Harmony and Conflict in the Living World - Alexander F. Skutch [25]
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hardiest and most adaptable survivors the materials they needed to preserve life.
Whether or not the earliest organisms that nourished themselves on other organisms consumed only dead ones, it is certain that eventually living things began to prey on one another. This prepared the way for a tremendously long and intricate evolution in two complementary directions. In the first place, the organisms most helpless in the face of the primitive predators would be devoured in greatest numbers; while those that could move away, or were protected by a resistant envelope or a peculiar chemical composition that made them unacceptable to their enemies, survived and multiplied. Every character that increased the security of victims of predation acquired survival value; mutations improving such features had still greater survival value; and lineages in which existence depended upon swift retreat, or concealment, or protective incrustations, or a fecundity able to compensate for high mortality started down the long evolutionary road. As the victims of predation became more adept at avoiding capture, the predators simultaneously increased their speed or craft or strength for overcoming their prey, for those best endowed in any of these ways were most adequately nourished and, on the whole, left more descendants. Another category of animals, specialized for predation, began to evolve, producing by adaptive radiation an ever-increasing array of types, and keeping pace with the prey, which by developing fresh modes of defense or escape fled them down the geologic ages.
Strife Intrudes into Reproductive Activities
At first, simple reactions sufficed for predatory animals to capture victims that possessed only equally stereotyped reactions for escaping. But with the increasing size and structural complexity of both predators and prey, more complex innate patterns of behavior were impressed upon their nervous systems, on the one hand promoting the capture of victims and on the other, escape from the pursuing predator. Concomitant with the evolution of the nervous system was an intensification of psychic life, which necessarily
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corresponded with each animal's mode of existence. Predators became bold and fierce, especially when pricked by the pangs of hunger; creatures whose safety lay in flight or concealment became timid and secretive. Intelligence, slowly increasing to give greater plasticity to the behavior of certain gifted animals, was at first almost wholly under the dominance of those appetites and emotions essential to the survival of the individual and its race, so that its mind was swayed by greed, rage, and anger, or by fear, hatred, and suspicion.
With the growth of the carnivorous habit among animals, death crept over Earth in countless guises, and to compensate for its ravages, the multiplication of individuals became urgent. Animals with many diverse parts could not, like their most primitive ancestors, multiply by simple fission, and more complex modes of reproduction became indispensable. Instead of giving its whole self to produce two replicas of itself, in the manner of the humblest organisms, the multicellular creature set apart a fraction of its body to generate several or many offspring at first wholly different in appearance from itself. Instead of a single individual's sufficing to propagate its kind, the cooperation of two individuals became necessary throughout the metazoa, the reason for this complex arrangement being that, by mingling the traits of individuals, a greater variety of offspring is produced, some displaying new characters or combinations of characters that bring advantages in the increasingly intense struggle to survive.
The cooperation of two individuals in reproduction demands a high degree of harmony between them.