A PowerPoint presentation on Sea Urchins for Marine Biology completed in 11th grade.

1. Sea Urchins
By Anthony Gryevtsov

2. Echinoderms
● Phylum Echinodermata
● Radially symmetric
● Tube feet to move
● Bilaterally symmetrical larvae
● Includes sea stars, crinoids, brittle stars, sea cucumbers, and sea urchins.

3. General Information
● Phylum Echinodermata / class Echinoidea
● “Urchin” is an old word for hedgehog
● They can in fact move
● Light Sensitive
● Radially Symmetric
● Eats algae
● Eaten by fish, eels, otters, humans, & others
● Spines can be poisonous
● Can live at any depth, in any ocean

5. Anatomy 1. Genital Plate
2. Gonopore
3. Anus
4. Madreporite
5. Axial gland
6. Gonad
7. Intestine
8. Ampullae
9. Test
10. Radial canal
11. Esophagus
12. Aristotle’s Lantern
13. Teeth
14. Mouth
15. Nerve Ring
16. Ring Canal
17. Test Plates
18. Tube Feet
19. Spines

9. Reproduction
Sea Urchins reproduce sexually
In most sea urchins, both males and females release their eggs into the water
After being fertilized, the larvae floats around with plankton while eating and developing
Eventually floats down and turns into a sea urchin
Develops for 3 years, until it becomes male, female, or in rare cases both.
Reaches maximum size at about 5 years

10. Food Web
Sea Urchins eaten by:
Humans
Otters
Crabs
Eels
Fish
Lobsters
Anything with teeth, pincers, or claws
Sea Urchins eat:
Algae
Seaweed
Random bits of anything