Animal Phyla: Arthoropoda

1. Animal Phyla: Arthoropoda Carrie Zellmer & Lily Comp

2. Information • Common Names: Insects, Arachnids, Crustaceans, Centipedes, & Millipedes. Spider Butterfly

3. Body Symmetry • Arthropods have bilateral symmetry as both sides of their bodies are the same. • Arthropods have jointed appendages and legs. • The bodies of Arthropods are divided into distinct parts.

4. General Arthropod Body Plan • An Exoskeleton • Body divided into distinct parts • Jointed appendages and legs • Bilateral symmetry

5. Insects Body Plan • Three Regions: Head, Thorax, Abdomen • Six legs attached to the Thorax • Adult with one or two pairs of wings attached to the Thorax (some insects have no wings) • Two antennae • Lateral compound eyes Colorado Potato Beetle

6. Arachnid Body Plan • Two body regions: Cephalothorax & Abdomen • Eight legs • No antennae • Mouth parts are chelicerae (modified appendages) which in spiders are fangs Banana Spider

7. Crustacean Body Plan • Two body regions • Two pairs of antennae • 5+ pairs of legs • Primarily aquatic, few terrestrial Durban Dancing Shrimp

8. Chilopod Body Plan • Well-defined head • First pair of legs modified for envenomation (process by which venom is injected into some animal by the bite (or sting) of a venomous animal) • Flattened top to bottom • One pair of antennae • One pair of legs per segment

9. Diplopod Body Plan • Two pairs of legs per segments, first four segments have one pair of legs • One pair of antennae • Well-defined head • Usually cylindrical North American Millipede

10. Support/Movement System • Hydrostatic Pressure: Forces fluid into legs and forces them to extend. (Spiders for Jumping) • Antagonistic pairs: flexors and extenders –little specific muscles (no sheets of muscle) • The Exoskeleton: Provides strong support, rigid levers that muscles can attach to & pull against, offers protection, & prevents infection.

11. Nutrition • Arachnids generally eat smaller arthropods. Parasitic ticks and mites and plant-feeding daddy longlegs are exceptions to this. • Ticks and mites are nourished by fluids obtained either from living animal or plant material or from decaying organic matter. • Daddy longlegs seem to be the only arachnids capable of ingesting small particles. Typically their prey is torn into small pieces. The liquid contents are they sucked out until only the exoskeleton of the prey remains.

12. Gas Exchange Process • The impermeability of the exoskeleton makes the passages of gases difficult. • Gas exchange is usually internal through invaginations of the integuments. Frog Leg Beetle

13. Defense Mechanisms • Fast movement • Exoskeleton- protection against predators • Pinchers • Camouflage • Poison glands

14. Excretion/Water Balance • Open circulatory system. • Crustaceans excrete through green glands. • Others use a network of Malpigian tubes which collects liquid wastes in the gut. • Water loss through evaporation is a big problem among many arthropods. • Water balance may changes with the weather. Crustacean

15. Reproduction • Separate sexes • External Fertilization in aquatic forms • Internal fertilization in the terrestrial forms • Some reproduce through metamorphosis Dung Beetles

16. Response to Stimuli • Arthropods orient themselves by responding to the stimuli they receive. • Have a well- developed nervous system. • Sensory receptors are associated with modifications of the exoskeleton. • Antennae and compound eyes help.

17. Other Information • Arthropods evolved along four main lines. • Must molt in order to grow. • Exoskeleton is divided into a number of plates and cylinders. • Arthropods to Avoid: Arthropods such as flies, lice, fleas, ticks, and mosquitoes can make your life uncomfortable if they bite you. • Some insects, arachnids, and millipedes produce poisons that can make people sick or even kill them. Arthropods are also indirectly responsible for many people dying. • Mosquitos are very dangerous, and may carry diseases like malaria and dengue fever. Malaria passed on to people by mosquitoes kills over 1 million people each year- that’s more than any other disease.