ANIMALS by Milliken Publishing Company – MP3407

ANIMALS – CLASSIFICATION
There are a million or so different animals in the animal kingdom. Scientists classify animals in the following way:
Phylum: Each phylum is broken down into classes.
Class: Classes are divided into orders.
Order: Orders are divided into families.
Family: Families are divided into genera.
Genus: Genera are divided into species.
Species

Look at the classification of a dog and a frog.

1. In the process of classification shown in the chart above, at what point do the dog and the frog
   differ?
2. From your experience, list several ways a dog and a frog are different.

NOTE:
The differences between the two animals are examples of characteristics of each animal. One way scientists classify animals is by shared characteristics.

ANIMALS – VERTEBRATES AND INVERTEBRATES
The major characteristic that divides the animal kingdom is a backbone. It divides animals into two main groups called vertebrates and invertebrates.

Invertebrates are animals without backbones. This group includes the amoeba, sponges, worms, centipedes, starfish, mollusks, and insects. There are many more invertebrates than vertebrates. In fact, invertebrates make up about 90 percent of all animals.

Vertebrates are animals with backbones that surround their nerve cords. The nerve cord is found along the back of an animal. Small bones, called vertebrae, make up the backbone. The bodies of most vertebrates have a head and a trunk. Many vertebrates have two pairs of limbs attached to the trunk. A person’s limbs are arms and legs. The ribs and bones which support the limbs are connected to the backbone. These bones give the body its shape and make up the skeleton.

1. What are a bird’s limbs?
2. What are a fish’s limbs?
3. There are five classes of vertebrates. Check your chart, then list them.
4. List at least five classes of invertebrates.