| A | B |
|---|
| Ecology | Scientific study of interactions among organisms and their environments |
| abiotic factors | nonliving parts of organisms environment (air currents, temperature, light, soil, etc.) |
| biotic factors | all living organisms that inhabit an environment |
| species | group of organisms so similar to one another that they can breed and produce fertile offspring |
| populations | group of organisms that belong to same species and live in the same area |
| communities | group of different populations that live together in a defined area |
| ecosystem | collection of all the organisms that live in a particular place, together with nonliving, or physical, environment |
| biomes | geographical region containing several ecosystems that have same climate and dominant communities (climax community) |
| biosphere | portion of planet where life exists |
| producers | organisms that make their own food |
| autotrophs | organisms that use energy from the environment to manufacture their own nutrients |
| photosynthesis | process of using light energy to convert carbon dioxide and water into oxygen and energy-rich carbohydrates |
| chemosynthesis | use chemical energy to produce carbohydrates |
| consumers | organisms that acquire energy from another organism |
| heterotroph | organisms that rely on other organisms for their energy and food supply |
| herbivore | obtain energy by eating only plants |
| carnivore | organisms that eat other animals |
| omnivores | organisms that eat both plants and animals |
| decomposers | organisms that break down organic matter for energy |
| food chain | series of steps in which organisms transfer energy by eating and being eaten |
| food web | network of complex interactions that links all the food chains in an ecosystem together |
| trophic level | each step in food chain or web |
| ecological pyramid | used to represent amount of energy or matter in each trophic level in a food chain or web |
| biogeochemical cycles | process by which elements, chemical compounds, and other forms of matter are passed (cycled) from one organism to another and from one part of the biosphere to another |
| limiting nutrient | when ecosystem is limited by single nutrient that is scarce or cycles very slowly |
| bloom | when aquatic ecosystems receive large input of limiting nutrient can cause rapid growth of producers |
| niche | all conditions (biological and physical) in which organism live and the way organism uses those conditions |
| predation | interaction when one organism captures and feeds on another |
| symbiosis | relationship in which two species live closely together |
| ecological succession | the gradual change in living communities that follows disturbance |
| plankton | general term for tiny, free-floating, weakly swimming organisms |
| photic zone | well-lt upper layer where photosynthesis takes place in aquatic ecosystems |
| aphotic zone | permanently dark area below photic zone |
| exponential growth | under ideal conditions with unlimited resources population will grow exponentially (j-shaped curve) |
| logistic growth | as resources are used up, population growth slows or stops after period of exponential growth (s-shaped curve) |
| density-dependant factors | limiting factor that depends on population size |
| density-independant factors | allect all populations regardless of population size |
| demography | study of growth rates, density, age structure to predict how its size will change |
| demographic transition | tendency of population to shift from high birth and death rates to low birth and death rates |
| global warming | increased amount of carbon dioxide and other greenhouse gases have caused Earth's temperature to rise. |
