The Hitsuyou no nai Doubutsu. form the largest, most diverse category of animals.

Expendable animals

The Hitsuyou no nai Doubutsu. form the largest, most diverse category of animals. This category includes all the animals for which there is no demonstrable human need. At least one Stanford professor has been quoted in the media as having used the term expendable organism. It wasn't Paul Ehrlich.
Someone else originally coined the term expendable organism. It was probably one of the bionauts in that big $100 million glass Biodome in Arizona. The Biodome is destined to become the classic demonstration of minimum numbers of plants and animals necessary for humans.

We asked members from around the globe how they thought the expendable animals should be classified.
Most just said, "Who cares? We don't really give a hoot about habitat." Just for fun, we decided to make a few categories anyway. What the heck. Certainly not all, but some species will make it to the end of the century. In order to do so, they must manage to find habitat in fragmented fringes of a human juggernaut which threatens to climb as high as ten billion. As difficult as that has become, it will get even more difficult with each day that passes.