Spreading far and wide over the soils of Brazil, Venezuela, Peru, Colombia, Ecuador, Bolivia, Guyana and Suriname, sheltering an area of 5,500,000 km² (2,123,562 sq mi) is the world’s largest tropical rain forest with many species of wildlife and some of them are undiscovered up to date. It was even listed to be voted in the new seven wonder of Nature in 2009. Not only as a rainforest untouched but because of its variation in flora and fauna plus the climate and its vastness, it beholds a very important place among most beautiful places found on Earth. Not to forget though this is a living laboratory, a rich reserve of Carbon and a store house of Oxygen and it’s our top priority to protect it.
It is believed that the name Amazon is said to arise from a war Francisco de Orellana fought with a tribe of Tapuyas and other tribes from South America. The women of the tribe fought alongside the men, as was the custom among the entire tribe. Orellana derived the name Amazonas from the ancient Amazons of Asia and Africa described by Herodotus and Diodorus in Greek legends.
Rainforest must have been formed during the Eocene. It must have formed following a global reduction of tropical temperatures when Atlantic Ocean expanded sufficiently to provide warm and moist climate to the Amazon basin. Since its formation it must have been existed the way it is for about 55 million years mostly free of Savannah type biomes. When the climate became drier the Savannah spread widely.
The extinction of the dinosaurs and the wetter climate may have allowed the tropical rainforest to spread out across the continent. From 65-34 Mya, the rainforest extended as far south as 45°. Climate fluctuations during the last 34 million years have allowed savanna regions to expand into the tropics. During the Oligocene, for example, the rainforest spanned a relatively narrow band that lay mostly above latitude 15°N. It expanded again during the Middle Miocene, then retracted to a mostly inland formation at the last glacial maximum. However, the rainforest still managed to thrive during these glacial periods, allowing for the survival and evolution of a broad diversity of species.
During the mid-Eocene, it is believed that the drainage basin of the Amazon was split along the middle of the continent by the Purus Arch. Water on the eastern side flowed toward the Atlantic, while to the west water flowed toward the Pacific across the Amazonas Basin. As the Andes Mountains rose, however, a large basin was created that enclosed a lake; now known as the Solimões Basin. Within the last 5-10 million years, this accumulating water broke through the Purus Arch, joining the easterly flow toward the Atlantic.
There is evidence that there have been significant changes in Amazon rainforest vegetation over the last 21,000 years through the Last Glacial Maximum (LGM) and subsequent deglaciation. Analyses of sediment deposits from Amazon basin paleolakes and from the Amazon Fan indicate that rainfall in the basin during the LGM was lower than for the present, and this was almost certainly associated with reduced moist tropical vegetation cover in the basin. There is doubt, however, over how extensive this reduction was. Some scientists argue that the rainforest was reduced to small, isolated refugia separated by open forest and grassland and other scientists argue that the rainforest remained largely intact but extended less far to the north, south, and east than is seen today. This has proved difficult to resolve because the practical limitations of working in the rainforest mean that data sampling is biased away from the center of the Amazon basin, and both explanations are reasonably well supported by the available data.
Based on archaeological evidence from an excavation at Caverna da Pedra Pintada, human inhabitants first settled in the Amazon region at least 11,200 years ago. Subsequent development led to late-prehistoric settlements along the periphery shespeaks of the forest by 1250 AD, which induced alterations in the forest cover. Biologists believe that a population density of 0.2 inhabitants per square kilometre (0.52 /sq mi) is the maximum that can be sustained in the rain forest through hunting. Hence, agriculture is needed to host a larger population.
Some 5 to 7 million people lived in the Amazon region, divided between dense coastal settlements, such as that at Marajó, and inland dwellers. For a long time, it was believed that those inland dwellers were sparsely populated hunter-gatherer tribes. Archeologist Betty J. Meggers was a prominent proponent of this idea, as described in her book Amazonia: Man and Culture in a Counterfeit Paradise. However, recent archeological findings have suggested that the region was actually densely populated.
One of the main pieces of evidence is the existence of the fertile Terra preta (black earth), which is distributed over large areas in the Amazon forest. It is now widely accepted that these soils are a product of indigenous soil management. The development of this soil allowed agriculture and silviculture in the previously hostile environment; meaning that large portions of the Amazon rainforest are probably the result of centuries of human management, rather than naturally occurring as has previously been supposed. In the region of the Xinguanos tribe, remains of some of these large settlements in the middle of the Amazon forest were found in 2003 by Michael Heckenberger and colleagues of the University of Florida. Among those were evidence of roads, bridges and large plazas.
As we all know, Amazon forest is amazingly rich in flora and fauna. Discussing through its wildlife one may find many varieties of native and indigenous species of frogs eg: Giant leaf frog, birds like Scarlet Macaw, and as many as 2.5 million of insect species. It is home for 40 000 plant species, 3000 fish, 1,294 birds, 427 mammals, 428 amphibians, and 378 reptiles. Scientists have described between 96,660 and 128,843 invertebrate species in Brazil alone.