Mutualistic relationships may evolve between two organisms that require different resources

When plants invaded the land between 400 and 500 million years ago, one of the biggest problems they faced was obtaining enough nutrients. Their aquatic habitat contained

Mineral Nutrition Plants

FIGURE 7.23

Nitrogenase is a bacterial enzyme complex found in nitrogen-fixing bacteria that converts atmospheric nitrogen gas (N2) to ammonia (NH3). Plants can use ammonia to make animo acids and other nitrogen-containing compounds for growth.

FIGURE 7.23

Nitrogenase is a bacterial enzyme complex found in nitrogen-fixing bacteria that converts atmospheric nitrogen gas (N2) to ammonia (NH3). Plants can use ammonia to make animo acids and other nitrogen-containing compounds for growth.

many decomposers that degraded large molecules, thereby increasing the availability of nutrients. As a result, aquatic organisms were literally bathed in nutrients. On land, however, the situation was different: most soils contained few fungi and therefore did not possess enough nutrients to sustain plant growth. One of the ways that plants adapted to life on land was by forming mutually beneficial associations between their roots and fungi. In effect, plants and fungi co-evolved for a life on land that helped ensure the continued availability of nutrients for their growth.

How might such a mutualistic relationship between two organisms evolve? A current hypothesis about the evolution of such beneficial interactions is that when one organism (species A) is better than another (species B) at acquiring a needed resource, species A benefits by specializing on the resource and trading any excess to species B. In return, species B specializes at obtaining a different resource and trades the excess to species A. This trading of resources is what many human businesses do, but scientists are now applying the model to living organisms. A mycorrhizal fungus and a plant both get more of the resources they need by specializing at obtaining different resources and trading their excesses with each other. Plants benefit from the ability of fungi to absorb and make available nutrients from the environment; fungi benefit because the plants provide them with sugar for growth. This relationship allows both organisms to benefit.

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Responses

  • ROSAURA
    Why might mutualistic relationships between plants and other organisms be expected to evolve?
    7 years ago
  • taina
    Why is mutualism a good relationship between two organisms?
    7 years ago
  • Folco
    Why micght mutualistic relationships between plants and other organisms be expected to evolve?
    5 years ago
  • briffo
    Why do species in a mutualistic relationship coevolve?
    5 years ago
  • adaldrida
    Why do mutualistic interactions evolve?
    4 years ago
  • jamie
    Why might mitualistic relationships between plants amd other organisms be expected to evolve?
    3 years ago
  • sirkka
    What is a name of mitualistic relationship between a fungus and plants roots?
    3 years ago

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