Holozoic organisms have special structures for capturing or obtaining their prey or food. These structures depend on whether the food is in a solid form or a liquid form. Solid food may be large of small.
Organisms feeding on large pieces of food or whole organisms use structures such as claws, tentacles, teeth and beaks to seize their food or prey. Those feeding on small pieces of food or tiny prey use filter feeding mechanisms to obtain their food. Fluid fees rs have structures for sucking fluid food.
Parasitic and saprophytic organisms take in food in fluid form. Saprophytes have special feeding mechanisms for changing solid food to liquid food before absorbing it. Many parasites have structures for boring into the bodied of their hosts and sucking the tissue fluid on which they feed.
In most holozoic animals, digestion and absorption of food take place in the alimentary canal or gut. A simple unicellular animal does not have an alimentary canal. Digestion takes place inside the cell with in a food vacuole. This is known ad intracellular digestion. A simple multicellular animals has a moth for taking in food. The mouth opens in to a sac like gut cavity where food is digested. Digestion in the gut is said to be extracellular because the gut cavity is an extension of the external environment into the animal's body. As such, food in the guy cavity is considered as being outside the animal's body. In most higher animals, the gut cavity or alimentary canal is a long tube with two openings:
• The mouth at the anterior end for taking in food, and
• The anus at the posterior end for getting rid of undigested food.
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