The collective action of humans – developing and paving over the landscape, clear-cutting forests, polluting rivers and streams, altering the atmosphere’s protective ozone layer, and populating nearly every place imaginable – are bringing an end to the lives of creatures across the Earth. Extinction of biological species is not necessarily a phenomenon initiated by human activity, some argue. Although the specific role of extinction in the process of evolution is still being researched and debated, it is generally accepted that the demise of any biological species is inevitable. Opponents of special efforts to protect endangered species invariably point this out.
They also suggest that the role of homo sapiens in causing extinction should not be distinguished from that of any other species. This position, most often espoused by individuals whose other views are curiously much more anthropocentric, is contrary to some well established facts. Unlike other creatures that have inhabited the Earth, human beings are the first to possess the technological ability to cause wholesale extermination of species, genera or even entire families of living creatures. This process is accelerating. Wildlife management efforts initiated during this century have been unsuccessful in stemming the tide. Most public attention given to endangered species has focused on mammals, birds, and a few varieties of trees.
Ecologists recognize a far greater threat to the much larger number of species of reptiles, fish, invertebrates, and plants that are being wiped out by human activity. In the past few decades, vast areas in several regions of the world have been cleared to make room for urban development or for food production. Modern agriculture techniques and industries’ need for raw material have contributed to the epidemic of extinction. During the last few centuries, growth in the human population and intensification of our use of resources has greatly increased the rate of species extinction. Today, this rate is at least 1,000 times higher than it was when the genus Homo made its appearance about 2 million years ago. According to the best estimates, an average of 200 species vanishes from the Earth every day.
By the year 2025, an estimated 20 percent of Earth’s species may have been pushed to extinction – a loss of species unmatched since the end of the Mesozoic 65 million years ago. For human beings, the consequences of this extensive wave of extinction’s will be severe, whether they are viewed from a moral, aesthetic, scientific, or economic perspective. Scientists fear that the vitality of our ecology may be seriously threatened by the reduction of biological diversity resulting from the lost genetic resource contained in the extinct species. They note that the ability of species to evolve and adapt to environmental change depends on the existence of a vast pool of genetic material. This problem joins the issue of endangered species with that of wilderness preservation. Unfortunately, the need to set aside vast undeveloped areas to prevent wholesale extinction is more acute in the poorer, more crowded regions of the world where people are pressured by both their own basic needs and the demand of the industrialized world for their resources.
The concept of biodiversity helps capture the magnitude of the problem. Biodiversity is the variety of, and interaction among, living organisms and the ecological complexes that they occur in, from the smallest habitat to the Earth as a whole. The concept also includes the genetic variability within these species, the raw material of both evolutionary adaptation and selective breeding by humans. In terms of biodiversity, extinction is more than the loss of individual species, it is the degradation of the ecological complexes that support all life on this planet. The set of plant, animal, fungus and microorganism species that occur together at a particular place make possible the functioning of an ecosystem at that place. Undisturbed ecosystems, with their natural level of biodiversity – regulate the flow of energy and the cycling of nutrients, which all life depends on.
The ongoing elimination of a sizable portion of the Earth’s biota is probably the clearest sign that the manner in which we use the natural environment is not sustainable. The intensity of our exploitation of natural resources is simply too great. In the past .
