April 08, 2013

Echinoderms(Phylum Echinodermata)

April 08, 2013

Examples of Echinoderms

Sea cucumbersSea stars

Sea urchinsSand dollars

April 08, 2013

Echinoderms are...

Invertebrates with an internal skeleton, have radial symmetry, and a system of fluid-filled tubes

called a water vascular system

ALL echinoderms live in SALT water

April 08, 2013

Body Structure

Endoskeleton is an internal skeleton that is made of hardened plates

Bumpy texture

Radial symmetry - the body parts (usually in multiples of 5) are arranged like wheel spokes

April 08, 2013

Movement

Water vascular system - internal system of fluid-filled tubes

Some of the tubes in this system can squeeze together and force water into the tube feet

The tube feet stick out from the side or underside of an echinoderm - the ends of the tube feet are sticky.

When the tube feet fill with water they act like suction cups the grip helps them move SLOWLY and capture food.

April 08, 2013

Reproduction & Life Cycle

- Almost all are either male or female- Eggs usually fertilized in the water- Female releases eggs / male releases sperm- Fertilized eggs develop into tiny larvae- Larvae look very different from adults- Undergo metamorphosis to become adults

April 08, 2013

Four major groups of Echinoderms

Sea StarsBrittle StarsSea Urchins

Sea Cucumbers

April 08, 2013

Sea Stars

- Predators that eat mollusks, crabs and other echinoderms- Use tube feet to move & capture prey- Can grasp prey with five arms- Release digestive chemicals to break down prey- Sucks partially digested food in through mouth

http://www.youtube.com/watch?v=A100m5EpfFI

April 08, 2013

Brittle Stars

- Arms are long and slender with flexible joints- tube feet have no suction cups- tube feet are used for catching food only- slither along the ocean bottom by waving their arms in a snakelike motion

http://www.youtube.com/watch?v=WOkppGxqcrM

April 08, 2013

Sea Urchins- Have no arms- Body is covered and protected by moveable spines- Look like a pincushion- Spines cover a central shell that is made of plates joined together- Use tube feet to move- Scrape and cut food (like seaweed) with 5 teeth-like structures that come out of their mouths

http://www.youtube.com/watch?v=D3W4OCnHyCs

April 08, 2013

Sea Cucumbers

- can be red, brown, blue or green- leather-like skin- bodies are soft, flexible, and muscular- have rows of tube feet on underside- crawl slowly along the ocean floor- have a mouth surrounded by tentacles, can lengthen tentacles to sweep food towards mouth- filter feeders

April 08, 2013