A living organism is a complex and fragile mechanism that requires continual maintenance and repair. Maintenance and repair of an organism depend on supplies of both material and energy. Some microorganisms obtain energy and structural materials from inorganic compounds in their environment. But the great majority of living organisms, both plant and animal, depend directly or indirectly on solar radiation for the energy to build and maintain their physical structure.
Humans obtain the material and energy for growth, cellular maintenance and physical action by consuming other organisms: either plants that derive energy directly from the sun, or animals that derive energy by consuming either plants or other animals.
Because all living creatures are mortal, perpetuation depends on reproduction. Hence, the basic human preoccupations: food and sex. Attention to all else, it might seem, is maladaptive.
But was the childless Sir Isaac Newton maladapted, was Saint Francis, or Jesus? Not necessarily. they each had a huge impact on the civilization in which they lived, and hence upon the survival and expansion of the gene pool to which their own genes belonged.
