Comp 3 Vocabulary Defined
**Remember one number is repeated on your sheet so I numbered it just like it is on
your sheet so no one would get confused.
** The first quiz will cover through #30 on this sheet—DENITRIFICATION
1. Ecology: the study of the interactions between organisms and the other living
and nonliving components of their environment
2. Interdependence: the dependence of every organism on its connections with
other living and nonliving parts of its environment
3. Biosphere: the part of Earth where life exists; includes all of the living
organisms on Earth
4. Ecosystem: a community of organisms and their abiotic environment
5. Community: a group of various species that live in the same habitat and interact
with each other
6. Population: a group of organisms of the same species that live in a specific
geographical area and interbreed
7. Habitat: the place where an organism usually lives
8. Biotic factor: an environmental factor that is associated with or results from the
activities of living organisms
9. Abiotic Factor: an environmental factor that is not associated with the activities
of living organisms
10. Niche: the unique position occupied by a species, both in terms of its physical
use
11. Producer: an organism that can make organic molecules from inorganic
molecules
12. Chemosynthesis: the production of carbohydrates through the use of energy
from inorganic molecules instead of light
15. Biomass: any organic material that has been produced in an ecosystem
13. Consumer: an organism that eats other organisms or organic matter instead of
producing its own nutrients or obtaining nutrients from inorganic sources
14. Herbivore: an organism that eats only plants
15. Carnivore: an organism that eats only animals
16. Omnivore: an organism that eats a variety of other organisms, including
animals and plants
17. Detritivore: a consumer that feeds on dead organisms or on the parts or
wastes of other organisms
18. Decomposer: an organism that feeds by breaking down organic matter from
dead organisms; includes bacteria and fungi
19. Trophic level: an organism’s relative position in a sequence of energy
transfers in a food chain or food pyramid
20. Food chain: the pathway of energy transfer through various stages as a result
of the feeding patterns of a series of organisms
21. Food web: a diagram that shows the feeding relationships among organisms in
an ecosystem
22. Biogeochemical cycle: the circulation of substances through living organisms
from or to the environment
23. Water cycle: the continuous movement of water between the atmosphere, the
land, and the oceans
24. Transpiration: the process by which plants release water vapor into the air
through stomata
25. Carbon cycle: the movement of carbon from the nonliving environment into
living things and back
26. Nitrogen cycle: the process in which nitrogen circulates among the air, soil,
water, plants, and animals in an ecosystem
27. Nitrogen fixation: the process by which gaseous nitrogen is converted into
nitrates, compounds that organisms can use to make amino acids and other
nitrogen-containing organic molecules
28. Ammonification: the formation of ammonia compounds in the soil by the
action of bacteria on decaying matter
29. Nitrification: the process by which nitrites and nitrates are produced by
bacteria in the soil
30. Denitrification: the liberation of nitrogen from nitrogen-containing
compounds by bacteria in the soil
31. Immigration: the movement of an individual or group into an area
32. Emigration: the movement of an individual or group out of an area
33. Exponential model: a model of population growth in which a constant and
unlimited growth rate results in geometric increases in population size
34. Limiting factor: an environmental factor that prevents an organism or
population from reaching its full potential of distribution or activity
35. Logistic model: a model of population growth that assumes that finite
resource levels limit population growth
36. Carrying capacity: the largest population that an environment can support at
any given time
37. Density-independent factor: a variable that affects a population regardless of
the population density, such as climate
38. Density-dependent factor: a variable affected by the number of organisms
present in a given area
39. Predation: a relationship between two species in which one species, the
predator, feeds on the other species, the prey
40. Interspecific competition: a relationship between two species in which both
species compete for limited resources such that both species are negatively affected
by the relationship
41. Symbiosis: a relationship in which two different organisms live in close
association with each other
42. Parasitism: a relationship between two species in which one species, the
parasite, benefits from the other species, the host, which is harmed
43. Mutualism: a relationship between two species in which both species benefit
44. Commensalism: a relationship between two organisms in which one organism
benefits and the other is unaffected
45. Primary succession: succession that begins in an area that previously did not
support life
46. Secondary succession: the process by which one community replaces another
community that has been partially or totally destroyed
47. Pioneer species: a species that colonizes an uninhabited area and that starts
an ecological cycle in which many other species become established
48. Climax community: a community that, after a process of ecological succession
has reached a generally stable state
49. Biome: a large region characterized by a specific type of climate and certain
types of plant and animal communities
50. Permafrost: in arctic regions, the permanently frozen layer of soil or subsoil
51. Epiphyte: a plant that uses another plant for support but not nourishment
52. Coniferous tree: a tree belonging to a group of tree species that bear their
seeds in cones and tend to be evergreen
53. Deciduous tree: a tree that sheds and regrows its leaves in response to
seasonal changes
54. Estuary: an area where fresh water from rivers mixes with salt water from the
ocean; the part of a river where the tides meet the river current
55. Ozone layer: the layer of the atmosphere at an altitude of 15 to 40 km in which
ozone absorbs ultraviolet solar radiation
56. Greenhouse effect: the warming of the surface and lower atmosphere of Earth
that occurs when carbon dioxide, water vapor and other gases in the air absorb and
reradiate infrared radiation
57. Biodiversity: the variety of organisms considered at all levels, from
populations to ecosystems
58. Chlorofluorocarbon: a type of hydrocarbon in which some or all of the
hydrogen atoms are replaced by chlorine and fluorine
59. Biological magnification: the accumulation of increasingly large amounts of
toxic substances within each successive link of the food chain
60. Acid precipitation: precipitation, such as rain, sleet, or snow, that contains a
high concentration of acids, often because of the pollution of the atmosphere