Question

Until recently, the plant family Dipterocarpaceae was thought to be restricted to Tropical Asia, where many species are ecologically dominant trees. Recently, a new species of tree in this family was discovered in the rainforest of Colombia, in northern South America. Propose a hypothesis that may explain its presence in South America. How could you test your hypothesis? How would your hypothesis change if these species were found in Africa, South America, and Australia?

Answer 1

Dipterocarpaceae trees were usually found in Asia. But because of long term evolutionary events and ecological factors some species under this family is found in Colombia, South America etc.The hypothesis by which these species are found in South America is the dispersal and colonisation of seeds by wind or water dispersal. By these methods these seeds would have reached South America. They require a tropical and arborescent climate which was found in the rainforest of America. Now the climate in these regions have become better favourable for these seeds. These plants might be found in Africa and Australia but our hypothesis remains the same as seeds are dispersed through wind or water. They would have reached these places from India or Asia.