1. Phylum: Arthropoda Insects, crabs, lobsters, etc….

2. General Information • Diversity: • Over 85% of all known animals are arthropods • The most successful animals on the planet! • They live in the widest range of habitats and eat the greatest varieties of food • “Arthropod” – jointed legs (appendages) • Appendages are used for eating, moving, mating, respiring, feeling, sensing, or defense

3. Group:Crustacea • The word crustacean originates from the crusty exoskeleton produced by crustaceans • Chitin – the organic material produced by the crustacean to form a hard exoskeleton • this distinguishes them from mollusks whose shells are made of calcium carbonate (CaCO3) • “Insects of the sea” • Live in all aquatic environments plus a few land-dwellers

4. Anatomy • Exoskeleton (outer shell) • Hard, protective outer surface; this shell must be molted in order for the arthropod to grow • Muscles attach to the inside of the skeleton • Cephalothorax • the fused head and thorax section; literally means “head breastplate” (Fig 7-4) • Swimmerets • the posterior pairs of jointed appendages (legs) that mostly function as swimming legs • Walking Legs • the middle pairs of legs that are used for most movement • Maxillae & Mandibles • The anterior appendages that are used for food getting apparatuses • Antennae • Anterior pairs of appendages that are used as sensory organs

5. Habitat • Most crustaceans live in the ocean • Lobsters, shrimp, crabs… • Some live in freshwater • Crayfish & crabs • Few live on land • Isopods and pill bugs • Even fewer are extremophiles! • Kiwahirsuta

6. Freshwater Crab Horseshoe Crab Another freshwater crab Kiwahirsuta or the Yeti Crab

8. Sexual Reproduction • Lobsters & Crayfish …. • Sex is determined by (somewhat) easy to see external structures • Swimmerets – • Males: • Large and point towards the front of the body • Use the 1st pair to transfer sperm to the female • Females: • Have hairs on the swimmerets that make them look like feathers • Used to hold fertilized eggs against the abdomen until ready to hatch

9. Sexual Reproduction • Crabs • They have smaller abdomens with not so easy to see reproductive structures • Males: • Narrow abdomen that fits into a groove on the underside of the cephalothorax • Females: • The abdominal flap is very broad and covers most of the underside of the cephalothorax • She can store sperm until her eggs are ready • The female holds the fertilized eggs between the abdominal flap and the body with a natural adhesive • This is sometimes referred to as “berrying” or “berried”