Ecosystems
Community of living organisms and its environment
Ecosystem
Plants and other food making organisms at the base of the food chain
Primary producers
Plants that grow under the trees of a forest
Undergrowth
Rays of light that have not been blocked or scattered
Direct sunlight
Large region of the biosphere where certain plants and animals thrive
Biome
Close relationship between two organisms
Symbiosis
Transfer of energy from one living thing to another for survival
Food chain
Water biome
Refers to a species that can no longer be found alive on the earth
Extinct
Land biome
Terrestrial
Elevation at which trees do not grow
Tree line
Study of ecosystems
Ecology
Organism that breaks down detritus so that nutrients can be returned to the soil
Decomposer
Top forest layer formed when trees grow closely together
Closed canopy
Rays of scattered or reflected light
Indirect sunlight
Nonliving influence in an ecosystem
Abiotic factor
Relationship in which two organisms struggle against one another for the same limited resources
Competition
Model that combines food chains to show all possible relationships at each food-chain level
Food web
Biome with large, grassy plains
Grassland biome
Permanently frozen subsoil
Permafrost
Part of the grassland biome located in tropical climate zones; savanna
Tropical grassland
Time of inactivity
Dormancy
All organisms of one species in an ecosystem
Population
Top-level consumer
Apex predator
Top forest layer formed when trees are spaced apart from one another
Open canopy
Energy from the sun; provides thermal energy and light energy
Solar radiation
Living influence in an ecosystem
Biotic factor
Symbiotic relationship in which both organisms benefit
Mutualism
Part of the tundra biome located on mountains above the tree line
Alpine tundra
Cold biome that is treeless because of permafrost or elevation
Tundra biome
Animal that feeds on trees and shrubs
Browser
Part of the tundra biome located in high latitudes of the Northern Hemisphere
Arctic tundra
Harvesting all the trees from a designated area at once
Clear-cutting
Living organisms of an ecosystem
Community
Animals that eat plants directly; herbivores
Primary consumers
Northern forest biome dominated by coniferous trees, having long, harsh, snowy winters; also called taiga
Boreal forest biome
Ideal range of abiotic factors in which an organism can flourish
Optimum range
Situation in which two factors rely on one another
Interdependence
Relationship in which one organism hunts, kills, and eats another organism
Predation
System or object that absorbs carbon dioxide from the environment
Carbon sink
Part of the grassland biome located in temperate climate zones; prairies, pampas, steppes, velds
Temperate grassland
Conservationist technique in which a controlled fire is set to encourage plant health
Prescribed burning
Hot and humid biome that receives plenty of precipitation, having great biodiversity; located at tropical grasslands
Tropical rainforest biome
Practice in which the harvest of trees is balanced with conservation
Sustainable forestry
Number and variety of species living within an ecosystem
Biodiversity
Animals that eat herbivores; either carnivores or omnivores
Secondary consumers
Deciduous forest biome with cold winters and hot summers
Temperate deciduous forest biome
Range of abiotic factors in which an organism can survive
Tolerance range
Niche
Negative symbiotic relationship in which one organism is harmed
Parasitism
Dead or decaying plant and animal matter
Detritus
Desert with dry summers and cold winters with rain or snow
Semi-arid desert
Process in which an ecosystem changes or recovers over time
Ecological succession
Dry biome with little or no precipitation; receives less than ten inches of rain per year
Desert biome
Arid land on one side of a mountain where moist air cannot reach
Rain shadow