Emergent properties are those which are unseen until a higher level of biological organization allows them to appear. Alone, the fungi in mycorrhizae can go about their lives as absorptive heterotrophs, and the plants work at photosynthesis. However, both grow rampantly when they cooperate, something which is not obvious until they come together. In the case of lichens, the fungal and algal partners are similarly able to exist without one another, but together they produce a dramatically different body and can perform functions such as the start of soil production and can live in dry, exposed conditions where neither partner would do well alone.
Work Step by Step
This is one of the overarching themes in this textbook— review Ch. 1 for more information on this topic, and then think imaginatively about how mycorrhizae and lichens present features which are found in neither the fungal nor the photosynthetic partners in those interactions.