Phylum: Echinodermata

1. Phylum: Echinodermata What are the characteristics common to all echinoderms? What are the structures and systems of a seastar? Protostome Vs deutrostome development�?

2. Echinoderm Characteristics� Echinoderms are marine animals All echinoderms have spiny skin (echin= spiny, derma=skin) An Endoskeleton- made of calcium, it supports the echinoderms body Radial Symmetry- body parts arranged around a central point Sexual Reproduction (many can also regenerate) Fertilization occurs in the water Water vascular system

3. The Water Vascular System A network of fluid filled tubes which allows echinoderms to move, obtain food and exchange gases Water enters through the sieve plate (dorsal surface) into the ring canal, and down the radial canal in each arm to the ampullae

4. How do seastars move? The ampulla force water into the tube feet As water is forced into tube feet, they extend. Suction cup ends attach to a hard surface. Muscles in tube feet contract, water flows back into ampullae ans sea star is pulled forward

6. Embryonic Development Review Fertilized egg becomes a blastula (hollow ball of cells) A blastopore forms where cells move inward. A gastrula of 2 or 3 layers forms. Inner layer =endoderm - digestive tract, respiratory system Outer layer = ectoderm � skin. Sense organs, nerves Middle = mesoderm � muscles, circulatory, reproductive, excretory system

7. Protostome and Deuterostome development Protostome �first mouth� Blastopore becomes the mouth. An anus develops later Ex. Mollusks, worms, arthropods Deuterostome �second mouth� Blastopore becomes the anus. A mouth develops later Ex. Echinoderms, chordates

8. Echinoderm Tree diagram

9. Asteroidea : Sea Stars Penta-radial symmetry Scavengers and carnivores Feed on gastropods, bivalves, crustaceans and other echinoderms Crown of thorns starfish eats coral

10. Ophiuroidea: Brittle Stars and Basket Stars Arms are longer, thinner and more mobile Tube feet lack suction cups No ampulla Move faster than seastars Scavengers and carnivores http://www.livestockusa.org/ylwbrittle1.jpg

11. Echinoidea: Sea Urchins and Sand Dollars Spherical or disc shaped Moveable spines - sometimes poisonous Sea urchins use tube feet and spines to move Sand dollars burrow Sea urchins graze, feed on sediment Sand dollars feed on sediment Fire Sea Urcin Asthenosoma varium

12. Holothuroidea: Sea Cucumbers 5 rows of tube feet run the length of the body Defends itself by shooting long thin tubules from its anus Sometimes it shoots out its digestive system Can regenerate digestive system in days http://www.richardseaman.com/Wallpaper/Nature/Underwater/Invertebrates/PricklyRedSeaCucumber.jpg

13. Crinoidea: Sea Lillies and Feather Stars Only a few species remain Sea lillies have stalks and are sessile Featherstars creep and swim The only echinoderms with a mouth on dorsal surface Tube feet capture plankton and move it to mouth http://animaldiversity.ummz.umich.edu/site/resources/jeffrey_jeffords/crinoids/Crinoid_blue.jpg/medium.jpg

15. Characteristics of Phylum: Chordata A dorsal hollow nerve cord � the anterior end develops into a brain A notochord � firm but flexible supporting rod. In vertebrates, the backbone replaces the notochord Gill slits � paired openings along the pharynx, for filter feeding A post anal tail � even humans have an embryonic tail extending beyond the anus!

16. Urochordata: Tunicates or sea squirts Leathery outer covering (tunic) Squirt seawater when distrubed Most adults are sessile Only gill slits are retained to adulthood Protein in seasquirt sperm may help in human infertility research Japanese consume 20 tonnes each year http://news.bbc.co.uk/olmedia/1035000/images/_1036855_sea_squirt300.jpg

17. Cephalochordata: Lancelets Biologists think Lancelet ancestors evolved into a fish-like vertebrate 4 chordate characteristics retained to adulthood Usually buried in sand, although they can swim Filter food particles through gill slits http://trc.ucdavis.edu/biosci10v/bis10v/week9/9webimages/Amphioxus34.jpg