Arthropods Chapter 28

Characteristics of Arthropods 1. Arthropods share four main characteristics: A. Segmented Bodies Arthropods can have up to three sections Head, Thorax and Abdomen

Three Body Sections

Characteristics of Arthropods 1. Arthropods share four main characteristics: B. Exoskeleton (or outer shell) Prevents evaporation of water ii. Used for protection

Characteristics of Arthropods 1. Arthropods share four main characteristics: C. Jointed Appendages Examples: Legs, wings and antennae Give animal flexibility

2. Shrimp, spiders and millipedes are all in the phylum Arthropods 2. Shrimp, spiders and millipedes are all in the phylum ARTHROPODA

Arthropods 3. Exoskeleton: Tough, external covering that is a suit of armor to protect the animal. 4. Purpose = Protection!

5. Arthropod literally means… “arthros” mean “jointed” “podos” means “foot” or “leg” Example: Wing, Legs and Antennae

Obtaining Food and Oxygen 6. Arthropods obtain food by: Scavengers: Eats dead plant and animals Herbivores: Eating plants Predators: Eating animals they have killed

Circulatory System 7. Arthropods have an open circulatory system. Blood leaves the blood vessels and moves through cavities. Not the same as earthworms!

8. Molting Molting: Shedding of the exoskeleton Insects shed their outer skeleton to grow Skin not flexible like ours

Classification 9. Arthropods are classified based on the number and structure of their body segments and appendages

Groups of Arthropods Group of arthropod Antennae Body Sections Mouth Parts/ Appendages Crustaceans (Crustacea) Two pairs Two or three body section Mandibles (chewing) Spiders and Relatives (Chelicerates) No antennae Two body sections Chelicerae (fanglike) Four pairs of legs Insects and Relatives (Uniramia) One pair Unbranched appendages (Insects have three sections) Jaws

Spiders and Relatives (Chelicerates What is it? Organism Group How do you Know? Spiders and Relatives (Chelicerates Two Body section Crustaceans (Crustacea) Two pair antennae Insects and Relatives (Uniramia) Three body sections

Crustaceans 11. Function of parts of crustaceans Cephalothorax: Fusion of the head with the thorax; houses most internal organs Carapace: Exoskeleton that covers the cephalothorax Manible: Mouthpart adapted for biting and grinding food Chelipeds: Large claws that are modified to catch, pick up, crush and cut food Swimmerets: Flipper-like appendages for swimming

Spiders and Their Relatives 12. Some Chelicerata include… Horseshoe crabs, spiders, mites, ticks and scorpians

13. Chelicerae vs Pedipalps Both are appendages that are attached near the mouth and adapted as mouth parts Chelicerae contain fangs and used to stab and paralyze prey Pedipalps are longer and usually modified to grab prey

Insects and Their Relatives 14. Centipedes, millipedes and insects belong to the subphylum Uniramia.

Centipedes & Millipedes 15. What’s the difference? “millipede” means “thousand feet” “centipede” means “hundred feet” NO SIGNIFIGANCE!

Insects Head Thorax Abdomen 16. Three parts of an insect: Appendages found on same section on all insects

Insects 17. Adaptations to respond to stimuli Compound eye to detect changes in color and motion Chemical receptors for taste and smell on mouthparts Chemical receptors also on their antennae and legs

Adaptations for Feeding 18. Insects have various mouth parts in order to get food in a way that best fits them

Metamorphosis Complete Gradual