| A | B |
|---|
| Generation | one complete life cycle, one of the alternate phases that complete a life cycle having more than one phase |
| Environment | the air, water, minerals, organisms, and all other external factors surrounding and affecting a given organism at any time |
| Traits | genetically determined characteristic or condition |
| Inheritable | capable of being inherited |
| Vestigial structure | Occurring or persisting as a rudimentary or degenerate structure |
| Adaptation | any alteration in the structure or function of an organism or any of its parts that results from natural selection and by which the organism becomes better fitted to survive and multiply in its environment |
| Evolution | change in the gene pool of a population from generation to generation by such processes as mutation, natural selection, and genetic drift |
| Fossil record | term used by paleontologists to refer to the total number of fossils that have been discovered, as well as to the information derived from them |
| Gene pool | the total genetic information in the gametes of all the individuals in a population |
| Homologous structure | having the same or a similar relation; corresponding, as in relative position or structure |
| Natural selection | the process by which forms of life having traits that better enable them to adapt to specific environmental pressures, as predators, changes in climate, or competition for food or mates, will tend to survive and reproduce in greater numbers than others of their kind, thus ensuring the perpetuation of those favorable traits in succeeding generations |
| Punctuated equilibrium | a hypothesis holding that the evolution of species proceeds in a characteristic pattern of relative stability for long periods of time interspersed with much shorter periods during which many species become extinct and new species emerge |
| Variation | a difference or deviation in structure or character from others of the same species or group |
| Origin | something from which anything arises or is derived |
