Biodiversity

Biodiversity, or biological diversity, is a broad term that includes all forms of life and the ecological systems in which they live. Biodiversity also refers to the degree of variety found in life and ecosystems (an area in which living things interact with each other and the environment). It suggests a level of healthy or balanced diversity of habitat, as well as animal and plant life. Biodiversity has also been described as the total richness of biological variety in a given place and can serve as a measure of the number of different types of organisms that live there. The opposite of biodiversity is the extinction of a species.

EDWARD WILSON COINS THE TERM BIODIVERSITY

As first put forth by the American biologist, Edward O. Wilson (1929–), biodiversity has become a standard against which scientists can measure the negative impact or damage that modern human societies have inflicted upon Earth and its creatures. The growing threat to biodiversity posed by human activities makes it one of the most important aspects of the present global environmental crisis that some scientists say we are experiencing. Humans have already caused permanent losses of biodiversity through extinction of certain species. Often this is caused indirectly by destroying a particularly distinctive natural environment in which these species lived. Some ecologists predict that unless there are major changes in the ways that humans affect ecosystems, there will be much larger losses of biodiversity in the near future. In the past, humans have hunted some creatures like the dodo bird into extinction, and sometimes simply crowded others out of their natural habitats. It is known that some 200 species of plants native to the United States already have become extinct, and that as much as 20 percent of all bird species around the world have gone extinct. Wilson estimates that at least 27,000 species of plants and animals are becoming extinct every year by cutting down the rain forests in Brazil's Amazon region. Since extinction is the permanent death of a species, the world will lose an enormous amount of biodiversity as the years pass.

EDWARD OSBORNE WILSON

Founder of the modern field of sociobiology (the study of what biologically determines social behavior) and the only person to receive both this nation's highest scientific and literary awards, American entomologist Edward O. Wilson (1929– )is one of the great naturalists in American history. His work has influenced the field of animal taxonomy (the science of classifying living things), and the discovery of pheromones (chemicals that are released by an animal and which affect another animal). He also has become a powerful voice condemning the steady loss of biodiversity (a broad term that includes all forms of life and the ecological systems in which they live).

Edward O. Wilson was born in Birmingham, Alabama, and is a descendant of farmers and shipowners. Always drawn to the outdoors, he decided at the age of seven to become a naturalist explorer. His plans changed, however, when he suffered an injury to his right eye while fishing, which made him change his plans. By the age of ten, after reading a National Geographicarticle titled, "Stalking Ants, Savage and Civilized," Wilson decided to become an entomologist. (Entomology is a branch of zoology that deals with insects.) After studying biology at the University of Alabama, he received his bachelor's degree in 1949. By the age of twenty-six, he had earned a Ph.D. in biology from Harvard University, where he continues to work. His early work led taxonomists (classifiers of organisms) to revise their procedures, and by the late 1950s, Wilson had begun to study how social insects, like ants, communicate. His work with the venom glands of fire ants led to his discovery that animal chemicals called pheromones are used to communicate complex instructions. He later wrote that pheromones were "not just a guidepost, but the entire message." In the 1960s, he offered the theory of species equilibrium, which demonstrates that the number of species on a small island would always remain constant.

In the 1970s, Wilson's work on the biological basis of social behavior caused a major controversy. In his 1975 book, Sociobiology: The New Synthesis, Wilson suggested that the way people act or behave in certain situations can sometimes be accounted for by their genetic makeup. This daring idea caused a great stir among many colleagues who argued that similar ideas had led to notions that people were "biologically determined" to act a certain way and were therefore not responsible. Wilson's critics also said that such an idea could lead to some of the policies followed by Nazi Germany during World War II (1939–45) when it claimed that certain races were genetically "inferior" to others. In 1978, Wilson defended his theory with his book On Human Naturein which he more fully explained his views. In this book and others, Wilson made a good case for not ignoring the role of biology in trying to understand human behavior.

In the 1990s, Wilson also became closely identified with the notion of biodiversity. Technically, this word means the variety of life or the biological diversity of species in an area. However, biodiversity also has come to mean the richness and balance of an ecological system. It does not necessarily mean huge numbers of life forms, but rather suggests equal numbers of individuals of different species. Biodiversity not only has commercial value to people but, argues Wilson, its continued loss is a signal of the worsening health of the environment. Wilson is very concerned with trying to minimize what he sees as mass extinctions that are happening in the modern world. As huge areas of rain forest are destroyed each year, species are going extinct in record numbers as they lose the habitat that support them. As people continue to drive plant and animal species to extinction, they also are killing the spirit and the beauty of the natural world. Today, Wilson is doing his best to prevent this from happening.

To biologists, biodiversity is not just a blanket term for the natural biological wealth found on Earth or a description of a healthy and richly varied ecosystem, but it is something that is good biologically. In other words, biodiversity is something to value, to maintain, and to try to protect. Both the term "biodiversity" and the concept were born in 1986 during the National Forum on Biodiversity, held in Washington, D.C. and sponsored by the National Academy of Sciences and the Smithsonian Institution. Most attribute both the word and the concept to Wilson. In his extensive writings, Wilson argues that the notion of biodiversity has a value of its own whether or not it is related to humans in any way. This argument brings up the ethical question of whether mankind has the "right" to do whatever it wants with Earth and its creatures—even to the point of destroying them. On a more practical level, Wilson says that preserving biodiversity has very specific benefits to humans, as illustrated by the fact that in the United States, one-fourth of our prescription drugs have active ingredients obtained from plants. Wilson gives two dramatic examples. The first is the rosy periwinkle plant that became the source of two of the most effective anticancer agents ever discovered. The other is cyclosporin, an obscure fungus that lives only in Norway. This fungus became a powerful immunosuppressant drug and is entirely responsible for our ability to do organ transplants. More generally, a biologically diverse planet is simply more liveable and functional since nature, if properly balanced, keeps water and air cleaner, recycles nutrients, removes waste, and even controls erosion.

Biodiversity is a very broad term. Overall, there are three general kinds of biodiversity: ecosystem or habitat diversity, species diversity, and genetic diversity. The diversity of an ecosystem refers to the variety of actual ecosystems or places where organisms live in a certain region. Thus a region with forests, streams, ponds, grasslands, and farmland is more biologically diverse than one that has only open agricultural fields. It goes without saying that when an ecosystem or habitat disappears, a great number of species disappear as well. Species diversity refers to the ability of many different types of organisms to exist at a certain time. Finally, genetic diversity refers to the level of variability that is found among individual members of a single species. Variability, or variation, refers to the natural differences between living things, and it is a very important phenomenon since it allows a species to adapt to environmental changes over time through evolution.

The threat to our planet's biodiversity is different from most other ecological problems in that it is irreversible. Once a certain species has gone extinct it has disappeared forever and its entire heritage that took millions of years to evolve is lost. Since scientists admit that the vast majority of species have not yet even been identified, humans may be destroying species about which nothing in known, and therefore never will. Finally, by trying to solve some of the problems associated with threats to biodiversity, people gain new knowledge about managing the Earth and using its natural products for the benefit of all.