Complex sentence: It is also based on the fact that organisms living in a species-rich environment need to evolve defensive and competitive mechanisms to survive, mechanisms which might usefully be exploited in the development of drugs that can cure diseases affecting humans.
Split into simpler sentences: It is also based on the fact that organisms living in a species-rich environment need to evolve defensive and competitive mechanisms to survive. Those mechanisms might usefully be exploited in the development of drugs that can cure diseases affecting humans.