Presentation is loading. Please wait.

Presentation is loading. Please wait.

Phylum Echinodermata Marine Invertebrates.

Similar presentations

Presentation on theme: "Phylum Echinodermata Marine Invertebrates."— Presentation transcript:

1 Phylum Echinodermata Marine Invertebrates

2 Characteristics All marine Known as spiny-skinned animals
Endoskeleton known as the test is made of calcium plates or ossicles with protruding spines Includes sea stars, brittle stars, sand dollars, sea urchins, & sea cucumbers

3 Characteristics Bipinnaria Larva Undergo metamorphosis from bilateral, free-swimming larva to sessile or sedentary adult Larval stage known as dipleurula or bipinnaria Adults have pentaradial (5 part) symmetry Lack segmentation or metamerism


5 Characteristics Coelomate Breathe through skin gills as adults
Capable of extensive regeneration

6 Characteristics Ventral (lower) surface called the oral surface & where mouth is located Dorsal (upper) surface known as aboral surface & where anus is located Have a nervous system but no head or brain in adults No circulatory, respiratory, or excretory systems

7 Characteristics Have a network of water-filled canals called the water vascular system to help move & feed Tube feet on the underside of arms help in moving & feeding One-way digestive system consists of mouth with oral spines, gut, & anus Deuterostomes (blastopore becomes the anus)


9 Characteristics Separate sexes Reproduce sexually & asexually
In sexual reproduction, eggs (up to several million) from females and spermatozoa from males are shed into the water (spawning), where the eggs are fertilized. Most echinoderms spawn on an annual cycle, with the spawning period normally lasting one or two months during spring or summer; several species, however, are capable of spawning throughout the year. Spawn-inducing factors are complex and may include external influences such as temperature, light, or salinity of the water.

10 Includes 5 classes: Crinoidea - sea lilies & feather stars
Asteriodea - starfish Ophiuroidea - basket stars & brittle stars Echinoidea - sea urchins & sand dollars Holothuroidea - sea cucumbers

11 1) Crinoidea Characteristics
Sea lilies & feather stars Sea lilies have a long stalk with branching arms that attach them to rocks & the ocean bottom Feather stars can detach & move around Mouth & anus on upper surface

12 1) Crinoidea Characteristics
May have 5 to 200 arms with sticky tube feet to help capture food (filter feeders) & take in oxygen Common in areas with strong currents & usually nocturnal feeders

13 2) Asteroidea Characteristics
Usually sedentary along shorelines Starfish or sea stars Come in a variety of colors Prey on bivalve mollusks such as clams & oysters

14 2) Asteroidea Characteristics
Have 5 arms that can be regenerated Arms project from the central disk Mouth on oral surface (underside) Range in size from  1 cm to 1 m

15 Body Plan of Sea Star Have an endoskeleton made of calcium plates
Sharp, protective spines made of calcium plates called ossicles found under the skin on the aboral (top) surface Have pedicellariae or tiny, forcep-like structures surrounding their spines to help clean the body surface Aboral Surface

16 Water Vascular System Network of canals creating hydrostatic pressure to help the starfish move Water enters through sieve plate or madreporite on aboral surface into a short, straight stone canal Stone canal connects to a circular canal around the mouth called the ring canal

17 Water Vascular System Five radial canals extend down each arm & are connected to the ring canal Radial canals carry water to hundreds of paired tube feet

18 Water Vascular System

19 3) Class Ophiuroidea Largest class of echinoderms
Includes basket stars & brittle stars Live on the ocean bottom beneath stones, in crevices, or in holes

20 3) Class Ophiuroidea Have long, narrow arms resembling a tangle of snakes Arms readily break off & regenerate Move quicker than starfish Feed by raking in food with arms or trapping it with its tube feet

21 4) Class Echinoidea Includes sea urchins & sand dollars
Internal organs enclosed by endoskeleton or test made of fused skeletal plates Body shaped like a sphere (sea urchin) or a flattened disk (sand dollar) Lack arms


23 4) Class Echinoidea Bodies covered with movable spines
Have a jawlike, crushing structure called Aristotle's lantern to grind food Use tube feet to move

24 4) Class Echinoidea Spherical shape Live on ocean bottom
Scrape algae to feed Long, barbed spines make venom for protection

25 4) Class Echinoidea Flattened body Live in sand along coastlines
Shallow burrowers Have short spines

26 5) Class Holothuroidea Includes sea cucumber Lack arms
Shaped like a pickle or cucumber Live on ocean bottoms hiding in caves during the day  Have a soft body with a tough, leathery outer skin


28 5) Class Holothuroidea Five rows of tube feet run lengthwise on the aboral (top) surface of the body Have a fringe of tentacles (modified tube feet) surrounding the mouth to sweep in food & water Tentacles have sticky ends to collect plankton Show bilateral symmetry Can eject parts of their internal organs (evisceration) to scare predators; regenerate these structures in days

29 5) Holothuroidea Bulb-like sacs or ampulla on the upper end of each tube foot contract & create suction to help move, attach, or open bivalves Rows of tube feet on oral surface (underside) are found in ambulacral grooves under each arm

30 Feeding & Digestion Tube feet attach to bivalve mollusk shells & create suction to pull valves apart slightly Starfish everts (turns inside out) its stomach through its mouth & inserts it into prey Stomach secretes enzymes to partially digest bivalve then stomach withdrawn & digestion completed inside starfish

Download ppt "Phylum Echinodermata Marine Invertebrates."

Similar presentations

Ads by Google