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Year 5 Science

Animal Classification

Learn how scientists sort animals into groups based on their features -- from backboned vertebrates to incredible invertebrates.

Vertebrates vs Invertebrates

Scientists group all animals into two main categories based on one key feature: whether or not they have a backbone (spine).

Vertebrates

Animals with a backbone (internal skeleton). About 5% of all animal species.

  • ●Mammals (kangaroos, humans, whales)
  • ●Birds (kookaburras, emus, cockatoos)
  • ●Reptiles (crocodiles, goannas, snakes)
  • ●Amphibians (frogs, salamanders)
  • ●Fish (barramundi, clownfish, sharks)

Invertebrates

Animals without a backbone. About 95% of all animal species!

  • ●Insects (ants, butterflies, beetles)
  • ●Arachnids (spiders, scorpions, ticks)
  • ●Crustaceans (crabs, prawns, yabbies)
  • ●Molluscs (snails, octopuses, oysters)
  • ●Worms (earthworms, leeches)

Amazing fact: There are more species of beetles in Australia than there are species of mammals in the entire world! Invertebrates massively outnumber vertebrates.

The Five Vertebrate Groups

🦘

Mammals

  • ● Warm-blooded
  • ● Have hair or fur
  • ● Feed babies with milk
  • ● Most give birth to live young
  • ● E.g. platypus, koala, wombat
🦅

Birds

  • ● Warm-blooded
  • ● Have feathers
  • ● Lay eggs with hard shells
  • ● Most can fly (but not all!)
  • ● E.g. emu, magpie, galah
🦎

Reptiles

  • ● Cold-blooded
  • ● Have dry, scaly skin
  • ● Most lay eggs on land
  • ● Breathe with lungs
  • ● E.g. saltwater croc, blue-tongue lizard
🐸

Amphibians

  • ● Cold-blooded
  • ● Moist, smooth skin
  • ● Lay eggs in water
  • ● Live in water AND on land
  • ● E.g. green tree frog, corroboree frog
🐟

Fish

  • ● Cold-blooded
  • ● Have scales and fins
  • ● Breathe through gills
  • ● Live in water
  • ● E.g. Murray cod, great white shark

Australia's Unique Animals

Australia is home to some of the most unusual animals on Earth. Many of our animals are found nowhere else in the world because Australia has been an isolated continent for millions of years.

Marsupials

Mammals that carry their babies in a pouch. E.g. kangaroos, koalas, wombats, possums, and Tasmanian devils.

Monotremes

Mammals that lay eggs! Only two kinds exist: the platypus and the echidna -- both found in Australia.

Unique Invertebrates

Australia has unique invertebrates too, like the giant cuttlefish of Spencer Gulf and thousands of native ant species.

Key Vocabulary

Vertebrate

An animal that has a backbone (spine) and an internal skeleton.

Invertebrate

An animal that does not have a backbone. Most animals on Earth are invertebrates.

Classification

The process of sorting living things into groups based on shared characteristics.

Warm-blooded

An animal that can maintain a constant body temperature regardless of its surroundings (e.g. mammals and birds).

Worked Examples

1

Is a kangaroo a vertebrate or invertebrate? What group does it belong to?

Step 1: Does a kangaroo have a backbone? Yes -- it has an internal skeleton with a spine.

Step 2: What are its key features? It is warm-blooded, has fur, feeds babies milk, and carries joeys in a pouch.

Answer: A kangaroo is a vertebrate and belongs to the mammal group (specifically, it is a marsupial).

2

A green tree frog has smooth skin, lays eggs in water, and lives near ponds. What vertebrate group is it?

Step 1: Smooth, moist skin -- not scales, feathers, or fur.

Step 2: Lays eggs in water, not on land. Lives both in water and on land.

Answer: It is an amphibian. Amphibians have moist skin and lay their eggs in water.

3

Why is a spider classified as an invertebrate?

Step 1: Does a spider have a backbone? No -- it has a hard outer covering (exoskeleton) instead.

Answer: A spider is an invertebrate because it has no backbone. It belongs to the arachnid group (8 legs, no antennae).

Knowledge Check

Select the correct answer for each question. Click "Check Answer" to see if you are right.

Question 1

What is the main difference between vertebrates and invertebrates?

Question 2

Which of these animals is an invertebrate?

Question 3

What makes the platypus so unusual as a mammal?

Question 4

Which vertebrate group has feathers?

Question 5

Approximately what percentage of all animal species are invertebrates?

Key Concepts Summary

Year 5: Water Cycle