Reply #39: I think of it this way: the plant doesn't need any more energy.

[hunter]

It's got enough to live and reproduce where it is.

In some environments the trees dominate, shading out their competition underneath, but in other environments growing taller isn't appropriate because there simply isn't enough water for trees -- either the place is dry, or the water is frozen for much of the year. Growing taller has an insignificant or negative value.

Plants can pack more or less chloroplasts (and thus more chlorophyll) into their energy collecting surfaces. Plants simply never needed more efficient energy collectors because other factors were limiting their growth. Greater collection efficiencies were of no value, just as those extra reptilian color receptors were of no value to a little mammal hunting mostly with its nose and whiskers. But the capacity for having additional color receptors remained

In the larger pictures of life, price doesn't matter. A thing has value, or it doesn't. I don't pay any attention at all to the price of things that have no value to me. If Oprah gave me a car it would have a negative value to me. I might give it to someone else to avoid paying taxes, or even to avoid having another car. I view cars as an irritation. My 25 year old truck works fine, so please Oprah, give the car to someone else.

The ecological world works very much the same way, it's not so much what things cost, but the value of things within a given environment.

Most plants and animals have a huge library of genetic processes that are simply inactive. When the environment changes it's never so much the innovations that allow a species to evolve into something more suited to the changed environment, it's more like a simple readjustment and reinterpretation of existing plans.

The model of evolution as an economic process is wrong. The model of human social and environmental relationships as an economic process are wrong too. The environment is very rich, and in any given place there's only a few limitations to expansion, and usually these are big limitations such as the availability of water, or some specific nutrient, the presence of toxins, or the availability light. Within these environments certain biological expressions are valuable, while others are not.

Personally I tend to think models of supply and demand, or costs and benefits, or even profits or losses, are grossly unstable and do not accurately reflect the basic biology of human beings and the earth's environment. By our careless use of these unstable models we have placed our society and billions of human beings in great jeopardy.