CHAPTER 10 SECT ION 5

ECHINODERMS

CHARACTERISTICS OF ECHINODERMS

• Phyla: Echinodermata• Characteristics• Invertebrates• Internal skeleton• Water vascular system• System of fluid-filled tubes

• Live in salt water• Radially symmetrical

BODY STRUCTURE

•Have endoskeleton• internal skeleton, made of hardened plates

•Body parts in multiples of 5 •Arranged like spokes on a wheel

MOVEMENT

•Water vascular system• Internal system of fluid-filled

tubes in echinoderms• Portions of the tubes in the

system contract, or squeeze together

• Tube Feet• Extensions of the water vascular

system• The function is for movement and

obtaining food• Sticky, act like sticky suction cups

PARTS OF A SEA STAR

REPRODUCTION AND LIFE CYCLE

• Either male or family• Eggs fertilized in water,

sperm is released• Fertilized eggs develop

into tiny, swimming larvae• Go through

metamorphosis

DIVERSITY OF ECHINODERMS

•Four major groups•Sea Stars•Brittle Stars•Sea Urchins•Sea Cucumbers

SEA STARS

• Eat mollusks, crabs, and even other echinoderms• Move using their tube feet• Also use tube feet to obtain food• Sea stars force their stomach out through its

mouth

• https://www.youtube.com/watch?v=l6dnmLDu6Eg

BRITTLE STAR

• Arms are long and slender, flexible joints• Slither along the ocean floor, snakelike motion•Use tube feet for catching food, no suction cups

SEA URCHINS

• No arms• Movable spines cover

and protect their bodies• Tube feet that extend

out from spines, aid in movement• Scrape and cut food

with five teethlike structures

SEA CUCUMBERS

• Look like cucumbers• Red, brown, green,

brown, blue…• Rows of tube feet on

underside enable them to crawl• Mouth surrounded by

tentacles, filter feeder, sweeps food toward mouth