Living Environment Translated Arabic 2014 | Page 90

14.Radioactive dating- a process that measures radioactive elements
in fossils to determine their approximate age
15. Embryology – the study of the stage of development after the
fertilized egg until the fetus is born.
16. Homologous structures- a body part that is similar in structure
on different organisms but performs different functions
17.Analogous structure- a body part that is similar in function as a
body part of another organism but is structurally different
18. Vestigial structures- a structure that doesn’t seem to have a
function , and may once have functioned in the body of an
ancestor
19. Primates- a group of mammals including humans , monkeys, and
apes that share characteristics such as opposable thumbs,
binocular vision, and flexible shoulders
20. Hominids- a humanlike primate that appeared about 4-6 million
years ago, ate both plants and meat, and walked upright on two
legs
21. Homo sapiens- early humans that likely evolved from CroMagnons
22. Cro-Magnon - an early human group that appeared about
40,000 years ago and are thought to be direct ancestors of
modern humans.
23. Neanderthals- an early human group that had short, heavy
bodies with thick bones, small chins, and heavy brow ridges.
They appeared about 125,000 years ago and disappeared about
30,000 years ago.
24. Paleontology- the study of fossils or extinct organisms
25. Gene pool- a collection of alleles ( genes) found in all the
individuals of a population
26. Speciation- the evolution of two or more species from one
ancestral species
27. Extinction- elimination of a species from the Earth