4 ms·
It is a very very old protein, stuck in local maximum more than anything else.
by chris_va 10y ago
It is a very very old protein, stuck in local maximum more than anything else.
- jessriedel 10y ago> stuck in local maximum more than anything else What's the argument that this is true, rather than it being better than more efficient proteins on some other metric?
- kibibyte 10y agoPlants in arid environments have evolved a more efficient carbon fixation process -- https://en.wikipedia.org/wiki/C4_carbon_fixation https://en.wikipedia.org/wiki/C4_carbon_fixation -- in response to decreased water in the environment. Despite this, C3 plants still dominate the planet, so somehow selection pressure hasn't shifted strongly towards C4 plants in non-arid environments.
- jessriedel 10y agoAccording to the wikipedia page, C4 is more efficient in water usage, but less efficient than C3 in energy production. https://en.wikipedia.org/wiki/C4_carbon_fixation https://en.wikipedia.org/wiki/C4_carbon_fixation
- kibibyte 10y agoOh makes sense. I somehow read over that sentence.
- gd1 10y agoSelection pressure may well have shifted towards C4 in the future if we hadn't come along and been kind enough to dig up some fossilized carbon and put it back into circulation.
- bigiain 10y agoI suspect there might well be an evolutionarily balanced tradeoff between "construction cost" and "lifetime energy output" of a plant's photosynthesis machinery - as well as a likely overabundance of available solar energy in terms of what a plant actually can use. (Why build a potentially more complex and fragile photosynthesis pathway that's 50% more efficient, if you can instead just grow twice as much leaf surface area?)
- jessriedel 10y agoBut there are places where plants compete fiercely for small amounts of sunlight, such as in forests (especially tropical rainforests). Doesn't your theory suggest they'd use more efficient systems there?
- lordnacho 10y agohttps://en.wikipedia.org/wiki/C4_carbon_fixation https://en.wikipedia.org/wiki/C4_carbon_fixation Example of such an evolutionary step. C4 vs C3 photosynthesis.
- jessriedel 10y agoC4 is more efficient in water usage, but less efficient than C3 in energy production
- Retric 10y agoDon't forget plants get the energy back from making a leaf in a few weeks. Solar panels take considerably longer. Generally plants are optimized to compete with others in their niche and as such it's exponential growth that's most important not total energy capture.
- int_19h 10y agoIs it actually tropical rainforests, or temperate, that limit sunlight most? Old-growth PNW forests often have large patches of western hemlocks that produce so much shade that no other tree can grow under it, not even conifers - and unless there's a fire to clear some space out, it can stay that way for centuries.