Age Structure
A population divided into groups by age. Sometimes the groups represent the actual number of each age in the population; sometimes the groups represent the percentage or proportion of the population of each age.
Birth Rate
The rate at which births occur in a population, measured either as the number of individuals born per unit of time or as the percentage of births per unit of time compared with the total population.
Death Rate
The rate at which deaths occur in a population, measured either as the number of individuals dying per unit time or as the percentage of a population dying per unit time.
Demographic Transition
The pattern of change in birth and death rates as a country is transformed from underdeveloped to developed.
Three stages
-The birth and death rates are high and the growth rate low
-The death rate decreases but the birth rate remains high as well as the
Growth Rate
The net increase in some factor per unit time.
Carrying Capacity
The maximum abundance of a population or species that can be maintained by a habitat or ecosystem without degrading the ability of that habitat.
Logistic Carrying Capaicty
The population size at which births equal deaths and there is no net change in the population.
Logistic Growth Curve
The S-shaped growth curve. A small population grows rapidly, but the growth rate slows down, and the population eventually reaches a constant size.
Zero population growth
A population in which the number of births equals the number of deaths so that there is no net change in the size of the population.
Total fertility rate
Avg. number of children expected to be born to a woman during her lifetime.
Family planning
A method of decreasing birth rates. The practice of controlling the number of children in a family and the intervals between their births, particularly by means of artificial contraception or voluntary sterilization.
Exponential Growth
Growth in which the rate of increase is a constant percentage of the current size. The growth occurs at a constant rate per time period.
Immigration
the movement of people into a destination country to which they are not native or do not possess its citizenship in order to settle or reside there.
Emigration
the movement of individuals out of a population.
Biogeochemical cycle
The complete path a chemical takes through the four major components, or reservoirs, of Earth's system.
(Four major reservoirs: Atmosphere, Hydrosphere, Lithosphere,Biosphere )
Carbon Cycle
The biogeochemical cycle by which carbon is exchanged among the four reservoirs of Earth's system.
(Enters the atmosphere through the respiration of living things, through fires that burn organic compounds, and by diffusion from the ocean, Removed from th
Nitrogen Cycle
is the process by which nitrogen is converted between its various chemical forms.
(One of the most important and most complex of the global cycles)
Phosphorus Cycle
the biogeochemical cycle by which phosphorus is exchanged among the four reservoirs of Earth's system.
(Unlike carbon and nitrogen, phosphorus DOES NOT have a gaseous phase on Earth. The rate of transfer of phosphorus in Earth's system is slow compared to
Rock Cycle
The rock cycle is a group of changes between rocks. Consists of numerous processes that produce rock and soils.
(classified as igneous, sedimentary, or metamorphic)
Hydrologic cycle/water cycle
The transfer of water from the oceans to the atmosphere to the land and back to the oceans.
(processes involved include evaporation of water from the oceans, precipitation on land; evaporation from land; and runoff from streams,rivers, and subsurface grou
Tectonics Cycle
Involves creation and destruction of the solid outer layer of Earth, the lithosphere.
Denitrification
The process of releasing fixed nitrogen back to molecular nitrogen.
Ex: When Organisms Die, Decomposing
Nitrification
the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate.
Ammonification
When a plant or animal dies or an animal expels waste, the initial form of nitrogen is organic. Bacteria or fungi convert the organic nitrogen within the remains back into ammonium.
Assimilation
Assimilation is the process by which plants and animals incorporate the NO3- and ammonia formed through nitrogen fixation and nitrification.
(Plants take up these forms of nitrogen through their roots.)
Nitrate
NO3-
Ammonia
A compound of nitrogen and hydrogen NH3
Phosphate
PO43?
Nitrogen Fixation
The process of converting inorganic, molecular nitrogen in the atmosphere to ammonia or nitrate is called nitrogen fixation.
Nitrogen fixing bacteria
microorganisms capable of transforming atmospheric nitrogen into fixed nitrogen.
(More than 90% of all nitrogen fixation is affected by these organisms.)
Macronutrient
Elements required in large amounts by living things. These include the big six: carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.
Micronutrient
Chemical elements required in very small amounts by at least some forms of life.
Ex: Copper, and molybdenum
Limiting Factor
The single requirement for growth available in the least supply in comparison to the need of an organism.
(originally applied to crops but now often applied to any species.)
Ecosystem
Simplest entity that can sustain life. Consists of several species and a fluid medium such as air or water.
Food Chain
The linkage of who feeds on whom.
Food Webs
Complex cases more than food chain.
Trophic Level
Consists of all those organisms in a food web that are the same number of feeding levels away from the original source of energy.
Autotroph
Organisms in the first trophic level, which make their own food and inorganic chemicals and a source of energy, are called autotrophs.
Heterotroph
Heterotrophs cannot synthesize their own food and rely on other organisms � both plants and animals � for nutrition.
Herbivore
organisms that feed on plants, algae or photosynthetic bacteria.
ex: sheeps,cows
Carnivore
meat-eaters that feed directly on herbivores make up the third trophic level.
ex: wolves, coyotes
Omnivore
animals that feed on both meat and plant
Community
an interacting group of various species in a common location
Consumer
An organism that generally obtains food by feeding on other organisms or organic matter due to lack of the ability to manufacture own food from inorganic sources such as a heterotroph
Producer
Producers are organisms that make their own food; they are also known as autotrophs.
Scavenger
A scavenger is an organism that mostly consumes decaying biomass, such as meat or rotting plant material. Many scavengers are a type of carnivore, which is an organism that eats meat.
Decomposer
Decomposers are organisms that break down dead or decaying organisms, and in doing so they carry out the natural process of decomposition. Like herbivores and predators, decomposers are heterotrophic.
Ex: Worms
Natural selection
Natural selection is the process by which species adapt to their environment. Natural selection leads to evolutionary change when individuals with certain characteristics have a greater survival or reproductive rate than other individuals in a population
Mutation
When DNA changes it is said to have undergone mutation
Evolution
is change in the heritable traits of biological populations over successive generations.
Gene
A single piece of genetic info
Species
A species is often defined as the largest group of organisms where two hybrids are capable of reproducing fertile offspring, typically using sexual reproduction.
Niche
The term niche is used to describe the role an organism or population plays within its community or ecosystem. It encompasses all relationships that the organism (or population) has with its environment and with other organisms and populations in its envi
Habitat
Where a species lives. An ecological or environmental area that is inhabited by a particular species of animal, plant, or other type of organism.
Fundamental niche
The fundamental niche of a species includes the total range of environmental conditions that are suitable for existence without the influence of interspecific competition or predation from other species.
Realized niche
Realized niche is a phrase relating to ecology defining the actual space that an organism inhabits and the resources it can access as a result of limiting pressures from other species
Predation
Occurs when an organism feeds on other live organisms usually of another species. Can increase the diversity of prey species
Biogeography
Biogeography is the study of the distribution of species and ecosystems in geographic space and through (geological) time.
Biodiversity
refers to the variety of life-forms, commonly expressed as the number of species in an area or the # of genetic types in an area.
Keystone species
A species that has a large effect on its community or ecosystem. Its removal or a change in its role within the ecosystem changes the basic nature of the community.
Ex: sea star
Migration
Human migration is the movement by people from one place to another with the intentions of settling temporarily or permanently in the new location.
Biomes
A kind of ecosystem, such as a desert, a tropical rain forest, a grassland
Theory of island biogeography
The two sources of new species on an island are migration from the mainland and evolution of new species in place, islands have fewer species than continents, the smaller the island, the fewer the species, the farther the island from a mainland, the fewer
Tropical rain forest
Occur where the avg temperature is high and relatively constant throughout the year and where rainfall is high and relatively frequent throughout the year. Famous for their diversity of vegetation. Soils tend to be very low in nutrients.
Temperate rain forest
Where temperatures are moderate and precipitation exceeds 250cm/year. Low diversity of plants and animals. The abundant growth of the dominant vegetation produces very deep shade in which few other plants can grow and provide food for herbivores.
Tropical seasonal forest
Low latitudes, where the avg. temperature is high and relatively constant throughout the year and rainfall is abundant but very seasonal. Disturbances are common but may be necessary to maintain these areas as savannas.
Temperate Shrublands/ Chaparral
In still drier climates, temperate shrublands called chaparral occur. Dominated by dense stands of shrubs. Chaparral occurs in mediterranean climates with low rainfall that is concentrated in the cool season. Highly modified around the world by human acti
Taiga/Boreal Forest
Includes forests of cold climates of high latitudes and high altitudes. Biological diversity is low. Disturbances are common.
Tundra
Treeless plains that occur in the harsh climates of low rainfall and low avg. temperatures. Two kinds of tundra: artic, high latitudes, and alpine, occurs at high elecations.
Temperate grassland
Occur in regions too dry for forests and too moist for deserts. Soils often have a deep organic layer, formed by the decaying roots of the grasses and the decaying stems and leaves of the prairie plants. Some of the best soils in the world for agriculture
Savanna
Low latitudes, where the avg. temperature is high and relatively constant throughout the year and rainfall is abundant but very seasonal. Greatest abundance of large mammals.
Deserts
Occur in the drier regions where vegetation can survive. Considerable amount of specialized vegetation. Soils have little or no organic matter
Wetlands
Include freshwater swamps, marshes, and bogs and saltwater marshed. All have standing water. Important in the biosphere. Can produce many edible plants.
Freshwaters
Critical to our water supply for homes, industry, recreation, and agriculture play important ecological roles. The areas most altered by human activities, especially by modern technology.
Intertidal area
made up of areas exposed alternately to air during low tide and ocean waters during high tide. Constant movement of waters transports nutrients into and out of these areas, which are usually rich in life and important to people as a direct source of food
Benthos
The bottom portion of oceans. Food is dead organic matter that falls from above. No plants grow no photosynthesis
Exotic species
native species transported accidentally by ships. are species of plants or animals that are growing in a nonnative environment. Alien species have been moved by humans to areas outside of their native ranges.
Biomass/pyramid of biomass
The total amount of organic matter on earth or in any ecosystem or area is called biomass.
Gross Production
The first step, production of organic matter before use, is called gross production.
Net production
The amount left after utilization is called net production
Respiration
The use of energy from organic matter by most heterotrophic and autotrophic organisms is accomplished through respiration. In respiration, an organic compound is combined with oxygen to release energy and produce carbon dioxide and water.
Chemoautotroph
Some autotrophic bacteria can derive energy from inorganic sulfur compounds; these bacteria are referred to as chemoautotrophs.
Primary production
The production carried out by autotrophs.
Secondary production
Production by heterotrophs, depends on the production of autotrophic organisms.
Photosynthesis
Most autotrophs make sugar from sunlight, carbon dioxide, and water in a process called photosynthesis, which releases free oxygen.
Trophic-level efficiency
A common ecological measure of energy efficiency. The ratio of production of one trophic level to the production of the next lower trophic level.
Succession
Recovery of disturbed ecosystems can occur naturally. This natural recovery can occur if the damage is not too great.Ecological succession is the observed process of change in the species structure of an ecological community over time.
Primary succession
the initial establishment and development of an ecosystem where one did not exist previously.
Secondary succession
reestablishment of an ecosystem following disturbances. There are remnants of a previous biological community, including such things as organic matter and seeds.
Restoration
goal is to return damaged ecosystems to some set of conditions considered functional, sustainable, and natural
Middle succession
We find trees of many species and many sizes
Late succession
Tend to be slower-growing and longer lived. Have evolved and adapted to environmental conditions in the late stages.
Early succession
Have evolved and are adapted to the environmental conditions. Biomass and biological diversity increase
Undernourishment
results from a lack of sufficient calories in available food, so that one has little or no ability to move or work and eventually dies from the lack of energy.
Rangeland
Most calle lives on rangeland. Provides food for grazing and browsing animals without plowing and planting
Pasture
Is plowed, planted, and harvested to provide forage for animals.
Grazing
a method of feeding in which a herbivore feeds on plants such as grasses.
Monoculture
Large areas planted with a single species or even a single strain or subspecies, such as a single hybrid of corn.
Mariculture
The farming of ocean fish, although producing a small part of the total marine fish catch, has grown rapidly in the last decades and will likely continue to do so.
Aquaculture
The farming of food in aquatic habitats - both marine and freshwater - is an important source of protein, is growing rapidly, and could be one of the major solutions to providing nutritional quality.
Crop Rotation
Different crops are planted in turn in the same field, with the field occasionally left fallow. A fallow field is allowed to grow a cover crop that is not harvested for at least one season.
Green Revolution
The name attached to post - World War 2 programs that have led to the development of new strains of crops with higher yields, better resistance to disease, or better ability to grow under poor conditions.
Bush fallow/milpa/fang/swidden agriculture
The traditional practice is to cut the forest in small patches but not cut it completely.
Irrigation
Irrigation is the artificial application of water to the land or soil.
Organic Farming
Typically considered to have 3 qualities : It is more like natural ecosystems than monocultures; it minimizes negative environmental impacts; and the food that results from it does not contain artificial compounds.
Sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice, and/or by the force of gravity acting on the particles.
Soil
Soil is the mixture of minerals, organic matter, gases, liquids, and the countless organisms that together support life on Earth.
No-till agriculture
involves not plowing the land, using herbicides and integrated pest management to keep down weeds, and allowing some weeds to grow.
Soil Fertility
the capacity of a soil to supply nutrients necessary for plant growth.
Humus
the organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms.
Overgrazing
When the carrying capacity is exceeded, the land is overgrazed. Overgrazing slows the growth of the vegetation, reduces the diversity of plant species, leads to dominance by plant species that are relatively undesirable to the cattle, hastens the loss of
Desertification
is the deterioration of land in arid, semiarid, and dry subhumid areas due to changes in climate and human activities
Silviculture
The professional growing of trees
Old Growth Forest
A nontechnical term often used to mean a virgin forest (one never cut),but also used to mean a forest that has been undisturbed for a long, but usually unspecified, time
Clear-cutting
The cutting of all trees in a stand at the same time
Plantation
Managed forests, in which a stand of a single species is typically planted in straight rows and harvested at regular intervals
Strip Cutting
In timber harvesting, the practice of cutting narrow rows of forest, leaving wooden corridors
Sustainable Forests
Effort to manage a forest so that a resource in it can be harvested at a rate that does not decrease the ability of the forest ecosystem to continue to provide the same rate of harvest indefinitely
Public Service Function
Functions performed by ecosystems that improve other forms of life in other ecosystems. Examples include the cleansing of the air by trees and removal of pollutants from water by infiltration through the soil
Historical Range of Variation
The known range of an environmental variable, such as the abundance of a species or the depth of a lake , over some past time interval
Catch Per Unit Effort
the numbers of animals caught per unit of effort, such as the number of fish caught by a fishing ship per day. It is used to estimate the population abundance of a species
Troposphere
The lowest part of the atmosphere, where weather occurs.
Stratosphere
Lies above the troposphere, the site of atmospheric warming that coincides with increases in altitudes.
Mesosphere
above the stratosphere
Thermosphere
above the mesosphere, the highest
Ozone Layer
Stratospheric ozone layer that absorbs ultraviolet radiation.
Air/atmospheric pressure
the weight of overlying atmosphere per unit area.
Climate
The representative or characteristic conditions of the atmosphere at particular places on Earth. Climate refers to the avg or expected conditions over long periods.
Weather
the particular conditions at one time in one place.
Earth System Science
The science of earth as a system. It includes understanding of processes and linkages between the lithosphere, hydrosphere, biosphere, and atmosphere.
Global circulation models
A type of mathematical model used to evaluate the global change, particularly related to climatic change. GCMs are very complex and require supercomputers for their operation.
Global warming
Natural or human-induced increase in the avg. global temperature of the atmosphere near earth's surface.
Global climate change
Change in mean annual temp. and other aspects of climate over periods of time ranging from decades to hundreds of years to several million years.
Electromagnetic Spectrum
All the possible wavelengths of electromagnetic energy considered as a continuous range. The spectrum includes long wavelength, infrared, visible, UV, x rays, and gamma rays
Greenhouse effect
Process of trapping heat in the atmosphere. Water vapor and several other gases warm the Earth's atmosphere because they absorb and remit radiation; that is, they trap some of the heat radiating from the Earth's atmospheric system.
Greenhouse gases
The suite of gases that produce a greenhouse
effect, such as carbon dioxide, methane, and water
vapor.
Anthropogenic
originating from human activity
Polar amplification
Processes in which global warming causes
greater temperature increases at polar regions.
Global Dimming
The reduction of incoming solar radiation
by reflection from suspended particles in the atmosphere and their interaction with water vapor (especially clouds).
Climate Forcing
An imposed perturbation of Earth energy
that balance major climatic forcings associated with global warming. Includes: greenhouse gases, such as carbon dioxide and methane; reflective aerosols in the atmosphere, black carbon. Forcing of the climate system
Albedo
Albedo is the fraction of solar energy (shortwave radiation) reflected from the Earth back into space. It is a measure of the reflectivity of the earth's surface.
Aerosol
a substance enclosed under pressure and able to be released as a fine spray, typically by means of a propellant gas. An aerosol is a colloid of fine solid particles or liquid droplets, in air or another gas. These are CFCs
Atmosphere
Layer of gases surrounding Earth.
Thermohaline circulation
vertical movement of ocean water is driven by density.
Milankovitch cycles
Milankovitch cycles refer to long term variations in the orbit of the Earth which result in changes in climate over periods hundred of thousands of years and are related to ice age cycles.
Ozone
A form of oxygen in which three atoms of oxygen
occur together. It is chemically active and has a short
average lifetime in the atmosphere. Forms a natural layer high in the atmosphere (stratosphere) that protects us from harmful ultraviolet radiation fro
UV-A
Least energetic form of ultraviolet radiation. It is capable of causing some damage to living cells, is not affected by stratospheric ozone, and is therefore transmitted to earth.
UV-B
Intermediate-wavelength ultraviolet radiation, damaging to living cells. Most is absorbed by stratospheric ozone, and therefore depletion of ozone leads to significant increase of this radiation. This is the ozone problem.
UV-C
Shortest wavelength and most energetic of the ultraviolet radiation. It is strongly absorbed in the atmosphere, and negligible amounts reach the surface of Earth.
Dobson Unit
Commonly used to measure the concentration of ozone.
Chlorofluorocarbons
Highly stable compounds that have been or are being used in spray cans as aerosol propellants and in refrigeration units (the gas that is compressed and expanded in a cooling unit). Emissions of chlorofluorocarbons have been associated with potential glob
Polar Stratospheric Clouds
Clouds that form in the stratosphere during the polar winter.
Ozone hole
The declining and depleting of ozone.
Polar vortex
Arctic air masses that in the winter become isolated from the rest of the atmosphere and circulate about the pole. The vortex rotates counterclockwise because of the rotation of earth in the southern hemisphere.
Montreal protocol
Acts that eliminated the production and use of CFCs.
HCFCs
Hydrochlorofluorocarbons, a group of chemicals containing hydrogen, chlorine fluorine, and carbon, produced as a potential substitute for chlorofluorocarbons.
HFCs
Chemicals containing hydrogen, fluorine, and carbons, produced as potential substitutes for chlorofluorocarbons.
Stationary sources
Air pollution sources that have a relatively fixed location, including point sources, fugitive sources, and area sources
Primary pollutants
Air pollutants emitted directly into the atmosphere. included are particulates, sulfur oxides, carbon monoxide, nitrogen oxides, and hydrocarbon
Secondary pollutants
Air pollutants produced through reactions between primary pollutants and normal atmospheric compounds. an example is ozone that forms over urban areas through reactions of primary pollutants, sunlight, and natural atmospheric gas.
Criteria Pollutants
They are particle pollution (often referred to as particulate matter), photo chemical oxidants and ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead.
Air toxics
Those air pollutants known or suspected to cause
cancer and other serious health problems from either long or short-term exposure.
Sulfur Dioxide
Colorless and odorless gas normally present at Earth's surface in low concentrations. an important precursor to acid rain. Major anthropogenic source is burning fossil fuels.
Nitrogen oxides
Occurs in several forms. Most important as an air pollutant is nitrogen dioxide, which is a visible yellow brown to reddish brown gas. it's a precursor of acid rain and produced through the burning of fossil fuels.
Carbon monoxide
Colorless, odorless gas that at very low concentrations is extremely toxic to humans and animals.
Particulate matter
Small particles of solid or liquid substance that are released into the atmosphere by many activities including farming, volcanic eruption, and burning fossil fuels. particulates affect human health, ecosystems, and the biosphere.
Lead
A heavy metal that is an important constituent of automobile batteries and other industrial parts. a toxic metal capable of causing environmental disruption and producing a health problem to people and other living organisms.
Volatile organic compounds
Are organic chemicals that have a high vapor pressure at ordinary room temperature. Have anthropogenic sources such as paints, cfc's, and fossil fuels.
Hydrocarbons
Compounds containing only carbon and hydrogen are a larger group of organic compounds, including petroleum products, such as crude oil and natural gas.
Acid rain
Rain made acid by pollutants, particularly oxides of sulfur and nitrogen. (natural rainwater is slightly acid owing to the effect of carbon dioxide dissolved in the water).
Global dimming
The process of reduction of incoming solar radiation by reflection from suspended particles in the atmosphere and their interaction with water vapor. (especially clouds).
Coal Gasification
Process that converts coal that is relatively high in sulfur to gas in order to remove the sulfur.
Benzene
Benzene is a chemical that is a colorless or light yellow liquid at room temperature. It has a sweet odor and is highly flammable.
Atmospheric inversion
A condition in which warmer air is found above cooler air, restricting air circulation; often associated with a pollution event in urban areas.
Photochemical smog
Sometimes called L.A type smog or brown air. Directly related to automobile use and solar radiation. Reactions that occur in the development of the smog are complex and involve both nitrogen oxides and hydrocarbons in the presence of sunlight.
Sulfurous smog
Produced primarily by burning coal or oil at large power plants. Sulfur oxides and particulates combine under certain meteorological conditions to produce a concentrated form of this smog.
Clean air act amendments
Comprehensive regulations that address acid rain, toxic emissions, ozone depletion. and automobile exhaust.
Fugitive source
Type of stationary air pollution sources that generate pollutants from open areas exposed to wind processes.
Area Source
Sometimes also called non point sources. These are diffused sources of pollution such as urban runoff or automobile exhaust. These sources include emissions that may be over a broad area or even over an entire region. They are often difficult to isolate a
Mobile Source
Sources of air pollutants that move from place to place, for example, automobiles, trucks, buses, and trains.
Asbestos
Term for several minerals that have the form of small elongated particles. Some types of particles are believed to be carcinogenic or to carry with them carcinogenic materials
Radon
Naturally occurring radioactive gas. Radon is colorless, odorless, and tasteless and must be identified through proper testing.
Chimney effect
Process whereby warmer air rises in buildings to upper levels and is replaced in the lower portion of the building by outdoor air drawn through a variety of openings, such as windows, doors or cracks in the foundations and walls.
Formaldehyde
Formaldehyde is a colorless, strong-smelling gas. It is used to make building materials and household products. Formaldehyde is used to make walls, cabinets, and furniture. Can cause irritation of the skin,eyes,nose, and throat. Also known to cause cancer