Lesson 3: Invertebrates Revision Notes
Lesson Objectives
Let's dive into a fascinating part of the animal kingdom called invertebrates. By the end of this lesson, you should be able to:
Grade C: Know some examples of invertebrates (animals without a backbone).
Grade B: Describe some of the key features (important parts or characteristics) of invertebrates.
What Are Invertebrates?
Invertebrates are animals that don't have a backbone or spine. Most animals in the world are invertebrates!
Examples of Invertebrates
Molluscs: Like snails, which often have a hard shell and move using a muscular foot.
Crustaceans: Like crabs, which have a hard, protective outer skeleton called an exoskeleton.
Arachnids: Like spiders, which have eight legs and live in all kinds of places, from forests to deserts.
Centipedes and Millipedes: Long, many-legged creatures that crawl on the ground.
Annelids: Like worms, which have long, tube-like bodies and live in the soil.
Echinoderms: Like starfish, which have arms radiating from a central body.
Insects: This is the biggest group, with creatures like butterflies and beetles.
Key Features of Invertebrates
They don't have a spine (a long series of bones that runs down the back of vertebrates).
Many have an exoskeleton (a hard covering on the outside of their body).
They can have different body structures, like the hydrostatic skeleton of a worm, which is supported by fluid pressure inside their bodies.
Why It's Important to Learn About Invertebrates
Knowing about invertebrates helps us understand how life on Earth works. It shows us the many ways animals can live and thrive without a backbone.
Test Yourself
Keywords and Simple Definitions
Invertebrate: An animal without a backbone. They can have soft bodies or hard outer shells.
Feature: A part or quality that is important or interesting. For example, the feature of a crab is its pincers.
Spine: A series of bones down the back that vertebrates have, but invertebrates do not.
Learning about invertebrates opens up a world of creatures that are both incredibly diverse and fascinating. They show us that there are many different ways to be an animal and thrive in the environment!
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