1. Common Group Name: Arthropods

2. Chelicerata (spiders)
Phylum: Arthropoda
Subphyla:
Crustaceans
Examples: crabs, shrimp, lobster, crayfish, barnacles
Chelicerata (spiders)
Examples: horseshoe crabs and spiders
Uniramia (insects)
Examples: insects

3. Body Plan
Body plan includes segmentation, exoskeleton, and jointed appendages.
The number of segments and jointed appendages vary in species
Exoskeleton is an outer covering made of chitin and can be leathery, hard, or waxy.

4. First group to show advanced mouthparts: Pincers, fangs, and jaws
Feeding
Herbivores, carnivores, omnivores, bloodsuckers, parasites, detrivores, and filter feeders.
First group to show advanced mouthparts:
Pincers, fangs, and jaws

5. Respiration
Most terrestrial arthropods breathe through branching tracheal tubes.
Air enters and leaves through spiracles.
Spiders breathe using book lungs- layers of respiratory tissues.
Aquatic arthropods breathe using featherlike gills or book gills.

6. Circulation Arthropods have an open circulatory system.
Blood Flow: Heart- arteries-tissues-leaves the blood vessels-sinuses and cavities-collects back in large sinus near heart-re-enters heart

7. Excretion
Terrestrial- use malpighian tubes- saclike organs that extract wastes from blood and add them to feces to move through the gut.
Aquatic- use diffusion

8. Response All arthropods have a brain.
Brain sends out instruction signals to muscles.
Two main nerves connect the brain to the ventral nerve cord.
Ganglia extend from nerve cord to coordinate the movement of legs and wings.
Sophisticated sense organs: eyes and taste receptors.

9. Movement Arthropods use well-developed groups of muscles.
Muscles are made up of muscle cells that contracted when stimulated by nerves.
Muscles pull on the exoskeleton.
Extension and flexion occur.

10. Reproduction
Terrestrial- sexual, internal fertilization: male place sperm in female or male places sperm into packet picked up by female.
Aquatic- internal or external fertilization

11. Reproduction in Insects
Usually involves metamorphosis- the process of changing shape and form.
Incomplete Metamorphosis- immature forms (nymphs) lack functional adult structures but look like mini-adults; similar appearance throughout life.
Complete Metamorphosis- insects undergo dramatic physical changes. Larva (different from parent) develops into pupa (looks different from larva) then completely remodels again to become adult.

12. COMPLETE
INCOMPLETE

13. Other Information
When they outgrow their exoskeleton, arthropods undergo molting- the shedding of the exoskeleton and production of a new larger one.
Molting is controlled by the endrocrine system which releases hormones.

14. Arthropod Subphyla

15. Body Plan Crustaceans: 2 antennae
2 or three segments (cephalothorax, abdomen),
Mandible- mouthpart for biting
1st pair of legs called chelipeds with large claws
4 pair of walking legs
swimmerets- flipper appendages

16. Body Plan Chelicerates: Mouthpart has chelicerae with fangs
2 body segments
4 pairs of walking legs
pedipalps- to catch prey
spiders have no jaw and must liquefy their food.

17. Body Plan Insects: Jaws 1 pair of antennae
3 parts: head-thorax-abdomen
3 pairs of legs
Most insects are adapted for flight

18. Feeding in Insects
Three pairs of appendages for mouthparts including two mandibles
Saliva present to help digest food.

19. Response in Insects
Compound eyes present
Taste and smell chemical receptors
They can detect movement
Ears present

20. Movement in Insects
Legs with spines and hooks for grasping and defense
Many can fly and usually have two pairs of wings.