ecology
The study of the interactions between organisms and the living and nonliving components of their environment.
interdependence
All organisms interact with other organisms in their surroundings and with the nonliving portion of their environment. Ecologists refer to this quality as....
ecological models
a model that represents or describes the relationships between the components of an ecological system
biosphere
the part of Earth where life exists
ecosystem
a community of organisms and their abiotic environment
community
a group of various species that live in the same habitat and interact with each other
population
a group of organisms of the same species that live in a specific geographical area and routinely interbreed.
habitat
the place where an organism usually lives
biotic factor
an environmental factor that is associated with or results from the activities of living organisms
abiotic factor
an environmental factor that is not associated with the activities of living organisms
tolerance curve
a graph of the performance of an organism versus the value of an environmental variable
acclimation
an organism's change in response to a change in the organism's environment
conformers
organisms that do not regulate their internal conditions; they change as their external environment changes
regulators
organisms that use energy to control some of their internal conditions.
dormancy
a state of reduced activity
migration
moving to a more favorable habitat
niche
the specific role, or way of life, of a species within its environment
generalists
species with broad niches
specialists
species that have narrow niches
producer
autotrophs, organisms that manufacture their own food.
chemosynthesis
use of energy stored in inorganic molecules to produce carbohydrates.
gross primary productivity
the rate at which producers in an ecosystem capture the energy of sunlight by producing organic compounds
biomass
organic material that has been produced in an ecosystem
net primary productivity
the measure of the rate at which biomass accumulates
consumer
heterotrophs, organisms that get energy by eating other organisms or organic wastes
herbivores
organisms that eat producers
carnivores
organisms that eat other consumers
omnivores
organisms that eat both producers and consumers
detritivores
consumers that feed on 'garbage' fo the ecosystem. This waste, or detritus, includes organisms that have recently died, fallen leaves, and animal wastes.
decomposers
many bacteria and fungi that are detritivores that cause decay by breaking down complex molecules into simpler molecules
trophic level
the organism's position in a sequence of energy transfers
food web
interrelated food chains in an ecosystem
biogeochemical cycles
the circulation of substances through living organisms from or to the environment
groundwater
water in the soil or in underground formations of porous rock
water cycle
movement of water between various reservoirs - includes evaporation, transpiration, and precipitation.
transpiration
the process by which water evaporates from the leaves of plants in terrestrial ecosystems.
carbon cycle
the movement of carbon from the nonliving environment into living things and back
nitrogen cycle
the process in which nitrogen circulates among the air, soil, water, plants, and animals in an ecosystem.
nitrogen fixation
the process of converting nitrogen gas to nitrate.
nitrogen-fixing bacteria
organisms that transform nitrogen gas into a usable form, usually bacteria living in the soil inside swellings on the roots of some kinds of plants.
ammonification
process of decomposers breaking down materials such as urine and dung and release the nitrogen they contain as ammonia.
nitrification
soil bacteria take up ammonium and oxidize it into nitrites
denitrification
nitrogen is returned to the atmosphere.
phosphorus cycle
the movement of phosphorus from the environment to organisms and then back to the environment.