Animals
The animal kingdom consists of multi-celled organisms with complex body structures that must consume other organisms to live. Unlike plants, animals are able to move to locate food and over long periods of time, have adapted to their environment to ensure their survival.
Today, there are over one million animal species that have been identified. They range from small microscopic worms to the blue whale, which is the largest organism on earth.
Because of the large number of different types of animals, scientists have divided the animal kingdom into two basic groups: invertebrates and vertebrates.
Invertebrates are animals that have no backbone. They are either soft-bodied animals, such as sea anemones or animals with hard protective shells, such as snails and insects.
There are eight different categories of invertebratessponges
stinging-cell animals(jellyfish, sea anemone)
flat worms(tapeworms)
roundworms(hookworms)
segmented worms(tubeworms,earthworms)
mollusks(soft-bodied animals with a hard shell - snails, octopus, oyster)
sea stars(animals with 5 parts- starfish)
arthropods(animals with exoskeletons - insects, spiders, crustaceans)
Vertebrates are animals with backbones. The five main categories of vertebrates are fish, amphibians, reptiles, birds, and mammals.
fish
cold-blooded animalslay eggs
have scales or bony plates
some have cartilage instead of bones
live in water
breathe through gills
use fins to swim
examples: sharks, swordfish, trout, salmon
amphibians
cold-blooded animals
usually lay eggs in water
lungs to breathe air on land
usually 4 feet with no claws
take oxygen through skin
most are insectivores
examples: frogs, newt, toads, salamanders
reptiles
cold-blooded animals
lay eggs with tough shells
breathe air
most have 4 feet with 5 claws/foot
can be herbivores or carnivores
examples: crocodiles, turtles, lizards, snakes, tortoises
birds
warm-blooded
feathers and wings
2 feet with a bill with no teeth
hollow bones
air sacs attached to the lings
create nests fro eggs
carnivores/ herbivores
examples: vulture, sparrow, emu
mammals
warm-blooded animals
only animal with hair
usually bear live young
nurse young with milk
sweat to stay cool
most fully developed brains
3 kinds of teeth
(incisors, molars, and canine teeth)
carnivores/herbivores/omnivores
examples: gerbil, tiger cow, bear, man
To sum up, the animal kingdom is a very large and diverse category. The two main divisions are animals with backbones and animals without backbones. These two groups are called vertebrates and invertebrates.
Within these two groups, the animals are further broken down into smaller groups by examining the differences between certain characteristics they possess. Examples of these traits are the food they eat, how they reproduce, and how they breathe.
Below are some pictures of vertebrates and invertebrates.
