Tropical rain forests have a high density of organisms. Tropical rain forests are mainly found in America, South America, Cargo river basin of Africa, South East Asia. In this biome, rainfall and warmth are abundant. Plant growth is luxuriant. This biome possess more than half of the flora and fauna of the world. Productivity is very high. Diversity of life is so high that a hectare of the forest may have $200$ species of trees. $70-80\%$ of all insects and $80 -85\%$ of all birds are known from tropical forests.