CHAPTER 8SUPPORT AND MOVEMENT

8.1 – Support System in Animals

1. The support system in all animals is made up of skeletal & the muscular system.

2. The 3 basic types of skeleton in animals are exoskeleton, endoskeleton and hydrostatic skeleton.

ENDOSKELETON EXOSKELETON HYDROSTATIC SKELETON

• Also called internal skeleton (skeleton is inside the body).• Muscles are attached to skeleton.• Consist of bones & cartilage.• Found in humans & vertebrates.

• Also called outer skeleton (hard material formed outside the bodies).• Land invertebrate (except shell of snails) outer covering made of cuticle.• Aquatic invertebrate: made of calcium carbonate.• Found in land & aquatic invertebrate.

• Soft-bodied animals are supported by liquids.• Cells and spaces between body organs consist mainly of water.•Ideal for aquatic invertebrates.

3. Land vertebrates have large and strong pelvic & pectoral girdles. The whole body weight is supported by skeletal system.

4. Aquatic vertebrates have small and light pelvic & pectoral girdles. The body is supported by buoyancy of water.

Comparison between the support system of land & aquatic vertebrates.

SimilarityConsist of bones & cartilage

Land vertebrates Differences Aquatic vertebrates

Endoskeleton Type of support system Buoyancy of water

Large Size of pectoral & pelvic girdles

Very small

Very strong Strength of pectoral & pelvic girdles

Very weak

Comparison between the support system of land & aquatic invertebrates.

SimilarityHave exoskeleton @ hydrostatic skeleton

Land invertebrates Differences Aquatic invertebrates

Smaller body size Size Bigger body size

More rigid exoskeleton Rigidity Less rigid exoskeleton

8.2 – Support System in Plants

• Plants depend on their stems & roots for support.

• Some plants develop special structures for additional support.

Support System Example

Buttress root Rain tree, angsana tree, durian tree

Prop roots Banyan tree,maize, pandan plant

Clasping roots Money plant, wild orchids

Tendrils Cucumber, pumpkin

Thorns Bougainvillea

Prickles Rose

Air sacs Brown alga

Stilt roots Mangrove tree

8.3 – The Importance of the Support Systems in Living Organisms

• A crippled person can use a cane, crutches @ a walking frame.

• Beached & stranded whales will die because its body weight will crush its internal organs.

• The support system helps to:1. Give definite shape to the organism2. Support the weight of the body3. Enable plants to stay upright4. Protects the internal organs from injury