Animals without a backbone
Look at the body, the legs and the covering of fifteen invertebrates, from butterflies and crabs to snails, leeches and starfish, then sort them into their groups.
Core concept
Invertebrates have no backbone; they are grouped by their body plan, such as jointed legs (arthropods), a soft body often with a shell (molluscs) or a body of rings (annelids)
Topic: Animals
Most animals on Earth have no backbone: they are invertebrates. Scientists sort them by their body plan. Arthropods, the biggest group, have jointed legs, a body in segments and a hard outer skeleton: insects, spiders, crabs and prawns. Molluscs have a soft body, often protected by a shell: snails, oysters and the octopus. Annelids are worms whose long bodies are made of ring-like segments: earthworms and leeches. Cnidarians have soft, jelly-like bodies with stinging tentacles: jellyfish and corals. Echinoderms live in the sea, with tough spiny skin and bodies in five parts: starfish and sea urchins.
What you will learn
- Explain what an invertebrate is.
- Describe the body plan of arthropods, molluscs, annelids, cnidarians and echinoderms.
- Classify invertebrates using their body, legs and covering.
- Give examples of invertebrates found in Nepal.
Before you start
- Know what a vertebrate is (an animal with a backbone).
Materials
- Pictures of invertebrates; a snail shell, a dead insect or a crab shell if you can find them
Equipment
- A hand lens
Procedure
- Pick an animal card and look at its body, its legs and its covering.
- Do this for at least eight animals.
- Sort every animal into its group.