Mutualism (biology)
In ecology, mutualism or mutualistic symbiosis refers to an interrelationship between living organisms of two species from which, in contrast to competition or predator-prey relationships, both partners benefit. In the U.S. literature, the word mutualism is used synonymously with the German term symbiosis in the narrow sense, while the word symbiosis - in contrast to the German term symbiosis - is used for any coexistence of living beings of different species. Some authors differentiate between symbiotic mutualism, in which both partners live together spatially on a permanent basis, and non-symbiotic mutualism, (e.g. in zoogamy or zoochory), in which the symbiotic partners meet only sporadically.
Various mathematical models are used in biology to describe and analyze mutualistically organized ecological relationships. Such models differ, among other things, in whether they describe the temporal dynamics of mutualistically interacting populations in a rather short (ecological) or rather long (evolutionary) time period. A particularly simple model, popular because of its wide applicability, can be written for mutualisms of two species in terms of ordinary differential equations: If N1 and N2 denote the population densities of two species in a mutualistic relationship, r1 and r2 intrinsic growth constants, K1 and K2 capacities, and b12 and b21 positive interaction coefficients indicating the strength of the mutualistic relationship, we obtain:
![{\displaystyle {\frac {\mathrm {d} N_{1}}{\mathrm {d} t}}=r_{1}N_{1}\left[1-{\frac {N_{1}}{K_{1}}}+b_{12}{\frac {N_{2}}{K_{1}}}\right]}](https://www.alegsaonline.com/image/5ec8cceb23cd80e1df205966a210e328b45ba55c.svg)
![{\displaystyle {\frac {\mathrm {d} N_{2}}{\mathrm {d} t}}=r_{2}N_{2}\left[1-{\frac {N_{2}}{K_{2}}}+b_{21}{\frac {N_{1}}{K_{2}}}\right]}](https://www.alegsaonline.com/image/fc80e98efc48238eb64f19de15eef74d8f1b2788.svg)
This type of model is a direct generalization of the logistic differential equation to the situation of two interacting populations. In this or similar form, mutualisms are given in many textbooks of theoretical biology (see Literature).
Examples
- Skin flora/intestinal flora
- Mycorrhiza
- Ant and aphid
- Clownfish and sea anemone
- Cleaning symbioses such as in the oxpecker, which collects parasites from large animals such as rhinos.
- Oak / jay (food for the bird; further seed dispersal over a wider area and not just under the tree).
See also
- Protocooperation
Questions and Answers
Q: What is mutualism?
A: Mutualism is a relationship between two organisms in which both benefit.
Q: What is symbiosis?
A: Symbiosis is the interaction between two different organisms living in close physical association.
Q: What does mutualism do for the organisms involved?
A: Mutualism improves the biological fitness of both parties involved.
Q: Can two animals of the same species have a mutualistic relationship?
A: No, the term mutualism is not used for any cooperation between animals of the same species.
Q: Who introduced the term mutualism into evolutionary biology and ecology?
A: Edouard van Beneden introduced the term into evolutionary biology and ecology in the 1870s.
Q: Do the two organisms involved in mutualism have to be from the same phylum or kingdom?
A: No, the two organisms usually come from widely different types, often from different phyla or even kingdoms.
Q: Can you give examples of mutualism?
A: One example of mutualism is the relationship between bees and flowers, where bees receive nectar and flowers are pollinated. Another example is the relationship between clown fish and sea anemones, where clown fish receive protection from predators and sea anemones receive food scraps.
