Carbon dating human fossils
Then, even if circumstances change such that it no longer provides any survival or reproductive advantage, the behavior will still tend to be exhibited -- unless it becomes positively disadvantageous in the new environment.
adaptive radiation: The diversification, over evolutionary time, of a species or group of species into several different species or subspecies that are typically adapted to different ecological niches (for example, Darwin's finches).
antibiotic resistance: A heritable trait in microorganisms that enables them to survive in the presence of an antibiotic.
aperture: Of a camera, the adjustable opening through which light passes to reach the film.
These all develop through an embryo that is enclosed within a membrane called an amnion.
The amnion surrounds the embryo with a watery substance, and is probably an adaptation for breeding on land.
Most amphibians are found in damp environments and they occur on all continents except Antarctica.Also used to describe the process of genetic change within a population, as influenced by natural selection.adaptive landscape: A graph of the average fitness of a population in relation to the frequencies of genotypes in it.amino acid sequence: A series of amino acids, the building blocks of proteins, usually coded for by DNA.
Exceptions are those coded for by the RNA of certain viruses, such as HIV.
analogous structures: Structures in different species that look alike or perform similar functions (e.g., the wings of butterflies and the wings of birds) that have evolved convergently but do not develop from similar groups of embryological tissues, and that have not evolved from similar structures known to be shared by common ancestors. Note: The recent discovery of deep genetic homologies has brought new interest, new information, and discussion to the classical concepts of analogous and homologous structures.