Wednesday, September 12, 2007

'Lots o' Fotsam' nature study

Today Cottesloe Primary School year 4's with some parents and their teacher, Mrs Marion Ewing joined Cottesloe Coastcare volunteers on the beach. We met marine experts Loisette Marsh, Mike Gregson and Kate Sputore for a marine nature walk.

We all braved some gusty wind and a few rain showers to collect 'lots o'flotsam' along the sea shore.

You will see in the pictures that the students then helped sort the material into groups of plants and animals. ( click on photos to enlarge them)

Some of us put the Sponges in with the plants but we soon learned that the sponges we found on the beach are actually the horny skeletons of many-celled animals. The Sponges, which are sedentry, mostly live in deep water, they can be brilliantly coloured and they filter their food from the water.

Kate showed us two species of sea grasses - which are flowering plants with roots and leaves. We had picked up some wire weed and some ribbon weed.

Then the seaweeds (many-celled algae) were divided into their classes. Among the green algae we found some Sea Lettuce and several beautiful green balls or 'Velvet Golf Balls'. We also collected various different species of red algae and brown algae. The children all seemed to know the name of the thick leathery brown algae or 'kelp'. We found one sea weed which was white and crisp. It was explained to us that this was a red algae that had been bleached by the sun and had also become lime-coated (calcified).

We learned about Jellyfish from Loisette, one jellyfish is the Blue Bottle and they were common on the beach today. Loisette showed us a Sea Urchin with its mouth in the middle of its underside and she told us how they move up and down Kelp columns as they feed, using their beak-like, self sharpening teeth! Other urchins we found had lost their spines. Molluscs were common too - we picked up turban shells, abalone shells, limpets, and cuttlebones.

We found several egg cases of Port Jackson Sharks and one small egg case from a Cat Shark. Kate told us that the female Port Jackson Shark uses her head to screw the egg case into a hole in the rock and there the baby shark develops over many months. Eventually it uses the sharp point on its head to help it escape its egg-case

Boys holding shark egg- cases.

We learnt lots of other fascinating information too and if you would like to learn more: click here to go to Coastcare's 'lots of flotsam'article, which inspired us all to take today's nature walk. After our lesson we returned all the plants and animals to the beach.
Thanks to everyone involved!


Anonymous CottPrimary year 4 said...

Today we did a great worksheet about our excursion to the beach. Our memories were a bit shaky so we used all the wonderful information on your website to help us fill in the boxes. We loved seeing our pictures on the site and in the paper. We are even publishing Eliza's worksheet in our school waterwise portfolio. Thanks for the worksheet and the fun excursion. Year4 Cott. Primary

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