Chapter 8 Flashcards
Half-Life
The time it takes for half of the radioactive isotopes in a sample to decay, used in radiometric dating to calculate the age of fossils or rocks.
Index Fossils
Fossils of organisms that existed for a short period of time but were widespread geographically, used to date rock layers and correlate strata across regions.
Oldowan Tools
The earliest known stone tool industry, dating to about 2.6 million years ago, associated with early hominins such as Homo habilis.
Acheulean Tools
A stone tool industry associated with Homo erectus, characterized by large, symmetrical hand axes, dating to about 1.76 million years ago.
Homo habilis
An early species of the genus Homo, dating to about 2.4 to 1.4 million years ago, known for its association with Oldowan tools and a slightly larger brain than australopithecines.
Homo erectus
An early species of the genus Homo, dating to about 1.9 million to 140,000 years ago, known for its larger brain size, use of Acheulean tools, and evidence of controlled use of fire.
Homo heidelbergensis
An archaic human species that lived between about 700,000 and 200,000 years ago, considered a common ancestor of Neanderthals and modern humans.
Neanderthals
An extinct species of archaic humans (Homo neanderthalensis) that lived in Europe and western Asia until about 40,000 years ago, known for their robust build and adaptations to cold climates.
Denisovans
An extinct group of archaic humans known primarily from DNA evidence, who lived in Asia and interbred with both Neanderthals and modern humans.
Multiregional Hypothesis
A model of human evolution suggesting that modern humans evolved simultaneously in different regions from local populations of Homo erectus.
Out of Africa Hypothesis
A model of human evolution suggesting that modern humans (Homo sapiens) evolved in Africa and then migrated to other regions, replacing other hominin species.
Mitochondrial Eve
The most recent common matrilineal ancestor of all living humans, traced through mitochondrial DNA, estimated to have lived in Africa around 150,000 to 200,000 years ago.
Y-Chromosomal Adam
The most recent common patrilineal ancestor of all living humans, traced through Y-chromosome DNA, estimated to have lived in Africa around 200,000 to 300,000 years ago.
Paleolithic
The “Old Stone Age,” a period of human prehistory characterized by the use of stone tools, spanning from about 2.6 million years ago to around 10,000 years ago.
Mesolithic
The “Middle Stone Age,” a transitional period between the Paleolithic and Neolithic, characterized by the development of more advanced tools and the beginnings of settled communities.
Neolithic
The “New Stone Age,” a period of human prehistory characterized by the development of agriculture, domestication of animals, and the rise of permanent settlements, beginning around 10,000 years ago.
Domestication
The process by which humans selectively breed plants and animals for desirable traits, leading to the development of agriculture and settled societies.
