Chapter 4 - Human Evolution and Macroevolution Lecture Notes

A comprehensive set of vocabulary flashcards covering the biological and geological concepts of human evolution, speciation, and mammalian development.

Human evolution

The biological and cultural process through which modern humans ($Homo sapiens$) developed from earlier primate ancestors over millions of years through evolutionary change.

Homo sapiens

The scientific name for modern humans, which translates to "Wise Human."

Chimpanzees and bonobos

The living primates to which humans are most closely related.

Central and West Africa

The geographic region where chimpanzees naturally live.

Sumatra and Borneo

The Southeast Asian islands where orangutans naturally live.

Macroevolution

Evolution above the species level involving the formation of new species (speciation) and the evolutionary relationships among species.

Speciation

The evolutionary process by which one species splits into two or more distinct species.

Isolating mechanism

Any factor that prevents gene flow between populations, eventually allowing them to evolve independently.

Gene flow

The movement of genes between populations through reproduction.

Geographic isolation

An isolating mechanism involving physical barriers such as rivers, mountains, oceans, deserts, and glaciers.

Biological isolation

An isolating mechanism involving reproductive factors such as sterility, miscarriage, or genetic incompatibility.

Social isolation

An isolating mechanism involving behaviors or rules such as courtship dances, songs, nest building, marriage customs, and kinship rules.

Cladogenesis

Branching evolution where one ancestral population splits into two or more descendant species.

Anagenesis

Evolution within a single species where changes accumulate over time without branching.

Heterochrony

A change in the timing of developmental events that alters body shape or size.

Neoteny

The retention of juvenile characteristics into adulthood, such as flatter faces and larger brains relative to body size in humans.

Homeobox gene

A regulatory gene that controls major aspects of body development and organization; small changes in these can produce major structural changes.

Punctuated equilibrium

A model proposing that long periods of little evolutionary change are interrupted by relatively short periods of rapid evolution.

Stephen Jay Gould and Niles Eldredge

The scientists who proposed the model of punctuated equilibrium.

Derived characteristic

A newly evolved trait not found in distant ancestors, such as human adaptations for bipedal walking.

Ancestral characteristic

A trait inherited from a common ancestor, such as bilateral symmetry.

Convergent evolution

The independent evolution of similar traits in unrelated species due to similar environmental pressures, such as the wings of birds and butterflies.

Homologous structures

Similar anatomical structures inherited from a common ancestor.

Analogous structures

Structures with similar functions but different evolutionary origins.

$65$ million years ago

The approximate time when dinosaurs became extinct, opening ecological niches for mammals to diversify.

Adaptive radiation

The rapid diversification of one ancestral species into many species adapted to different ecological niches.

Continental drift

The movement of Earth's continents over millions of years due to plate tectonics.

$190$ million years ago

The approximate time when true mammals first appeared.

Mammal-like reptiles

Ancient reptiles that evolved many mammalian characteristics before the appearance of true mammals.

Preadaptation

Possessing a trait that later becomes advantageous under new environmental conditions.

Homeotherm

An animal, such as a mammal, that maintains a relatively constant internal body temperature.

Isotherm

Also known as an ectotherm, an animal whose body temperature changes with the surrounding environment.

K-selected species

A species that produces relatively few offspring while investing heavily in parental care, a category that includes most mammals.

r-selected species

A species that produces many offspring with little parental care.