Which part of the world has a high density of organism?

Tropical rain forests are mainly found in central America, along Amazon and Orinoco rivers, South America, Congo river basin of Africa, Malagasy Republic and South east Asia including India. Diversity of life is so high that a hectare of the forest may have as many as 200 species of trees, (70 \%-80 \%) of all insects and (80-85 \%) of all birds are known from tropical forests. Productivity of this biome is also very high and life is abundant. It has different varieties and number of plants and animals.