Transcript Arthropods
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) • 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 • Centipedes have 1 pair of legs per body segment. Legs 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 worms Millipedes Millipedes • 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 Far out!! Insects have 3 pairs of legs on their thorax INSECTS undergo 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 Drosophila flight Common blue damselfly 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 Mites Spiders 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 Cephalothorax Cephalothorax is the head attached to the thorax. Vision Only have simple eyes Arachnids have poison to kill their prey Brown Recluse Arachnid feeding Arachnids use enzymes to dissolve food before ingestion. Camel Spider Real spider Trick photography 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