| A | B |
|---|
| Species | a group of similar organisms that can breed and produce fertile offspring |
| Population | a group of individuals that belong to the same species and live in the same area |
| Ecosystem | a biological community of interacting organisms and their physical environment |
| Biotic Factors | all the living organisms that inhabit an environment |
| Abiotic Factors | nonliving components of environment |
| Atmosphere | all the gases that surround Earth |
| Hydrosphere | all Earth's fresh water and salt water, including water vapor and rain in the atmosphere and water underground |
| Geosphere | the mostly solid, rocky part of the Earth; extends from the center of the core to the surface of the crust |
| Autotroph | organisms that can capture energy from nonliving sources and convert it into forms living cells can use |
| Primary Producer | first producer of energy-rich compounds that are later used by other organisms |
| Heterotroph | organism that obtains energy from the foods it consumes; also called a consumer |
| Consumer | an organism that obtains energy by feeding on other organisms |
| Decomposers | oreganisms that break down wastes and dead organisms and return raw materials to the environment |
| Food Chain | a series of steps 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 | each step in a food chain or food web |
| Energy Pyramid | diagram that shows the relative amounts of energy or matter within each trophic level in a food chain or food web |
| Biomass | total amount of living tissue within a given trophic level |
| Carrying Capacity | largest number of individuals of a population that an environment can support |
| Limiting Factor | an environmental factor that prevents a population from increasing |
| Niche | full range of physical and biological conditions in which an organism lives and hte way in which the organism uses those conditions |
| Predator-Prey Relationship | when one organism feeds on another organism |
| Herbivore-Plant Relationship | animal feeds on plants |
| Keystone Species | a species that influences the survival of many other species in an ecosystem |
| Symbiosis | a relationship in which two different organisms live in close association with each other |
| Mutualism | a relationship between two species in which both species benefit |
| Parasitism | a relationship in which one organism lives on or in a host and harms it |
| Commensalism | a relationship between two organisms of different species where one benefits and the other in neither harmed nor benefited |
| Biosphere | the parts of the Earth where life exists |
| 10% Rule | only 10% or the total energy produced at each trophic level is available to the next level. The amount of energy passed up to the levels of the food pyramid reduces as you go up |
| Biodiversity | the number of different species in an area |
| Conservation | protecting and preserving natural resources and the environment |
| Habitat | place where an organism lives |
| Human Activity | mining, burning fossil fuels, burning forest, and cutting trees |
| Invasive Species | species that enter new ecosystems and multiply, harming native species and their habitats |
