| A | B |
|---|
| autotrophs | use sun for energy |
| producer | can produce food |
| photosynthesis | use light energy to power chemical reaction |
| chemosynthesis | use chemical energy to produce carbohydrates |
| heterotrophs | obtains energy from the foods it consumes |
| consumer | relies on other organisms for its energy and food supply |
| herbivore | obtains energy by eating only plants |
| omnivore | obtains energy by eating both plants and animals |
| detritivore | feeds on plant and animal remains and other dead matter |
| decomposer | breaks down and obtains energy from dead organic matter |
| food chain | series of steps in an ecosystem in which organisms transfer energy by eating and being eaten |
| food web | network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem |
| trophic level | step in a food chain or food web |
| ecological pyramid | diagram that shows the relative amounts of energy |
| biomass | total amount of living tissue within a given trophic level |
| evaporation | process by which water changes from a liquid into an atmospheric gas |
| transpiration | water leaves plant |
| nutrient | chemical substance that an organism requires to live |
| nitrogen fixation | process of converting nitrogen gas into ammonia |
| primary productivity | rate at which organic matter is created by producers in an ecosystem |
| limiting nutrient | single nutrient that either is scarce or cycles very slowly, limiting the growth of organisms in an ecosystem |
| algal bloom | an immediate increase in the amount algae and other producers that results from a large input of a limiting nutrient |
| biotic factors | biological in fluence on organisms within an ecosystem |
| abiotic factors | physical, or nonliving, factor that shapes an ecosystem |
| niche | the full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions. |
| resource | any necessity of life, such as water, nutrients, light, food, or space |
| predation | interaction in which one organism captures and feeds on another organism |
| symbiosis | relationship in which two species live closely together |
| mutualism | symbiotic relationship in which both species benefit from the relationship |
| commensalisms | symbiotic relationship in which one member of the association benefits andthe other is neither helped nor harmed |
| parasitism | symbiotic relationship in which one organism lives in or on another organism and harms it |
| primary succession | succession that occurs on surfaces where no soil exists |
| pioneer species | first species to populate an area during primary succession |
| secondary succession | succession following a disturbance that destroys a community without destroying the soil |
| population density | number of individual per unit of area |
| immigration | movement of individuals into an area occupied by an existing population |
| emigration | movement of individuals out of a population |
| carrying capacity | largest number of individuals of a population that a given environment can support |
| limiting factor | factor that causes the growth of a population to decrease |
| subsistence hunting | hunting only to acquire basic necessities for survival |
| green revolution | introduction of intensive farming practices that lead to a substantial increase in crop yield |
| nonrenewable resource | one that cannot be replensihed by natural process |
| renewable resource | can regenerate and are therefore replaceable |
| sustainable use | way of using natural resources at a rate that does not deplete it |
| soil erosion | wearing away of surface soil by water and wind |
| desertification | parts of the world were a with dry clumate a combination of farming, overgrazing, and drought has turned productive areas into deserts |
| deforestation | loss of forests |
| aquaculture | farming of aquatic ecosystems |
| smog | mixture of checmicals that occurs as a gray brown haze in the atmosphere |
| pollutant | harmful material that can enter the bioshphere throught the land, air, or water |
| acid rain | gases that combine with water vapor in the air, they form drops of nitric acid and sulferic acid |
