Annelids, Arthropods, and Echinoderms By: Abby Nerenhausen & Brock Franko Animalia

Annelids Members of the class Polychaeta are marine worms. Members of the class Oligocheata are earthworms. Members of the class Hirudinea are parasitic worms. Reproduction occurs through an exchange of sperm packets

Annelids Annelids that burrow are very similar to the ones of the open ocean – Body cavity – Segmentation – Organ system – Bristles Move by using… External bristles called satae satae fleshy appendeges calles parapodia Annelid- Latin word for anus meaning “ring”

Organ System Cephalization – Led to the development of the brain Ganglia & Nerve Chords – Make movement of segments of annelids possible Majority of Annelids have closed Circulatory System – Moves Blood Faster Under greater pressure Annelids don't have actual hearts – Enlarged Blood vessels serves as heart Ex. Earth worms Also do not have lungs or gills

12000 Know species – Close to 8000 species of polychaete worms – 3100 species of Oligochaete (earth worms) – 600 species of leeches Range in size (1mm-3m)

Evolution of Annelids Evolved from the sea Pholeychaete antecessor group – Oligochaetes evolved from these Leeches evolved from these Polychaete- marine worms – Feed on small animals – Others burrow tunnels – Eat by pumping water through body Some iridescent Have heads

Polychaete Fertilization Either male of female – Usually fertilize externally – Males have no distinct sex organs to produce sperm Sperm produced from cells in males coelem – Females usually attach eggs to rocks – Egg fertilized by sperm released into water Will result in growth of larvae After time change to juvenile polychaetes

Arthropods 9 important characteristics 1. Jointed appendages 2. Segmentation 3. Head 4. Exoskeleton 5. Compound eyes 6. Spiricles 7. Circulation 8. Malpighian tubules 9. Wings

Arthropods Shed exoskeleton to grow Signaled by hormones – Forms back by a couple of hours 3 groups of Athropods – Chelicerata (spiders and scorpions) – Crustace (crabs and lobsters) – Uniramia (insects and millipedes)

Arthropods Members of the class crustacea – 5 pairs of legs and 2 body regions Lobsters, crabs – Respiration use gills Also chilopoda – Many body segments with one pair of legs per segment Centipede – respiration use trachea and spiricles Most undergo a change of metamorphis

Arachnids 3 major orders 1. Scorpions 2. Spiders 3. Mites – Of the class arachnida – Reproduction for arthropods and arachnids are internal fertilization (sexually)

Respiration Use book lungs – Hollow flat plates, that air circulates through. Hemolymph flows through the plates and is exchanges with carbon dioxide and oxygen

Crustaceans Aquatic Group called decapods – Greek for deka meaning 10 and pous meaning foot Most common food source in the marine food chain is.. – tiny copepods – Minute ostracods – Fairy shrimp – Water flees

Echinoderms Adult echinoderm body has no head, brain, or complex sensing organs 4 major characteristics – Endoskeleton – Five part radial symmetry – Water-vascular system – Coelomic circulation and respiration

Echinoderms 5 living classes are… – Sea stars – Feather stars and sea lillies – Brittle stars – Sea urchins and sand dollars – Sea cucumbers – Sea stars brittle stars

Reproduction