8.1 support systems in animals

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Support Systems in

Animals

Tuesday, July 26, 2011


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Learning outcomes:

A student is able to :

explain the support systems in

vertebrates and invertebrates

compare and contrast the support

systems between land and aquatic

vertebrates

compare and contrast the support

systems between land and aquatic

invertebratesTuesday, July 26, 2011


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An organism is made up of varioustissues which are soft and delicate.

A support system is needed to protectand support these tissues. This support

system is called the skeleton.

The size and habitat of organismsdetermine their support system.



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The skeleton of organism can bedivided into three types :

a) endoskeleton

b) exoskeleton

c) hydrostatic skeleton



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The endoskeleton has the followingfunctions:

a) supports the body

b) Protects the internal organs like thebrain, heart, lungs and spinal cord.

c) maintain the shape of the body.

d) enables movement

e) the bone marrow produces bloodcells.

f) stores minerals such as calcium and

phophorusTuesday, July 26, 2011


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Exoskeleton

Exoskeleton is the external skeleton ofan organism.

Invertebrates like insects, spiders,centipedes, prawns and crab have

exoskeletons that are called cuticles.

The cuticles are hard, waterproofcoverings made of chitin. Chitin is a

glossy, waxy multi-layered structure.


Oth i t b t lik il d


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Other invertebrates like snails andshellfish have very hard shells made of

calcium carbonate.

Since the exoskeleton is located on theoutside of the body, it limits the growth

of the body.

Invertebrates with cuticles will shedtheir exoskeletons and form new ones

several times before they reach adult

stage.

The process in which the exoskeleton isshed after a new one has been formed

underneath is called ecdysis or

moulting.Tuesday, July 26, 2011


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Chitin is waterproof and preventswater escaping from the body.

The functions of exoskeleton are:(a) To give body shape and maintain

rigidity of the body against the

atmospheric pressure.(b) To protect internal organs, like

lungs and brains from injuries

(c) Muscles are attached to the

skeleton. Contractions and relaxationof muscles allow movement of the

organism

(d) To support the body weight



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The hydrostatic skeleton is also knownas hydroskeleton

It consist fluid-filled body body cavitieseach of which is surrounded by a

muscular wall.

Contraction of the muscular wallcreates a fluid pressure that can force

the fluid in any direction, resulting

movement.

Hydrostatic Skeleton



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Hydrostatic skeletons are found in soft-bodied invertebrates such as the

earthworm, caterpillar, slug, hydra,

sea anemone , jellyfish and octopus.

The hydrostatic skeleton has thefollowing functions:

a) supports the body

b) protects the soft body parts

c) maintains the shape of the body

d) enables movement



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Slug

Jelly fish

caterpillar

Tuesday July 26 2011

8.1 support systems in animals

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