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Ecosystem Unit Vocabulary
Ecosystem - a community of organisms and their abiotic environment (93)
Organism - a living thing; anything that can carry out life processes independently
Species - a group of organisms that are closely related and can mate to produce fertile offspring
and would do so under natural conditions.
Population - a group of organisms of the same species that live in a specific geographical area
and interbreed.
Community - a group of populations of various species that live in the same habitat and
interact with each other
Habitat - the place where an organism usually lives, must have food, water, shelter and space.
Niche - the unique position occupied by a species, both in terms of its physical use of its habitat
and its function within an ecological community. Like a species’ role or job in the ecosystem.
Commensalism - a relationship between two organisms in which one organism benefits and
the other is unaffected
Competition - the relationship between two species (or individuals) in which both species (or
individuals) attempt to use the same limited resource such that both are negatively affected by
the relationship
Parasitism - a relationship between two species in which one species, the parasite, benefits
from the other species, the host, and usually harms the host
Predation - an interaction between two species in which one species, the predator, feeds on the
other species, the prey
Mutualism - a relationship between two species in which both species benefit
Symbiotic Relationship - a relationship in which two different organisms live in close
association with each other
Photosynthesis - the process by which plants, algae, and some bacteria use sunlight, carbon
dioxide, and water to produce carbohydrates and oxygen.
Producer - an organism that can make organic molecules from inorganic molecules; a
photosynthetic or chemosynthetic autotroph that serves as the basic food source in an ecosystem
Consumer - an organism that eats other organisms or organic matter instead of producing its
own nutrients or obtaining nutrients from inorganic sources
Cellular Respiration - the process by which cells produce energy from carbohydrates;
atmospheric oxygen combines with glucose to form water and carbon dioxide
Heterotrph -living organism that obtains its energy from carbohydrates and other
organic material. All animals and most bacteria and fungi are heterotrophic.
Autotroph- Organisms that are able to make their own food (in the form of sugars) by
using the energy of the Sun are called autotrophs, meaning "self-feeders”
Trophic Level - one of the steps in a food chain or food pyramid; examples include producers
and primary, secondary, and tertiary consumers
biomagnifications - the accumulation of pollutants at successive levels of the food chain
Herbivore – An Animal that primarily eats plants.
Carnivore – An animal that eats primarily meat (other animals).
Omnivore – An animal that eats both plant and animal matter.
Decomposer - an organism that feeds by breaking down organic matter from dead organisms;
examples include bacteria and fungi
Nitrogen-Fixing Bacteria - bacteria that convert atmospheric nitrogen into ammonia
Ammonia (NH4) – an important source of nitrogen for living systems. Although
Nitrogen gas (N2) is abundant in the atmosphere, few living creatures are capable of
utilizing this nitrogen. Nitrogen is required for the synthesis of amino acids, which are the
building blocks of protein. Most plants rely on ammonia and other nitrogenous wastes
incorporated into the soil by decaying matter.
Ecological Succession - a gradual process of change and replacement in a community
Primary Succession - succession that begins in an area that previously did not support life
Secondary Succession - the process by which one community replaces another community
that has been partially or totally destroyed.
Pioneer Species - a species that colonizes an uninhabited area and that starts an ecological
cycle in which many other species become established
Climax Community - a final, stable community in equilibrium with the environment