1. Echinoderms – and we’re back

2. echinoderm Echino = spiny Dermis = skin 580 million years old
5 part radial symmetry
“tube feet”
Internal skeleton (endoskeleton)
Water vascular system

3. A closer look – Form and Function
Closely related to humans???
At least amongst inverts
5 part body
No anterior
No posterior
No brain
2 sided – oral (mouth) vs. aboral (“back”)

4. Form and function continued
Internal water vascular system – important
Madreporite = Outside sieve
Hydraulic pumps
Hundreds of movable tube feet
Act like vacuums/suction cups
“walking”

5. Feeding Tube feet pry open shells Stomach flip out!
Eat animal in its own shell
Algae scrapers
Filter feeders
Detrius feeders

6. Respiration + Internal transport
Thin walled tube feet
Diffusion
Skin gills
No system to carry away CO2 and waste
Distribution performed by digestive glands
Fluid in body cavity

7. Excretion Feces = anus Cellulose waste = ammonia Except brittle stars
Tube feet and skin
Sea cucumber bum 

8. Response Primitive nervous system Nerve ring around mouth
+ radial nerves
200 light-sensitive cells
Eyespots on arms
Statocysts
Balance
Spines and hiding

9. Movement Tube feet Movable spines – sea urchins Flexible arms
Wings???
Sea Cucumber – like a worm

10. Reproduction (and regeneration)
Male or female
Testes or ovaries (in arms!)
Detection of gametes
Larvae metamorphose
Regeneration – must contain part of a middle

11. Different types Sea stars (“starfish) Brittle Stars
Tropical
Longer, flexible arms
Shed arms & run
Sea urchins/Sand dollars
Disc shaped
Sea Cucumbers
Sea lilies/Feather stars

12. Echinoderms and us… Control population of other marine life
Other animals
Distribution of algae
Delicacies (food)
Medicine
Anti-cancer/anti-viral
Embryology + testing drugs