1. Animal Kingdom Phylum Arthropoda Chp 26

2. Why are there so many arthropods? Appeared more than 600mya Started in water then moved to land First body form is similar to the trilobite- thick outer covering, many segments, pair of appendages Most today have fewer body segments and the appendages are specialized for feeding or movement

3. Key Features Tough Exoskeleton Series of jointed appendages Segmented body Brain at dorsal part of the head Ventral nerve cord Open circulatory system with single heart

4. Body Plan -Exoskeleton Exoskeleton made of a carb called chitin. Some are very hard or flexible Keeps water inside Protects against damage

5. Appendages Jointed appendages (arthro-joint, pod-foot) Antennae, claws, walking legs, wings, flippers are all appendages All have segmented bodies as well

6. Feeding Varies Herbivores (locusts) Carnivores (spiders) Parasites (ticks) Filter feeders (marine)

7. Respiration Gills (crabs and shrimp) –small feather-like structures under the exoskeleton Book gills (horseshoe crabs)-layers of tissues for gas exchange –beneath the body Book lungs (spiders and kin)-contained in a sac in the body and connect to a spiracle –opening Tracheal tubes-tubes that extend into the body (as they move they shrink and expand air)-very small animals.

8. Internal Transport Heart pumps blood into an open- circulatory system (blood does not always travel in blood vessels) Blood moves from arteries to smaller vessels to tissues and then collects in sinuses (spaces within tissue) Collects in a cavity around the heart and re- enters the heart

9. Excretion Solid waste containing Nitrogen Through Malphigian tubules they remove waste from blood and transport through the anus. Aquatic organisms release wastes through gills

10. Response Most have a well developed nervous system Brain with ganglia in the head Pair of ganglia at each segment Compound eyes- more complex than human Taste with mouthparts, antennae, legs Hear above human sounds- but ears are in odd places Escape from predators by using venom, drop a claw or leg, or use camouflage

11. Movement & Reproduction Coordinated muscle system with exoskeleton Usually male & female produce sperm & egg cells and fertilization is within the female

12. Growth and Development To grow arthropods must molt and shed the exoskeleton Hide from predators during this process Some perform a metamorphosis- and dramatically change form Incomplete metamorphosis- gradual change and the young(nymph) look very similar to the adult (grasshopper)

13. Complete Metamorphosis Eggs hatch into larvae Grow and molt and form a pupa (protective covering and grow adult structures) Decreasing levels of juvenile hormone advance it to the next stage

14. Insects Head, thorax, and abdomen 3 pairs of legs attached to the thorax Pair of antennae, eyes, 2 pair of wings, and tracheal tubes Feeding-3 pair of appendages that are mouth parts, and use mandibles (vary among each insect) Some secrete enzymes to digest food

15. Movement 3 pairs of legs with spines and hooks to hold on Jumping Capturing and holding prey Flying varies Many mitochondria for energy

16. Insect Societies Social insects live in societies There is a division of labor There are several castes- types Reproductive females(queens) Reproductive males (stay with queen) Workers perform all other tasks

17. Insect Communication Sound, visual, chemical signals Pheremones are chemical messangers Can be used when food was found, death of a member, alarm for danger Round dance-source of food within 50m more changes in direction-better quality Waggle Dance-food is more than 50m away(longer the dance, farther away) direction of dance indicates direction of food

18. Why are Arthropods important? Food source for many carnivores Plants need them for pollination Agriculture would not be possible Honey and silk Food source for people Useful chemicals-purity of meds, surgical thread and stitches