| A | B |
|---|
| stimulus | a thing or event that causes a response |
| phototropism | growth that happens in organisms in response to light |
| hydrotropism | growth that happens in organisms in response to water |
| geotropism | a growth that happens in organisms in response to gravity |
| hibernation | deep sleep where animals slow down to save energy |
| internal stimulus | a change within the organism that causes the organism to respond |
| transpiration | the emission of water vapor from the leaves of plants |
| homeostasis | the body's ability to keep the internal balance of the body stable |
| migration | movement to other stable environments |
| turgor pressure | pressure exerted by water inside the cell on the cell wall |
| external stimulus | a change in the environment outside the organism that causes a response |
| motion | the change in the position of an object |
| flora | one of world's major communities classified according to predominant vegatation |
| geology | study of the origin of Earth's structures |
| adaptation | the process of change by which an organism becomes better suited to its environment |
| limiting factor | a factor that limits the ability of a habitat to sustain a population |
| microhabitat | very small specialized habitat |
| population | group of individuals belonging to the same species that leave in the same region at the same time |
| pioneer species | first to occur in an environment such as a lava flow |
| ecology | the study of how organisms interact with their environment |
| ecosystem | system consisting of all interactions between biotic and abiotic factors within an environment |
| biodiversity | the number of different species of plants and animals in an area |
| species | a group of living organisms capable of exchanging genes or interbreeding |
| niche | position of a species within an ecological community |
| interaction | the effects that an organism in a community has on another |
| habitat | where an organism naturally lives and grows |
