Geologic Time Scale and Early Hominins

A set of vocabulary flashcards defining key geologic time divisions and early hominin species based on lecture material.

Fossil

Preserved remains of an organism buried underground for a long period of time.

Eon

The first and largest division of the geologic time scale, consisting of two main divisions: Precambrian and Phanerozoic.

Era

The division that makes up each Eon; unlike a calendar year, it is categorized based on major events that took place rather than a fixed number of days.

Historical Artifacts / Objects from the Past

Objects from the past that undergo processes like paleomagnetism and thermoluminescence to determine their age.

Hadean Eon

The period when the solar system was just starting to form, during which no living organisms existed on Earth.

Epoch

The division that makes up each Period, categorized by events and changes in the layering of soil in a specific location.

Period

The division that makes up each Era, categorized by important events, with the Paleozoic Era having the most of them.

Geologic Time Scale

A system of dividing time related to geographical conditions, formed from the study of sedimentary rock layers in the ground.

Proterozoic Eon

The period when unicellular marine life flourished, enriching the atmosphere with oxygen and giving rise to multicellular life.

Archean Eon

The period inhabited by the oldest fossils or tiny bacteria on Earth, inhospitable due to an atmosphere filled with toxic gases.

Neanderthal

Hominin that lived from 230,000 to 30,000 years ago in cold areas, possessing agile yet robust limbs.

Millenium Man

A hominin as small as a chimpanzee, also known as 'Millenium Man', with human-like teeth, particularly its molars or canines.

Kenyanthropus

One of the early hominins with limited expert knowledge compared to Australopithecus, distinguished primarily by its flat face.

Ardipithecus

Hominin resembling earlier genera and Australopithecus, with hip bones showing a mix of ape-like and human-like traits.

Homo sapiens

Species that emerged 195,000 years ago to which modern humans belong, categorized into subspecies with sophisticated lifestyles.

Australopithecus

Also called 'Southern Apes' because they were excavated in South Africa, possessing a larger skull reflecting a bigger brain compared to earlier hominins.

Homo erectus

Hominin species that lived 1.8 million to 300,000 years ago, with a protruding snout, large molars, a short chin, and a body size larger than modern humans.

Homo rudolfensis

Discovered in 1977 in Kenya, featuring a square jaw, long face, and teeth smaller than Australopithecus but larger than other Homo species.

Zinj skull

A fossil skull discovered in Kenya by anthropologist Mary Leakey.