Echinoderms Kari Van Zuilen

Classification Kingdom: Animalia Phylum: Echinodermata 5 Classes: Asteroidea (Sea Stars) Crinoidea (Sea Lilies and Feather Stars) Ophueroidea (Brittle Stars) Echinoidea (Sea Urchins) Holothuroidea (Sea Cucumbers)

Characteristics 6,000 species Radial Symmetry (Adults) Bilateral symmetry (Larvae) Spiny skinned (where its name comes from) Tube feet Controlled by water vascular system Water-filled system of interconnected canals and tube feet (used to crawl along the sea floor, collect food, and respiration) No heart, brain, or eyes *radial symmetrical (arranged around the axis of the mouth in equal sectors) *the larvae usually have bilateral symmetry— *meaning of echinoderm: spiny skin *echinoderm can extend and contract its tube feet for locomotion, food collection and respiration.

Where they are found Globally distributed in almost every ocean depth Highest diversity in: Reef environments Shallow shores Deep ocean With the help of ocean currents larvae can swim great distances and this creates global distribution *obviously we don’t live by the ocean so none are found around here

Reproduction Asexual Echinoderms can regenerate missing limbs, arms, spines and even intestines (sea cucumber) Some brittle stars and sea stars can reproduce asexually by breaking a ray or arm, or by splitting the body in half (fission) Each half then becomes a whole new animal Asexual reproduction in echinoderms usually involves the division of the body into two or more parts (known as fission)

Reproduction Sexual Release sperm and eggs into the water Most species produce pelagic (free floating) planktonic larvae Larvae are bilaterally symmetrical, unlike their parents When they settle to the bottom they change to the typical echinoderm features *During the process of maturing, the echinoderm will change its body shape and settle down on the sea floor

Asteroidea Sea Stars

Radial symmetry (5 arms or more) Skeleton: ossicles 1,600 species Radial symmetry (5 arms or more) Skeleton: ossicles Small calcareous plates that move with one another forming flexible joints Live on coral reefs, sand, and rocks Most are carnivorous and scavengers They eat clams, oysters, coral, fish, and other animals Stomach extrudes over prey, digestive juices are secreted and the tissue of the prey is liquefied Tube feet are important Locomotion Food collection Respiration

*bottom side– mouth and ambulacral grooves with the tube feet *top side– anus and madreporite (where the water enters in the water vascular system) * How the water vascular system works--water goes in the madreporite and then goes into the ring canal then out to the radial canals then to the tube feet (important for moving around and holding on to their food)

Sea Lilies Feather Stars Crinoidea *curl up during day light because they are nocturnal

Unique because of mouth/anus on upper surface Sea lilies 80 living species Sessile (attached to the ocean floor) Feather Stars 520 living species Not fully sessile Can crawl along the surface and swim short distances Unique because of mouth/anus on upper surface Filter feeders (eat whatever they find floating by) Feeding: pinnules wraps prey in mucous secretions, and ciliary tracts on the groove floor then transport it toward the mouth Feed on plankton (that’s why they like habitats with strong currents)

Pinnules– grab food Aboral cup– where the mouth is

Ophiuroidea Brittle Stars

Most active and fastest moving 2,000 species Most active and fastest moving Long slender arms (similar in looks to sea star) Used for locomotion (not dependant on tube feet) Skeleton: ossicles Scavengers and detritus feeders Feed on small crustaceans, plankton or worms No anus (just digestion) they push out their stomachs to eat food like the sea star does

Diagram of what they look like--- Usually 5 skinny arms Bottom side– has the mouth and teeth

Echinoidea Sea Urchins

Spine covered (used for protection, and some are poisonous) 900 living species Spine covered (used for protection, and some are poisonous) lack distinct arms Hard skeleton: ossicles are fused (known as “test”) Eat using Aristotle’s Lantern (located in mouth on underside of their body, waste is sent out the anus at the top) 5 teeth Used to pull and rip algae off rocks Herbivores Seaweed Algae Bits of plants and animals

Bottom side– shows their mouth and 5 teeth called aristotle’s lantern Top side– anus Spines and test (skeleton)

Holothuroidea Sea Cucumbers

Soft bodies, tough and leathery skin 1,500 species Soft bodies, tough and leathery skin Skeleton: ossicles have degenerated and buried in fleshy body Mouth is surrounded by several tube feet that have been modified into tentacles that capture small organisms they eat When threatened they can throw up their insides and grow new ones back Filter feeder Feed on plankton

*They have rows of tube feet on their sides and on the bottom of their tentacles for getting around (water vascular system used in these also) *mouth is surrounded by the tentacles *anus is located at the other end

Sources http://en.wikipedia.org/wiki/Echinoderm http://www.bio200.buffalo.edu/labs/echinoderms.html http://www.starfish.ch/reef/echinoderms.html http://www.oceaninn.com/guides/echino.htm http://tolweb.org/Asteroidea http://www.allthesea.com/Sea-Cucumbers.html http://library.thinkquest.org/J001418/urchin.html http://tolweb.org/Echinodermata http://library.thinkquest.org/26153/marine/enchino.htm