1. Starfish

2. Starfish Characteristics
Invertebrates
Phylum Echinoderm “spiny-skinned” animals
Radically symmetrical - ie a bicycle wheel (usually have 5 arms, or multiples of 5)

3. Beginning of life of a starfish
starfish begin life microscopic, bilaterally symmetrical, free-swimming larva.
Larva changes and becomes sessile, attaching to the ocean floor
Metamorphosis occurs producing arms and an upper and lower surface

4. 2 types of sea stars (starfish)
1. Asteroideas – arms connect to one another
2. Ophiuroideas – arms do not connect to one another

5. Locomotion
Starfish move using tiny tube feet and the water-vascular system
Water enters a tube, causing them to elongate, and the sucker attached to a surface
Tube foot contracts, water is forced back, starfish moves forward

6. Reproduction expel enormous numbers of eggs and sperm into the ocean
fertilization is external.
After fertilization, the tiny, transparent, bilaterally-symmetrical larvae (baby sea stars) travel many miles as they are swept along by ocean currents for about two months.
Larva eat phytoplankton

7. Diet carnivores (meat-eaters).
Eat clams , fish, coral, sponges etcother animals.
They push their stomach out through their mouth, releasing digestive enzymes and digest the prey.

8. Anatomy
do not have a brain; they have a simple ring of nerve cells that moves information around the body.
Eyespots (primitive light sensors) are at the tip of each arm.
If a sea star's arm is cut off, it will regenerate (regrow).