1. Kingdom Animalia Phylum Echinodermata The Spiny Skins
Biology 11
Kingdom Animalia
Phylum Echinodermata
The Spiny Skins

2. Deuterostomes
We now move to the other great branch of animal evolution; the deuterostomes
This branch is dominated by the vertebrates which we will study next
The other phylum of deuterostomes seems a strange evolutionary mate for the vertebrates
They are the Echinoderms

4. Objectives How echinoderms are more advanced than arthropods
Defining characteristics of echinoderms
4 classes and example organisms
The body plan and systems of a seastar

5. Phylum Echinodermata Spiny skinned animals Characteristics:
1. Exclusively marine
2. Semi flexible endoskeleton of calcarious plates
3. Show pentaradial symmetry where all structures are in 5’s (as seen in this sand dollar).
4. Reproduction mostly sexual but good powers of regeneration.

6. Phylum Echinodermata
5. Unique system called “water vascular” system (more details to come!) - Externally shows as tube feet
6. Contains 4 classes:
- Class Asteroidea
- Class Echinoidea
- Class Holothuroidea
- Class Crinoidea

7. Water Vascular System
Sealed system of tubes that contain water, used for: movement, catching food, circulation, respiration, excretion, sensory reception
Madreporite: water enters, filter
Stone Canal: connects madreporite to ring canal
Ring Canal: sends the water to each of the radial canals
Radial Canal: sends water to each ampulla
Ampulla: controls the functioning of the tube foot via water pressure
Tube Foot: used to hold on to or let go of a surface, sensory reception

8. General External Anatomy

9. General Internal Anatomy

10. Class Asteroidea: Sea stars
Feather Star
Basket Star

11. Class Echinoidea:
sea urchins
Class
Holothuroidea:
sea cucumbers

12. Class Crinoidea: Sea Lilies