anatomy: (1) The structure of an organism or one of its parts. ancestral homology: Homology that evolved before the common ancestor of a set of species, and which is present in other species outside that set of species. anthropoid: A member of the group of primates made up of monkeys, apes, and humans.antibacterial: Having the ability to kill bacteria.Species adapt when succeeding generations emphasize beneficial characteristics.agnostic: A person who believes that the existence of a god or creator and the nature of the universe is unknowable.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).
amino acid sequence: A series of amino acids, the building blocks of proteins, usually coded for by DNA.
amniotes: The group of reptiles, birds, and mammals.
These all develop through an embryo that is enclosed within a membrane called an amnion.
Exceptions are those coded for by the RNA of certain viruses, such as HIV.
ammonoid: Extinct relatives of cephalopods (squid, octopi, and chambered nautiluses), these mollusks had coiled shells and are found in the fossil record of the Cretaceous period.