ECHINODERMS
Feeding And Digestion
sea lilies
Water vascular system
Water vascular system:a system of fluid-filled, closed tubes that work together to enable echinoderms to move and get food.
Sea Stars
extend their arms and trap food
madreporite:The strainerlike opening to the water-vascular system
prey on alot of mollusks and other organisms
Tube feet :are small, muscular, fluid-filled tubes that end
in suction-cuplike structures and are used in movement, food collection, and respiration
ampulla:The opposite end of the tube foot
is a muscular sac
brittle stars
push their stomachs out of their mouths and onto their prey.
Respiration, circulation, and excretion
Respiration:
-Echinoderms also use their tube feet in respiration
-Oxygen diffuses from the water
-Other echinoderms have thin-walled skin gills that are small pouches extending from the body
they can trap organic materials in mucus on their arms
sea urchins
use teethlike plates, shown to scrape algae off surfaces
sea cucumbers
extend their branched, mucus-covered tentacles to trap floating food.
Circulation:Circulation takes place in the body coelom and the water- vascular system,
Movement
Excretion: By Diffusion
feather stars
move by grasping the soft sediments of the ocean bottom with their cirri long, thin appendages on their ventral sidesor by swimming with up-and-down movements of their arms.
Response to stimuli
-have both sensory and motor neurons,Sensory neurons respond to touch, chemicals dissolved in the water, water currents, and light
brittle stars
use their tube feet and their arms in snakelike movements for locomotion
Sea stars
use their arms and tube feet for crawling
Sea Urchins
move by using tube feet and burrowing with their movable spines
Sea Cucumber
Reproduction and development
crawl using their tube feet and body wall muscles.
sexually:
1-The females shed eggs and the males shed sperm into the water where fertilization takes place
2-The fertilized eggs develop into free-swimming larvae with bilateral symmetry
3-the larvae develop into adults with radial symmetry
Ju
Dana AlShathri
Asexually:regenerating