WE live under the shadow of a gigantic question mark.
Who are we?
Where do we come from?
Whither are we bound?
Slowly, but with persistent courage, we have been pushing this question
mark further and further towards that distant line, beyond the horizon,
where we hope to find our answer.
We have not gone very far.
We still know very little but we have reached the point where (with a
fair degree of accuracy) we can guess at many things.
In this chapter I shall tell you how (according to our best belief) the
stage was set for the first appearance of man.
If we represent the time during which it has been possible for animal
life to exist upon our planet by a line of this length, then the tiny
line just below indicates the age during which man (or a creature more
or less resembling man) has lived upon this earth.
Man was the last to come but the first to use his brain for the purpose
of conquering the forces of nature. That is the reason why we are going
to study him, rather than cats or dogs or horses or any of the other
animals, who, all in their own way, have a very interesting historical
development behind them.
In the beginning, the planet upon which we live was (as far as we now
know) a large ball of flaming matter, a tiny cloud of smoke in the
endless ocean of space. Gradually, in the course of millions of years,
the surface burned itself out, and was covered with a thin layer of
rocks. Upon these lifeless rocks the rain descended in endless torrents,
wearing out the hard granite and carrying the dust to the valleys that
lay hidden between the high cliffs of the steaming earth.
Finally the hour came when the sun broke through the clouds and saw how
this little planet was covered with a few small puddles which were to
develop into the mighty oceans of the eastern and western hemispheres.
Then one day the great wonder happened. What had been dead, gave birth
to life.
The first living cell floated upon the waters of the sea.
For millions of years it drifted aimlessly with the currents. But during
all that time it was developing certain habits that it might survive
more easily upon the inhospitable earth. Some of these cells were
happiest in the dark depths of the lakes and the pools. They took root
in the slimy sediments which had been carried down from the tops of the
hills and they became plants. Others preferred to move about and they
grew strange jointed legs, like scorpions and began to crawl along
the bottom of the sea amidst the plants and the pale green things that
looked like jelly-fishes. Still others (covered with scales) depended
upon a swimming motion to go from place to place in their search for
food, and gradually they populated the ocean with myriads of fishes.
Meanwhile the plants had increased in number and they had to search for
new dwelling places. There was no more room for them at the bottom of
the sea. Reluctantly they left the water and made a new home in the
marshes and on the mud-banks that lay at the foot of the mountains.
Twice a day the tides of the ocean covered them with their brine. For
the rest of the time, the plants made the best of their uncomfortable
situation and tried to survive in the thin air which surrounded the
surface of the planet. After centuries of training, they learned how
to live as comfortably in the air as they had done in the water. They
increased in size and became shrubs and trees and at last they learned
how to grow lovely flowers which attracted the attention of the busy big
bumble-bees and the birds who carried the seeds far and wide until the
whole earth had become covered with green pastures, or lay dark under
the shadow of the big trees. But some of the fishes too had begun to
leave the sea, and they had learned how to breathe with lungs as well as
with gills. We call such creatures amphibious, which means that they
are able to live with equal ease on the land and in the water. The first
frog who crosses your path can tell you all about the pleasures of the
double existence of the amphibian.
Once outside of the water, these animals gradually adapted themselves
more and more to life on land. Some became reptiles (creatures who
crawl like lizards) and they shared the silence of the forests with
the insects. That they might move faster through the soft soil, they
improved upon their legs and their size increased until the world was
populated with gigantic forms (which the hand-books of biology list
under the names of Ichthyosaurus and Megalosaurus and Brontosaurus)
who grew to be thirty to forty feet long and who could have played with
elephants as a full grown cat plays with her kittens.
Some of the members of this reptilian family began to live in the tops
of the trees, which were then often more than a hundred feet high.
They no longer needed their legs for the purpose of walking, but it was
necessary for them to move quickly from branch to branch. And so they
changed a part of their skin into a sort of parachute, which stretched
between the sides of their bodies and the small toes of their fore-feet,
and gradually they covered this skinny parachute with feathers and
made their tails into a steering gear and flew from tree to tree and
developed into true birds.
Then a strange thing happened. All the gigantic reptiles died within a
short time. We do not know the reason. Perhaps it was due to a sudden
change in climate. Perhaps they had grown so large that they could
neither swim nor walk nor crawl, and they starved to death within sight
but not within reach of the big ferns and trees. Whatever the cause, the
million year old world-empire of the big reptiles was over.
The world now began to be occupied by very different creatures. They
were the descendants of the reptiles but they were quite unlike these
because they fed their young from the "mammae" or the breasts of the
mother. Wherefore modern science calls these animals "mammals." They
had shed the scales of the fish. They did not adopt the feathers of
the bird, but they covered their bodies with hair. The mammals however
developed other habits which gave their race a great advantage over the
other animals. The female of the species carried the eggs of the young
inside her body until they were hatched and while all other living
beings, up to that time, had left their children exposed to the dangers
of cold and heat, and the attacks of wild beasts, the mammals kept their
young with them for a long time and sheltered them while they were still
too weak to fight their enemies. In this way the young mammals were
given a much better chance to survive, because they learned many things
from their mothers, as you will know if you have ever watched a cat
teaching her kittens to take care of themselves and how to wash their
faces and how to catch mice.
But of these mammals I need not tell you much for you know them well.
They surround you on all sides. They are your daily companions in the
streets and in your home, and you can see your less familiar cousins
behind the bars of the zoological garden.
And now we come to the parting of the ways when man suddenly leaves the
endless procession of dumbly living and dying creatures and begins to
use his reason to shape the destiny of his race.
One mammal in particular seemed to surpass all others in its ability
to find food and shelter. It had learned to use its fore-feet for the
purpose of holding its prey, and by dint of practice it had developed a
hand-like claw. After innumerable attempts it had learned how to balance
the whole of the body upon the hind legs. (This is a difficult act,
which every child has to learn anew although the human race has been
doing it for over a million years.)
This creature, half ape and half monkey but superior to both, became
the most successful hunter and could make a living in every clime. For
greater safety, it usually moved about in groups. It learned how to make
strange grunts to warn its young of approaching danger and after many
hundreds of thousands of years it began to use these throaty noises for
the purpose of talking.
This creature, though you may hardly believe it, was your first
"man-like" ancestor.