Arthropods

General Characteristics All have jointed legs Evolved from annelids (segmented worms)

All have an exoskeleton made of chitin All have bilateral symmetry

WOW BEHAVIOR! All molt- shed skin to allow for growth (lobster example)All molt- shed skin to allow for growth Spiders molt too

Body Arrangement All have 3 body segments – head, thorax and abdomen

Arthropods all have an open circulatory system “Blood” is confined to vessels for only a small portion of it’s circuit through the body.

FIVE CLASSES Centipede – one pair of legs per segment Millipede- two pair of legs per segment Insects- 3 pair of legs per thorax Arachnids- 4 pair of legs per thorax Crustaceans-5 pair of legs per thorax

Centipedes

Legs Centipedes have 1 pair of legs per body segment.

Defenses Have large poisonous fangs on their first appendages.

Centipede Name means 100 feet. Do they have 100 feet?

Centipedes Have longer antennae than other animals in the same class. Antennae are sensory organs, used for touch and smell

Feeding Usually are carnivorous, eating other arthropods Eat snails, slugs, and wormsEat snails, slugs, and worms

Millipedes

Millipedes have 2 pair of legs per segment.Millipedes have 2 pair of legs per segment. Body has many segments; as many as 100

Millipedes Generally not poisonous to humans

Millipedes Name means 1000 feet. Does it have 1000 feet?

Millipedes Millipedes spit cyanide acid at prey.

Insects Insects Far out!!

Insects have 3 pairs of legs on their thorax

INSECTS undergo metamorphosis Complete metamorphosis:Complete metamorphosis –Egg –Larvae –Pupa –adult

INSECTS undergo metamorphosis Incomplete metamorphosis: –Egg –Nymph –adult

Insects have 3 simple eyes between two compound eyes

Insects breathe through holes in their sides (usually the thorax) called spiracles

Many insects have camouflage

More Camouflage

Insects mimic environment

Flight was an evolutionary advantage to insects Damselfly goes from water to flight Common blue damselfly Drosophila flight

The miraculous honey bee! Honey bees and relationship to humans

Wild and wonderful Praying Mantis at the snake buffet Weevil family Amazing Mantis!!

Wild and wonderful Monarch butterfly Swallow tail species Viceroy butterfly

Arachnids

Arachnid Includes Spiders Mites scorpions

Arachnids have 4 pairs (8)of legs

All spiders have 2 pair of mouthparts

Spiders have fangs

Arachnids breathe by book lungs

Horseshoe Crabs are more closely related to arachnids then to crustaceans.

Malpigian tubules are used as kidneys to filter the “blood ”

Arachnids produce a strong elastic silk from spinerettes to build a web to capture their prey build a web

Cephalothorax Cephalothorax is the head attached to the thorax.

Vision Only have simple eyes

Arachnids have poison to kill their preypoison Brown Recluse

Arachnid feeding Arachnids use enzymes to dissolve food before ingestion.

Camel Spider Trick photography Real spider

Crustaceans

Crustacean Crustaceans all have a cephalothorax Examples are crayfish, shrimp, lobster, and crabs

Most are aquatic EXCEPT – rolly polly (pill bugs)

Locomotion Have 5 pairs of appendages Crustaceans have a special appendage used for swimming called a swimmerets

Green Gland Have an organ called the green gland: which regulates the amount of salt and water in the body

Carapace – hard outer shell – protects inner organs

Internal Anatomy

Amount of Legs All crustaceans have five pair of appendages And crustaceans have two pair of antennae

General Information Crustaceans breathe though gills Mostly scavenge for food

Some have a long appendage called a telson-tail