Jim Henninger, age 12, of Huntington Beach, California, for his question:
What was the world like a million years ago?
Our earth has romped and whirled through some four billion years of geological history. And the name of the game is change. However, each era was a link between the past and the future. The dim past now seems alien, but chances are we would recognize our earth as it was a million years ago.
We are living in the geological Cenozoic Era that opened more than 60 million years ago. For an era, it is still young. Its first chapter, the Tertiary Period is past history. Our own chapter, the Pleistocene Period, opened just about one million years ago. Previous eras had established the continents in their familiar shapes and places. Our mountain ranges had humped up their backs and our major rivers had more or less decided their paths to the sea. A line of young mountains was beginning to grow along our Pacific Coast, upsetting the landscape with fiery volcanos and shuddering earthquakes.
The shape of the world would not surprise us. But some of its animals would startle us clear out of our wits. We might meet a woolly mammoth, ten feet tall. An overgrown rhino with a shaggy coat and two fierce horns also roamed through most of the now temperate zones. There was a saber toothed tiger with catty fangs nine inches long. Outsized bears turned our ancestors out of their caves. Giant sloths scrambled their clumsy way around South America, sharing their world with armor plated glyptodonts. These giant, armadillo¬type beasts had pliable tails tipped with spiky balls of armor.
Most of the birds were like those of today, though there were more varieties. The plants were the same, though they grew in different locations. Some of our tropical plants grew almost as far north as the Arctic Circle. But evergreen forests grew on the cool slopes of most high mountains. The human family had arrived on the scene and our caveman ancestors coped with this world of a million years ago. They also coped with a series of disasters that was to follow.
The Pleistocene Period was scheduled for a series of cruel Ice Ages. Four times the massive glaciers crept down from the Arctic and retreated. Each time they crushed and t. ° buried vast areas of the Northern Hemisphere with ice fields more than a mile deep. Man
and animals retreated southward as the relentless cliffs of ice advanced. Those that sur¬vived returned as the ice melted and retreated. Plants and trees were crushed and frozen by the ice. Some of them gradually returned as their seeds were strewn into the soggy soil left by the melting glaciers.
None of these icy events could be foretold by the people of one million years ago. But they and the animals had to cope with the Ice Ages as they advanced and receded. The giant red deer, the chamois and a few other animals held their territory by taking to life in the high crags. Hippos, tiger and an assortment of other animals retreated to the tropics and stayed there. But, over the course of time, some of the great mammals became extinct. The woolly mammoth, the great bears, the saber toothed tiger and the shaggy giant rhino perished and these animals never will be seen again. Only their fossil bones remain.