ABBOTTSCOLLEGE

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PHYLUM ARTHROPODA

ANIMAL KINGDOM

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• From the Greek ἄρθρον (árthron - "joint“) & ποδός (podós - "leg“)

• Includes insects, arachnids, and crustaceans• Most abundant and diverse phylum: make up

80% of all living animals• Occupy the widest variety of habitats• They affect humans both adversely and

positively• They are the most successful group of land

animals

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BODY PLAN OF ARTHROPODS3

Bilaterally symmetrical Have a coelom

is reduced and replaced by a haemocoel = blood filled space

Triploblastic tissue layers Cephalisation A through gut Segmentation

Nervous system similar to Annelids, but sensory organs are more advanced

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HAEMOCOEL7

A blood filled space Forms an open blood system with a heart to

pump the fluid around Less efficient than a closed blood system

CLASSIFICATION OF ARTHROPODA8

Are classified into five subphyla:

1. Trilobites

2. Chelicerata

3. Myriapoda

4. Crustacea

5. Hexapoda

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TRILOBITES10

Group of marine animals Died in the the Permian-Triassic extinction

CHELICERATA11

Includes spiders, mites and scorpions Have chelicerae (pincer like mouthparts) Four pairs of legs Cephalothorax

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MYRIAPODA13

Includes millipedes and centipedes

Have many body segments, each bearing one or two pairs of legs

CRUSTACEA

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An aquatic group Include lobsters, crabs, barnacles and crayfish Have branched appendages And chewing mandibles (mouthparts)

HEXAPODA15

Made up of insects

Have: Six thoracic legs Body divided into head,

thorax and abdomen A single pair of antennae And compound eyes

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SUCCESS

Have an adaptable body plan: • Waterproof skeleton made of chitinous cuticle• A degree of segmentation• Paired, jointed appendages• Complex muscle system• Development involves metamorphosis

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Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation.

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Chitinous Cuticle

• Made of lipd, protein, chitin molecules & may be impregnated with calcium carbonate

• Hardened to various degrees• Prevents water loss so that they can live on land• Cuticles must be shed regularly to allow animals to

grow – called moulting

TO DO

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LEARNING ACTIVITY 2

BODY PLANS OF ARTHROPODS

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THE END

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