Phylum Molluska
Mollusks are soft bodied animals that usually have an internal or external shell. This grouping consists of snails, clams, slugs, squid, octopi, etc. Many of these animals share similar developmental stages. They have a mouth, cilia, an anus, and stomach.
These animals have true coeloms surrounded by the mesoderm tissue.They have complex, interrelated organ systems that function together to maintain the whole body. They have a foot, which is a musclular mass that can capture prey and help them move. It has different forms. The mantle is a thin layer of tissue covering most of the mollusk's body. The shell is made of glands in the mantle and secrete calcium carbonate. Visceral mass is under the mantle. It contains the internal organs.
They can be herbivores, carnivores, filter feeders, detrivores, or parasites. They have a radula, a flexible tongue shaped structure with tiny teeth which is used by snails and slugs. Food is carried by water, and enters the siphon- a tube-like structure where water enters and leaves the body.
Mollusks breathe using gills. Water passes through the mantle and the oxygen in the water moves to the blood flowing through the gills and carbon dioxide pumps out. Some have open circulatory systems, blood pumps through vessels by a simple heart. Blood leaves the vessels and works through the sinuses where carbon dioxide and oxygen are traded, then it's pumped back to the heart. Other mollusks have closed systems, which makes them faster-moving than the open system mollusks.
Mollusks excrete by using nephridia, which removes amonia from the blood and releases it outside of the body.
Two-shelled Mollusks have very simple nervous systems. Octopi and their relatives have the most highly developed nervous systems. They have well developed brains that allow for long term memory and highly advanced eyesight.
Snails secrete mucous and move over surfaces with rippling muscles. An octopus draws in water to the mantle, forces it out through the siphon, and propels itself in the opposite direction.
Some mollusks reproduce sexually with external fertilization. Some are hermaphroditic. Others reproduce sexually with internal fertilization.
There are three main groups of mollusks: gastropods, bivalves, and cephalopods.
These animals have true coeloms surrounded by the mesoderm tissue.They have complex, interrelated organ systems that function together to maintain the whole body. They have a foot, which is a musclular mass that can capture prey and help them move. It has different forms. The mantle is a thin layer of tissue covering most of the mollusk's body. The shell is made of glands in the mantle and secrete calcium carbonate. Visceral mass is under the mantle. It contains the internal organs.
They can be herbivores, carnivores, filter feeders, detrivores, or parasites. They have a radula, a flexible tongue shaped structure with tiny teeth which is used by snails and slugs. Food is carried by water, and enters the siphon- a tube-like structure where water enters and leaves the body.
Mollusks breathe using gills. Water passes through the mantle and the oxygen in the water moves to the blood flowing through the gills and carbon dioxide pumps out. Some have open circulatory systems, blood pumps through vessels by a simple heart. Blood leaves the vessels and works through the sinuses where carbon dioxide and oxygen are traded, then it's pumped back to the heart. Other mollusks have closed systems, which makes them faster-moving than the open system mollusks.
Mollusks excrete by using nephridia, which removes amonia from the blood and releases it outside of the body.
Two-shelled Mollusks have very simple nervous systems. Octopi and their relatives have the most highly developed nervous systems. They have well developed brains that allow for long term memory and highly advanced eyesight.
Snails secrete mucous and move over surfaces with rippling muscles. An octopus draws in water to the mantle, forces it out through the siphon, and propels itself in the opposite direction.
Some mollusks reproduce sexually with external fertilization. Some are hermaphroditic. Others reproduce sexually with internal fertilization.
There are three main groups of mollusks: gastropods, bivalves, and cephalopods.