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

2. General Information Diversity: “Arthropod” – jointed legs (appendages)
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) Cephalothorax Swimmerets
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 Some live in freshwater
Lobsters, shrimp, crabs…
Some live in freshwater
Crayfish & crabs
Few live on land
Isopods and pill bugs
Even fewer are extremophiles!
Kiwa hirsuta 

6. Freshwater Crab
Horseshoe Crab
Another freshwater crab
Kiwa hirsuta 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”