BIOLOGICAL DIVERSITY / BA Second Year English

BIOLOGICAL DIVERSITY UNDER 

Biologists have described one million species of the earth. In addition, they have estimated the number of the species from three million to thirty million. More than half of the species have their home in tropical forests. However, tropical forests rapidly being destroyed humans. Millions of hectares of tropical forests in Brazil, Indonesia and Malaysia have been cut down or burnt. The destruction of tropical forests is causing the rapid extinction of the natural species that are native there. Out of 2 million species living in the tropical rain forests, 4,000 to 6,000 species are being disappeared every year, and it might reach up to 27,000 in the future. First, rain forests species are a valuable resource because their genes may enable scientists to strengthen domesticated species. Researchers are using genes from the wild American oil palm to develop resistance to the disease called spear rot in domesticated African oil palm. Second, the wild species of the tropical forests are an underused, valuable source of wild plants that could be domesticated. Next, the endangered species of the tropical rain forests could be a source of important new medications. Vinblastine and vincristine are extremely effective in the treatment of two forms of cancer.

Although the rapid loss of tropical species cannot be stopped completely, it can be slowed if we address all its causes. First, conservation is a necessary component of a solution to the biodiversity crisis. By protecting the habitat of this species, it shows their extinction. Next, to provide the information needed for conservation and education, we need to speed up research into the species of the tropical rain forests. Only then people will realize the value of conservation. Finally, we need to reduce the economic pressures that force people to destroy the rain forests.

UNSUSTAINABLE DEVELOPMENT AND THE MAYAN CIVILIZATION

UNSUSTAINABLE DEVELOPMENT AND THE MAYAN CIVILIZATION

The use of pesticides and the fossil fuel are not the only causes of environmental damage in the present time. Humans have been damaging the environment for much longer than the last century. Clearing fields for agricultural use, which began ten thousand years ago, had a very disruptive effect on the environment. But man used water and fertilizing material to sustain agriculture. The settled societies that agriculture made possible also placed considerable strain on the environment. They cut down trees for fuel and farming land. Mesopotamia, the Mediterranean basin, and the Central America rain forests were areas where the ecology was disrupted by early human activities. Here the Mayan civilization will be discussed in detail.

The Mayas had built many cities with wonderful temples, palaces, and public buildings. And the total Mayan population was 5 million. To grow the crops needed to support their large population, the Mayas replaced the forest with a complex artificial environment consisting of raised fields and terraces with a drainage system. The MayasÚ expanding system of agriculture collapsed when the ecology of the region could no longer sustain it. There was soil erosion in the hills and the lowland was flooded. As a result, the crops decreased. The loss of food production caused increase fighting for the available resources Ù this destroyed the Mayan civilization. Like many other cases, the expansion of the Mayan civilization was unsustainable it ultimately destroyed the environment that supported it.

ECOLOGY, OVERPOPULATION, AND ECONOMIC DEVELOPMENT

ECOLOGY, OVERPOPULATION, AND ECONOMIC DEVELOPMENT

Up until two hundred years ago, humans did not have a significant effect on the ecology of planet earth because there were not more than one billion people. Because of the massive increase in population in the last two centuries, damage to the ecology from human activities is considerable and may become much worse. Locally, people respond to the pressure of overpopulation in ways that destroy the ecology of the areas they live in. They cultivate the hilly areas, where soil erosion makes the land unproductive very soon. The disappearance of tropical forest – a result of countries attempts at economic development – is causing great damage to the natural resources and the ecology of those nations. The destruction of the world's tropical forests will have negative consequences for the entire globe.

Family-planning programs, which have proved successful in some developing countries, could contribute to the solution of the overpopulation problem. They could make economic growth increase. The number of children currently in the worldÚs population means that birth control cannot be the sole solution to the problem of overpopulation. The worldÚs population is sure to increase. Social and economic development is also an essential part of a solution to the environmental damage caused by overpopulation. Economic development, which is the answer to the problem of overpopulation, is also the cause of massive damage to the environment. Europeans and North Americans today are asking the people of the developing nations not to overexploit natural resources, which they have been doing for centuries to develop themselves. In both developing and developed countries, traditional economic development must be replaced by policies and practices that are sustainable.

THE ARAL SEA: AN ENVIRONMENTAL CRISIS GETTING INTO THE TOPIC

THE ARAL SEA: AN ENVIRONMENTAL CRISIS GETTING INTO THE TOPIC

The pressure to make economic development and the short- sighted responses to this pressure are the cause of a great damage. It will make economic development impossible and the region unliveable. The recent history of the Aral Sea has proved this fact. In the 1950s the sea covered 66,000 square kilometres. It had an average depth of 16 meters. Its water was fresh. But by 1990 the Aral Sea became almost half and was divided into two separate lakes. Its water became just one third of its 1950s volume. The seaÚs salt content has increased by almost 300 percent. The basic cause of the damage to Aral Sea was the use of irrigation to expand agriculture.

The reduced flow of water into the Aral Sea has had disastrous environment and economic consequences for the sea and its basin fish has died. Cotton plantation has become impossible. Birds and mammals have halved. In addition, the salt carried by the storm has made the surrounding land infertile. Short-sighted agricultural practices have increased the levels of salts, pesticides, and other damaging chemicals in the environment. Because of the chemical contamination of drinking water, there has been an increase in human health problems. In 1990, a scientific conference decided that the Aral Sea region was an ecological disaster area in need of urgent action to prevent its complete destruction. The story of the Aral Sea is one example of the global problem of desertification through human activities. In addition, it has helped us to find out the cause of desertification and an alternative model for economic development.