Another interesting quote from the book I'm reading:

One major question needing to be examined is the general attitude of nature. A century ago there was a consensus about this: nature was ‘red in tooth and claw’, evolution was a record of open warfare among competing species, the fittest were the strongest aggressors and so forth. Now it begins to look different. The tiniest and most fragile of organisms dominate the life of the earth: the chloroplasts inside the cells of plants, which turn solar energy into food and supply the oxygen for breathing, appear to be the descendants of ancient blue-green algae, living now as permanent lodgers within the cells of ‘higher’ forms; the mitochondria of all nucleated cells, which serve as engines for all the functions of life, are the progeny of bacteria which took to living as cells-inside-cells long ago. The urge to form partnerships, to link up in collaborative arrangements, is perhaps the oldest, strongest and most fundamental force in nature. There are no solitary, free- living creatures; every form of life is dependent on other forms. The great successes in evolution, the mutants who have, so to speak, made it, have done so by fitting in with, and sustaining, the rest of life. Up to now we might be counted among the brilliant successes, but flashy and perhaps unstable. We should go warily into the future, looking for ways to be more useful, listening more carefully for signals, watching our step and having an eye out for partners.
-- Lewis Thomas, The Key Reporter (Autumn 1980)