Tropical Rainforest Biome

The first thing you’ll notice when you visit a tropical rainforest is the abundance of plants, both in shear biomass and total biodiversity. Plants thrive when the yearly average temperature and precipitation, in the form of tropical rains, is high. Below, we describe their main characteristics, where they’re found, the layers of the forest and some common animals you might see on a visit to this biome.

Characteristics of the Tropical Rainforest Biome

All biomes are characterized by the dominant vegetation. In the rainforest biome there are tall trees and warm temperatures all year. The yearly average rainfall is from 50 to 260 inches. The temperature is warm but not hot. Almost every rainforest you might visit has a temperature range of 93°F to 69°F.  The average humidity is between 77 and 88 percent.

Where are Rainforests Found?

Tropical Rainforests are found in a tropical belt around the equator where annual temperature and precipitation are high. However, rainforests now cover much less of Earth’s surface than they once did.

Biodiversity of Rainforests?

Today, about 6 percent of the surface of Earth is covered in rainforests, and more than half of all the world’s plant and animal species live in them. The shear biomass of plants in the rainforest help produce about 40 percent of Earth’s oxygen.

Estimates of the Earth’s biodiversity originally came from studies in Panama, where tree species were logged and the number of insects within them categorized and counted. Estimates range from 10 to 100 million species on earth, most of them being insects found in the tropical rain forests.

The tropical rainforests have more kinds of trees than any other biome in the world. In a rainforest in South America, scientists counted from 100 to 300 species of tree in 2.5 acre sections of the forest. Not all plants in the rainforest are trees though. While they are the easiest to observe, there is a great diversity of epiphytes, plants that live on other plants, that make the rainforest their home. Plants like orchids live on rainforest trees high in the canopy.

It has been estimated that about 25 percent of the medicines we use come from plants in the rainforest, such as:

  • Curare, a tropical vine, is used as an anesthetic and muscle relaxant during surgery.
  • Quinine from the cinchona tree is taken to treat malaria.
  • Rosy Periwinkle from Madagascar is used to treat lymphocytic leukemia.

The look of a typical rainforest

All tropical rain forests resemble one another in some ways. Many of the trees have straight trunks that don’t branch out for 100 feet or more; there is no sense in growing branches below the canopy where there is little light. The majority of the trees have smooth, thin bark because there is no need to protect the them from water loss and freezing temperatures. It also makes it difficult for epiphytes and plant parasites to get a hold on the trunks. The bark of different species is so similar that it is difficult to identify a tree by its bark. Many trees can only be identified by their flowers.

Despite these differences, each of the three largest rainforests–the American, the African, and the Asian–has a different group of animal and plant species. Each rainforest has many species of monkeys, all of which differ from the species of the other two. In addition, different areas of the same rainforest may have different species. Many kinds of trees that grow in the mountains of the Amazon rainforest do not grow in the lowlands of that same forest.

Visiting The Tropical Rainforests

There is no one place to visit if your destination is tropical rainforests. The crew of Untamed Science particularly like the rainforests of Central and South America, but we have many other favorites as well. We spent nearly 9 months in Panama shooting videos and staying at the Smithsonian Tropical Research facility, Barro Colorado Island (BCI).  The following video is a short glimpse into what BCI is like.

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Written by Rob Nelson

Rob is an ecologist from the University of Hawaii. He is the co-creator and director of Untamed Science. His goal is to create videos and content that are entertaining, accurate, and educational. When he's not making science content, he races whitewater kayaks and works on Stone Age Man.

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