In parasitism, one organism lives on or in another organism at the expense of this organism, which is called the host. Parasites may destroy the host. An example of parasitism is the hookworm. Hookworms may live in the intestines of human beings and other animals.
In commensalism, one organism benefits from the host, which is unaffected. For example, a type of marine worm lives in the shells occupied by hermit crabs. When the crab feeds, the worm comes out to share the host's meals.
In mutualism, both parties benefit. For example, certain kinds of ants live in thorny plants. The plants provide food and nesting sites for ants. In return, the ants provide protection from insect pests. Mutualism also occurs when an alga and a fungus grow together to form a lichen, which differs from either organism. The fungus, which cannot produce its own food, gets its food from the alga. The fungus helps the alga get water.
Symbiosis is any kind of relationship between two species, even predation and herbivory are types of symbiosis.MWP admin wrote:Maybe my biology needs some polishing, but is it really parasitism a form of symbiosis? Is symbiosis when the 2 organsisms benefit from each other (ore there is no harm affeced to the other)?
Actually there are more than three types of symbiosis:
1) neutralism (not really a type of symbiosis in the 'classic' sense, this means that two species living in the same habitat without overlapping niches, meaning that none of them is affected by other eg. mosquito and beetle)
2) competition (both species are inhibited by each other eg. grey squirrel vs red squirrel)
3) mutualism (organisms are partners and usually cannot exist without each other eg. a lichen, mycorrizhae)
4) proto-cooperation (organisms are not necessarily dependent upon one another, but when they are both present the result is a positive one for both eg. oak tree and woodpecker)
5) commensalism (obligatory for one species, the other is unaffected eg. barnacles on whales, worms in hermit crab shells)
6) amensalism (one species inhibited, the other unaffected eg. rabbit and cow)
7) parasitism (eg. rabbit and fleas)
predation/ herbivory (eg. lion and zebra, zebra and grass)
I am still very curious with my photos. Whether an uncommon lichen, or a calcium ore, both are interesting for me, perhaps the latter a bit more since I never seen a 'real' ore except at the museums