The wealth of plant life in the tropical rainforest seems staggering. The warm, humid climate of the world's tropical rainforests contain more than 2/3 of the world's plant species. The largest unbroken stretch of rainforest exists in the Amazon River basin in South America. Other large areas of rainforest include those in Indonesia and the Congo Basin.
The rainforest contains four layers of plant life including the emergent layer consisting of the tops of the tallest trees in the forest, most of which grow to 200 feet or more. The next layer down, the canopy, features trees that grow up to 150 feet tall. The understory consists of plants that grow large leaves to soak up all the light they can in this dark and humid part of the forest. The bottom layer, the rainforest floor, contains little plant life since it receives less than 2 percent of available sunlight.
Some plants in the rainforest developed unique traits to access food, sunlight, or water to survive. Carnivorous plants such as Nepenthes rafflesiana, similar to the Venus flytrap, grow up to 30 feet tall with traps 12 inches long where insects get stuck. The plant also eats the small mammals and reptiles who try to steal the insects in the trap. Other plants such as orchids, mosses, ferns and lichens fall into the epiphytes category. Also known as air plants, epiphytes start their lives in the canopy of the forest rather than in the soil. Many of these plants live their entire lives without ever touching the ground.
More than 2,250 plants identified by the United States National Cancer Institute as active against cancer come from the rainforest. At least 25 percent of the ingredients used in today's cancer-fighting drugs come from organisms found only in the rainforest. One anti-cancer drug, Vincristine, is extracted from the periwinkle, a plant found in the rainforest. Since its first use, Vincristine has drastically increased the survival rate for acute childhood leukemia.
More than 25 percent of Western pharmaceuticals come from plants found in the rainforest. But scientists have only tested less than 1 percent of the trees and plants in the rainforest. Based on the rate of destruction in the rainforest as of 2010, scientists worry that life-saving plants may be disappearing before they even get a chance to test their potential.
The rainforest provides food and shelter for a wide variety of animals, birds and insects. Each layer of the forest appeals to different wildlife. The canopy provides food and shelter to sloths, lemurs, spider monkeys, parrots and toucans who find most of their food in this layer, rarely touching the ground.