Final answer:
Symbiosis is a biological term for a close relationship between two species, where at least one benefits. Key types include mutualism, commensalism, and parasitism, with lichens being a mutualistic example.
Step-by-step explanation:
The term symbiosis refers to a close, typically long-term interaction between two different biological species. In a symbiotic partnership, at least one of the parties involved derives benefit from the relationship. There are various forms of symbiosis:
- Mutualism: Both organisms benefit from the relationship.
- Commensalism: One organism benefits, while the other is not significantly harmed or helped.
- Parasitism: One organism benefits at the expense of the other.
An example of a symbiotic relationship is that between algae and fungi in lichens. The algae are capable of living independently while the fungus requires the symbiotic relationship to survive, indicating a form of mutualism where the algae contributes through photosynthesis, and the fungus provides structure and protection.