| Flap 1 | Flap 2 |
| neuron | a nerve cell that is specialized to receive and conduct electrical impulses |
| emigration | the moving of an individual or group out of an area |
| omnivore | eats plants and animals |
| gestation | in mammals, the process of carrying young from fertilization to birth |
| oncogene | a gene that induces cancer, or uncontrolled cell proliferation |
| succession | a series of stages a community goes through before it reaches its most stable stage |
| biosphere | the part of the earth where life exists; includes all of the living organisms on earth |
| community | a group of various species that live in the same habitat and interact with each other |
| population | a group of organisms of the same species that live in a specific geographical area and interbreed |
| permafrost | in arcitc regions, the permanently frozen layer of soil or subsoil |
| acclimation | an organism's change in response to a change in the organisms environment |
| ecosystem | a community of organisms and their abiotic environment |
| appendages | a structure that extends from the main body, such as a limb, tentacle, fin, or wing |
| fermentation | the breakdown of carbohydrates by enzymes, bacteria, yeasts, or mold in the absence of oxygen |
| prehensile | can grasp objects, as in primate's hand, foots, or tail |
| trophic level | an organism's relative position in a sequence of energy transfers in a feed chain or food pyramid |
| leucocyte | a white blood cell |
| phylogeny | the evolutionary history of a species or taxonomic group; the relationships by ancestry among taxonomic groups |
| viviparous | an organism whose offspring develop within the mother's body and are born alive |
| opposable thumb | in primates, a thumb that can touch and move in opposition to the other fingers of the hand |
