PS : 4217 MOT : SCIENCE I

Presenter : Alice Lim Wen Pei 08B0916

Unit 3 Classification Of

Invertebrates

Objectives By the end of the lesson, student should be able to :

Define what is invertebrate

State animals without backbone (molluscs, annelids and arthropods)

State the for types of arthropods (insects, arachnids, crustaceans and myriapods)

Give examples for each of the group

What is invertebrate?Animals without backbones.There are many groups of

invertebrates.The three important groups of

invertebrates are :

Molluscs (animals with shells)Annelids (segmented worms)Arthropods (invertebrates with

jointed legs)

Molluscs (animals with shells)

Have shellsHave soft bodies and a muscular foot

Have tentaclesExamples : Snail, Octopus and Mussel

Snail

Octopus

Mussel

Annelids (segmented worms)Body is divided into segments (parts)

There are bristles on the segmentsExamples : Earthworm, Leech and Ragworm

Earthworm

Leech

Ragworm

Arthropods (invertebrates with jointed legs)

Bodies have three parts :i. Headii. Thoraxiii.Abdomen

Have a hard exo-skeleton (skeleton on the outside of the body)

Can be divided into 4 types :1. Insects – 3 pairs of legsExamples : Bee, Mosquito, Cockroach

Mosquito

Bee

2. Arachnids – 4 pairs of legsExamples : Spiders and Scorpions

Spider

Scorpion

3. Crustaceans – eight to ten legs Examples : Crabs, Prawns and Lobsters

Crab Prawn

4. Myriapods – many legs Examples : Centipedes and Millipedes

Centipede Millipede

Exercise

SUMMARY :What is invertebrate ? - Animals without backbone.

What are the three main group of invertebrates? - Molluscs, Annelids and Arthropods.

Example for :Molluscs – SnailAnnelids – EarthwormArthropods – Grasshopper

Arthropds can be classify into 4 types. What are they?

- Insects - Arachnids - Crustaceans - Myriapods

Thank you for listening