It is characterized by average annual temperatures of 25 ° C, abundant rainfall of up to 4.500 ml per year and limiting factor is light. High temperatures and humidity rise too many layers or floors of trees, struggling to reach the light, which come only copies giants rising to a height of 40 to 50 meters.
Another name given to this evergreen forest ecosystem, as some species of trees retain their leaves over a year and others do not lose at the same time but in different seasons. Thus, while some trees shed their leaves, others sprout. As new shoots grow quickly, retains its green jungle. This distinguishes it from other ecosystems, where the trees are leafless in the dry and bloom until it rains again.
Rainforests are often called "the world's largest pharmacy" because of the large amount of natural medicines from them. According to scientists, the cure of many diseases present in the future will be achieved thanks to the richness of plant chemicals present in these ecosystems.
According to Charles Darwin's theory on the evolution of species, human ancestors evolved from primates who lived in forests and tropical forests, where they feed on stems, leaves, roots, seeds and berries. Hominids, primates group which included the man-today-only representative, soon left the forest, but continued taking advantage of the resources it provided them not only food but for fire and weapons, homes and even transportation.
In the past, forests covered larger areas than today. It is likely to extend the African jungle to the east and north to join the wilds of Arabia and India. It is believed that human influence on climate change altered the space in those regions. Studies have shown that there virgin forests since the time of the Cretaceous, more than 100 million years. Fossils of those times confirm that northern Europe was populated with forests similar to those which now cover the tropics.
The soil, which provides water and minerals, is very fertile in the jungle, and that organic matter is rapidly decomposed by the heat and humidity, and nutrients are washed away by heavy rains. There is accumulation of iron and aluminum oxides that give particular red. In addition, it remains moist, as the foliage absorbs nearly all light and does not allow passage of sunlight into the interior.
Water is important because it helps the forest soil to be fertile. This is possible because of the continuously falling leaves, fruits and even tree branches to form a layer that covers the ground. So tiny bacteria go into action, which helped the environment so wet, rotting in a short time the topsoil, which allows nutrients to return to the ground and serve as natural fertilizer for new plants. This layer of dead organic matter called humus.