AboutBiodiversity
Glossary

accession. In plant and animal collecting, an accession is a record in a database that represents an item in a collection. It can be a description of the item, or a sample of it. Some accessions are stored in protected “banks” at low temperatures to keep them viable.

bacteria. Organisms, very small, that consist of only one, or sometimes several, cells. A single such organism is called a bacterium. Bacteria exist virtually everywhere — in soil, water, air, and on our skin. Like viruses, some bacteria can perform useful roles, while others can cause disease.

benthic. Refers to the bottom of a body of water (the benthos). Benthic organisms are bottom-dwelling creatures.

biological control, biocontrol. The use of natural enemies to cope with pests and pathogens in, especially, food crops. The natural enemies can be bacteria, fungi, parasites, and predator insects. Their use keeps the enemy populations under control. Growers who use biocontrol don’t really want to wipe out the enemies completely, because that would leave nothing for the biocontrol agents to eat.

biotechnology. Originally, this meant the use of technology — pretty much any technology — in connection with living organisms. Today it is more likely to refer to the techniques of molecular biology (the study of biology at the molecular level) and DNA technology to create plants and animals with traits not normally found in Nature.

biotic functions. The functions performed by the living organisms in a specific area, which can be as small as a mud puddle or as big as a mountain range. Those organisms are referred to as the region’s biota.

carbon cycle. The cycle created by the movement of the essential element carbon. Great quantities of carbon reside (are sequestered) in forests, stored in the tissues of plants. (The Amazon basin holds about 20 percent of Earth’s forest-based carbon.) When a forest is cut down or burned, carbon escapes into the atmosphere, disrupting an importance global balance. This distortion of the carbon cycle has been named as a major factor in global warming and climate change. For more on the cycle, click here.

center of diversity. The geographic region in which the greatest genetic variability of an organism may be found. See also center of origin.

center of origin. The place where an organism, usually a plant, is believed to have originated. This may or may not coincide with its center of diversity.

chlorophyll. The green-colored pigment, found in most algae and higher plants, that captures the light in photosynthesis. It is essential to plant growth.

classification, classify. The sorting of organisms, both plant and animal, into categories, based on their relationships. The groups are named taxa (plural) or taxon (singular), then kingdom (for animals) or division (for plants), then classes, then families, then genus, then species. For more, click here.

clone. An individual organism with an identical genetic makeup to another individual. Clones descend from an individual parent. Several of the foods we eat (potatoes bananas, plantains, strawberries, applies, olives, citrus, pineapples) are clones. When a clone contains a variant from the original, which can result from a change in a single gene, it is called a mutant.

cross. The mating of a female and male of an animal or plant species. If the parents are unrelated, the offspring is called a hybrid.

cultivar. A variety of a plant that is created by deliberate selective breeding. Usually the breeding is done in order to get a more desirable plant.

Darwin (Charles). The English naturalist (1809-92) who developed modern ideas about evolution. His countryman, Alfred Russel Wallace, came up with similar ideas at about the same time, but Darwin is the better remembered.

deforestation. The clearing of forested land to make way for agriculture or settlement or to produce lumber.

describe. To record, usually in writing, the basic characteristics of a species. Description is an essential ingredient in the classification of organisms.

desertification. The conversion of once-productive land into desert. The process can be brought on by natural events, such as drought, or by human intervention.

developed world. The countries of the world that are considered “industrialized,” meaning they have higher standards of living than others. The others are often called “developing countries” or inhabitants of the “developing world.” Policy-makers use the terms little now, preferring more politically correct words such as “low-income economies,”“middle-income economies,” and “high-income economies.” To make matters more confusing, politicians now speak also of the “newly-industrializing nations.” See also Third World.

developing countries, See developed world, Third World.

ecosystem. A community of organisms, plant and animal, and the environment in which they live. The definition includes the organisms’ interactions with one another and with the environment, as well. The environment can be a small body of water, a forest, or any other such area. Not only does the ecosystem consist of living organisms, but it also includes many other factors, such as rainfall, climate, and minerals in the soil. Humans are definitely part of any ecosystem in which they live.

environmental erosion, See genetic erosion

environmental indicator. Something that serves as an indicator of the health of an ecosystem, community of organisms, or defined area. A fever thermometer is an indicator of your well-being when it measures your body temperature. Researchers often use the presence or absence of a species as a monitoring device for the health of a place. When it became obvious in recent years that frogs were declining in abundance in many parts of the world, scientists realized that the decline was an indicator of something — of what, they’re still not sure. (For a closer look, click here.)

estuary. The area where a river meets the sea. This is where salty and fresh water mix.

evolve, evolution. “Evolve” comes from a Latin word meaning “to unroll,” and “evolution” refers to the change of species, which could be thought of as an “unrolling” of their development. Charles Darwin and others argued that changes in the genetic makeup of organisms (which can be thought of as mutations) are passed on to succeeding generations. Some of the changed organisms have died out; others, which were better suited for their environment, have survived and gone on to produce other generations. That process is known as natural selection. Some people dispute Darwin’s conclusions and have since he first published them in 1859 in Origin of Species. There are many counter-explanations for species change, some rooted in religious thought. The notion of evolution as conceived by Darwin is the explanation that is accepted today by most scientists.

extinct, extinction. Dead and gone. Animals and plants that die out are referred to as extinct. Practical extinction can occur even before the very last organism in a species dies; if the last remaining creatures or plants are too old to produce offspring, or if only males or only females remain, a species is finished. Extinctions occur all the time, always have, and always will, as species evolve and natural calamities occur, such as meteor impacts and volcanic eruptions. This is called the “background rate” of extinction. In recent years, however, human use of Earth (forest clearing, various forms of pollution) has increased the rate of extinction far past the "background rate.".

food web, food chain. The linkages through which energy and matter are transferred by organisms. The chain starts with solar energy, which is changed by photosynthesis to food for plants and animals. These consumer-producers are then consumed by other consumers, and so on up the line to (in humans’ thinking) human beings. There are usually four to six links in a food chain. Each link in the chain obtains food from the one proceeding it, and then provides food for the succeeding link. A web, then, could consist of plants, eaten by rabbits, which are eaten by foxes, which are eaten by eagles.In the sea, a food may consist of plankton, eaten by larger organisms, eaten by larger fish, eaten by humans. A food web comprises all the food chains in a community of organisms.

fungus (plural: fungi). A plant that lacks chlorophyll, may consist of only one cell, and that lives on nutrients it draws from other organisms. Fungi are either parasites or saprophytes (organisms that live on dead or decomposing materials).

gene. The basic unit of heredity. It transmits information from one cell to another, and so from one generation of an organism to the next. Genes are made up of deoxyribonucleic acid (DNA) and are arranged along an organism’s chromosomes.

gene flow. The movement of genes from one population of a species to another. (In this usage, a population is the total number of breeding organisms in a particular place. So identical species of birds in Hawaii and in China may be considered two separate populations.)

gene pool. The total genetic diversity in a population is known as the gene pool. A population (see gene flow) will contain similar organisms, but individual members will contain differing amounts of the population’s genetic diversity.

genebank, gene bank. A place where samples of genetic diversity are stored, along with identifying information about them. Such samples may be stored in very cold, low-humidity places in order to keep them viable for long periods of time, or they may be continuously grown out and replaced.

genetic erosion. A decline of genetic diversity. It can be brought on by the destruction of forests or pollution of waterways or any of many other causes. For more information click here.

germplasm. As with many of the terms used with biodiversity research, germplasm means different things to different people. By one definition, it is all the seeds, plants, and plant parts. By another, it is all those that are useful in breeding more organisms. Agricultural scientists may think of germplasm as seeds and plants that are useful in breeding new cultivars.

grow out. To start plants from seeds. From time to time, agricultural scientists grow out germplasm stored in their genebanks to test the seeds' viability.

gut. The passageway in an animal or insect that leads from the mouth to the anus. It is essential to the ingestion of food, digestion and conversion of the nutrients in food, and the elimination of the leftovers (fecal material).

heredity. The movement of an organism’s characteristics (such as eye color, size, and the like) from one generation to a succeeding generation. The transmission is done by genes and chromosomes.

hermaphrodite. An organism that has both female and male sex organs. In a plant, one that has both stamens and carpels in the same flower.

host, See parasite

hybrid, See cross.

inherit. To receive characteristics from an ancestor. See heredity.

invertebrate. Animals that have no backbones. They include many microscopically small creatures such as nematodes, as well as spiders, earthworms, and many insects. Vertebrates, the creatures that do have backbones, include fishes, amphibians, reptiles, birds, and mammals.

landrace, land race. Groups of related plants that have been grown in a place over considerable years. They are well-adjusted to their environment, and they contain much biological diversity. In the words of a U.S. National Academy of Sciences report, “Landraces are the products of centuries of planting, selecting, and replanting by farmers.”

microbe, See microorganism.

microorganism. One-celled organisms (such as a viruses, bacteria, and protozoa). Sometimes fungi are also included.

mite. Members of the order Acarina, which are Arachnids with claw-like additions on their mouths. For some great photos of mites, click here.

monoculture. A planting, usually large, of a single species of food crop. Such a setup may be efficient, allowing the farmer to plant, fertilize, and harvest on a set schedule, but it leaves the entire field vulnerable to attack by a single variety of pest or pathogen.

nervous system. The term “nervous system” may sound like it’s associated with being jumpy and nervous, but that’s not what it means. An organism’s nervous system is the bundle of nerves, receptors, and stimuli that multi-celled animals use to manage their activities — receive messages from various stimuli (electrical, chemical, mechanical, or heat- or cold-related) and translate them into commands for various organs to respond. When you touch a hot stove top and say “Ouch!” while pulling your hand quickly away, that’s your nervous system at work.

parasite, parasitize, host, vector, saprophyte. A parasite is an organism that lives at the expense of another organism.A host is the organism on which the parasite lives. A vector is an organism that transmits a parasite. A certain species of mosquito, for example, is the vector for the tropical disease malaria; the human who is infected by the parasite and its vector is the host. A tick is a parasite that receives its nutrition from human and other animal blood. A saprophyte is an organism that lives off dead or decomposing material.

parasitoid. Usually applied to a fly or wasp that lives both as a parasite and as an independent insect. As a parasite, it can deposit its eggs in a host organism and infect it.

pathogen. An organism (such as some bacteria and viruses) that causes disease.

pests. Creatures, often insects, that humans consider harmful. Bugs that compete with farmers for their crops are invariably called “pests.” (The bugs probably have the same feelings about farmers.)

photosynthesis. The process in plants, usually employing chlorophyll, that uses light to turn inorganic molecules into organic ones.

phylum, See classification

population, See genepool

predator, predatory. Any animal that survives by eating other animals. The predator can be a tiny insect or a very large lion, and anything in between.

protozoa. One-celled organisms. Most live in water, but some live in the soil. Despite their microscopic size, protozoa carry out the bodily functions of higher animals, such as digestion, respiration, and excretion.

roots and tubers. Food plants whose below-ground parts are harvested and eaten by humans. A tuber is an enlarged section of a root. Potatoes are roots, as are carrots and parsnips.

saprophyte, See parasite

semen. The liquid that is ejected from the male reproductive organ. It contains sperm, along with nutrients that keep the sperm viable. The sperm’s task is to fertilize the female’s egg.

soil erosion.The removal or disappearance of soil by water (flooding, rain) or by wind.

species. The most basic level by which plants and animals may be grouped. Scientists have an ongoing friendly debate about how to define a species. One commonly held view is that the group is the lowest level of organisms that can breed with one another and that cannot breed freely with other groups of plants and animals. As technology allows researchers to peer ever more deeply into the genetic makeup of organisms, the definition comes under increasing challenge. Perhaps the most valuable characteristic of a species is the fact that it’s the basic unit of classification.

spore. An agent of reproduction that’s formed by one or a few cells. The cells themselves are created by division of parent cells. Spores are a common method of dispersion for fungi and bacteria.

taxonomy. The science of classification.

Third World. A term that is generally used to refer to the poorer nations and people of Earth. After the end of World War II, many nations generally aligned themselves into two categories: those who believed in capitalism (the U.S., several European nations, Australia), and those who followed communism (the former Soviet Union and its satellites). These were referred to, respectively, as the First World and the Second World. But there were many nations that were unaligned — they held three-fourths of Earth’s population — and they became known as the “Third World.” They included Africa, some of the Middle East and Asia, Latin America, and the island nations of Oceania. Although there’s considerable confusion about what places should and should not be called “Third World,” the term still stays around as a shorthand way to refer to the less-wealthy parts of the world.

	Part of a topographical ("topo") map. Do the lines give you an idea of elevations? (US Geological Survey)

topography. The graphic depiction of the shapes and features, and especially the elevations, of an area. This is usually depicted on maps and charts, using printed lines that represent the contours of the surface. Biodiversity is strongly linked to the elevation of the environment, so a knowledge of topography is essential to researchers. For decades, topographical maps were created by land-based surveyors, using altimeters and transits. Now, stunning maps are produced by remote sensing from high-flying airplanes and satellites and even radar. These maps can show not only elevation and land-based features such as streams and lakes, but also (using colors) the sorts of vegetation growing below.

tuber, See roots and tubers

vector, See parasite

viable. Living. Viability refers to the chances an organism has of remaining alive.

virus. A microbe that comprises nucleic acid (DNA or RNA), usually surrounded by a coating of protein. Viruses infect other organisms and thus can control the organisms’ lives, sometimes for the better and often for the worse.

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Abbreviations (some of which appear in photo credits):

ARS. The Agricultural Research Service of the U.S. Department of Agriculture.

LTER. Long Term Ecological Research Network (U.S.). You can learn more by clicking here.

NASA. National Aeronautics and Space Administration of the U.S. government.

NREL. Natural Resouce Ecology Laboratory, Colorado State University, Fort Collins, Colorado, U.S.A.

USDA. United States Department of Agriculture