PHYLUM ECHINODERMATA (STARFISH, SEA URCHINS)
• Greek for "spiny skin". • Evolutionary advanced phyla.
• 7000 species • All found in ocean. Super colorful.
TYPES
Feather Stars, Starfish, Sea Urchins, Brittle Stars, Sea Cucumbers, Sand Dollars, etc.
SYMMETRY
Mostly radial; sometimes bilateral.
Adults are radially symmetrical; life starts as a bilateral larvae for them.
REPRODUCTION
Sexual reproduction. External fertilization (sperm and eggs released into the ocean and hopefully fertilize one another).
BODY PLAN
Deuterostomes (first opening in a developing embryo becomes the anus). None of the earlier phyla shown are deuterostomes; they are all protostomes SO, this is an important development in animal phylogeny. Echinoderms have an internal skeleton, a water vascular system, tube feet, a coelom, etc.. No head or brain. Nervous system is made up of a "nerve ring". On the skin of these organisms lay pedicellariae, or small piers that aid in catching food and in removing foreign materials from the skin; can also have spines (example of sea urchins).
WATER VASCULAR SYSTEM
These animals have a system of canals that branch out throughout the body into tube feet. The water vascular system replaces the duties of the blood and carries oxygen to vital organs. The water vascular system hydraulically operates the tube feet (feeding tentacles). Ultimately, it is a system of fluid-filled closed tubes that work together to enable echinoderms to move and to obtain food.
MY THOUGHTS
These are some of the coolest organisms in the sea! They (including Patrick the Sea Star) can regenerate lost parts! I wish I could do that. Then, being a dancer would be so much easier. They also have no brain. They are predators. One really cool fact is that sea cucumbers, a type of echinoderm, will explode if placed in fresh water.
• 7000 species • All found in ocean. Super colorful.
TYPES
Feather Stars, Starfish, Sea Urchins, Brittle Stars, Sea Cucumbers, Sand Dollars, etc.
SYMMETRY
Mostly radial; sometimes bilateral.
Adults are radially symmetrical; life starts as a bilateral larvae for them.
REPRODUCTION
Sexual reproduction. External fertilization (sperm and eggs released into the ocean and hopefully fertilize one another).
BODY PLAN
Deuterostomes (first opening in a developing embryo becomes the anus). None of the earlier phyla shown are deuterostomes; they are all protostomes SO, this is an important development in animal phylogeny. Echinoderms have an internal skeleton, a water vascular system, tube feet, a coelom, etc.. No head or brain. Nervous system is made up of a "nerve ring". On the skin of these organisms lay pedicellariae, or small piers that aid in catching food and in removing foreign materials from the skin; can also have spines (example of sea urchins).
WATER VASCULAR SYSTEM
These animals have a system of canals that branch out throughout the body into tube feet. The water vascular system replaces the duties of the blood and carries oxygen to vital organs. The water vascular system hydraulically operates the tube feet (feeding tentacles). Ultimately, it is a system of fluid-filled closed tubes that work together to enable echinoderms to move and to obtain food.
MY THOUGHTS
These are some of the coolest organisms in the sea! They (including Patrick the Sea Star) can regenerate lost parts! I wish I could do that. Then, being a dancer would be so much easier. They also have no brain. They are predators. One really cool fact is that sea cucumbers, a type of echinoderm, will explode if placed in fresh water.