| A | B |
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| Biogeochemical cycle | the cycles that move water, carbon, oxygen, and nitrogen through living and nonliving parts of the ecosystem |
| Precipitation | water that travels from the atmosphere to the ground |
| Transpiration | the evaporation of water from the leaves of plants |
| Photosynthesis | a plant process that uses energy from the sun to covert carbon dioxide into carbohydrates |
| Carbon fixation | converting inorganic carbon, as in carbon dioxide, to organic carbon, as in sugar |
| Cellular respiration | process used by all living organisms that use energy from carbohydrates and releases carbon dioxide back into the atmosphere |
| Combustion | the burning of fuels that releases carbon dioxide into the atmosphere |
| Nitrogen-fixing bacteria | a type of bacteria found living in the soil or on root nodules; convert nitrogen gas into ammonia |
| Nitrogen fixation | a process that converts nitrogen gas into ammonia |
| Nitrification | a process that converts ammonia into nitrates and nitrites |
| Decomposers | organisms, such as bacteria and fungi, that break down dead organisms and put nitrogen back into the soil |
| Denitrification | a process that converts nitrates in the soil back into atmospheric nitrogen gas |
| Ecology | the study of living organisms as they interact with their environment |
| Organism | an individual living thing; examples: a mouse, an ant, a mountain lion |
| Species | a group of similar organisms that can interbreed and produce fertile offspring |
| Population | organisms of the same species that live in the same place and at the same time |
| Community | different populations of different species that live in the same place at the same time |
| Ecosystem | a community of living organisms plus their nonliving environment |
| Biotic factors | the living organisms in an ecosystem |
| Abiotic factors | nonliving parts of an ecosystem; examples: rocks, soil, air, water |
| Biosphere | all the combined ecosystems of the world where organisms can live |
| Niche | an organism's role in its environment |
| Habitat | the place where an organism lives |
| Herbivore | an animal that eats plants |
| Predator | an animal that catches and eats another animal |
| Prey | an animal that is subject to being caught and eaten by another animal |
| Carnivore | an animal that eats only other animals |
| Omnivore | an animal that eats both plants and animals |
| Competition | the conflict between organisms when they try to use the same resources at the same time |
| Cooperation | the relationship among members of a population that helps one another; example: hunting as a pack |
| Mutualism | a symbiotic relationship in which both species benefit |
| Commensalism | a symbiotic relationship in which one species benefits and the other is neither helped nor harmed |
| Parasitism | a symbiotic relationship in which one species benefits and the other is harmed |
| Parasite | an organism that gets its nutrients by feeding on another living organism |
| Host | an organism on which a parasite feeds |
| Producer (autotroph) | organism that makes its own food usually by using energy directly from the sun |
| Consumer (heterotroph) | organism that cannot make its own food and must get energy by eating |
| Primary consumer | a consumer that eats producers (usually plants) |
| Secondary consumer | a consumer that eats a primary consumer |
| Tertiary consumer | a consumer that eats a secondary consumer |
| Decomposer (saprotroph) | organism that eats dead or decaying organisms |
| Food chain | a simple representation of how energy is passed from a producer to consumer |
| Food web | a more complex representation of how energy is passed from producers to consumers in an ecosystem |
| Trophic level | each 'step' in a food chain that represents how many times energy has been transferred from one organism to the next |
| Energy pyramid | a representation in the shape of a pyramid that shows how energy is passed from one trophic level to the next |
| Top consumer (apex predator) | animal at the top of a food chain; usually a carnivore that has no natural predators |
| Biome | a physical environment that has certain characteristic plant and animals mainly due to climate |
| Carrying capacity | the largest member of organisms that can be supported to live in an ecosystem |
| Logistic growth | natural population growth that follows an S-shaped pattern |
| Limiting factors | things that limit how many organisms can live in a population |
| Immigration | the movement of organisms into an area |
| Emmigration | the movement of organisms out of an area |
| Density dependent factors | limiting factors that depend on the number of organisms in a population; examples: available food, water, and suitable habitats |
| Density independent factors | limiting factors that do not depend on the number of organisms in a population; examples: natural disasters or human activities |
| Exponential growth | unrestricted population growth that follows a J-shaped curve |
| Biomass | the mass of living matter |
| Ecological succession | predictable changes in an ecosystem |
| Primary succession | the type of changes that occurs in an ecosystem that has no soil; occurs after a major disturbance |
| Pioneer species | the first organisms to live in an ecosystem |
| Climax community | the final community of organisms in an ecosystem once it becomes stable |
| Secondary succession | the type of change that changes that occurs in an ecosystem after a disturbance that does not remove the soil |
| Algal bloom | an excessive growth of algae due to fertilizer run-off |
| Biological magnification | the buildup of chemicals in consumers as the chemicals are passed up the food chain |
| Ozone layer | a layer in the upper atmosphere that protects the earth's surface from ultraviolet radiation coming from the sun |
| Biodiversity | the variety of life in an area |
| CFC's (chlorofluorocarbons) | chemical compounds used in aerosol cans that destroy atmospheric ozone |
| Natural resources | materials found in nature and used by humans |
| Biodegradable | describes objects that easily decompose in the environment |
| Ecologist | a scientist who studies the relationships between living organisms and their environment |
| Coevolution | the evolution of two or more interacting species that exert selective pressures on each other |
| Mimicry | a type of protective resemblance that causes an animal to look like something that its predators would rather avoid than eat |
| Predation | the capturing of prey by a predator; the predator-prey relationship |
| Protective resemblance | an adaptation of some animals that causes them to look like something else in their environment |
| Symbiosis | a community interaction that results from two species living in close physical association |
| Population density | the number of individuals living in a defined area at a given time |
| Population dispersion | the way individuals are spread out in a defined area |
| Detritus | organic matter that is broken down from dead organisms |
| Scavenger | a heterotroph that eats dead animals and plants that are often leftovers from other consumers |
| Biomass pyramid | an ecological pyramid that shows the amount of biomass in each trophic level; biomass generally decreases as trophic levels increase |
| Pyramid of Numbers | an ecological pyramid that shows the number of organisms in each trophic level; the number of organisms generally decreases as trophic levels increase |
| Global Warming | the trend of increasing average temperatures around the world attributed to an increase in greenhouse gases |
| Carbohydrates | different types of sugars made by plants, made up of monosaccharides |
| Eutrophication | the depletion of oxygen in a body of water; can occur when chemical nutrients increase and cause an overgrowth of aquatic plants and algae |
| Desertification | the process of dry but fertile land becoming less and less able to support plant and animal life usually through the use of unsustainable or irresponsible farming methods |
| Extinction | the complete death of a species |
| Migration | the movement of animals, such as birds, from one area to another, usually occurring during a change of seasons |
| Albedo | the fraction of solar radiation (energy) reflected from the earth back into outer space |
| Anthropogenic global warming (AGW) | an increase in global temperatures caused specifically by human activites |
| Climate sensitivity | the change in temperature caused by radiative forcing |
| Radiative forcing | the change in the earth's energy balance (energy coming in vs. energy going out) caused by a given variable, such as a change in greenhouse gas concentration |
| Solar irradiance | the rate of energy received from the sun |
