Our Environment Contents

Glossary

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Algae
A heterogeneous group of unicellular, colonial and multi-cellular eukaryotic photosynthetic organisms of simple structure. Traditionally included in the plant kingdom, they are aquatic or live in damp habitats on land. Lawrence (1995).

Anaerobic
'Without oxygen'. An anaerobic organism is one which does not require oxygen to live and grow.

Anthropogenic
Applied to substances, processes, etc. of human origin, or that result from human activity. Allaby & Allaby (1990).

 Amino acids
An organic compound containing an amino group and a carboxyl group; amino acids are the units or building blocks that make peptide and protein molecules. Allaby & Allaby (1990).

Aquifer
A body of permeable rock (e.g. unconsolidated gravel or a sand stratum) that is capable of storing significant quantities of water that is underlain by impermeable material. Allaby (1994).

 Assets
Things which are advantageous/have value.

Assimilate
To make similar or like, to convert into a substance similar to itself, to be incorporated or absorbed. Chambers (1994).

Atmosphere
The gaseous envelope surrounding planets. Chambers (1994). The term is generally applied to the whole body of terrestrial air. The earth's atmosphere is composed mainly of nitrogen, oxygen, argon and carbon dioxide.

Bacteria
A group of extremely metabolically diverse, prokaryotic, unicellular micro-organisms, usually possessing cell walls. They are ubiquitous in soil and water. The many forms include parasitic and disease-causing organisms and those which play an important part in the breakdown of dead organisms. Lawrence (1995)

Benign
Favourable; gracious and kindly; of a mild type. Chambers (1994).

Binary fission
The chief mode of division in prokaryotic organisms, in which a cell divides into two equal daughter cells, each containing a copy of the chromosome. Lawrence (1995).

Bio-magnification
The build-up of toxins from pesticides, herbicides, and domestic and industrial waste such that these toxins are more and more concentrated in living organisms with movement up the food chain. For example, in the 1950s, DDT was used as an insecticide near certain lakes in the USA. The toxin ingested by the midges was absorbed by the fish which ate them, and then by the grebes which lived on the fish, causing a severe decline in the birds' ability to reproduce. The toxins are not easily broken down and hence they accumulate in the organisms at the top of food webs. Mayhew (1997).

Biomes
Broad, regional types of naturally occurring communities characterized by distinctive life forms which are adapted to the broad climatic and soil types. Mayhew (1997).

Biosphere
The regions of the earth's crust and atmosphere that are occupied by living organisms. Chambers (1994).

Capital
One of the four factors of production, along with land, labour, and enterprise, capital includes all the items designed by society to further the creation of wealth. Mayhew (1997)

Carbon dioxide (CO2)
A colourless, odourless gas at normal temperatures, composed of one atom of carbon and two of oxygen. It makes up about 0.03% of the atmosphere by weight. Carbon dioxide is consumed in photosynthesis by green plants and produced by the respiration of plants and animals and the burning of fossil fuel.

Carrying capacity
The level of use an environment or resource can sustain without being destroyed or suffering unacceptable deterioration. Lawrence (1995).

Catchment
The area of land from which rainwater is collected and transported to a river or reservoir. Chambers (1994)

Cell cytoplasm
All the living part of a cell inside the cell membrane and excluding the nucleus. Lawrence (1995).

Continental shelf
The part of a continent which is submerged beneath the sea to a maximum depth of 200m.

Cyanobacteria
A large and varied group of photosynthesising bacteria which were formerly regarded as algae - hence the common name 'blue green algae'. They are believed to have been the first oxygen-producing organism. Many species can fix atmospheric nitrogen. Some produce toxins which can become a health hazard when algal blooms occur. Lawrence (1995); Allaby (1994).

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DDT
Dichlorodiphenyltrichloroethane - an organochlorine compound. DDT was widely used to control arthropod parasites and as an insecticide. Its use was curtailed in many countries due to the bio-magnification along the food chain. Allaby (1994).

Desertification
The degradation of terrestrial ecosystems as a result of deforestation, overgrazing, and poor soil and irrigation management. Examples are found in areas of the Sahel, notably Sudan.

Diversity
Variety or dissimilarity. Chambers (1994).

DNA
Deoxyribonucleic acid (DNA) is found in the nuclei of cells and carries the necessary hereditary information to enable highly specific proteins to be constructed. Lawrence (1995).

Ecocentric
A position or ideology which advocates environmentally benign development, typically through small scale, localised initiatives and practices.

Ecology
The scientific study of the interrelationships among organisms and between organisms, and between them and all aspects, living and non-living, of their environment. Allaby (1994).

Ecosystem
A community of plants and animals within a particular physical environment which is linked by a flow of materials through the non-living (abiotic) as well as the living (biotic) sections of the system. Thus, ecosystems can range in size from the whole earth to a drop of water, although in practice, the term ecosystem is generally used for units below the size of biomes, such as sand dunes, or an oak woodland. Mayhew (1997).

Endosymbiosis
Symbiosis in which one organism lives inside the another.

Environmentalism
Concern about the environment and its preservation from the effects of pollution, etc. (Chambers 1994).

Erosion
The process of wearing away the land surface, by processes which transport rock debris. Erosion frequently refers to the loss of soil due to wind or as a result of washing away by water.

Eukaryotes
Organisms with cells possessing a membrane-bound nucleus in which the DNA is complexed with histones and organised into chromosomes, i.e. protozoans, algae, fungi, plants and animals. Lawrence (1995).

Eutrophication
The process of nutrient enrichment (usually by nitrates and phosphates) in aquatic ecosystems, such that the productivity of the system ceases to be limited by the availability of nutrients causing a rapid increase in the population of one or more organisms in an ecosystem. It occurs naturally over geological time, but may be accelerated by human activities (e.g. by fertilisers being washed from fields into rivers and lakes.): such activities are sometimes termed ‘cultural eutrophication’. The rapid increase in nutrient levels stimulates algal blooms. Allaby (1994).

Evaporation
The changing of a liquid into a vapour, or gas, at a temperature below boiling point of that liquid. Evaporation occurs at the surface of a liquid, and energy is required to release the molecules from the liquid into the gas. Mayhew and Penny (1992).

Evolution
The development of new types of living organisms from pre-existing types by the accumulation of genetic differences over long periods of time. Lawrence (1995).

Extinction
The complete disappearance of a species from the earth. Lawrence (1995).

Finite
Having an end or limit, subject to limitations or conditions. Chambers (1994).

Fossil fuel
A fuel derived from the remains of ancient plant or animal life. The main forms used are oil, gas and coal.

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Glaciations
The processes and results of erosion and deposition arising from the presence of an ice mass on a landscape. Whitten and Brooks (1977).

Global warming
The increase in the Earth's mean atmospheric temperature and is associated with periodic variations in the earth's orbit and ice ages. In recent years the focus of attention and research has been upon the effects of pollution and fossil fuel use on these climatic variations.

Greenhouse effect
The warming of the atmosphere as some of its gases absorb the heat given out by the earth. These gases include carbon dioxide, methane, CFCs, water vapour and ozone. Mayhew & Penny (1992)

Groundwater
All water found under the surface of the ground which is not chemically combined with any minerals present, but not including underground streams. Mayhew (1997).

Hominoid
A primate of a group (superfamily Hominoidea) that includes humans, their fossil ancestors, and the great apes. Pearsall (2001).

Hypersaline environments
Having a significantly greater salinity (salt concentration) than average oceanic salinity.

Industrial Revolution
Generally accepted as having occurred in Britain in the late eighteenth and early nineteenth centuries. The revolution was in technology - new techniques involving new machinery and new processes - but was accompanied by social and political change. Mayhew and Penny (1992).

Infrastructure
The component systems of a larger structure. Often refers to the system of transport (road, rail etc.) and services (water, sewerage, power etc.) in a city or region.

Inorganic
With reference to chemistry: of, or relating to, compounds which do not contain carbon. Also: not of animal or vegetable origin. Chambers (1994).

Invertebrates
General term for all animals without backbones. Lawrence (1995).

Irrigation
To provide water by means of canals or watercourses. Chambers (1994)

K-Pg Boundary
The boundary between the Cretaceous period and the Paleogene period of the Cenozoic era, around 66 million years ago. It is marked by an extinction event which includd the dinosaurs and almost all other large vertebrates.

Leaching
The removal and transport of elements in solution from and through a soil.

Local Agenda 21
Developed at the UN conference on Environment and Development (the Rio earth summit) in 1992. The process of developing local policies for sustainable development and building partnership between local authorities and other sectors to implement them. It is a crucial part of the move towards sustainability.

Meteorites
Small, extraterrestrial bodies, most of which probably originate in the asteroid belt, that enter the Earth's atmosphere and land on the surface. Most are only a few centimetres in size. Allaby and Allaby (1990).

Methane (CH4)
A colourless, odourless gas. It is the chief constituent of natural gas and occurs in coal mines and landfill sites. It is also an agricultural byproduct from rice and livestock production.

Minerals
Naturally occurring homogenous inorganic substances of definite composition and crystal structure.

Natural capital
An extension of the economic notion of capital (manufactured means of production) to environmental 'goods and services'. It refers to a natural stock (e.g., a forest) which produces a flow of goods (e.g., new trees) and services (e.g., carbon sequestration, erosion control, and habitat). Natural capital can be divided into renewable and non-renewable.

Neanderthal man
A subspecies of Homosapiens, H.Sapiens neanderthalensis. From the Pleistocene, extinct perhaps 50,000 years ago. Human brain size, heavy brow ridges, low forehead, no chin prominence, did not walk fully erect. Abercrombie, Hickman and Johnson (1980).

Neolithic revolution
This is also known as the second great revolution and occurred around 4 - 8000 BC. It was marked by the start of agriculture - the cultivation of food crops and the domestication of animals.

Nutrients
Any substance that organisms take in and use for growth and maintenance.

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Oxygen (O)
A gas without taste, colour or smell, forming part of the air, water, etc., supporting most forms of life and also necessary for combustion. (Atomic number 8). Chambers (1994).

Ozone (O3)
In the lower atmosphere it forms a dangerous pollutant but in the stratosphere (upper atmosphere) ozone is essential for the continuation of life of earth because it forms an ultraviolet absorbing shield which is needed to protect the biosphere from mutagenic radiation.

Paradigm
A basic theory, a conceptual framework within which scientific theories are constructed. Chambers (1994).

Photosynthesis
The process by which green plants convert light energy into chemical energy (food), through the use of chlorophyll. The main chemical components are water and carbon dioxide.

Phyla
Plural of Phylum -Classification of a primary group consisting of animals constructed on a similar general plan, and thought to be evolutionarily related. Lawrence (1995).

Plankton
Minute aquatic organisms that drift with water movements, generally having no method of independent movement. The phytoplankton (plants) are comprised mainly of diatoms, which form the basis of aquatic food chains. The zooplankton (animals) which feed on the diatoms include protozoans, small crustaceans and the larval stages of many larger organisms. Allaby and Allaby (1990).

Precautionary principle
A principle urging restraint from actions whose consequences are unknown (or known to be harmful).

Primordial
An adjective describing something that exists 'at the beginning', usually used to denote something from 'the beginning of time'. Can also mean 'basic' or 'fundamental'.

Prokaryotic bacteria
The bacteria (including mycoplasmas and antinomycetes) and the cyanobacteria (blue-green algae), unicellular organisms whose small simple cells lack a membrane-bounded nucleus, mitochondria, chloroplasts and other membrane bounded organelles typical of plant, animal and fungal protozoan or algal cells. Lawrence (1995).

Radioactive
An unstable isotope of an element that decays spontaneously and releases subatomic particles or units of energy. Radioactivity is the emission of these highly energetic, rays or particles by radioactive substances.

Raw materials
The unprocessed substances used in manufacturing. Mayhew and Penny (1992).

Recycling
Recycling is the collection, separation, clean-up and processing of waste materials to produce a marketable material or product. Williams (1998).

Resource
(a) Land, labour and capital. Characterised by their scarcity (as used in an economy or firm to produce and distribute goods and services). (b) Environmental entities which have value or utility to humankind.

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Salinisation
The build-up of salts at or near the surface of a soil. In dry climates, surface water evaporates rapidly causing soil moisture and dissolved salts, to come to the surface by capillary action. The water then evaporates, leaving behind a crust of salts on the surface. Mayhew & Penny (1992).

Stakeholders
Individuals or groups with an interest in a particular issue.

Stratosphere
The layer of the atmosphere above the troposphere in which temperature increases with height. It extends from the top of the troposphere (10-15km above ground level) to a height of 50km and contains the ozone layer.

Stratum (plural Strata)
In geology, a layer of distinctive deposits with surfaces roughly parallel to those above and below.

Stromatolites
A laminated, mounded structure, built up over long periods of time by successive layers or mats of Cyanobacteria that trapped sedimentary material. They are found in shallow, marine waters in warmer regions. Allaby and Allaby (1990).

Sustainable development
The approach to environment and development issues which seeks to produce a balance between continuously satisfying human needs and maintaining the capacity of the environment to cope with the consequences.

Sustainability
Capable of being sustained, to support, to maintain, to keep going. In ecology, the amount or degree to which the earth's resources may be exploited without deleterious effects. Chambers (1994).

Symbiosis
Close association of two organisms of different species living together. Lawrence (1995).

Tropical rain forests
Tropical rain forest is a species-rich biome consisting of stratified communities of broad leafed shrubs, trees, epiphytes, lianas, numerous insects, birds and other animals. Average monthly temperatures are normally in excess of 25oC. Rainfall is between 1250 and 12,500 mm per year.

Troposphere
The lowest layer of the atmosphere in which temperature generally decreases with height. It extends from ground level to a height of 10 to 15 km and contains most of the atmospheric gases and is where "the weather" occurs.

Ultraviolet (UV) Radiation
The ultraviolet spectral region lies at shorter wavelengths than the visible region. Ultraviolet radiation is characterised by having a wavelength below 400 nanometres.

Urban
Situated in or belonging to a city. Chambers (1994).

Vertebrates
Animals classified by the possession of a brain enclosed by a skull , ears, kidneys and other organs, and a well formed vertebral column or backbone enclosing the spinal cord. Lawrence (1995).

Volcanic activity
The process by which a volcano expels gases and particulate material. Large clouds (as at Mount St. Helen's) can result with or without the production of lava.

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