1. Arthropods Jointed-legged invertebrates

2.  There are more species in the Phylum Arthropoda than in all the other animal phylums combined. (There are over 1 million species of arthropods that have been described. However the total number of arthropods may be as high as 1 billion billion.) Arthropod Characteristics

3.  Three characteristics shared by all arthropods are: 1. exoskeleton 2. segmented body 3. jointed appendages (which includes walking legs, claws, antennae, and wings.) Arthropod Characteristics

4. Exoskeleton  The exoskeleton provides protection from being eaten by animals and from drying out. -The exoskeleton can bend at the joints. -The exoskeleton is nonliving and cannot grow, so the animals must molt.  Molting is the shedding of the exoskeleton that occurs at regular periods as the arthropod grows.

5. Arthropod Characteristics  Open circulatory system (the blood is not contained within small tubes) Blood is pumped from the heart into the space of the arthropods body The blood of arthropods carries food but not oxygen throughout the body.  Complete digestive tract  They have any of 3 special respiratory organs: gills (Crab), book lungs (spider), or tracheal tubes (grasshopper)

6. Body Parts  They have 3 main body parts: 1. Head - first part of body and contains sense organs. 2. Thorax or chest - middle body part with walking legs attached. 3. Abdomen - last body part containing reproductive and digestive organs.

7. Metamorphosis  Metamorphosis is a series of distinct changes in form through which an organism passes as it develops from an egg to an adult.  Reduces competition between stages for Food Living space

8. Metamorphosis  Two types of metamorphosis: Incomplete metamorphosis is where insects pass through 3 stages of development: Egg (female lays eggs in a hole she has dug. Nymph is an immature form that looks like a small adult. Adult is an animal that has grown and developed enough to reproduce. example: grasshopper, cricket, termites, dragonflies

9. Complete metamorphosis is where insects pass through 4 stages in its development : Egg Larva is an insect in the worm like stage. Example: caterpillar, mealworm (Larva hatch from the egg and immediately begin eating a great deal and growing.) Pupa is the third stage that occurs inside a cocoon. (Within the cocoon the tissues of the larva reorganize to form the adult insect.) Adult example: most insects, butterfly, ants, bees, moths

10. Reproduction  Sexual Reproduction

11. Arthropod EVOLUTION

12. Taxonomy of Arthropods  5 subphyla Myriapoda (centipedes, millipedes) Hexapoda (insects) Chelicerata (Spiders, ticks) Crustacea (Lobsters, Crabs) Trilobita (all extinct)

13. Myriapoda  “myriapod”- means many-footed  2 body parts Head Trunk- contains many paired appendages  Use tracheae for respiration

14. Myriapoda  4 classes: Class Chilopoda- centipedes Class Diplopoda- millipedes Class Pauropoda- pauropods Class Symphyla- symphylans

15. Hexapoda  Six legs  3 body parts- head, thorax and abdomen with appendages on head and thorax

16. Hexapoda  Classes: Class Insecta-Beetles, Butterflies Class Entognatha- Mayfly

17. Chelicerata  Horseshoe crabs, spiders, ticks and mites, scorpions, and sea spiders.  Have two main body parts Cephalothorax – 6 pairs of appendages that include a pair of licerae (mouthparts), a pair of pedipalps, and 4 pairs of walking legs. Abdomen  No antennae  Suck liquid food from prey

18. Chelicerata  3 classes: Class Merostomata- horseshoe crabs Class Pycnogonida- Sea spiders Class Arachnida- spiders, scorpions

19. Crustacea  Mainly marine, some freshwater and terrestrial  Two pairs of antennae (first antennae)  One pair of mandibles  Gills for respiration  16-20 segments (some can have 60 or more)

20. Crustacea  6 classes: Class Remipedia- remipede Class Cephalocarida- cephalocarid Class Branchiopoda- daphnia, fairy shrimp Class Ostracoda- copepod Class Maxillopoda- fish louse Class Malacostraca- lobsters, crabs, krill

21. Trilobita  They have been extinct for 200 million years.  Dorsoventrally flattened bottom dwellers  Scavengers  Could roll up their bodies  2-67cm in length