Final answer:
Symbiosis describes a close relationship between two organisms of different species, typically involving benefits to at least one. There are three types: mutualism, where both species benefit; commensalism, where one benefits without affecting the other; and parasitism, where one benefits at the expense of the other.
Step-by-step explanation:
Definition of Symbiosis
Symbiosis is a term used to describe a close, long-term association between two organisms of different species. Within this relationship, at least one of the organisms benefits. There are three main types of symbiotic relationships: mutualism, commensalism, and parasitism.
In a mutualistic relationship, both species benefit from the interaction. An example of this is the relationship between bees and flowers; bees get nectar from the flowers, which they use as food, while the flowers benefit from the pollination performed by the bees. Commensalism involves one species benefitting while the other is unaffected, such as a barnacle attaching to a whale's skin. Lastly, parasitism occurs when one species benefits at the expense of the other, like a tick feeding on a dog.
An example of symbiosis provided in the question illustrates a potential mutualistic relationship where birds pick food from a deer's fur. Although not directly mentioned, the deer may benefit by having ticks or other parasites removed by the birds, which supports its health and well-being.