potasio-argón

potasio-argón

A radiometric dating method based on the fact that potassium-40 in volcanic rock decays into argon-40 and calcium-40 at a known rate. The half-life of potassium-40 is approximately 1. 3 billion years. Chronometric dates are determined by measuring the amount of argon-40 in a sample. Similarly, argon-40 and argon-39 ratios can be used for chronometric dating.

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Valdkond/domeen: Anthropology
Category: Physical anthropology
Company: Palomar College
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termoluminiscencia (TL)

Anthropology; Physical anthropology

A radiometric dating method based on the fact that trace amounts of radioactive atoms, such as uranium and thorium, in some kinds of rock, soil, and clay produce constant low ...

enfermedad endémica

Anthropology; Physical anthropology

A disease that remains at a more or less constant frequency of affected individuals in a population all of the time. Examples: hypertension, tooth decay, and malaria.

polimorfismo

Anthropology; Physical anthropology

A genetic trait controlled by more than one allele, each of which has a frequency of 1% or greater in the population gene pool. See balanced polymorphism.

modelo de asimilación

Anthropology; Physical anthropology

A hypothesis to explain the origin of modern Homo sapiens. It proposes that the first modern humans evolved in Africa, but when they migrated into other regions they did not ...

pedernal

Anthropology; Physical anthropology

A kind of hard, rock with a glassy opaque appearance. It was a favorite raw material for many prehistoric humans for the manufacture of tools such as knives and scraping ...

trisomía 21

Anthropology; Physical anthropology

A genetically inherited form of mental retardation usually resulting from the inheritance of an extra autosome 21. Down syndrome individuals also typically are short and stocky in ...

cigoto

Anthropology; Physical anthropology

A "fertilized" ovum. More precisely, this is a cell that is formed when a sperm and an ovum combine their chromosomes at conception. A zygote contains the full complement of ...