World fertility surveys indicate that anywhere from one third to one half of the babies born in the Third World would not be if their mothers had access to cheap, reliable family planning, had enough personal empowerment to stand up to their husbands and relatives, and could choose their own family size.
It's a fair guess that at the rate we're destroying habitat, especially but not exclusively in the tropics, we're pushing to extinction about one species every hour. That doesn't count the species whose populations are being reduced so greatly that diversity within the population is essentially gone.
Biodiversity can't be maintained by protecting a few species in a zoo, or by preserving greenbelts or national parks. To function properly, nature needs more room than that. It can maintain itself, however, without human expense, without zookeepers, park rangers, foresters or gene banks. All it needs is to be left alone.