By preserving biodiversity locally will have a global effect how? Well if we did not preserve biodiverseity then there would be a reduction of oxygen and there would be a lot more pollution. The pollution would cause illnesses which we might not be able to cure because Their ingredients come from organisms which will not have a large population if at all. They will not have a large population because their keystone will die and because they depended on that organism they will also die. By preserving biodiversity we can further our studies that could save lives.
A habitat is where an animal reproduces. When humans takeover their habitats they are forced to move somewhere else and they will not reproduce until they find a new habitat. This is usually a place where already inhabitated by other species. So now the breeding grounds are smaller and because of an increase of population there might not be enough food to go around. Another factor is that it might have taken the animals a while before they abandoned their home, so they might be ill because of being exposed to something their body is not used to and it could spread to the other animals in their new habitat.
Preserving biodiversity could enhance human life with their contribution to medicines and drugs. Because of tiny microorganisms and bacteria people can be cured of an illness.