THE ANIMAL KINGDOM

UNIT 3 NATURAL SCIENCE

The Animal Kingdom is divided into two groups:

Invertebrates – All animals without back bones are called Invertebrates. Earthworms, starfishes, squids, snail fall in this category.

• Marine Invertebrates - There are a wide variety of interesting ocean animals that are invertebrates. These include sponges, corals, jellyfish, anemones, and starfish.

• Mollusks - Mollusks have a soft body that is covered by an outer layer called a mantle. Many mollusks live inside a shell, but not all of them. Some examples of mollusks include squid, snails, slugs, octopuses, and oysters.

Vertebrates – All animals with back bones are called vertebrates (mammals, birds, fish, amphibians and reptiles).

Mammals are a particular class of animal. 

What makes an animal a mammal are several things. 

First, they must have glands that give milk. This is to feed their babies. 

Second, they are warm-blooded. 

Third, all mammals have fur or hair. 

Humans are mammals and so are dogs, whales, elephants, and horses. Most mammals have teeth with the exception of the ant eater which doesn't have any teeth.

Where do they live? 

Mammals live in all sorts of environments including the ocean, underground, and on land. Some mammals, bats for example, can even fly. 

Mammals have unique brains and are often very intelligent. Humans are the most intelligent. 

Other intelligent mammals include the dolphin, the elephant, the chimpanzee, and the pig. That's right, pigs are thought to be one of the smartest animals! 

What is it that makes an animal a bird? 

The main characteristic of a bird is feathers. No other animal has feathers. Other important features for birds are wings and hollow bones. Birds also lay eggs, like reptiles, however they are warm-blooded, like mammals. 

Feathers are important to birds because they keep them warm, help them to fly, and provide camouflage. 

There are all sizes of birds. Hummingbirds are some of the smallest birds, while ostriches are some of the biggest. 

What makes a fish a fish? 

All fish are cold-blooded animals that live in the water. They have backbones, fins, and scales. 

Fish come in more varieties than any other group of vertebrate animals. There are 32,000 different species of fish. 

All fish have gills that allow them to breathe water. Just like we use our lungs to exchange oxygen for carbon dioxide from the air, the gills of a fish perform a similar function from water. So fish still need oxygen to live, they just get it from the water instead of the air. 

• The biggest, or heaviest, fish is the ocean sunfish which can weigh as much as 5,000 pounds. 
• The longest fish is the whale shark which has been known to grow to over 40 feet long. 
• The fastest fish is a sailfish which can swim as fast as 68 miles per hour. 
• The smallest fish is the dwarf goby at only 9mm long.

A lot of people like to have fish as pets. There are special aquariums and food you can get to take care of your fish. They can be fun to have and also beautiful to look at. Although they are fairly easy to take care of as pets, you will need to do some work. You need to keep the 

What is a reptile? 

Reptiles are animals that are cold-blooded. Most reptiles lay eggs and their skin is covered with hard, dry scales. 

What does cold-blooded mean? 

Animals that are cold-blooded don't automatically maintain a constant body temperature. They have to lay out in the sun to keep their body heat up, like Jack and Barbossa! 

There are many types of reptiles. The main categories are snakes, crocodiles and alligators, turtles, and lizards. Reptiles can be found on every continent except for Antarctica.

What's the difference between reptiles and amphibians? There are a few major differences that separate reptiles and amphibians. Amphibians go through a larval stage, like the tadpole which turns into a frog. Reptiles don't do this. Also, their skin is different where reptiles have scales for skin, but amphibians have moist, glandular skin. 

What are amphibians? 

Amphibians are a class of animals like reptiles, mammals, and birds. They live the first part of their lives in the water and the last part on the land. When they hatch from their eggs, amphibians have gills so they can breathe in the water. 

They also have fins to help them swim, just like fish. Later, their bodies change, growing legs and lungs enabling them to live on the land. 

The word "amphibian" means two-lives, one in the water and one on land. 

Amphibians have adapted to live in a number of different habitats including streams, forests, meadows, bogs, swamps, ponds, rainforests, and lakes. Most of them like to live in or near water and in damp areas.