Starfish
Starfish can re grow severed arms.
They have a very simple life cycle.
The female lays eggs in the water.
The male releases millions of sperm which fertilises the eggs.
Starfish move by using a water pumping system. This is connected to their feet.
They draw water in and pump it out to lengthen or shorten their feet. This enables them to climb and cling to rocks.
Most starfish are predators.
Sea stars, sea urchins and sand dollars all belong to the same group called echinoderms.
Cushion Star
The most common starfish are cushion stars. You will find them in rock pools. They cling tightly to rocks or under stones.
They have five arms.
Their colours range from yellow to purple. Greyish green is the most usual colour.
They have tube feet tipped with suckers. These are on the underside of their arms.
They browse on filmy green seaweeds and digest them by extruding their stomach over them. They also feed on matter found on the bottom of the sandy pools. Cushion stars are omnivores and eat live or dead organisms. If they don't get eaten by predators they may live for up to ten years.
Sun Stars
Sun stars love to eat mussel.
They hold the mussel in their arms and pull it apart with hundreds of their feet working in relays.
At the same time the stomach also secretes an acid fluid which puts the mussel to sleep.
When the mussel is pulled apart the starfish extrudes its stomach through its mouth and digests the mussel.
Printout Activities.
Starfish topic words.
Starfish word search.
Take an Online quiz.
Links
Echinoderms
Common sea star diagram.
The Rock Pool.
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