Phylum Arthropoda Phylum Arthropoda arthro jointed poda foot

Phylum Arthropoda

Phylum Arthropoda • arthro = jointed • poda = foot • members of this phylum have jointed walking legs

Exoskeleton • skeleton on the outside of the body • Made of chitin • has holes in it to allow the air to pass through to the respiratory system – holes = spiracles

Exoskeleton Limitations • It is shed when the animal grows too large • loses its protection • Too heavy (largest arthropods live in water)

Phylum Arthropoda • display bilateral symmetry • have a segmented body • are the largest phylum of animals

• there are several classes in Phylum Arthropoda • Class Arachnida • Class Crustacea • Class Insecta • Class Chilopoda • Class Diplopoda

Class Arachnida • includes spiders, scorpions, . . . • has two body sections • abdomen • cephalothorax • has four pairs of walking legs which attached to the cephalothorax

Class Arachnida • has pedipalps which are structures used to manipulate food • has chelicera which is a structure used to pierce the food • spiders produce a web which is used to capture its prey – uses the chelicera to pierce and poison the prey

Class Crustacea • Includes lobsters, crabs, crayfish, barnacles, shrimp, . . • Have two body sections • Cephalothorax/carpace (covering the head and thorax) • Abdomen

Class Crustacea • Has five pairs of walking legs • Two pairs of antennae • Uses gills for respiration • Are the largest members of the Phylum Arthropoda (as the water helps keep them buoyant)

• The pincher/first walking legs is known as the chelipeds • The mouth parts are known as the maxillipeds

Class Insecta • Largest group of living organisms • Have three body sections • Head • Thorax • Abdomen

Class Insecta • Has three pairs of walking legs which connect to the thorax section • May have up to two pairs of wings • One pair of antennae

Class Insecta • Has spiracles in the exoskeleton to allow gas to flow from the outside to the respiratory system

There are two types of wings Primitive – many veins Advanced – few veins

Class Chilopoda • Includes centipedes • Have two legs per section

Class Chilopoda • Exoskeleton plates overlap • It has fangs that are poisonous • Swift moving and longer more joined legs • Smaller body • Predator and carnivorous

Class Diplopoda • Includes millipedes • Has two pairs of walking legs per section

Class Diplopoda • Are slow moving • Have no fangs • Have jaws • Segments are fused together