| A | B |
|---|
| organism | a single, living thing |
| habitat | the environment that provides the things living organisms need to live, grow and reproduce |
| biotic | living parts of an ecosystem |
| abiotic | nonliving parts of an ecosystem |
| photosynthesis | process by which plants use sunlight, water and carbon dioxide to create their own food |
| species | a group of organisms that are physically similar and that can mate and produce offspring |
| population | all the species in a particular area |
| community | all the different populations in an area |
| ecosystem | the community of organisms along with the nonliving surroundings |
| birth rate | the number of births in a population over a given amount of time |
| death rate | the number of deaths in a population over a given amount of time |
| immigration | moving into a population |
| emigration | moving out of a population |
| limiting factor | an environmental factor that causes a population to stop growing (can include water, space, light, soil composition, food and weather conditions |
| carrying capacity | the largest population an area can support |
| producer | an organism that can make its own food |
| consumer | an organism that obtains its energy by feeding on other organisms |
| herbivore | consumers that eat only plants |
| omnivore | consumers that eat both plants and animals |
| carnivore | consumers that eat only animals |
| scavenger | carnivores that feed of the bodies of dead animals |
| decomposers | organisms that break down wastes and dead organisms and return raw materials to the ecosystem |
| food chain | a series of events where one organism eats another to obtain energy |
| food webs | many overlapping food chains |
| energy pyramid | shows the amount of energy that moves from one feeding level to the another in a food web |
| natural selection | the process where characteristics that make organisms more suited to their environment become common in that organism |
| adaptations | behaviors and physical characteristics that allow organisms to live successfully in their environments. |
| niche | the role of an organism, or how it makes its living |
| competition | the struggle between organisms to survive as they use the same limited resource |
| predation | when one organism kills another for food |
| predator | the killing organism |
| prey | the organism that is killed for food |
| symbiosis | a close relationship between two organisms that benefits at least one organism |
| mutualism | relationship in which both species benefit |
| commensalism | relationship in which one organism benefits and the other is neither helped or harmed |
| parasitism | relationship in which one organism benefits and the other organism is harmed |
| host | the organism on which the parasite lives |
| carbon/oxygen cycle | processes by which carbon and oxygen are recycled and linked |
| nitrogen cycle | the process by which nitrogen moves from the air to the soil, into living things, and back into the air |
| water cycle | the process by which water is continually recycled through evaporation, condensation and precipitation |
| nitrogen fixation | changing free nitrogen into a usable form of nitrogen |
| succession | a series of predictable changes that occur in a community over time |
| primary succession | changes that occur in an area where no soil or other organisms exist |
| pioneer species | the first species to populate an area |
| secondary succession | changes that occur in an area over time where some soil and organisms still exist |
