Of Man and Manta Omnibus

by Piers Anthony

  Sooner or later those parallel crossings would intersect, and Earth would meet Earth with an insufficient spacing between them. A decade perhaps, or a minute - and there would be unique war.

  Better that this Earth ravish this Paleo, delayed by the manta. Better that the lesson be learned that way, now. Coexistence had to be learned, and the very hardest coexistence was with oneself. Earth might get along with an alien world, but not with another Earth. The rivalry would be too immediate, too specific. Without bloody experience of the Earth-Paleo nature, the later and major confrontation would be disastrous. As the three-year-old might fight with the two-year-old for a favored toy, and gradually learn to interact more reasonably, so Earth would fight with Paleo.

  But it remained hard to abide, the brutality of this first meeting. If only there were some way to come at maturity (individual, species, world) without passing through immaturity...

  Memory. It began far, far back in the half-light, wetter and warmer than much of what followed. He floated in a nutrient medium and absorbed what he needed through his spongy exterior. He reached for the light, a hundred million years later, needing it ... but brushed against the enclosing shell and was restrained. He had to wait, to adapt, to grow.

  There was warmth, but also cold. He moved restlessly, trying to achieve comfort, to get all of his suspended body into the warm section of his environment. And he remembered that too: somewhere a billion years ago he had struggled between freezing darkness and burning light, and satisfied his compelling hunger by growing into an absorbtive cup, a cylinder, a blob with an internal gut, by extruding fins and flukes and swimming erratically after game. He formed eyes, and gills, and a skeleton, and teeth, and lungs, and legs, Ornet remembered.

  POSTSCRIPT CALVIN POTTER

  The Cretaceous enclave of a world otherwise representative of the Paleocene epoch of Earth captures one of the more remarkable episodes in the history of our planet. For more than two hundred million years the reptiles dominated land, air, and the surface of the sea; then abruptly all but a few forms vanished, vacating the world for the primitive mammals and birds.

  Quite a number of theories have been advanced over the years to account for this 'time of great dying' but none have been completely satisfactory. It has been suggested for example that 'racial senescence' was responsible: the notion that species, like individuals, gradually age and die. No evidence supports this, and it fails to explain the survival and evident vigor of reptiles such as the turtles and crocodiles, or the much longer tenure of creatures like the horseshoe crab. Another theory was pandemic illness: perhaps a plague wiped out most reptiles without affecting mammals or birds or amphibians. Apart from the fact that disease simply does not work this way - it can decimate, but seldom exterminate, a widespread and varied population - the gradual diminution of numbers of species in the late Cretaceous argues against this. Why should it attack one species at a time, then later strike many others simultaneously? Various types of catastrophes have also been proposed - solar flare, worldwide flood, etc. - but again, the selectivity of such an occurrence is not explained, and no record of it is found in relevant sedimentary deposits. The rocks show an orderly continuity from Cretaceous to Tertiary, wherein the great reptiles disappear and, later, the small mammals appear. The changeover could not have been violent.

  More recent theories have been more sophisticated. Did world temperature become too cool for most reptiles, so that they gradually became torpid and unable to forage effectively? This would account for the survival of the warm-bodied mammals and birds. But a substantial cooling would have been necessary, and there was none at the time, as illustrated by plant life. Could the opposite have happened: a devastating heat wave? Again, the record denies this.

  Rathation? A science-fiction writer suggested that fluctuations in Earth's magnetic field should periodically permit the planet to be bathed in increased rathation from external sources, increasing the mutation rate of animals disastrously. If a magnetic lapse occurred when rathation from a nearby supernova struck, there could indeed be biological havoc. But why only among the reptiles and certain sea creatures? Rathation is one of the least selective forces.

  There was a radical change in vegetation during the Cretaceous period. The angiosperms - flowering plants - suddenly became dominant. Did the herbivorous dinosaurs find the new vegetation, particularly the grasses, too tough to cut and digest? Another science-fiction writer thought so. But plant revolution came before the extinction of the dinosaurs and many of the hugest reptiles flourished for millions of years amid the flowers. They were able to adapt, and the dent equipment of Triceratops, for example, shames any developed since short of a lumbermill.

  Could the mammals have competed so strongly with reptiles as to exterminate them? Direct physical oppression seems an absurdity, for the dinosaurs held the mammals check quite readily for a hundred million years. One has or to visualize a pack of mice attempting to bring down Tyranosaurus. Mammals might, however, have eaten reptile eggs but again, it is strange they would wait so long, then be completely effective. The swimming reptile Ichthyosaurus gave live birth, so should have survived. And why did the land eggs of the turtle and crocodile escape?

  No - to comprehend the decline of the great reptiles, must first grasp the geologic cycle of which they were a part. No form of life exists in isolation, and evolution and extinction is never haphazard. Definite conditions promoted the ascendence of the reptile orders while suppressing the amphibians and mammals. The later reversal of these conditions demoted the reptiles in favor of the mammals and birds. The dinosaurs were doomed to transience by their very nature.

  The surface of the Earth has always been in motion. One facet of this is termed 'continental drift'. The continents owe not only their positions but their very substance to the convective currents of Earth's mantle. This turbulence brought up the slag and guided it into floating masses that accumulated considerably. Though normally separate, at one point several came together to form the segments of the supercontinent, Laurasia/Gondwanaland.

  Such a situation has occurred more than once in the past. It is marked by a particular complex of phenomena: subsidence of mountains, the intrusion of large, shallow bays or inland seas, diminution of tremors and volcanic activity, and extraordinarily even climate. In sum: a very quiet, conducive environment for life.

  In such case, the competitive advantages of amphibianism or internal temperature control are academic. When the temperature of land, water, and atmosphere at sea level varies only from 10° F. to 20° F., day and night, season to season, century to century, warm-bloodedness is a complication irrelevant to rival. Indeed, it may be moderately detrimental, since it requires a higher rate of metabolism and therefore makes food intake more critical. The mammals perfected this control, involving the development of a hairy covering (to retain body at), compact torso (same), sweating mechanism (to cool at compact furry body when necessary), improved teeth, ribs, and posture (to hunt and feed more effectively, to meet demands of increased appetite), live birth (because infant posure would be fatal), and sophisticated internal regulatory mechanisms. But while the mammals struggled through the numerable false starts and the tens of millions of years necessary to accomplish all this, the reptiles were simply growing large and savage. The birds undertook a similar pro-and were similarly overshadowed by their flying reptile cousins.

  Thus developed the age of reptiles, extending from the Premian period through the Triassic, Jurassic, and Cretaceous: two hundred twenty million years. The reptiles were not as complicated as the birds and mammals, but they dominated the world-continent.

  But eventually this tremendous land mass began to break up, as the convection currents formed a new pattern. North to south, east to west, the continent was sundered. The Americas were shoved away from Europe and Africa; Antarctica broke from both, and from Australia. A crack in the land widened into a chasm, to a strait, to a channel, to a bay, and finally to a sea: the Atlantic Ocean. This wa
s no overnight occurrence; it took millions of years. Though there were many severe tremors associated with the upthrusting of matter through this rift and the other rifts of the world, they posed no immediate threat to life on land. The severance of the Americas became complete just before the end of the Cretaceous; the other continents separated at other times, but geologically the fragile menting was rapid.

  The consequences of this breakup were multiple. The ocean floor was re-sculptured, disturbing ancient breeding and foraging grounds. Enormous quantities of continental debris were dumped into the oceans, for a time affecting the chemical properties of the water. Volcanism was restimulated, affecting the atmosphere. And the motion of the fragments brought about stresses leading to new orogeny: tremendous mountain ranges like the Rockies and Andes, that remade weather! patterns and dehydrated inland plains. The physical restructuring of the world inevitably brought about a shift in climate, and this in turn affected life.

  The plants reacted massively. Forms that had been minof suddenly had a competitive advantage: the angiosperms, or flowering plants, that did not leave their reproduction to chance. The increased winds and mountains and oceans and deserts worked against random fertilization. The older gymnosperms did not become extinct, but assumed a minority role in the new ecology.

  This change in vegetation necessarily affected the animals. The arthropods - chiefly the insects - radiated astonishingly because of the offerings of the flowers, and the spiders followed them. The insectivores - mainly mammalian and avian, together with the reptilian lizards and amphibian frogs - multiplied in response, for this food supply seemed inexhaustible.

  The large reptiles were only indirectly affected. They were not insectivores, and even the flying ones were adapted to prey on fish, not flies. Reptile herbivores were capable of adjusting to the new foliage, or surviving in reduced numbers on the less plentiful old-style plants. The variety, but not the vigor, of their species declined, while the carnosaurs continued much as before. But their young began to be crowded by the burgeoning other life. Full-grown mammals and birds, hunting in packs or flocks, began to deviate from their normal diet and prey on newly hatched reptiles, and so added a factor to the ecological balance. This was an annoyance rather than a calamity, for even new-hatched reptiles were more than a match for most other species, but it presaged the new order.

  The revised geography struck far more specifically. The ponderous omithischians could not thrive in steep mountains dry deserts or icy wastes, and were restricted by the violence of the landscape. As these untoward conditions developed, they migrated from large sections of the new continents, and the saurs of course accompanied them. The disappearance of vast continental seas and swamps severely limited the range the massive sauropods and the paddlers of the shallows. Unkind wind patterns ravaged the pterodactyls. But many suitable places remained, and the net effect of the change was concentrate the reptile orders in smaller sections of the world and reduce their meanderings, not to bring them anywhere near extinction.

  The climate was another matter. The overall temperature changed only slightly, becoming cooler. This by itself was important. What counted was not the average but the range, so-called temperate climate developed: actually about as temperate as the world has ever known. The even seasons lifted to hot summers and cold winters. An individual summer's day might range from 50° F. low to 100° F. high. A winter's day could begin at that low and drop fifty degrees, reptile biology simply was not equipped to handle such extremes. A heat wave in summer could wipe out enormous numbers; a prolonged freeze in winter did the same. The i-bodied creatures, in contrast, were ready, and only a fraction of their number failed to adapt. This, more than anything else, drove the reptiles as a group to the tropics, and reduced their territory drastically.

  And here the most direct aspect of the continental breakup came into play. For the individual land masses were not contiguous. They were now isolated by deep water. The reptiles could not migrate far enough. North America, for example, drifted too far north to have a tropical zone, and was completely separated from South America for some time. Stranded, the reptiles were subject to the full ravages of geography and climate, and they expired. Some few survived for a time in local enclaves, but such existence was tenuous. These extremely confined areas were subject to volcanism and recurring tremors and drastic alteration by shifts in the prevailing winds or drainage. Inevitably the reptiles there were destroyed, whether in a few hundred years or a few million.

  The dinosaurs could have survived all the other changes and met the challenge from other classes of vertebrates - had they been able to travel freely over the world, for there was always suitable pasture somewhere. But the fragmentation of the original land mass restricted them at the very moment, geologically, that they could least afford it. Far from being coincidence, this was inevitable. The age of reptiles on land was finished.

  The sea reptiles had their own problems. Those tied to the shallows who laid their eggs on land, such as Elasmosaurus, expired with the others, for the shallows were gone. Those fully adapted to deep water, such as Ichthyosaurus, suffered severe competition by flourishing sharks and, more deviously, by restriction of their diet. For an earlier revolution had occurred in the water: the teleosts, the so-called bony fishes, had appeared. These had stronger skeletons than did the earlier types, and possessed an air bladder modified from a one-time lung that enabled them to match the density of the surrounding water and float at a given level without muscular effort. For the first time, vertebrates were able to compete specifically with the invertebrate ammonites, who for hundreds of millions of years had possessed this controlled flotation ability and thrived. The fish, however, were superior swimmers. This did not eliminate the ammonites, but it did restrict them. When the continental breakup ravaged the oceanic geography and chemistry, the ammonites lost out. Those swimming reptiles who preyed exclusively on ammonites followed them into oblivion.

  Thus, medium by medium and type by type, the life of the world was transformed by the breakup of the master continent. It was not that the birds drove out the flying reptiles, or that the teleosts and sharks drove out the ammonites and certain corals and swimming reptiles, or that the angiosperms drove out the gyrnnosperms, and certainly the mammals did not drive out the land reptiles. But the conditions of each habitat changed significantly, and shifted the balance to favor new species. Those forms of life that were ready for harsh extremes of geography and climate and chemistry prospered; those that were not did not.

  But what of the few surviving reptiles? These were the ones who were equipped to endure the new regime. The crocodiles and turtles were able to forage either on land or in the deep sea, so neither the sharks nor severe temperature extremes could eliminate them entirely. They were able to migrate from an unkind continent to a kind one, and did so, and have lasted until the present. The duckbills might have joined them, as they were strong swimmers and fast runners on land - but they had to feed on land, so could not remain in the water for weeks at a time. The snakes and lizards were small enough, and suitably shaped, to reside on and in the ground and trees; for them the arthropods and small mammals represented an improved diet, and deep burrows shielded them from winter's cold and summer's heat. They survived largely because they were small enough to utilize such shelter; the dinosaurs' specialization in large size worked against them fatally.

  Have there been other extinctions as the continents drifted into new configurations? Certainly, many of them, though few as impressive as this one. There will surely be more. When the land moves, life must follow. The real mystery is not the great dying, but why this natural course remained a mystery for so long...

  THE END

  Ox

  Book 3

  Chapter 1 - TRIO

  It had a shiny black finish, solid caterpillar treads, a whirling blade -- and it was fast. It was seemingly a machine -- but hardly the servant of man.

  Veg fired his blaster at it. The project charge shoul
d have heated the metal explosively and blown a chunk out of it. But the polished hide only gave off sparks and glowed momentarily. The thing spun about with dismaying mobility and came at him again, the vicious blade leading.

  Veg bounded backward, grabbed the long crowbar, and jammed it end first into the whirring blade. "Try a mouthful of that!" he said, shielding his eyes from the anticipated fragmentation.

  The iron pole bucked in his hands as the blade connected. More sparks flew. The blade lopped off sections, two inches at a time: CHOP CHOP CHOP CHOP! Six feet became five, then four, as the machine consumed the metal.

  At that point Veg realized he was in a fight for his life. He had come across the machine chewing up the stacked supplies as he emerged from transfer and thought it was an armored animal or a remote-controlled device. It was more than either; it had an alarming aura of sentience.

  He tried the rifle. The flash pan heated as he activated it; steam filled the firing chamber. Bullets whistled out in a rapid stream, for the steam rifle was smoother and more efficient than the explosive-powder variety. They bounced off the machine and ricocheted off the boulders on either side. He put at least one bullet directly in its eye-lens, but even this did no apparent harm.