Arthropods Chapter 28 Characteristics of Arthropods 1 Arthropods

Arthropods Chapter 28

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

Three Body Sections

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

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

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: a. Scavengers: Eats dead plant and animals b. Herbivores: Eating plants c. 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 Crustaceans (Crustacea) Spiders and Relatives (Chelicerates) Insects and Relatives (Uniramia) Antennae Two pairs No antennae One pair Body Sections Mouth Parts/ Appendages Two or three Mandibles body section (chewing) Two body sections Unbranched appendages (Insects have three sections) Chelicerae (fanglike) Four pairs of legs Jaws

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 • 16. Three parts of an insect: –Head –Thorax –Abdomen 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