Ecology Vocabulary
biosphere the thin volume of Earth and its atmosphere that supports life.
community all interacting organisms living within one area.
ecology the study of interactions between organisms and the living and nonliving components of their environment.
ecosystem small unit of the biosphere that includes all of the organisms and the nonliving environment found in a particular place.
greenhouse effect the mechanism that insulates Earth from the deep freeze of space on which heat is reflected back to the earth from water vapor and carbon dioxide.
population small unit of a community that includes all the members of a species that live in one place at one time.
abiotic factor nonliving factor of an ecosystem (i.e. physical and chemical characteristics of the environment like temperature, humidity, pH value, etc.).
acclimation the adjusting of tolerance against abiotic factors.
biotic factor living components of the environment.
conformer organisms that do not regulate internal conditions (they change as their environment changes).
dormancy a state of reduced activity that allows organisms to withstand abiotic factors.
fundamental niche range of conditions a species can tolerate and the range of resources it can potentially use.
generalist species with a broad niche.
habitat that location at which a species lives.
migration moving to a more favorable habitat (defense against unfavorable abiotic factors).
niche the way of life of a species or the role it plays in the environment.
realized niche the range of resources a species actually uses.
regulator organisms that use energy to control their internal conditions.
resource energy and materials a species needs (food, energy, etc.)
specialist organisms with narrow niches.
tolerance curve a graph of performance versus values of an environmental variable.
age structure the distribution of individuals among different ages in a population (often presented as a graph).
birth rate the number of births occurring in a period of time.
death/mortality rate the number of deaths occurring in a period of time.
dispersion the spatial dispersion of individuals within a population.
life expectancy the amount of time (on average) an individual is expected to live.
population density measure how crowded a population is (expressed by the number of individuals per unit of area or volume)
survivorship curve graphs showing the likelihood of survival at different ages throughout an organisms lifetime.
carrying capacity the number of individuals an environment can support over a long period of time.
density-dependent factor limitations triggered by increasing population density (like resource limitations, etc.).
density-independent factor factors occurring regardless of the size of a population (like weather, floods, fires, etc.).
emigration the movement of individuals out of a population.
exponential growth a trend of growth symbolized by more rapid augmentation as the population grows.
exponential model describes a population that increases rapidly after only a few generations.
growth rate the amount by which a populations size changes in a given amount of time.
immigration the movement of individuals into a population.
inbreeding the act of mating with relatives.
limiting factor a factor that restrains the growth of a population.
logistic growth occurs when the birth rate equals the death rate.
logistic model like the exponential growth model, but accounts for limiting factors.
agricultural revolution the revolution that occurred when people 10,000-12,000 years ago discovered how to domesticate animals and cultivate certain plants for food.
developed
countries modern, industrialized
countries (20% of the world inhabit these nations;
developing countries poorer countries whose populations are growing faster than those in the developed nations (growth rate of >.02 per capita)
hunter-gatherer lifestyle the lifestyle by which humans lived years ago when they went around in nomadic tribes and obtained food by hunting animals and gathering natural foods.
character displacement the phenomenon of the greatest differences occurring between potential competitors where their ranges overlap.
commensalism an interaction in which one species is benefited and one is not effected.
competition results from a fundamental niche overlap.
competitive exclusion describes situations in which one species is eliminated from a community because of the competition for the same limited resource.
ectoparasite external parasites that live on their hosts but do not enter the hosts body (like ticks, fleas, lice, leeches, lampreys, mosquitoes, etc.).
endoparasite internal parasites that live inside the hosts body (like disease-causing bacteria, malaria parasites, tapeworm, etc.).
herbivore animals that eat only plants.
host the individual that parasites feed upon.
mimicry a defense in which a harmless species resembles a poisonous or distasteful species.
mutualism a cooperative relationship in which both species derive some benefit.
parasite an individual that feeds upon a host and slowly kills it.
parasitism a species interaction that resembles predation in that one organism is harmed while another benefits (kills host slowly).
pollinator animals that carry pollen (taking part in a mutualistic relationship)
predator in predation, the organism that captures, kills, and consumes another (the prey).
prey the animal that is captured, killed, and consumed by the predator in predation.
resource partitioning the act of one species only using a portion of available resources in an environment where similar species that require the same resources coexist.
secondary compound chemicals from products of an organisms metabolism that is poisonous, irritating, or bad-tasting.
symbiosis an interaction among species (predation, parasitism, competition, mutualism, commensalism).
species-area effect the relationship between species variety and space that states that larger areas usually contain more species than smaller areas do.
species diversity relates the number of species in a community to the relative abundance of each species.
species richness the number of species an area contains.
stability an indicator of a communitys resistance to change.
climax community a stable end point to a predictable series of stages as succession occurs.
pioneer species the species that predominante early in succession
primary succession development of a community in an area that has not supported life previously (like bare rock, sand dune, island formed by volcanic eruption, etc.).
secondary succession the sequential replacement of species that follows the disruption of a specific community (could stem from natural disaster or human intervention).
succession the gradual, sequential regrowth of species in an area.
biomass organic material in an ecosystem.
carnivore consumers that eat other consumers.
chemosynthesis the process of producing carbohydrates by using energy from inorganic molecules.
consumer animals that cannot manufacture their own food (heterotrophs).
decomposer a class of detrivore that cause decay by breaking down the complex molecules in dead tissues and wastes into simpler molecules.
detrivore a consumer that feeds on the garbage of an ecosystem, such as organisms that have recently died.
food chain a single pathway of feeding relationships among organisms in an ecosystem that causes energy transfer.
food web the interrelated food chains in an ecosystem that causes energy transfer.
gross primary productivity the rate at which producers in an ecosystem capture energy.
herbivore consumers that eat producers (i.e. animals that eat only plants).
net primary productivity the rate at which biomass accumulates.
omnivore consumers that eat both producers and consumers.
producer organisms that are capable of capturing energy and using it to make organic molecules for food (also called autotrophs).
trophic level the level that indicates an organisms position on the sequence of energy transfers (producers = level 1, herbivores = level 2, predators of herbivores = level 3).
ammonification the process by which decomposers break down the corpses and wastes of organisms and release the nitrogen they contain as ammonia (reintroducing nitrogen into the ecosystem).
biogeochemical cycle the cycle through which all substances travel, moving from the abiotic portion of the environment into living things and back again.
carbon cycle the cycle during which photosynthesis and cellular respiration produce ATP for energy.
dentrification occurs when anaerobic bacteria break down nitrates and release nitrogen gas back into the atmosphere.
ground water water in the soil or in underground formations of porous rock.
nitrification the oxidation of ammonia into nitrates and nitrites (following ammonification).
nitrogen cycle the complex pathway nitrogen follows within an ecosystem.
nitrogen fixation the process of converting nitrogen gas into ammonia.
nitrogen-fixing bacteria bacteria that converts nitrogen gas into ammonia, which plants can absorb to use and make proteins.
transpiration the process that occurs as plants take in water through their roots and release water and take in carbon dioxide through the stomata in their waves.
water cycle the movement of water between various reservoirs.
biome a large terrestrial ecosystem that contains a number of smaller but related ecosystems within them.
canopy a continuous layer formed by treetops in tropical rain forests that blocks sunlight from stimulating growth on the ground.
desert an area that receives an average of less than 25cm of rainfall annually.
epiphyte small plants that live on the branches of tall trees to obtain sunlight (like mosses and orchids).
permafrost a permanently frozen layer of soil under the surface of the tundra.
savanna a tropical or subtropical grassland with scattered trees and shrubs.
taiga a forested biome south of the tundra dominated by cone-bearing evergreen trees (like pines, firs, hemlock, spruce, etc.).
temperate deciduous forest forests characterized by trees that lose all their leaves in the fall.
temperate grassland lands dominated by grasses that form in the interior of continents, where rainfall amounts are too low to support tree growth.
tropical rain forest forests characterized by tall trees that have abundant rainfall and a stable, year-round growing season.
tundra
a cold and largely treeless biome that forms a continuous belt across
cause-and-effect relationship a relationship in which a change in one variable directly leads to a change in the other variable.
chlorofluorocarbons ozone-destroying chemicals that have been used as coolants in refrigerators and air conditioners and as the propellant in aerosol spray cans.
convection cell a drawing representative of the rising and falling of air.
correlation a relationship that might lead to a cause-and-effect relationship between two entities.
El Niρo a condition that occurs around Christmas in which the warm surface water cuts off the upwelling of nutrients.
environmental science the field of study in which biological principles are used to look at the relationships between humans and the Earth.
upwelling a rising current of cold water that replaces warm water in the ocean to bring organic material and nutrients that support an abundance of plankton.
biodiversity refers to the variety of organisms in a given area.
debt-for-nature swamp a system in which richer countries or private conservation organizations pay off some of the debts of a developing country.
ecotourism an idea where people pay for nature guides, food, and lodging.
evenness the amounts of individual organisms that belong to each species.
genetic diversity the amount of genetic variation.
nonutilitarian value the belief that some life forms have value because they exist, not necessarily as a result from any benefit to humans.
utilitarian value the belief that some life forms have value because of their benefits to humans.
conservation biology a discipline that seeks to identify and maintain natural areas.
flyway routes that migratory birds follow (usually along rivers, mountains, coastlines, etc.).
migratory
bird a bird that travels twice
yearly from
restoration biology a discipline that seeks to repair human wrongdoings environmentally (i.e. drainage of wetlands, mining, etc.).
urban ecology a new environmental field that involves people who are interested in the challenge of increasing biodiversity in the most heavily developed areas.