Contributor: Samantha Penna. Lesson ID: 11486
How many legs do you have? What if you had none, or 1,000, and no skeleton? You would be in the largest group of creatures in the world: Invertebrates! Watch them, find them, and then describe them.
Feel your spine.
Animals that don't have backbones make up 95% of the known animal population. They are everywhere!
This means you have a spine. Mammals, reptiles, amphibians, birds, and fish all have spines. Some animals don't have backbones! These animals are called invertebrates.
Invertebrates do not have a backbone!
That's right! They don't have a backbone. Push that fact into your brain and keep it there, because you will need it for the whole lesson.
During this lesson, use a pencil and paper to write down any important facts you learn during the lesson. You should have at least two facts for each example of invertebrates.
Invertebrates are everywhere. They are the insects that fly around your food at a BBQ. They are the snails that eat your mother's garden, and they are the crabs that pinch your toes at the beach.
There are so many different types of invertebrates. Insects, worms, arachnids, snails, clams, sea stars, sea urchins, coral, sponges, jellyfish, crabs, lobsters, and leeches are all examples of invertebrates.
Great! Below are some examples of insects.
Which do you recognize and what those insects do?
You see insects everywhere. You see them during the day and at night.
Fantastic! Leaving a light on at night attracts insects. Insects get confused and end up flying around your lights. Insects are invertebrates. Say what the word "invertebrate" means out loud.
Great work! You remember that invertebrates do not have backbones. All insects have things in common. They all have six jointed legs, an exoskeleton, three body parts, and lay eggs.
Jointed legs are similar to your legs. They are able to bend. An exoskeleton is a hard, outer shell that protects insects.
Say it out loud. Excellent! Insects have a head, thorax, and abdomen.
Point to each of the three body parts on the ant below. Start with the head. It is the easiest. Then, move down the body until you get to the thorax. Count the legs on the ants.
Say it out loud.
Arachnids are another type of invertebrate. They may scare you.
That's right! Spiders are arachnids. They do not have a spine.
That's right! They have eight legs. Their eight legs are jointed. This means they have joints like people do! It is almost like they have knees! Spiders lay eggs just like insects do. They also have an exoskeleton to protect their body.
Think about a time you saw a spider.
Spiders live in webs or in burrows. You may find them crawling around your home. The spider below isn't so scary, is it? It's fuzzy and colorful.
Spiders are very important. They eat disease-carrying insects like mosquitoes!
Crustaceans are invertebrates, too! They don't have a spine!
Crustaceans, like crabs, lobsters, shrimp, and crayfish, can be found all over the earth. Most crustaceans live in the ocean.
Crustaceans have multiple jointed legs. Jointed legs are legs that can bend. Crustaceans lay eggs.
If you did, you were eating a crustacean!
Mollusks don't have backbones, either. They are invertebrates.
Some mollusks, like snails, have shells. They use their muscular foot for moving. Snails, slugs, octopuses, squids, clams, and mussels are all examples of mollusks. Mollusks do not have bones.
Corals are also invertebrates.
If you said an animal that does not have a backbone, your are correct! An invertebrate does not have a backbone. Coral has an exoskeleton for protection.
Most coral energy from consuming small organisms like plankton. They use the sun to get their food. Corals live in colonies. They are often found living with similar types of corals. Corals make great homes for fish in the ocean.
Worms are also invertebrates.
Worms have no limbs. They breathe through their skin because they don't have lungs. They also don't have brains!
Think about what you noticed about the worms you saw.
Next time you see a worm stuck out in the hot sunlight, pick it up and place it in the shade. Worms are great for the soil. They filter the earth's soil and keep it clean.
These are just some of the many examples of invertebrates. All invertebrates do not have a backbone. Some more examples of invertebrates include: jellyfish, horseshoe crabs, and sponges. Write down what you know about these types of invertebrates.