Geology Reference
In-Depth Information
oil or water. Our pipelines grow when contractors attach new pipes to the ends of old
ones. Likewise, 'old school' mycelia were thought to grow by adding new tips to their
hyphae whenever food was sufficiently abundant in their supposedly constant environ-
ments. Then, when a predictable quantity of resources had been gathered, the mechan-
ical mycelium would, in essence, make a mushroom and reproduce.
But, like all complex systems, including living ones, mycelia are intelligible but in-
herently unpredictable. Unlike human pipelines, mycelia read their surroundings like a
text and change their organisational patterns accordingly. Mycelia have learnt to live
with uncertainty in both space and time. If you are a fungus, it is hard to know where
good food is, or how long it will last. Mycologist Alan Rayner points out that mycelia
deal well with these uncertainties because their dynamic, highly flexible fluid-filled
pipelines use local feedback to adjust the balance between four principal processes: ex-
ploration, assimilation, conservation and redistribution.
When a mycelium senses itself to be in unpalatable surroundings, it can enter into
exploration mode. Individual hyphae close up to the outside world and come together
to form fast growing mycelial cables, or superhighways, along which fungal protoplasm
streams at speed in search of new edible domains. When such a place has been found,
the mycelium goes into assimilative mode. The hyphae stop their onward rush. They
settle down, branch like Christmas trees, open up and start digesting. When they have
colonised several good sites separated by unfavourable terrain, mycelia go into conser-
vation mode—they consolidate their territory using cables that branch like river deltas to
connect the patches of good habitat. Finally, when a patch is no longer suitable, perhaps
because the mycelium has used up all the food it contained, or if parts of the mycelium
are using up too many scarce resources, the organism goes into redistributive mode. The
mycelium digests its own hyphae and sends the nutrients to other more needy parts of
the network.
Human brains work in similar ways. Strong memories are kept alive by the accumu-
lation of neurones in dense tracks. Weak memories peter out when neurones are re-direc-
ted to other tasks. Even the pattern of our conversations mirrors the way in which fungal
spores germinate and explore their habitats. New conversations and newly emerged my-
celia both tend to grow radially, like the spokes of a bicycle, until a good topic or a fallen
branch (food) are discovered. Then, when the symmetry breaks, protoplasm and ideas
flow in more definite directions. When a spore of a decomposer fungus germinates on
a suitable patch on the forest floor, it feeds and sends out exploratory hyphae in all dir-
ections. Soon enough, the radial symmetry is broken when one of these hyphae finds an
abundant source of food. Then all unsuccessful exploratory routes are abandoned and
the whole mass of fungal protoplasm migrates towards the new site to engulf the food.
