George Dodge, age 9, of Janesville, Wisconsin, for his question:
Why are there animal classes?
The experts have counted about a million different animals. What's more, every year they find another few hundred and the list grows longer. To make the study of them easier and more orderly, the animals that are somewhat alike have been sorted into families, classes and other small groups.
In countries that speak English, a dog is called a dog. The French call him a chien. The dog has a Dutch name, a Greek name and different names in other languages. Scientists need to talk over their work with experts in other lands. Dozens of different names for ' the same animal would bewilder them. Suppose that each one of the million known animals had 20 different names. World wide discussion would get nowhere at all. This is why each animal is given a scientific name that is the same in every language. To do this fob properly, all the animals must be sorted and classed in groups that get smaller and smaller.
To help you to~learn these tricky groups, Andy passes along to you this playful sentence. Kitty Put Catnip On Fido's Ground Steak. Each of the capital letters stands for one of the ' animal groups used by world scientists. Kitty's first letter stand for "kingdom," the Animal Kingdom. It is the biggest group and it has a million members. These animals are sorted into "phyla," which is a scientific term borrowed from an old word for "tribe." Each one of these groups is called a "phylum." Fido and Miss Kitty both belong in "phylum Cordata." So do all the other animals that have backbones.
A phylum is sorted into smaller groups called "classes" and, of course, "class" begins with the same letter as "catnip.", Cats and dogs belong in the Animal Class "Mammalia." So do dozens of other furry, warm blooded, backboned animals that feed their babies on mother's milk. There are other classes in the Cordata PhylgmvOrvwepf3,les, birds and amphibians. The Class Maamalia has room for pigs and porcupines, mice and monkeys, sheep and seals. The mammals all share some likenesses, but there are great differences among them. So the big class is broken up into smaller groups called "orders." Fido and Miss Kitty both belong in the animal order "Carnivore." So do many other meat eating mammals.
It is time now to separate the dogs from the acts. So the Carnivore order is sorted into "families." Fido belongs in the Canidae family, with the wolves and foxes. Kitty belongs with the lions and tigers in the family Felidae. Now the families are sorted into still smaller groups called "genera," which is the plural of "genus." Fido belongs with a few wild dogs in the genus "Cants." Kitty is separated from the lions and put into the Genus "Fells." A genus is divided into the smallest possible unit. It is the "species" and it has room for only one type of animal. An animal's scientific name gives his genus, with a capital letter, and his species, with a small letter. In the world of science, a tame dog is known as "Canis familiaris." Miss Kitty goes under the scientific name of "Fells domestictis
Every animal can claim a place in the king sized Animal Kingdom. But the members of a phylum must have a few points in common. The members of a class must have still more features in common. The animals in an order are even more alike. Those in a family look like relatives and the members of a genus usually look and act like cousins. Only one type of animal belongs in a species and every member of the huge Animal Kingdom has a species all to himself though, of course, you can break the species down even further. There are Persian cats and Siamese cats, for example, or Labrador retrievers and Mexican hairless dogs.