Mark Phillips, age 11, of Lansing, Michigan, for his question:
How many species of animal are there?
If we count all the animals that have been named and classified, the number comes to well over a million. But who knows whether they missed some shy little rodent, living high on a forgotten mountain? Or perhaps they missed a rare frog species, at home by some untravelable river. In the dim steamy, jungles, no doubt there are a few glamorous butterflies waiting to introduce themselves. Naturally, we can count only the animal species we have met and at present the list is incomplete.
It would take quite a while to count the million plus species so far identified. A Noah's Ark parade of the animals would take many weeks to pass by. And such a parade would bring a few mayor surprises. In our everyday lives, our closest animal friends and associates are the furry zoaakmals. For this reason we may tend to assume that mammals make up the bulk of the animal kingdom.
Actually the mammals are the second smallest minority. Since the mammals tend to be sizeable animals, probably almost all their species have been found, named and classified. All told, there are about 5,000 species of mammal living at this time. The handsome grey wolf, the magnificent blue whale and several others, sad to say, are threatened with extinction in the near future.
Though most reptiles tend to keep out of sight, we are aware of certain snakes and crocodiles, turtles and lizards. The number of known reptiles is about 6,000 1,000 more than the mammal group.' Chances are you might underestimate the bird world. The answer is more believable after you consider the vast variety of bird populations that inhabit the different climate zones and add the sea birds. Even so, it is surprising to learn that there are more than 9,000 known bird species.
No doubt you can name some of the species of fishes. But remember that most of our planet is covered with water and that almost all of this water supports fishy populations. If your estimate of the known fish species is around 30,000, you are about right. This figure, however, does not include the multitudes of non fishy creatures that inhabit the seas.
Most of them are classified in the enormous group of arthropod creatures. This largest phylum of the animal kingdom includes assorted shrimps, lobsters and other crusty coated creatures with jointed appendages. And the most numerous group of arthropods is the class Insects. The list of known insects includes some 500,000 species.
The list of animals also includes crusty shelled crabs and mollusks, the octopus and his kinfolk, assorted worms and various soft bodied creatures of the deep. Without a doubt, the largest group is the insect class. The smallest group is the 3,000 or so froggy amphibians who were, strange to say, among the first boldies who left the ancient seas to live on the land.