APES Vocabulary Chapter 3 House

Intrinsic Value

Value of an organism, species, ecosystem, or the earth's biodiversity based on its existence, regardless of whether it has any usefulness to us.

Instrumental Value

Value of an organism, species, ecosystem, or the earth's biodiversity based on its usefulness to us.

Watershed

a ridge of land that separates two adjacent river systems

Provisions

a stock or supply of foods

Ecosystem

a system formed by the interaction of a community of organisms with their physical environment

Resistance

an environments unwillingness to change

Heterotroph

an organism that depends on complex organic substances for nutrition

Scavengers

an organism that feeds on the dead bodies of other organisms.

Trophic Level

each step in a food chain or food web

Resilience

how quickly an environment recovers from change

Trophic Pyramid

illustrates the flow of energy through an ecosystem, energy is lost at each level

Decomposers

organisms that break down wastes and dead organisms and return raw materials to the environment

Detritivores

organisms that consume organic litter debris and dung.

Autotroph

plant capable of synthesizing its own food from simple organic substances

Biogeochemical Cycles

process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another

Leaching

removal of dissolved materials from soil by water moving downwards

Limiting Nutrient

single nutrient that either is scarce or cycles very slowly, limiting the growth of organisms in an ecosystem

Photosynthesis

synthesis of compounds with the aid of radiant energy (especially in plants)

Nitrogen Fixation

the assimilation of atmospheric nitrogen by soil bacteria and its release for plant use on the death of the bacteria

Transpiration

the emission of water vapor from the leaves of plants

Cellular Respiration

the metabolic processes whereby certain organisms obtain energy from organic moelcules

Hydrologic Cycle

the natural process by which water is purified and made fresh through evaporation and precipitation. The cycle provides all the fresh water available for biological life.

Runoff

the occurrence of surplus liquid (as water) exceeding the limit or capacity

Biosphere

the regions of the surface and atmosphere of the Earth (or other planet) where living organisms exist

Net Primary Product

the remaining energy available for consumers

Gross Primary Product

the total amount of chemical energy stored by photosynthesis, much of which is used by producers

Biomass

the total mass of living matter in a given unit area

Standing Crop

total biomass of photosynthetic autotrophs present at a given time

Food Chain

(ecology) a community of organisms where each member is eaten in turn by another member

Food Web

(ecology) a community of organisms where there are several interrelated food chains

Macronutrients

A chemical substance that an organism must obtain in relatively large amounts

Primary Consumer

An organism that eats producers

Restoration Ecology

Applying ecological principles in an effort to return ecosystems that have been disturbed by human activity to a condition as similar as possible to their natural state.

Ecological Efficiency

Percentage of energy transferred from one trophic level to another in a food chain or web

Intermediate Disturbance Hypothesis

The concept that moderate levels of disturbance can foster greater species diversity than low or high levels of disturbance.