| A | B |
|---|
| ecology | the scientific study of interactions among organisms and between organisms and their environment or surroundings. |
| biosphere | contains the combined portions of the planet in which all of life exists, including land, water, and air or atmosphere. |
| species | a group of organisms so similar to one another that they can breed and produce fertile offspring. |
| population | groups of individuals that belong to the same species and live in the same area. |
| community | assemblages of different populations that live together in a defined area. |
| ecosystem | a collection of all the organisms that live in a particular place, together with their nonliving, or physical environment. |
| biome | a group of ecosystems that have the same climate and similar dominant communities. |
| autotroph | organisms that can capture energy from sunlight or chemicals and use that energy to produce food. |
| producer | organisms that make their own food. |
| photosynthesis | the process by which plants and some other organisms use light energy to power chemical reactions that convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches. |
| chemosynthesis | a process by which some organisms use chemical energy to produce carbohydrates. |
| heterotroph | an organism that obtains energy from the foods it consumes; also called a consumer. |
| consumer | an organism that relies on other organisms for its energy and food supply. |
| herbivore | an organism that obtains energy from eating only plants. |
| carnivore | an organism that obtains energy from eating only animals. |
| omnivore | an organism that obtains energy from eating both plants and animals. |
| detritivore | an organism that feeds on plant and animal remains and other dead matter. |
| decomposer | an organism that breaks down and obtains energy from dead organic matter. |
| food chain | a series of steps in an ecosystem in which organisms transfer energy by eating and being eaten. |
| food web | a network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem. |
| trophic level | a step in a food chain or food web. |
| ecological pyramid | a diagram that shows the relative amounts of energy or matter within each trophic level in a food chain or food web. |
| biomass | the total amount of living tissue within a given trophic level. |
| biogeochemical cycle | a process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another. |
| evaporation | the process by which water changes from a liquid to an atmospheric gas. |
| transpiration | the loss of water from a plant through its leaves. |
| nutrient | a chemical substance that an organism requires to live. |
| nitrogen fixation | the process of converting nitrogen gas into ammonia. |
| denitrification | the conversion of nitrates into nitrogen gas. |
| primary productivity | the rate at which organic matter is created by producers in an ecosystem. |
| limiting nutrient | a single nutrient that either is scarce or cycles very slowly, limiting the growth of a population in an ecosystem. |
| algal bloom | an immediate increase in the amount of algae and other producers that results from a large input of a limiting nutrient. |
