, implying an old Earth.

Gradualism

The view that geological and evolutionary changes occur slowly and steadily over long timescales.

Scala Naturae (Great Chain of Being)

A ladder-like hierarchy of life with fixed, hierarchical ranks from simplest to most complex.

Natural theology

The belief that God created and designed life in a fixed, unchanging manner; used before evolutionary explanations.

Biogeography

Study of the geographic distribution of species and how it informs evolutionary history.

Comparative morphology

Comparing anatomical structures across organisms to infer evolutionary relationships (e.g., homologous structures).

Fossil

Preserved remains or traces of past organisms used to study evolutionary history.

Vestigial structures

Nonfunctional or reduced features that were functional in ancestors (e.g., pig digits that no longer touch the ground).

Homologous structures

Anatomical features in different species that share a common ancestry and structure, even if function differs.

Hox genes

Regulatory genes that control body plan and limb development; changes can alter morphology.

ZRS (Zone of Polarizing Activity Regulatory Sequence)

A regulatory DNA element that influences Shh expression and limb development; mutations can affect limb formation in snakes.

Archaeopteryx lithographica

A transitional fossil showing both dinosaur and bird characteristics, linking non-avian dinosaurs to birds.

Darwin’s voyage on the Beagle

1831–1836 circumnavigation that provided critical observations leading to the theory of evolution.

Galápagos finches (Geospiza spp.)

Darwin’s finches with diverse beak shapes illustrating adaptive radiation and natural selection.

Modern Synthesis

Early 20th-century integration of Darwinian evolution with Mendelian genetics, emphasizing population genetics and gradual change.

Population genetics

Study of genetic variation within populations and how evolutionary forces change allele frequencies over time.

Microevolution vs. macroevolution

Microevolution: small genetic changes within populations; Macro-evolution: larger-scale changes leading to new species and lineages.