Humans are not only the intelligent species. There are many animals involved in other intelligent activities, for example, Dolphins are the second intelligent species. Once one animal has a stronghold on a niche, it is hard for another animal to get into that niche, so it evolved differently. According to Greg Steven, humans are the most intelligent as they are capable of thinking far. As per the evolution theory, humans are smarter than chimps, chimps are smarter than dogs, dogs are smarter than mice and mice are smarter than starfish. In the world, there are many variations in shape and sizes, such thing happen in the intelligence of a human. Darwin once said that there is no fundamental difference between man and the higher mammals in their mental faculties – he firmly believed that the difference between human and animal intelligence is small (Halley, 2012).
Though humans are most intelligent, still they are harmful to the other species even on the various endangered species. Human is the only reason for the present bad condition of bio-diversity which affects the food chain of the environment. Humans threaten ecosystem by producing waste, damaging habits and severely affected the other species like water plankton and zoo planktons etc. Humans destroy wild land by cutting trees and building homes, shopping malls and factories etc. The birds and animals become homeless, and day by day, they disappeared. In the crop fields, the farmers spray chemical reagent which can be harmful to the planktons that lives in an aquatic habitat. Excluding humans, all other species are not as harmful as human, as they do not affect the environment so much. The research is carried out by the institutes and it requires huge investment in order to achieve the required result.