The study of the history of families and the line of descent from their ancestors.

The branch of biology that deals with heredity and genetic variations. The genetic makeup of an organism or group of organisms.

The change in the relative frequency in which a gene variant [allele] occurs in a population due to random sampling and chance: The alleles in offspring are a random sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces. A population's allele frequency is the fraction of the gene copies that share a particular form. Genetic drift is an important evolutionary process, which leads to changes in allele frequencies over time. It may cause gene variants to disappear completely, and thereby reduce genetic variability. In contrast to natural selection, which makes gene variants more common or less common depending on their reproductive success, the changes due to genetic drift are not driven by environmental or adaptive pressures, and may be beneficial, neutral, or detrimental to reproductive success. The effect of genetic drift is larger in small populations, and smaller in large populations.

A category in the taxonomic classification of related organisms, comprising one or more species. Similar genera are grouped into families.

Relating to imagery that thematically consists primarilv of nonfigurative, abstract-geometric configurations.

A ground figure created by scraping away the patinated surface material of desert pavement to expose the underlying lighter colored soil; also known as intaglio. For example, the ancient Nasca lines of Peru.

Rock art motif that is essentially geometric in shape, both curvilinear and rectilinear.

Short form for petroglyph.

An Upper Palaeolithic culture after the Aurignacian and before the Solutrean, between 28,000 and 22,000 years ago. It is characterized by the Gravette point, named after the site of La Gravette in the Dordogne region of France.

Design created on the ground surface by various techniques or combinations of techniques; see geoglyph and petroform.

A distinctive style of rock art found in the Kimberley region of Western Australia. The Aboriginal term for these paintings is Gwion Gwion. Archaeologists estimate that there may be more than 100,000 sites spread over 50,000km of the Kimberley. In 1996 one of the paintings was dated by thermoluminescence [see thermoluminescence] analysing an ancient wasp nest covering it. The nest was found to be over 17,000 years old, indicating that some paintings are at least this old. However, because it has been proven that Australia was colonized as early as 65,000 years ago, some argue that these paintings are possibly much older, and possibly the earliest figurative rock art.