The term can also be applied to larger groups of organisms, as in "the adaptive radiation of mammals." adaptive strategies: A mode of coping with competition or environmental conditions on an evolutionary time scale.Species adapt when succeeding generations emphasize beneficial characteristics.

acquired trait: A phenotypic characteristic, acquired during growth and development, that is not genetically based and therefore cannot be passed on to the next generation (for example, the large muscles of a weightlifter).

adaptation: Any heritable characteristic of an organism that improves its ability to survive and reproduce in its environment.

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.

antibacterial: Having the ability to kill bacteria.

antibiotics: Substances that destroy or inhibit the growth of microorganisms, particularly disease-causing bacteria.In a diploid cell there are usually two alleles of any one gene (one from each parent).Within a population there may be many different alleles of a gene; each has a unique nucleotide sequence.allometry: The relation between the size of an organism and the size of any of its parts.For example, an allometric relation exists between brain size and body size, such that (in this case) animals with bigger bodies tend to have bigger brains.They have moist scaleless skin which is used to supplement the lungs in gas exchange.