Summary
Close, long-term interaction between species, including mutualism, commensalism and parasitism.
In depth
Mutualism (+/+) such as clownfish and anemones; commensalism (+/0) such as epiphytic orchids on trees; parasitism (+/-) like tapeworms and ticks. Boundaries can shift with conditions.
Interactions can change along a spectrum depending on conditions. Parasites may influence host behaviour. Obligate symbiosis shows tight coevolution.
Example: cleaner fish and clients show mutualism that can break down when cheating occurs.
Symbiosis means living together, and the outcome can change with conditions: a gut bacterium can be mutualist in a healthy gut and pathogenic elsewhere. Endosymbionts live inside cells, as the Buchnera bacteria in aphids that supply amino acids, and lichens are a partnership of a fungus with an alga or cyanobacterium.
Human microbiota contain about as many bacterial cells as human cells and help with digestion, vitamin K production and immune training. Parasites can manipulate hosts: the fungus Ophiocordyceps controls ant behaviour. Cleaner fish, mycorrhizae and coral are other examples.
Common mistake: assuming that symbiosis always means mutual benefit; it is a broad term for close associations.
Frequently asked questions
What is Symbiosis?
Close, long-term interaction between species, including mutualism, commensalism and parasitism.
Which area of biology covers Symbiosis, and how advanced is it?
Symbiosis is one of the 54 topics in Ecology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Mutualism, Ecosystem, Microbial Ecology.
Can you give an example of Symbiosis?
Gut bacteria help digest food and make vitamin K while receiving nutrients and a habitat.
What should I learn before Symbiosis?
Symbiosis is a Beginner topic, so no earlier topic is required. Other Beginner topics in Ecology that pair well with it include Ecology, Ecosystem, Biotic and Abiotic Factors.
What topics are related to Symbiosis?
The closest topics to Symbiosis are Mutualism, Ecosystem, Microbial Ecology, Exponential Growth. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Symbiosis?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Symbiosis. To practise the whole of Ecology, use the Ecology quiz.
How is Symbiosis different from Mutualism?
Symbiosis: Close, long-term interaction between species, including mutualism, commensalism and parasitism. Mutualism: An interaction benefiting both species, like bees and flowering plants or mycorrhizal fungi and roots. Read both side by side and note what each one explains.
What is a common mistake about Symbiosis?
Assuming that symbiosis always means mutual benefit; it is a broad term for close associations.
How should I study Symbiosis step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Mutualism and explain the difference aloud. Finally, take the Ecology quiz and come back to this page for any question you miss.