Environmental Science Terms

Environmental Science
 The interdisciplinary study of humanity’s relationship with other organisms and the nonliving physical environment.
;An educated guess that provides an explanation for an ovbservation that can be tested.

;;A recreation of an event or occurance in a way that enables a scientist to support or disprove a hypothesis.
Extreme Poverty
;A condition in which people cannot meet their basic needs for adequate food, clothing, shelter, education, or health.;$2/day –Nearly 1 in 4 people.;
Ecological Footprint
;The amount of productive land, fresh water, and ocean required on a continuous basis to supply that person food, wood, energy, water, housing, clothing, transportation, and waste disposal.

People Overpopulation
A situation in which there are too many people in a given geographic area.
Consumption Overpopulation
A situation that occurs when each individual in a population consumes too large a share of resources.
Common (Global Commons)
Those parts of our environment available to everyone but for which no single individual has responsibility – the atmosphere, fresh water, forests, wildlife, and ocean fisheries.
  • Management of natural resources on a sustainable basis.
  • Allows the use of resources in a “responsible” manner to preserver for future generations.
  • Keeps the “wilderness” as created or free of human influence.
  • “Locks up” the resources.

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Environmental Impact Statement
A document that summarizes the potential and expected adverse impacts on the environment associated with a project, as well as alternatives to the proposed project. They help federal agencies and the public consider the impacts of proposed activities.
  • Study of how people use their limited resources to satisfy their unlimited wants.
  • “The world is a marketplace and everything has a price.”
  • Depend on the natural environment as sources for raw materials and sinks for waste products.
Marginal cost of pollution
;The cost, in environmental damage, of a unit of pollution that is emitted into the environment.
Marginal cost of pollution abatement
  • The cost, in terms of giving up goods, of elminating pollution.

  • The cost associated with reducing a small additonal amount of pollution.
Environmental ethics
;Concerned with the issue of responsible moral conduct with respect to the natural environment.
  • The study of systems that include interactions among organisms and between organisms and their abiotic environment.
  • Broadest field in biology.
  • “Living Environment”
  • Includes all organisms


Abiotic Environment
  • “Nonliving, or physical surroundings.”
  • Includes living space, sunlight, soil, precipitation, and wind.

  • A community and its physical environments.
  • Includes all the biotic interactions of a community as well as the interactions between organisms and their abiotic environment.
  • The parts of Earth’s atmosphere, ocean, land surface, and soil that contain all living organisms.

  • Contains earth’s communities, ecosystems and landscapes.


  • The ability or capacity to do work.
  • Exists as stored (potential) or kinetic (motion).

  • Chemical, radiant, thermal, mechanical, nuclear, electrical.
Study of energy and its transformations.
Closed system
  • Does not exchange energy with surroundings.
  • Rare in nature.
Open system
  • Exchanges energy with surroundings.
  • Biological process by whichh energy from the sun (radiant energy) is transformed into chemical energy of sugar molecules.

  • Energy captured by plants via photosythesis is transferred to the organisms that eat the plants.
Cellular respiration
  • The process where the chemical energy captured in photosynthesis is released within cells of plants and animals.
  • This energy is then used for biological work…Creating new cells, reproduction, movement, etc.

  • Utilize inorganic raw materials (e.g. hydrogen sulfide, hydrogen gas) to produce carbohydrate molecules and energy.
  • Bacterica possessing enzymes that cause the inorganic molecule hydrogen sulfide to react with oxygen, producing water and sulfur or sulfate.
Food chain
  • Energy from food passes from one organism to the next in a sequence.
  • Each “link” is a trophic level.

Food web
  • A representation of the interlocking food chains that connect all organisms in an ecosystem.
  • A realistic model of the flow of energy and materials through an ecosystem.
Energy Flow
  • Passage of energy in a one-way direction through an ecosystem.
  • Producers
  • Primary consumers
  • Secondary consumers
  • Decomposers


Trophic level
An organism’s position in a food chain, which is determined by its feeding relationships.

Ecological Prymaid
Graphically represent the relative energy value of each trophic level. –Important feature is that large amount of energy are lost between trophic levels to heat.
The amount of biomass (biological material) produced in a given area during a given period of time.
GPP — Gross Primary Productivity
Total amount of photosynthetic energy captured. 
NPP– Net Primary Productivity
Energy stored in excess of plant’s needs (plant cellular respiration)
  • Cumulative genetic changes that occur over time in a population of organisms.
  • Explains many patterns observed in the natural world.


Biological community
Two or more populations or organisms that live in the same place at the same time.

 Primary Succession
  • The change in species composition over time in a previously uninhabited environment.
  • Starts with a pioneer community–the intial community that devolps.
Secondary Succession
  • The change in species composition that takes place after some disturbance destroys the existing vegetation; soil is already present.
  • Begins in an environment following distruction of all or part of the earlier community.

  • Any intimate relationship or association between members of two or more species.
  • Participants may be benefited, harmed, or unaffected by the relationship.
  • Result of coevolution
+,+A symbiotic relationship in which both partners benefit.;”Sharing Benefits”
+, oSymbiotic relationship where one species benefits and the other is neither harmed nor helped.

;”Taking without harming”

+, –A symbiotic relationship in which one species is benefited and the other is harmed.;”Taking at another’s expense.”
  • The consumption of one species (the prey) by another (the predator).
  • Results in an evolutionary “arms race.”


  • The interaction among organisms that vie for the same resources (such as food or living space) in an ecosystem.

  • Intraspecific–competition between individuals in a population.
  • Interspecific–competition between individuals in two different species.
Ecological Niche
  • The totality of an organism’s adaptations, its use of resources, and the lifestyle to which it is fitted.
  • Refers to the fundamental role of an organism in the community.

Limiting resources
Any environmental resource that, because it is scarce or at unfavorable levels, restricts the ecological niche of an organism. EX. soil mineral content, temperature extremes, precipitation.
Keystone species
A species, often a predator, that exerts a profound influence on an entire ecosystem. If it disappears, other organisms in the ecosystem may become more common, rare, or disappear.

Species richness
The number of  different species in a community. **Usually greater at the edge of two communities, than in the center**
A transitional zone where two or more communities meet–contains all or most of the ecological niches or the adjacent community.
Ecosystem services
Important environmental benefits that ecosystems provide to people; include clean air to breath, clean water to drink, and fertile soil in which to grow crops.
  • The first step in the nitrogen cycle.

  • žN to ammonia–

    The conversion of gaseous nitrogen to ammonia.
  • The process gets its name from the fact that nitrogen is fixed into a form that organisms can use.
  •  Second step in the nitrogen cycle.
  •  The conversion of ammonia to nitrate.

  •  Third step in the nitrogen cycle.
  • Plant roots absorb nitrate and incorporate the nitrogen into plant proteins.
  • Animals then consume the plant nitrogen compounds and convert them to animal compounds. (proteins)
  • Fourth step in the nitrogen cycle.
  • The conversion of biological nitrogen compounds into ammonia and ammonium ions.
  • These ammonia produced enter the nitrogen cycle and are once again available for the processes of nitrification and assimilation.

  • Final step of the nitrogen cycle.
  • The reduction of nitrate to gaseous nitrogen.
  • nitrate to N2
  • The process recverse the action of nitrogen-fixing and nitrfying bacteria.


The proportional reflectance of solar energy from the Earth’s surface, commonly expressed as a percentage.;**Dark surfaces have lower albedo, absorb more.**;
Coriolis effect
  • The effect of the earth’s rotation on the direction of the wind.
  • Tends to turn fluids (air and water) toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere.
  • Large, circular ocean current systems that often encompass an entire ocean basin.

Ocean conveyor belt
Refers to the conditions in the atmosphere at a given place and time; it includes temperature, atmospheric pressure, precipitation, cloudiness, humidity, and wind.
Average weather conditions that occur in a place over a period of years. Two most important factors include temperature and precipitation.
Polar easterlies
Trade winds
Rain shadow
Dry conditions, often on a regional scale, that occur on the leeward side of a mountain barrier; the passage of moist air across the mountains removes most of the moisture.
El Nino
  • Where deeper waters come to the surface, occurs in the Pacific Ocean along the S. America coast.
  • Provides nutrietts for microscopic algae, which support a complex food web.
  • Weakens considerably during years with El Nino events.
Earth’s outermost rigid rock layer composed of seven large plates.
Plate tectonics
The study of processes by which the lithospheric plates move over the asthenosphere.
A large, relatively distinct terrestrial region with a similar climate soil, plants, and animals, regardless of where it occurs in the world.;**9 Major Biomes**
Vertical zonation
Aquatic ecosystems
One of the main categories of aquatic ecosystems.;–Small microscopic organisms that are relatively feeble swimmers.–They are carried about at the mercury of currents and waves.
Larger than plankton, more strongly swimming organisms such as fishes, turtles, and whales.
Bottom dwelling oragnisms that fix themselves to one spot (sponges, oysters and barnacles), burrow into the sand (worms, clams, and sea cucumbers), or simply walk on the bottom (crawfish, aquatic insect larvae, and brittle stars.)
Lands that shallow fresh water covers for at least part of the year.;–Marshes, swamps.
Type of freshwater wetlands, in which grasslike plants dominate.
Type of freshwater wetlands in which woody trees or shrubs dominate.
Spring turnovers
Fall turnovers
A coastal body of water, partly surrounded by land, with access to the open ocean and a large supply of fresh water from a river.
A chemical with adverse human health effects.;;
Acute toxicity
Adverse effects that occure within a short period after exposure to a toxicant.
Chronic toxicity
Adverse effects that occur some time after exposure to a toxicant, or after some extended exposure to the toxicant.
A characteristic of certain chemicals that are extremely stable and may take many years to be broken down into simpler forms by natural processes.
The buildup of a presistent toxic substance, such as certain pesticides, in an organism’s body, often in fatty tissues.
The increased concentration of toxic chemicals, such as PCBs, heavy metals, and certain pesticides, in the tissues of organisms that are at higher levels in food webs.
Endocrine disrupters
A chemical that mimics or interferes with the actions of the endocrine system in humans and wildlife.

The amount that enters the body of an exposed organism.
The type and amount of damage that exposure to a particular dose.
The study of the effects of toxic chemicals on human health.
The study of the effects of toxic chemicals and diseases on human populations.
The study of contaiminants in the biosphere, including their harmful effects on ecosystems.
Risk assessment
The scientific process of estimating the threat a hazard poses to human health.
Cost-benefit analysis
The estimated cost of regulation is compared with potential benefits to determine how much expense society is willing to incur to derive the benefits.