Rainforests cover 2 percent of the earth's surface, or 7 percent of its land mass. Tropical rainforests are the Earth's oldest continuous ecosystem. Fossil records show that the forests of South East Asia have existed for 70 to 100 million years. Rainforests are being destroyed at an estimated rate of about one football-field-sized area per second. The soil has few nutrients so it makes poor farmland. An area of rainforest cleared for farming or grazing cattle becomes unproductive in …showed first 75 words of 314 total…

…showed last 75 words of 314 total…become extinct. The indigenous people of the tropical rainforests are the greatest source of knowledge about medicines from rainforest plants. These people have traditionally passed their knowledge on to their children. But this is changing as children are choosing not to follow in their ancestors' footsteps. One of the major uses of former rainforest land is for grazing cattle for beef that is sold around the world. This inexpensive beef is frequently used in fast-food.