Tuesday, June 3, 2008

Talk: Jonathan Yim

Jonathan Yim: Biodiversity in the Amazon

The Amazon is the largest tropical rainforest in the world, occupying nine different countries. It has the richest biodiversity of any forest in the world. In just one hectare, more species are present than all of the species present in all of Europe. One tree in the Amazon was found to contain 72 different species of ants! A great many species remain undiscovered. The soil in the Amazon is not very rich; 80% of the nutrients in the Amazon are contained in the vegetation, not in the soil. This is due to the constant flooding and draining of the rivers, which leaches nutrients out of the soil. The Amazon produces many natural resources of use to humans. Plants produce fruits (cupuacu, acai, guarana), oils, and fibers.
Lots of mammals live in the Amazon, including the capybara, the largest rodent in the world. The largest mammal in the Amazon is the jaguar, however. The sloth, the slowest animal in the world, moves only a kilometer a month and sleeps eighteen hours a day. More than 3000 species of fish have been found in the Amazon. There are seventeen tributaries of the Amazon of more than 1000 miles in length; a lot of water! Pirarucu can get up to five meters in length; they are the longest freshwater fish in the world. Over 1000 species of amphibians have been found in the Amazon. Frogs in the Amazon can be found far from bodies of water, because the humidity is so high; in fact, they often lay their eggs on leaves, not in the water. There are more species of insects in the Amazon than any other type of animal. One square mile of rainforest can have 50,000 species of insect, the bulk of which are ants. One third of all the world's bird species are found in the Amazon. The largest is the macaw, and the rarest bird in the world is a type of macaw as well.
Deforestation is threatening this biodiversity, due to exploitation of resources. The Amazon acts as the world's lungs, cleaning the air and absorbing carbon dioxide; its importance is global.

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