The Quaternary Period: Climate, Megafauna, and Extinctions

Comprehensive vocabulary flashcards covering the key terms, geological epochs, megafauna species, adaptations, scientific evidence, and extinction events of the Quaternary Period.

Quaternary Period

The most recent geological period in Earth's history, spanning from $2.58$ million years ago to the present day, characterized by repeated ice ages, climate shifts, human evolution, and megafaunal extinctions.

Pleistocene

The earlier epoch of the Quaternary Period, lasting from $2.58$ million years ago until $11{,}700$ years ago (commonly known as the Ice Age), marked by alternating glacial cycles and warmer interglacial intervals.

Holocene

The current geological epoch of the Quaternary Period, beginning approximately $11{,}700$ years ago and extending to the present day.

Morphological adaptation

A physical or anatomical feature that helps an organism survive in its specific environment.

Physiological adaptation

An internal biological or biochemical body process that supports an organism's survival.

Natural selection

The evolutionary process through which heritable traits that improve survival and reproductive success become more common in a population over successive generations.

Megafauna

Large animals within an ecosystem, particularly large-bodied mammals.

Extinction

The permanent disappearance or termination of a biological species.

Woolly mammoth (Mammuthus primigenius)

A large, hairy Ice Age herbivore adapted to arctic cold with thick fur, insulating fat, small ears, curved tusks, and grinding teeth.

Woolly rhinoceros (Coelodonta antiquitatis)

A large Ice Age mammal characterized by thick fur and two horns that lived in cold steppe and tundra regions.

Saber-toothed cat (Smilodon)

A Quaternary predator of large herbivores characterized by powerful jaws and elongated canine teeth.

Giant ground sloth (Megatherium)

A very large, heavy herbivorous mammal that inhabited forests and grasslands during the Quaternary.

American mastodon (Mammut americanum)

A large proboscidean herbivore of forests and grasslands, similar to mammoths but distinguished by straighter tusks.

Glyptodon

A large, heavily armored herbivorous mammal of South America that was not a true armadillo.

Food web

An ecological model illustrating feeding connections among organisms, linking primary producers, herbivores, predators, and decomposers.

Fossils

Preserved remains, traces, or imprints of ancient organisms providing direct evidence of prehistoric life and morphology.

Ancient DNA

Genetic material preserved in ancient remains used to reconstruct evolutionary relationships and identify specific physiological adaptations.

Stable isotopes

Non-radioactive chemical atomic signatures preserved in tissue or bone that reveal past diet, trophic level, and environmental conditions.

Radiocarbon dating

A radiometric age-dating technique used to determine the chronological age of suitable carbon-bearing organic remains.

Pollen records

Microscopic plant pollen grains recovered from geological strata used to reconstruct ancient plant communities and paleoclimate conditions.

Late Quaternary megaherbivore extinction

The extensive loss of megafauna wherein $46$ of $57$ terrestrial megaherbivore species weighing at least $1{,}000\,\text{kg}$ went extinct prior to the modern era.

Bering land bridge (Bering region)

An exposed continental land bridge created by lower sea levels during glacial periods that permitted animal and human migration between Asia and North America.