Tropical rainforests support the greatest diversity of living organisms on Earth. Although they cover less than 2 percent of Earth’s surface, rainforests house more than 50 percent of all plants and animals found on land.
Here are some examples of the richness of rainforests:
Rainforests have 170,000 of the world’s 250,000 known plant species. That's more than two-thirds of all plants!
The United States has 81 species of frogs, while Madagascar, which is smaller than Texas, may have 500 species.
An area of rainforest the size of two football fields (one hectare) may have more than 400 species of trees, while an equal area of forest in the United States may have fewer than 20.
Europe has 570 butterfly species, while Manu National Park, a single reserve in Peru, has 1,300 species.
Table showing countries with the highest number of species for various groups of organisms. A longer list is available here.
Rainforests have an abundance of plants and animals for the following reasons:
Climate: because rainforests are located in tropical regions, they receive a lot of sunlight. The sunlight is converted to energy by plants through the process of photosynthesis. Since there is a lot of sunlight, there is a lot of energy in the rainforest. This energy is stored in plant vegetation, which is eaten by animals. The abundance of energy supports an abundance of plant and animal species.
The Canopy: the canopy structure of the rainforest provides an abundance of places for plants to grow and animals to live. The canopy offers sources of food, shelter, and hiding places, providing for interaction between different species. For example, there are plants in the canopy called bromeliads that store water in their leaves. Frogs and other animals use these pockets of water for hunting and laying their eggs.
It is important to note that many species in the rainforest, especially insects and fungi, have not even been discovered yet by scientists. Every year new species of mammals, birds (slideshow), frogs (slideshow), and reptiles (slideshow) are found in rainforests.