Final answer:
Competition is not one of the three main forms of symbiosis. The three forms of symbiosis are mutualism, commensalism, and parasitism, where mutualism is a beneficial relationship for both species, commensalism benefits one without affecting the other, and parasitism benefits one at the expense of the other.
Step-by-step explanation:
The form of symbiosis that is not one of the three main types is competition. Symbiosis is defined as a close, long-term interaction between two organisms of different species where at least one organism benefits. The three types of symbiotic relationships are mutualism, commensalism, and parasitism.
In mutualism, both organisms benefit from the relationship. An example of mutualism is the relationship between bees and flowering plants, where bees get nectar for food and in return pollinate plants.
Commensalism is a type of symbiosis where one species benefits while the other species is neither harmed nor benefited, such as when barnacles attach themselves to the shell of a turtle. The barnacles gain mobility and access to more food sources, while the turtle is not affected by their presence.
Parasitism occurs when one organism, the parasite, benefits at the expense of the other, the host. An example of parasitism is a tapeworm living in the intestine of a mammal, where the worm derives nutrition at the host's expense.
Competition, on the other hand, is an interaction where organisms vie for the same resources in an ecosystem, such as food, space, or mates, and is not a form of symbiosis.