Lesson ⁦2-1⁩: Invertebrates

Science · Fourth Grade, Primary · Unit 2: Animal Kingdom · First Semester

A 10-question quiz; after every question you'll see the right answer with an explanation.
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What will you learn in this lesson?

Most animals on Earth have no backbone, such as sponges, jellyfish, worms, insects, and spiders. In this lesson you learn the main groups of invertebrates and how to tell each group apart by its traits.

  • Defines invertebrates as animals that have no backbone
  • Classifies invertebrates into their groups: sponges, cnidarians, worms, mollusks, arthropods, and echinoderms
  • Distinguishes an insect from a spider by the number of legs and body parts
  • Describes how sponges and jellyfish get their food

💡 Tip: A common mistake: counting a spider as an insect. An insect has 6 legs and a body in 3 parts, while a spider has 8 legs and a body in 2 parts.

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Worked examples from the Invertebrates lesson questions

What are invertebrate animals?
  • Animals that have no backbone
  • Animals that have a backbone
  • Animals that live only in water
  • Animals that only fly
✓ Animals that have no backbone
Invertebrates are animals that lack a backbone, such as insects, worms, and jellyfish.
Which of the following animals is an invertebrate?
  • The locust
  • The dhub (spiny-tailed lizard)
  • The falcon
  • The fish
✓ The locust
The locust is an insect with no backbone, while the dhub (spiny-tailed lizard), the falcon, and the fish are vertebrates.
Show more examples (3)
How many legs does an insect have?
  • 6 legs
  • 8 legs
  • 4 legs
  • 10 legs
✓ 6 legs
An insect has 6 legs, and its body is divided into three parts: the head, the thorax, and the abdomen.
Fahd saw an animal with 8 legs and a body divided into two parts. Which group does it belong to?
  • Arachnids
  • Insects
  • Mollusks
  • Worms
✓ Arachnids
Spiders and scorpions are arachnids; they have 8 legs and a body made of two parts, so they are not insects.
What are the three body parts of an insect?
  • The head, the thorax, and the abdomen
  • The head, the tail, and the legs
  • The thorax, the wings, and the abdomen
  • The head, the foot, and the shell
✓ The head, the thorax, and the abdomen
An insect's body is made of a head, a thorax, and an abdomen, and the six legs are attached to the thorax.

FAQ about the Invertebrates lesson

What is the difference between insects and spiders?

An insect has 6 legs and a body in 3 parts: the head, the thorax, and the abdomen, and many insects have wings and antennae. A spider has 8 legs and a body in 2 parts, and it has no wings.

What are arthropods?

The largest group of invertebrates. They have jointed legs and a hard exoskeleton that protects their body, and the group includes insects, spiders, and crustaceans such as shrimp.

How do I study the lesson Invertebrates and test myself on it?

Start the lesson quiz on Study with Ghada: 10 questions from the Science Fourth Grade, Primary question bank. After each answer you'll see the right answer with an explanation, and any questions you miss move to “Review my mistakes” until you master them.

Are Study with Ghada quizzes free and aligned with the curriculum?

Yes, completely free. They're built on the Science - Grade 4 - Semester 1 lessons in the same order as the book, and every question is reviewed and approved by a teacher before students see it.