Photosynthesis
the process by which primary producers use sunlight to convert carbon dioxide and water into sugars, releasing oxygen
Chemosynthesis
the process by which bacteria use energy stored in bonds of hydrogen sulfide to convert carbon dioxide and water into sugars
Consumer
an organism that relies on other organisms for energy and nutrients; also called heterotroph
Herbivore
an organism that eats plants
Carnivore
an animal that kills and eats other animals,
Omnivore
an animal that eats both plants and animals
Detritivore
an organism that scavenges the waste products or dead bodies of other community members
Decomposer
an organism (e.g., a fungus or bacterium) that breaks down nonliving matter into simple parts that can then be taken up and reused by primary producers
Trophic level
a rank in a feeding hierarchy
Biomass
the total amount of living tissue in a trophic level,
Food chain
a linear series of feeding relationships
Food web
diagram of feeding relationships and energy flow showing the paths by which nutrients and energy pass from organism to organism as one consumes another,
Keystone species
a species that has a strong or wide-ranging impact on a community
Primary succession
the somewhat predictable series of changes in a community that follows a disturbance so severe that no vegetation or soil life remains
Pioneer species
one of the first species to colonize newly exposed land
Secondary succession
the somewhat predictable series of changes in a community that follows a disturbance
Invasive species
a nonnative species that spreads widely in a community
primary producers
An autotroph, usually a photosynthetic organism. Collectively, autotrophs make up the trophic level of an ecosystem that ultimately supports all other levels.
lichen
symbiotic association between a fungus and a photosynthetic organism