Phylum Echinodermata
Bailey Boone
Laura Brown Maryann Ashley
Title: May 20­4:03 PM (1 of 8)
Phylum Echinodermata ‐‐ "Spiny Skinned"
Characteristics
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relatively large
aquatic
extracellular digestion and one­way digestive tube
external fertilization
sexual reproduction
some can regenerate (asexual reproduction)
adult body has radial symmetry
larvae has bilateral symmetry
three germ layers
body cavity (coelom) and organ systems
open circulatory system ­­ no vessels
oral and radial nerve cords
respiration by diffusion
first group to have true endoskeleton
Phylum Echinodermata is the phylum most like Phylum Chordata, the phylum humans belong to, due to early developmental similarities!
Title: May 22­8:50 PM (2 of 8)
Members of Phylum Echinodermata
7000 species (six classes), including:
Starfish
Sea Urchin
Sand Dollar
Sea Cumcumber
Title: May 22­8:51 PM (3 of 8)
Representative ‐‐ Starfish
(Sea Star)
Title: May 22­8:51 PM (4 of 8)
Title: May 22­8:51 PM (5 of 8)
Representative ‐‐ Starfish
Food Getting and Digestion
• water vascular system (tube feet, central canal, radial canal) used to pry open prey (clams and oysters)
• wraps arms around prey and attaches tube feet to shell
• shellfish tires and opens
• extends stomach out mouth into mollusk + uses enzymes to help digest prey
• food enters stomach and stomach is pulled back into body
• food goes into digestive glands in the arms where digestion is finished
Respiration
• diffusion across skin gills
Excretion
• diffusion through body surface
Movement
• hundreds of tube feet carries it along (suction)
• loosely connected skeleton for flexibility
Movement of Tube Feet
Title: May 22­8:51 PM (6 of 8)
Representative ‐‐ Starfish
Reproduction
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separate sexes
gametes leave through central disk
fertilization in water
bilateral, free­swimming larvae
larvae attaches to a solid surface and develops
Regeneration
• possible as long as a single arm and part of the central disk is included
• used to cut up starfish to get rid of them ­ until they realized they regenerate!
Title: May 22­8:51 PM (7 of 8)
Jeopardy!
The Little Mermaid Starfish Characteristics
of Phylum
Other Echinodermata
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