Unit 7 Phylum: Echinoderms

I. Sea Stars A. Sea Star Structures Appendages- usually 5 or multiples of 5 radiating from a central body Endoskeleton- the internal skeleton 3. Spines- Found on the skin -Help support and protect sea star -Made of calcium carbonate

4. Coelom Fluid filled spaces under the skin (on dorsal side) Are lined with skin gills

5. Skin gills Small, cilliated finger-like projections Help with breathing Found on the coelom

6. Suction discs Found at the end of each arm Used to cling to hard surfaces

B. Feeding in Sea Stars Some feed on detritus (-Organic matter) Most are carnivores (sponges, mollusks etc.) Surrounds the prey (clam etc.), and pulls on it until it weakens and opens The stomach is extended over the prey Digestive juices are secreted Prey’s tissues are liquefied The digested food and stomach are sucked back in.

C. Locomotion in Sea Stars Have a water vascular system (-water filled canals and tubes) Water enters the sieve plate (on dorsal side) Water travels through radial canals in each arm Water enters tube feet which are on radial canals The contraction and release of tube feet help the star move and grasp objects

D. Reproduction in Sea Stars Sexual: Have separate sexes -Fertilization is external (sperm and egg released into water) -Development is external

Asexual: Through regeneration -if an area is torn off and part of the central disc is left, a whole new star can form

II. Sea urchins Structures of the sea urchin 1. Spines- Sharp, pointed, can be venomous 2. Aristotle’s lantern- centrally located mouth structure, used to scrape algae 3. Tube feet- Used to help it move

B. Feeding in Sea urchins 1. Most graze on algae 2. Some feed on sponges and other small animals **Many sea urchins in an area can be a sign of bad water conditions

C. Locomotion in Sea urchins 1. Use tube feet 2. Also use the small spines on the underside of the body

D. Reproduction in Sea urchins -is Sexual and external -Are zooplankton as larvae -From fertilization to adult is 2-5 years

III. Brittle Stars

A. Movement in brittle stars 1. Have muscles in the skinny arms to help with movement

B. Behavior of brittle stars 1. Are nocturnal 2. Are solitary (live alone) 3. Can detach (or let go of) an appendage when attacked

C. Feeding in brittle stars Use arms to gather debris off seafloor Or… 2. Filter feed

IV. Sand dollar 1. 5 Part Radial Symmetry A. Structures: 1. 5 Part Radial Symmetry 2. Hard skin made of calcium carbonate

3. Bottom (ventral side) has mouth,. spines and cilia (all for getting 3. Bottom (ventral side) has mouth, spines and cilia (all for getting food) 4. Tube feet are used as gills

V. Sea cucumber A. Body 1. soft, oblong body 2. tube feet arranged in 5 rows across the body 3. 8-30 tentacles around the mouth

Fast Facts Type: Invertebrate Diet: Omnivore Average life span in the wild: 5 to 10 years Size: 0.75 in to 6.5 ft (2 to 200 cm) Size relative to a 6-ft (2-m) man:                     

Tropical Sea Cucumber

Diet 1. eat decaying matter off seafloor Leopard Sea Cucumber

When threatened, some sea cucumbers discharge sticky threads to ensnare their enemies. Others can mutilate their own bodies as a defense mechanism. They violently contract their muscles and jettison some of their internal organs out of their anus. The missing body parts are quickly regenerated.

Video -- Animals, Travel, Kids -- National Geographic

VI. Sea Lilly A. The most ancient echinoderms B. Have feathery arms on jointed stalks C. Are sessile (don’t move around)

VII. Feather star A. crawl or swim in a limited manner across the bottom B. Feed by waving arms and capturing zooplankton