Genuine (if idle) question- why do plants have leaves which permanently face away from the sun? It's not zero-cost to the plant to produce such leaves...so why does it?
There is a major assumption throughout this thread -- that trees maximize solar energy capture. In fact, the exact opposite is true. Many features of trees (and plants in general) reduce the efficiency of solar conversion. This is useful for plants to reduce the need for other resources like water. If leaves were arranged to optimally harvest solar energy, the tree would need an enormous amount of water to combat the resultant heat and evaporation.
Trees only convert 1-3% of the solar energy that falls on them -- so trees are a very poor system to mimic if the goal is to maximize solar energy collection.
My educated guess is that there is some benefit to having a uniform distribution of solar power over the course of a day. If all leaves pointed in one optimal direction, then more energy would be directed at the tree in a single day, but it would collect this energy in a narrow time span. It's possible a tree could not efficiently process this energy in this time span, similar to how you would not be able to eat a deer in one sitting.
By having a generally spherical orientation of leaves, the tree is always receiving power throughout the day.
All the cells in one string (i.e. all the cells in series, connected positive to negative terminal) need uniform sunlight. Otherwise some cells can go into reverse bias and dissipate the power of the other cells in the string. This happens, for example where there is uneven shade, or dirt on the array.
a.) If adding leafs is has net gains, the tree will do this even if it's not the most efficient way (where say it could only have 50% of the leafs).
b.) A tree is fighting with it's environment for light and space, a linear setup of leaves might not be the best position to fight other plants for light.
c.) A tree needs to support all leafs with water, nutrients etc. A tree layout might be more efficient
Remember how evolution works: If a being stumbles on an imperfect solution and then never experiences a selection pressure strong enough to force a change, it won't get changed. Similarly, if there never arises a mutation that would change it, it won't get changed. Evolution is not focused on finding optimal solutions; it may eventually find one, but it is not guaranteed as part of the process.
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Genuine (if idle) question- why do plants have leaves which permanently face away from the sun? It's not zero-cost to the plant to produce such leaves...so why does it?
There is a major assumption throughout this thread -- that trees maximize solar energy capture. In fact, the exact opposite is true. Many features of trees (and plants in general) reduce the efficiency of solar conversion. This is useful for plants to reduce the need for other resources like water. If leaves were arranged to optimally harvest solar energy, the tree would need an enormous amount of water to combat the resultant heat and evaporation.
Trees only convert 1-3% of the solar energy that falls on them -- so trees are a very poor system to mimic if the goal is to maximize solar energy collection.
My educated guess is that there is some benefit to having a uniform distribution of solar power over the course of a day. If all leaves pointed in one optimal direction, then more energy would be directed at the tree in a single day, but it would collect this energy in a narrow time span. It's possible a tree could not efficiently process this energy in this time span, similar to how you would not be able to eat a deer in one sitting.
By having a generally spherical orientation of leaves, the tree is always receiving power throughout the day.
Again, this is all just my hypothesis.
All the cells in one string (i.e. all the cells in series, connected positive to negative terminal) need uniform sunlight. Otherwise some cells can go into reverse bias and dissipate the power of the other cells in the string. This happens, for example where there is uneven shade, or dirt on the array.
a.) If adding leafs is has net gains, the tree will do this even if it's not the most efficient way (where say it could only have 50% of the leafs). b.) A tree is fighting with it's environment for light and space, a linear setup of leaves might not be the best position to fight other plants for light. c.) A tree needs to support all leafs with water, nutrients etc. A tree layout might be more efficient
leaves serve other purposes as well (for example, stomata are used for gas exchange) which do not directly involve sunlight.
Remember how evolution works: If a being stumbles on an imperfect solution and then never experiences a selection pressure strong enough to force a change, it won't get changed. Similarly, if there never arises a mutation that would change it, it won't get changed. Evolution is not focused on finding optimal solutions; it may eventually find one, but it is not guaranteed as part of the process.