CLAMS IN ACTION!

Check out this short video on clams! It's interesting to see the muscular foot in action!

Click here:
Moving clams

EXTERNAL AND INTERNAL FEATURES OF A CLAM



 We have observed external and internal features of clams. We have identified the dorsal and ventral sides of the shell. On the dorsal side there is a small bump which is the oldest part of the shell, it is called the umbo. There is also a hinge ligament which joins the two valves together. The hinge ligament allows the valves to open and close. It is softer than the shell so it doesn't crack. We also saw the growth rings on the shell that indicates its age.

The first thing we saw when we opened the shell were the adductor muscles. These are used to open and close the valves. If we pull them off, muscle scars are left on the shell. You can often see the adductor muscle scars on the shells when you eat molluscs! We also located the muscular foot used to move and to bury itself into the sand. We saw the mantle, a fine membrane that covers the mollusc and the gills used to breathe. The gills are easy to recognise because of the folds they have to increase the respiratory surface. We also located the incurrent and excurrent siphon. If you look carefully at the photograph you can see the parts.

Nudibranch - marine gastropod molluscs

Check out this video on nudibranch! Nudibranch are marine gastropod molluscs with no shells. They are noted for their stunning colours and forms.

Click here:
National Geograpic video on nudibranch

IDENTIFYING MOLLUSCS

Molluscs are invertebrate animals. Most are aquatic e.g. mussels, clam, squid, cockles, cuttlefish, whelk etc. Others, like snails and slugs are terrestrial. Their main characteristic is that they have a soft body and a shell.The body has three parts: a head that contains sensorial organs, a main body part, that contains the main organs and a muscular foot, they use to move or to bury themselves in the sand. Shells can be made up of one or two parts called valves or can be internal. Some molluscs don't have a shell, e.g. slugs. Aquatic molluscs breathe through gills and terrestrial through lungs. Most molluscs are hermaphrodites.

Variety of molluscs

Molluscs are divided into three groups:
Gastropods: They have a spiral shaped shell with only one valve.
Bivalve: They have a shell with two valves.
Cephalopods: They have an internal shell.

We have observed a variety of molluscs in the class, identified them and also identified the group they belong to.
Here are some of the molluscs we have seen.

Razor clam - Bivlave

Snail - Gastropod

Cockle - Bivalve

Whelk - Gastropod



Whelk - Gastropod


 

Mussel - Bivlave



Clam - Bivalve

Scallop - Bivlave

Did you enjoy the experiment?

Microscopic preparations of animal and plant cells

Living things are made of cells. Cells are the smallests units of life. They undergo the three vital functions: nutrition, interaction and reproduction. We have studied prokaryotic and eukaryotic cells. Prokaryotic cells are the most primitive. Scientists believe that the first cells to exist on Earth were prokaryotic. They don't have a nucleus and their genetic material is dispersed in the cytoplasm. Prokaryotic cells exist today as bacteria. Cells evolved and protected their genetic material in a nucleus. These are eukaryotic cells.
Cells have three main parts: cell membrane, nucleus and cytoplasm. In the cytoplasm there are other organelles like vacuoles, mitochondria, chloroplasts. We have also studied the differences between animal and plant cells. Plant cells have a cell wall, chloroplasts and a big vacuole.
We have made microscopic preparations of cells and observed them with the microscope.

Do you recognise these cells? How did we obtain these cells? What can you say about their shape? What parts can you see? Where is the nucleus located?

These are human cheek cells. May be yours!

 We have made microscopic preparations of plant cells.

These are onion cells. They have a polyhedral shape and if you look carefully you can see that the nuclei are not in the centre. They are located to one side of the cell. Do you know why?

WELCOME!

Welcome to Science Magazine! This blog has been created for those students that are science enthusiasts.
Here you will be able to read about interesting things related to our science class, read about the latest science discoveries, also curiosities of the past, go over the experiments we do in the class, comment or make suggestions, publish your science topics...and lots more! ..Enjoy!