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Bamboo Mathematicians

phenomena.nationalgeographic.com

81 pointsrobrenaud13 comments

As opposed to the Periodical cicadas[0] which breed on a 13 or 17 year cycle, which are specifically prime numbers, and therefore specifically not products of small factors.

[0] http://en.wikipedia.org/wiki/Periodical_cicadas

Why is this only a problem for bamboo and not other trees?

A few years ago the flowering of bamboo was posted as a TIL on reddit. A few commentors had interesting stories about how the flowering of bamboo was a dark omen, since rats would feast on the fruits on multiply like crazy during the rare bamboo season.

Perhaps it's to do with the fact that these particular bamboo species are monocarpic, i.e. in one life-cycle they set seed just once and then die. So the timing of this event is more crucial for their reproductive success than for typical trees (which are polycarpic and not grasses).

Oak trees vary their acorn production substantially year by year, probably to avoid an excess of acorn "predators". And since Oaks don't die when producing acorns, they have less incentive to avoid the predators.

So the same pressures can be observed many places but the particular biology of each species varies the results.

http://www.hastingsreserve.org/oakstory/Acorns2.html

I grew up in a house whose yard was filled with oak trees ... I'm pretty convinced they survive due to the stupidity of squirrels rather than "overwhelming" these predators. There were oftens way more acorns than needed, but every year the squirrels would work furiously to bury them ... then promptly forget where they put them. So the squirrel population was held in check by the number of acorns they could find the rest of the year and the acorns had the advantage of being buried (versus germinating on the surface).

And why don't other plants in the same forest also synchronize their flowering to the same time, so that all trees in one forest would flower say every 60 years? A bit like bird colonies that have many different species, enjoying the protection. Maybe they would not be synchronized to the same part of the year, losing most synchronization benefits.

That would probably not be the best strategy for those plants that need animals to help them reproduce. Animals and plants could co-evolve, yes, but getting there likely is slower.

Also, Wikipedia (http://en.m.wikipedia.org/wiki/Bamboo_blossom#Mechanism) mentions a competing theory: "the fire cycle hypothesis, argues that periodic flowering followed by death of the adult plants has evolved as a mechanism to create disturbance in the habitat, thus providing the seedlings with a gap in which to grow. This argues that the dead culms create a large fuel load, and also a large target for lightning strikes, increasing the likelihood of wildfire. Because bamboos can be aggressive as early successional plants, the seedlings would be able to outstrip other plants and take over the space left by their parents."

If that is a factor in synchronized blooming it only can be beneficial for those plants that are pioneer species (http://en.m.wikipedia.org/wiki/Pioneer_species)

There is a large number of plants don't use animals for pollinating. For example Conifers.

There are so many factors at play in a diverse ecosystem. For one, the plants compete on many levels that it becomes too "chaotic" for an immediately discernible overall synchrony to arise. Even then there will likely be a number of symbiotic relationships between different species that depend on the presence of varying flowering/life cycles. The bamboos come out all "well behaving" and synchronized perhaps only because the natural evolutionary process is trying out everything everywhere and something somewhere will be judged to be synchronized with distinction.

bamboo have decoupled spreading out from reproduction.

    Unlike all trees, individual bamboo stems, or culms,
    emerge from the ground at their full diameter and grow
    to their full height in a single growing season of three to four months. [1]

They have little need for flowering except to create genetic diversity. So don't just look at it as solving a problem: it could also be bamboo playing to its strengths.

Of Bamboo is probably also solving some unique problems perhaps related to be closely located instead of further spread out.

[1] http://en.wikipedia.org/wiki/Bamboo

I'm just speculating here. Maybe the seeds of other trees are not as tasty for rodents? So other trees might not be facing the same problems as the bamboos, and could have a better chance of survival

Bamboo is amazing. Here is a very interesting talk about how it is being used in construction (well worth the 10 mins)

http://www.ted.com/talks/elora_hardy_magical_houses_made_of_...

So, is it possible to use this mathematical model to calculate backwards the number of years from the 120 year cycle plant to the one-year cycle plant, to deduce how far in the past the "family tree" reaches?

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