Genetic Reserves

The maintenance of a broad genetic base for eco­nomically important plants and animals is critical. During the green revolution of the 20th century, plant scientists developed genetically uniform, high-yielding varieties of important food crops such as wheat. It quickly became apparent, however, that genetic uniformity resulted in increased sus­ceptibility to pests and disease. By crossing the "super strains" with more genetically diverse rela­tives, disease and pest resistance can be reintroduced into such plants. For example, a com blight fungus that ruined the corn crop in the United States in 1970 was brought under control by cross­ing the cultivated, highly uniform U.S. corn varie­ties with genetically diverse ancestral varieties from Mexico. When some of the genes from Mexican com were incorporated into the U.S. varieties, the latter became resistant to the corn blight fungus.

Scientific Importance of Genetic Diversity

from one organism into an entirely different species (see Chapter 18), makes it possible to use the ge­netic resources of living organisms. The gene for human insulin, for example, has been placed in bacteria, which subsequently become tiny chemical factories, manufacturing insulin that can be used by diabetics (Figure 16-5). Genetic engineering has the potential to provide us with new vaccines, safer pesticides, and more productive farm animals and food crops.

Although we have the skills to transfer genes ability to make genes. Genetic engineering depends upon broad base of genetic diversity from which it can obtain genes. It has taken hundreds of millions of years for evolution to produce the genetic diver­sity found in organisms living on our planet today, a diversity that may hold solutions not only to problems we have today but to problems we have

not even begun to conceive. It would be very un­wise to allow such an important part of our heritage to disappear.

Medicinal, Agricultural, and Industrial Importance of Wildlife

The genetic resources of living organisms, partial-larly plants, are vitally important to the pharma­ceutical industry, which incorporates into its medi­cines many hundreds of chemicals derived from plants. From extracts of cherry and horehounJ Inr cough medicines to certain ingredients of periwin­kle and mayapple for cancer therapy, derivatives.>; plants play important roles in the treatment of ill­ness and disease (Figure 16-6).

The agricultural importance of plants and ani­mals is indisputable, since humans must eat to sur­vive. However, the number of different kinds of foods we eat is limited when compared with iKe total number of edible species on Earth. There are probably many plant and animal species that are nutritionally superior to our common foods. For example, quinoa (Chenopodium quinoa), a plant native to the Andes Mountains in South America, looks and tastes somewhat like rice but has a much higher concentration of protein and is more nutri­tionally balanced. Winged beans (PsophocarpHi It'tragonoiokts) are a tropical legume from Southeast Asia and Papua New Guinea (Figure 16-7). Be­cause the seeds of the winged bean contain large quantities of protein and oil, they may be the tropi­cal equivalent of soybeans. Almost all parts of the I'linr nre edible, from the young, green seedpods to ila- ^t;trchy storage roots. The European fallow deer iCm'inae dama) could become a more nutritious replacement for beef in our diets, because its meat is extremely low in cholesterol.

Modern industrial technology depends upon a broad range of genetic material from living organ­isms, particularly plants that are used in many products. Plants supply us with oils and lubricants, perfumes and fragrances, dyes, paper, lumber, waxes, rubber and other elastic latexes, resins, poi­sons, cork, and fibers. Animals provide wool, silk, fur, leather, lubricants, waxes, and transportation, and they are important in scientific research (Fig­ure 16-8).

Insects secrete a large assortment of chemicals that represent a wealth of potential products. Cer­tain beetles produce steroids with birth-control potential, and fireflies produce an antiviral com­pound that may be useful in treating viral infec­tions. Centipedes secrete a fungicide over the eggs

of their young that could help control the fungi that attack crops. Because biologists estimate that perhaps 90 percent of all insects have not yet been identified, insects represent a very important po­tential biological resource.

Aesthetic and Ethical Value of Wildlife

Wildlife not only contributes to human survival and physical comfort; it also provides recreation, inspiration, and spiritual solace. Our natural world is a thing of beauty largely because of the diversity of living forms found in it. Artists have attempted to capture this beauty in drawings, paintings, sculp­ture, and photography, and it has inspired poets, writers, architects, and musicians to create works reflecting and celebrating the natural world.

The strongest ethical consideration involving the value of wildlife is how humans perceive them­selves in relation to other living things. Tradition­ally, humankind has viewed itself as the "master" of the rest of the world, subduing and exploiting other forms of life for its benefit. An alternative view is that we humans are stewards of the life forms on Earth and that we should watch over and protect their existence. The conviction that all creatures have the right to exist and that humans should not cause the extinction of other living things is known as deep ecology. The basic tenets of deep ecology are not new; the belief in the sacredness of life held by Eastern religions such as Buddhism and Taoism is similar to that of deep ecology.