PHYLUM ARTHROPOD BY: ARIANA MEJIA

CHARACTERISTICS  Segmented body plan  Exoskeleton  Has an open circulatory system  Nervous system has a dorsal brain and a ventral nerve chord  Bilateral symmetry  Sexual reproduction

Class Insecta  It is the largest group in the animal kingdom with 29 orders and 800,000 known species  Insects are in the subphylum Tracheata because they breathe through a trachea  All insects have an exoskeleton, that sheds periodically  Mouth parts are perfected for licking, piercing, crushing or sucking.  Insects have three body sections, known as the head, thorax, and the abdomen  They are the most successful forms of life on earth  Normally they are very small, but normally the largest insect is the size of a human hand

INSECTS!!!!!

Class Crustacea  About 30,000 species of this class  Most are marine but some live in fresh water  This includes lobsters, crabs, crayfish, shrimp, and several other organisms  Most are free-living, but some are sessile and a few are parasitic.  The legs include specialized chelipeds, and may be used to capture prey.  They breathe through gills  Like other arthropods, this class has an exoskeleton

CRUSTACEANS!!!!!!!!!

Class Arachnida Includes a very diverse group of arthropods: spiders, scorpions, ticks, mites, harvestmen, and their cousins. Includes a very diverse group of arthropods: spiders, scorpions, ticks, mites, harvestmen, and their cousins. There are 75,000 different species and most of them are spiders There are 75,000 different species and most of them are spiders Most arachnids are carnivorous, mostly feeding on insects Most arachnids are carnivorous, mostly feeding on insects Arachnids provide an important service, keeping insect population under control Arachnids provide an important service, keeping insect population under control Order Araneae (spiders) : Order Araneae (spiders) : No antennae No antennae Abdomen joined to cephlothorax by slender pedicel. Abdomen joined to cephlothorax by slender pedicel. They have four parts of legs They have four parts of legs Order Acari (mites and ticks): Order Acari (mites and ticks): No antennae No antennae Abdomen joined by cephlathorax (no pedicel) Abdomen joined by cephlathorax (no pedicel) Order Scorpiones (scorpions): Order Scorpiones (scorpions): No antennae No antennae 4 pairs of legs on cephlathorax 4 pairs of legs on cephlathorax Scorpions mostly feed on insects and spiders Scorpions mostly feed on insects and spiders

ARACHNIDS!!

CLASS CHILOPODA They are the centipedes They are the centipedes Their bodies are made up of a chain of many flattened segments. Their bodies are made up of a chain of many flattened segments. Centipedes feed on soil invertebrates Centipedes feed on soil invertebrates All centipedes are terrestrial All centipedes are terrestrial Range in size from a few millimeters to about 30 cm Range in size from a few millimeters to about 30 cm 8,000 species 8,000 species Some centipedes can be hazardous to humans because of their venomous bites. Some centipedes can be hazardous to humans because of their venomous bites. Smaller centipedes normally do not puncture humans. Smaller centipedes normally do not puncture humans.

CHILOPODA!!

CLASS DIPLOPODA The millipedes They also have bodies made up of numerous segments. Millipedes lack poisonous fangs, and do not bite. But to discourage predators they will roll into a ball and release foul smelling substances. 10,000 species Female millipedes lay eggs in nests Two pairs of legs per segment They eat decaying leaves and other dead plant matter. Common millipedes have around legs

MILLIPEDES

CLASS MEROSTOMATA Marine class of horseshoe crabs and eurypterids. Only 4 species Have a large shield that covers the cephalothorax. Compound eyes are reduced

HORSESHOE CRABS