Earth Biography and Human Evolution Flashcards

These vocabulary flashcards cover major geological time scales, biological milestones from the Precambrian to the Phanerozoic, supercontinent cycles, global climate shifts, and the phylogenetic evolution of the human lineage.

Stromatolites

First prokaryotic microscopic organisms appearing around $3.8\,Ga$ that oxygenated the atmosphere through photosynthesis by $2.3\,Ga$.

Phanerozoic Eon

The geological eon spanning from $542\,Ma$ to the present, characterized by major biological diversity and abundant fossils with hard parts.

Cambrian Explosion

A period around $542\,Ma$ marked by the rapid diversification of life and the emergence of the first skeletonized organisms with internal and external hard parts.

Craton

The interior core that stabilized to form the first crust after the cooling of Earth's surface by the end of the Hadean.

Banded Iron Formation (BIF)

Evidence of marine sediments and oxygenation that appeared in the Archean Eon, indicating the arrival of $H_2O$ molecules on Earth's surface.

Rodinia

The first proto-supercontinent assembled approximately $1.1\,Ga$ that began to drift apart around $750\,Ma$.

Snowball Earth

A period of extreme global glaciation occurring between $700-582\,Ma$.

Ediacaran fauna

The oldest true soft-bodied multi-celled organisms with tissues (~$600\,Ma$) discovered in Australia, resembling segmented worms, disks, or jellyfish.

Tiktaalik

A noteworthy transitional fossil fish that represents the evolutionary form between fish and amphibians/land creatures.

Lystrosaurus

A fossilized mammal-like reptile that existed during the Phanerozoic Eon.

Archaeopteryx

A transitional fossil representing the evolutionary link between dinosaurs and birds.

Pangea

A supercontinent formed by Gondwana and Laurentia during the Carboniferous-Triassic periods that drifted apart starting in the Jurassic.

Paleocene-Eocene Thermal Maximum (PETM)

An interval of extreme global warming (~$27^{\circ}C$–$34^{\circ}C$) caused by massive $CO_2$ injection into the atmosphere from volcanism and rapid mid-Atlantic sea floor spreading.

Oligocene Global Cooling

A drastic climate change caused by the expansion of the Antarctic Ice Sheet and the rise of the Himalayas and Tibetan plateau through continental collisions.

Grassland Explosion

A Cenozoic environmental shift where forests shrank and grasslands expanded, leading to the rapid evolution of grazing mammals like the Equidae family (horses, donkeys, zebras).

Hominoidea

The superfamily that includes humans, all apes, and gibbons.

Hominini

The tribe consisting of the direct human lineage, including all bipedal species such as Homo sapiens and extinct ancestors like Australopithecus.

Panini

The tribe consisting of the chimpanzee and bonobo lineages, characterized by knuckle-walking locomotive behavior.

Homo habilis

The first species in the genus Homo, appearing around $2.6\,Ma$, characterized by an enlarged brain ($650\,cc$) and the use of Oldowan stone tools.

Homo erectus

An early human species with a large brain ($900\,cc$) known for the controlled use of fire and the creation of hand axes.

Homo neanderthalensis

An extinct member of the Hominini tribe found in the fossil record with a brain size of approximately $1400\,cc$.

Pleistocene Epoch

The geological epoch from $2.6\,Ma$ to $10,000$ years ago, characterized by repeated glaciations (Ice Age) interrupted by warm interglacial periods.

Holocene Epoch

The current warm interglacial period starting $10,000$ years ago, which allowed for sedentary settlements, early farming, and cultivation.

Anthropocene

The informal term for the Industrial Age (last $200$ years) marked by significant human impact on Earth's environment and recent temperature increases.