65:2.1 The story of man's ascent from seaweed to the lordship of earthly creation is indeed a romance of biologic struggle and mind survival. Man's primordial ancestors were literally the slime and ooze of the ocean bed in the sluggish and warm-water bays and lagoons of the vast shore lines of the ancient inland seas, those very waters in which the Life Carriers established the three independent life implantations on Urantia.
65:2.2 Very few species of the early types of marine vegetation that participated in those epochal changes which resulted in the animallike borderland organisms are in existence today. The sponges are the survivors of one of these early midway types, those organisms through which the gradual transition from the vegetable to the animal took place. These early transition forms, while not identical with modern sponges, were much like them; they were true borderline organisms—neither vegetable nor animal—but they eventually led to the development of the true animal forms of life.
65:2.3 The bacteria, simple vegetable organisms of a very primitive nature, are very little changed from the early dawn of life; they even exhibit a degree of retrogression in their parasitic behavior. Many of the fungi also represent a retrograde movement in evolution, being plants which have lost their chlorophyll-making ability and have become more or less parasitic. The majority of disease-causing bacteria and their auxiliary virus bodies really belong to this group of renegade parasitic fungi. During the intervening ages all of the vast kingdom of plant life has evolved from ancestors from which the bacteria have also descended.
65:2.4 The higher protozoan type of animal life soon appeared, and appeared suddenly. And from these far-distant times the ameba, the typical single-celled animal organism, has come on down but little modified. He disports himself today much as he did when he was the last and greatest achievement in life evolution. This minute creature and his protozoan cousins are to the animal creation what bacteria are to the plant kingdom; they represent the survival of the first early evolutionary steps in life differentiation together with failure of subsequent development.
65:2.5 Before long the early single-celled animal types associated themselves in communities, first on the plan of the Volvox and presently along the lines of the Hydra and jellyfish. Still later there evolved the starfish, stone lilies, sea urchins, sea cucumbers, centipedes, insects, spiders, crustaceans, and the closely related groups of earthworms and leeches, soon followed by the mollusks—the oyster, octopus, and snail. Hundreds upon hundreds of species intervened and perished; mention is made only of those which survived the long, long struggle. Such nonprogressive specimens, together with the later appearing fish family, today represent the stationary types of early and lower animals, branches of the tree of life which failed to progress.
65:2.6 The stage was thus set for the appearance of the first backboned animals, the fishes. From this fish family there sprang two unique modifications, the frog and the salamander. And it was the frog which began that series of progressive differentiations in animal life that finally culminated in man himself.
65:2.7 The frog is one of the earliest of surviving human-race ancestors, but it also failed to progress, persisting today much as in those remote times. The frog is the only species ancestor of the early dawn races now living on the face of the earth. The human race has no surviving ancestry between the frog and the Eskimo.
65:2.8 The frogs gave rise to the Reptilia, a great animal family which is virtually extinct, but which, before passing out of existence, gave origin to the whole bird family and the numerous orders of mammals.
65:2.9 Probably the greatest single leap of all prehuman evolution was executed when the reptile became a bird. The bird types of today—eagles, ducks, pigeons, and ostriches—all descended from the enormous reptiles of long, long ago.
65:2.10 The kingdom of reptiles, descended from the frog family, is today represented by four surviving divisions: two nonprogressive, snakes and lizards, together with their cousins, alligators and turtles; one partially progressive, the bird family, and the fourth, the ancestors of mammals and the direct line of descent of the human species. But though long departed, the massiveness of the passing Reptilia found echo in the elephant and mastodon, while their peculiar forms were perpetuated in the leaping kangaroos.
65:2.11 Only fourteen phyla have appeared on Urantia, the fishes being the last, and no new classes have developed since birds and mammals.
65:2.12 It was from an agile little reptilian dinosaur of carnivorous habits but having a comparatively large brain that the placental mammals suddenly sprang. These mammals developed rapidly and in many different ways, not only giving rise to the common modern varieties but also evolving into marine types, such as whales and seals, and into air navigators like the bat family.
65:2.13 Man thus evolved from the higher mammals derived principally from the western implantation of life in the ancient east-west sheltered seas. The eastern and central groups of living organisms were early progressing favorably toward the attainment of prehuman levels of animal existence. But as the ages passed, the eastern focus of life emplacement failed to attain a satisfactory level of intelligent prehuman status, having suffered such repeated and irretrievable losses of its highest types of germ plasm that it was forever shorn of the power to rehabilitate human potentialities.
65:2.14 Since the quality of the mind capacity for development in this eastern group was so definitely inferior to that of the other two groups, the Life Carriers, with the consent of their superiors, so manipulated the environment as further to circumscribe these inferior prehuman strains of evolving life. To all outward appearances the elimination of these inferior groups of creatures was accidental, but in reality it was altogether purposeful.
65:2.15 Later in the evolutionary unfolding of intelligence, the lemur ancestors of the human species were far more advanced in North America than in other regions; and they were therefore led to migrate from the arena of western life implantation over the Bering land bridge and down the coast to southwestern Asia, where they continued to evolve and to benefit by the addition of certain strains of the central life group. Man thus evolved out of certain western and central life strains but in the central to near-eastern regions.
65:2.16 In this way the life that was planted on Urantia evolved until the ice age, when man himself first appeared and began his eventful planetary career. And this appearance of primitive man on earth during the ice age was not just an accident; it was by design. The rigors and climatic severity of the glacial era were in every way adapted to the purpose of fostering the production of a hardy type of human being with tremendous survival endowment.