| A | B |
|---|
| Natural Selection | Process by which individuals that are better adapted to the environment are more likely to survive and reproduce than others. |
| Adaptation | The behaviors and physical characteristics of species that allow them to live successfully in their environment |
| Niche | An organism's particular role in an ecosystem, or how it makes a living |
| Competition | The struggle between organisms for the limited resources in a habitat |
| Predation | An interaction in which one organism kills and eats another |
| Predator | The organism that does the killing in predation |
| Prey | An organism killed in predation |
| Symbiosis | A close relationship between species that benefits at least one of the species |
| Mutualism | A relationship between two species in which both species benefit |
| Commensalism | A relationship between two species in which one species benefits and the other is neither helped or harmed |
| Parasitism | A relationship in which one organism lives on, or inside another and harms it |
| Parasite | The organism that benefits by living on or in a host in parasitism |
| Host | The organism that a parasite lives in or on in parasitism |
| Sampling | Counting the number of organisms in a small area to estimate the population in a larger area |
| Mark and Recapture | A procedure that involves marking and recapturing organisms to estimate population size |
| Direct observation | Counting all the members of a population |
| Indirect observation | Looking for signs of the organisms to make population estimates |
| Saprophyte | Organism that feeds on dead or decaying tissues of other organisms |
| Pathogen | An organism that can cause disease |
| Biodiversity | The number of different species in an area |
