the other Birds compete with squirrels for nuts and seeds Parasitism + -- Population , the parasite, generally smaller than , the host Ascaris and tapeworm in human digestive tract Predation + -- Population , the predator, generally larger than , the prey Lion predatory on deer XII Std Zoology Chapter XII Std Zoology Chapter Organisms and Populations Fig. . Owls competing for food and protection from the host. Parasites exhibit adaptations to exploit their hosts.
The parasites may be viral parasites (plant / animal viruses), microbial parasites (e.g., bacteria / protozoa / fungi), phytoparasites (plant parasites) and zooparasites (animal parasites such as Platyhelminthes, nematodes, arthropods). Parasites may inhabit or attach to the surface of the host (Ectoparasites - Head lice, Leech) or live within the body of the host (endoparasites – ascaris, tapeworm). The endoparasites usually live in the alimentary tract, body cavities, various organs or blood or other tissues of the host. Parasites may be permanent or temporary.
Temporary parasites spend only a part of their life cycle as parasites. For example, Glochidium larva of Anadonia (fresh water mussel) attaches itself to the body of fish. Permanent parasites spend their life completely dependent on their host organism. The common examples of permanent parasites are Plasmodium , Entamoeba , Round worms, Pin worms, Tape worms, etc., PREDATION (+, --): It is a form of interaction, where one animal kills another animal for food.
Like parasitism, predation is important in community dynamics, but both differ in the point that a predator tends to be larger than its prey, and it catches its prey from without, while a parasite is smaller than its host and consumes it from within. • Egrets usually are present near cattle. They catch insects which are disturbed by the cattle. The bird benefits, while the cattles are not affected ( Fig.
Egrets near cattle; barnacles on whale COMPETITION ( -- , -- ): It refers to the type of interaction in which individuals of a species or members of different