The Digestive System of the Hard Clam
The Hard Clam is a filter feeder. This mean that they eat algae, dust, and other particles that help filter the water. Without them the algae would grow so much that we wont even see the water. Although hard Clams are very small, they have an amazing digestive system. They really don't have to do much only open their mouths.
1. First the algae or "food" enters the incurrent siphon not the excurrent siphon because the excurrent siphon is the opening for waste products.
2. After that it goes to the gills where the water and the particles are separated. The gills have mucus that allow the particles to stick to it and this is how it separates the particles to the water. The gills also get oxygen from the water. (1)
3. Cilia has a very important role in the digestive system of the Hard Clam. It grabs the algae and helps it travel to the mouth and libial palphs.
4. The labial palp are like our lips. It sort out foods before entering the mouth (2) For example, silt or excess matter. These rejected matter get out with the help of the mantle and are released like pseudofeces.
5. The next step is for the food to go to the mouth. But, the mouth is only an opening to the stomach so it doesn't do much or simply put it doesn't do anything at all.
6. Then the food goes to the stomach were the food is processed and it is broken down.
7. It then goes to digestive gland where it undergoes more breakdown to be able to pass to the intestine. (3)
8. In the intestine the proteins and nutrients are captured and sent to the blood cells.
9. The second to last step is the rectum passage. This is where the waste goes to wait until the Clam feels like pooping.
10. Finally the wage reaches the anus and it is there where the waste is extracted.
(1) http://animals.howstuffworks.com/marine-life/clam-info.htm
(2) http://shellfish.ifas.ufl.edu/PDFs/Getting%20Started/Biology%20and%20Anatomy%20of%20Hard%20Clam.pdf
(3) http://barnegatshellfish.org/mercenaria01.htm
There are many other websites that are great to find more information and http://www.biology.ualberta.ca/facilities/multimedia/uploads/zoology/Clam.html is a great one it shows a great cartoon about the digestive system.