This first stage in the evolution of mankind, which is substantially longer than the second, is further subdivided into two stages according to man’s relationship with his environment and with the materials he used. Therefore, we have the Stone Age, during which Man fundamentally used stone to fabricate the tools he needed in his daily life, and the Metal Age, when humans learned, with the help of fire, to fuse some minerals to transform them into metals, and later use them as tools.
The Origin of Life
After so many years of development, advances in science and technology, the origin of life remains a mystery that continues to challenge and baffle scientists. The “big bang” of biology, a definitive and irrefutable theory on the origin of life that is accepted by all, has yet to be discovered. No one has so far managed to recreate the real conditions of primitive Earth when life first appeared; that is to say, no one has been able to turn back the clock and recreate the conditions that favored the transition of inorganic nonliving matter into organic living matter.
The recreation in laboratory of environments that could be similar to that of primitive Earth did not result in the appearance of life form. The old Aristotelian derived theory of spontaneous generation harbored by some, that fully-formed complex living organisms could arise naturally and spontaneously from nonliving matter, has long been put to death once and for all by Louis Pasteur in the nineteenth century with his famous swan-neck flask experiment, from which he concluded that “life only comes from life”.
“The most complex machine man has devised – say, an electronic brain – is child’s play compared with the simplest of living organisms,” wrote American biologist and Nobel Prize winner in Medicine, George Wald. “The especially trying thing is that complexity here involves such small dimensions. It is on the molecular level; it consists of a detailed fitting of molecule to molecule such as no chemist can attempt.”
We know that the force of gravity was responsible for the agglutination of matter and space dust, and the formation of planets and stars. It is unknown if there is an analogous force in biology that causes different organic molecules to come together to form a prokaryotic cell.
To date, all that biology has been able to establish is that, under very peculiar conditions, inorganic molecules can be transformed into organic molecules, but the transition from these simple organic molecules like amino acids to something that is complex enough that it can self-replicate, and endowed with metabolism, remains a great mystery. It is known, however, that the microorganisms at that period used methane or hydrogen for metabolism instead of oxygen: they were organisms with anaerobic metabolism. Fermentation is a modern example of this type of metabolism.
Long before photosynthesis, and the eukaryotic cells that perform it, the first living beings on our planet would have the aspect of single-celled microorganisms or prokaryotic cells, like today’s bacteria and archaea, and would have lived in extreme environments, next to thermal springs in the primitive seas, nourishing themselves from the reactions between inorganic substances. From these first living beings, those capable of carrying out fermentation emerged, later the photosynthetic and, lastly, the heterotrophic beings, that is, living beings that, unlike plants, are not able to produce their own food.
The Evolution of Species
Then God said, “Let the earth put forth vegetation: plants yielding seed, and fruit trees of every kind on earth that bear fruit with the seed in it.” (…) And God said, “Let the waters bring forth swarms of living creatures, and let birds fly above the earth across the dome of the sky.” (…) And God said, “Let the earth bring forth living creatures of every kind: cattle and creeping things and wild animals of the earth of every kind.” And it was so. Genesis 1:11, 20, 24
The theory of evolution of species that Charles Darwin published in 1858 is the result of empirical research conducted during his voyage to the Galapagos Islands, which led him to conclude that life on this planet comes from a common stock, that is, that all living beings on this planet, both plants and animals, are related. All individuals have common ancestors.
The diversification of living beings or the evolution of species occurs by adaptation to the environment and natural selection – the better equipped, the strongest, prevail over the weakest or, as the proverb says, “the weak do not recite history”. Those that best adapt to the environment will eliminate their rivals and manage to pass on their genes to the next generation because the females instinctively allow themselves to be fertilized by the strong and reject the weak.
The first living beings appeared 3.5 billion years ago and one billion years later, the first photosynthetic living beings appeared, followed by the eukaryotes soon after. Around 543 million years ago, there was a period of great explosion of evolutionary changes in life form on this planet known as the Cambrian Period; there are many fossils that document this phase of life on Earth.
The first living beings were the microscopic organisms, primitive plants and invertebrates (worms and arthropods). Fish were the first vertebrates to emerge. It was 570 million years ago that plants invaded the dry land from the sea. Some animals had already done so before, but they did not stay on dry land permanently, because there was no food available there.
Animals came on dry land periodically, but remained most of the time in the sea: these were the amphibians. About 438 million years ago, they began to increase their time on land and 30 million years later, they evolved into reptiles. From the reptiles, evolution took two different paths: some reptiles evolved into mammals and others into birds.
Around 360 million years ago, the dinosaurs reigned on our planet. Some time later, the mammals which already coexisted with the dinosaurs but were insignificant began to stand out. About 245 million years ago, the dinosaurs became extinct and the mammals increased in number due to the absence of predators. About 66 million years ago, the primates appeared. Then 55 million years ago, the common ancestor of the pongids and hominids evolved. The earliest hominids emerged 8 million years ago.
Ontogenesis and Phylogenesis
Ontogenesis recapitulates phylogenesis by postulating that there is a similarity between the aspect of the embryonic stages of the human fetus, from conception to birth, and the development of the different life forms, from the unicellular origin to the human being. It is a discarded theory today, but it is close to the analogy that is often established between different fields of knowledge.
From the conception of an individual to his birth, the evolution of life on Earth is recapitulated, from the single-celled origin to the complexity of a human being. The diverse forms that the embryo acquires in its development resemble, in some way, the forms that life has assumed in the evolution of the species, from the prokaryotic archaea to the human being.
Furthermore, after birth, the development of an infant to self-awareness, that is, until he realizes that he exists as a person and begins to communicate, he recapitulates the evolution of the human race from the last primate that was not yet bipedal and did not speak to the Homo sapiens who stand erect walking upright and have the ability to communicate.
The Evolution of Human Life
For these reasons the Teaching Authority of the Church does not forbid that, in conformity with the present state of human sciences and sacred theology, research and discussions, on the part of men experienced in both fields, take place with regard to the doctrine of evolution, in as far as it inquires into the origin of the human body as coming from pre-existent and living matter - for the Catholic faith obliges us to hold that souls are immediately created by God. Humani Generis, 36 – Pope Pius XII, 1950
“There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been and are being evolved.” Charles Darwin, The Origin of Species, 1858
Charles Darwin never said that humans evolved from the present day monkeys. According to the British naturalist, humans, monkeys, chimpanzees and gorillas, all have a series of common ancestors. These ancestors lived on the African continent about 6 and 5 million years ago. Scientists named this species the Sahelanthropus tchadensis.
After this, between 5 and 3.5 million years, the Australopithecus afarensis emerged. Lucy, found in Ethiopia, belongs to this family, which marks the moment when the human race learned to walk. A little later, 2.6 million years ago, the first human tools appeared. Following this, 2.5 million years ago, the Homo habilis appeared, so called for the use he made of the tools.
The mastering of fire took place 1.5 million years ago; food began to be cooked about one million years later, and 400 thousand years ago, Homo neanderthalensis left Africa to inhabit the western part of Eurasia. The Homo sapiens remained in Africa. Then 350 thousand years ago, the Neanderthals developed and occupied Eurasia, from Portugal to Siberia.
About 100 thousand years ago, the Homo sapiens left Africa and appeared in Israel. Five thousand year later, they arrived in Malaysia, and 55 thousand years after that, in Australia. At that same time, they invaded Europe, defeating the Neanderthals or interbreeding with them. About 28 thousand years ago, we have the last evidence of the Neanderthals who became extinct. Fourteen thousand years ago, the Homo sapiens passed from Siberia through the Bering Strait and entered America through Alaska, gradually moving south, until they occupied the entire continent.
The Paleolithic or the Old Stone Age (2.5 million BC – 10 000 BC)
In this era, human beings were nomadic and did not build permanent dwellings. Because of this, they lived in caves, and had to compete with wild animals for this type of habitat. When food in that region was used up, families had to migrate to another region.
They lived by hunting small, medium and large animals, fishing and gathering fruits, leaves and roots. The economy during the Paleolithic phase was subsistence, that is to say, the group did not amass or produce for trade, but only for their own survival.
This period is also known as the age of chipped-stone tools. The first humans, who mastered and knapped stones, had the practice of producing materials by taking two stones and hitting them together to generate sharp points. These artifacts served, especially, for cutting meats and animal skins. They used instruments and tools made from pieces of bones and stones (axes, spears, staves, knives etc.). The goods produced were for collective use and property.
The Discovery of Fire
One of the greatest discoveries of this period was the production of fire through two processes. The most rudimentary was the friction of two stones over a pile of dry straws. The sparks produced ignited the straws.
In a second more elaborate procedure, a small stick was turned in a hole made in a piece of dry wood. This method, through friction, generated heat that passed to the straw, creating the fire.
- As we have commented in another text, fire had a great importance for the cohesion of families and communities, because everyone gathered around the fire for warmth. Since no one wanted to be left out in the cold, fire acted as a deterrent to antisocial attitudes.
- It allowed the light of the day to extend into the night, and because it was impossible to work at night, the two or three hours of tenuous light served for cultural events, to share experiences and for the handing down of culture from parents to children.
- The light in the night promoted safety of human beings in relation to animals that hunted at night, as it served to scare them away.
- However, the most important use of fire at that time was in the preparation of food. Cooked or roasted food has improved human diet. Certain foods are more nutritious cooked than raw. Fire and cooking of food are responsible for population growth and human survival.
- Finally, it was precisely fire that allowed humans to move from the Stone Age to the Metal Age.
The men organized themselves in small groups, where the leader was the strongest and the most skilled. The men had the task of hunting, fishing and protecting the group. The women had the job of preparing food and caring for the children.
Communication
The communication in this period was based on the emission of some sounds (noises), without the elaboration of words, and physical gestures. Another widely used form of communication was cave paintings (drawings made on cave walls). Through these drawings (cave paintings) men marked time, exchanged experiences and transmitted messages and feelings.
Rituals
In the Paleolithic, men already performed funeral rituals. Archaeologists have found, in various regions, ceramic pots with human remains and personal objects inside caves. Religious rituals were also performed with the use of fire.
Hominids that lived in the Paleolithic Period
Australopithecines, Homo habilis, Homo erectus, Neanderthal Man or Homo neanderthalensis, Homo sapiens and Cro-Magnon Man, the earliest known European.
The Mesolithic or the Middle Stone Age (10 000 BC – 8 000 BC)
The Mesolithic is an intermediate period of the Prehistory, between the Paleolithic and Neolithic periods. This phase did not occur in all the regions of the world, but only in those where glaciation or the ice age had the most considerable effects.
In this intermediate period, the human being became more related to nature and began to make the first experiences of its domination. The nomadic lifestyle and dependence on external food did not allow development. Man learned to domesticate animals rather than hunt them, thus always having food at his disposal. On the other hand, instead of gathering fruits, plants and roots, he began to cultivate them. In this way, he managed to maintain a certain independence from the environment.
According to these regions, many humans maintained a life similar to that of the Paleolithic, depending on whether they were more dedicated to the domestication of animals or the cultivation of crops. The shepherds would be nomadic, for they followed their herds to pasture, while the farmers settled on the most fertile lands near the rivers.
The Neolithic or the New Stone Age (8 000 BC – 4 000 BC)
The Neolithic is also known as the New Stone Age. The beginning of this period is marked by the end of the ice age, a period when almost the entire planet was covered in ice, and ended with development of writing in Sumer in the Mesopotamia region.
The development of agriculture has allowed human beings to have a life less dependent on nature. With this advancement, they no longer needed to gather wild fruits, vegetables and roots, although these activities continued to be practiced.
The domestication of animals (goats, oxen, pigs, horses and birds) also contributed to the improvement in the quality of life. Together with agriculture, the domestication of animals allowed man to significantly increase the amount of food produced, eliminating the dependence on hunting.
As a result of the development in agriculture and the domestication of animals, humans ceased to be nomadic (with no fixed address) to become sedentary (with fixed address). This fact enabled the development of the first communities (tribes, villages, towns and cities). These first communities developed along the banks of rivers and lakes. In addition to meeting basic needs, water took on a new role in human life: the irrigation of crops.
With the increase in food production, the need for storage was created. In the Neolithic period, there was a great development of ceramic art. Vessels and pots were shaped and fired. According to archaeologists, the first ceramic objects were made around 8,500 years ago.
In the first communities that were formed, it became necessary to organize the work. The men were in charge of hunting, fishing and safety of the community (military protection function). The women were left with the tasks of caring for their children, agriculture and food preparation.
With the increase in production came the surplus. In addition to storing for periods of greatest need, men began to exchange these products with other communities. This was the beginning of trade economy.
With more food, there was a significant increase in population. This fact led to the need for more advanced forms of administration, including the establishment of more specific leadership and task allocation within the community.
In the Neolithic, men began to build more resilient dwellings because they needed to remain in fixed locations. Houses of wood, clay and blocks of stone were built in the villages. On the banks of rivers and lakes, stilts were more common (wooden houses with stakes fixed at the bottom of the river or lake).
The first civilizations arose and developed in the Neolithic period. Among them, we can mention: the Mesopotamian civilization (between the Tigris and Euphrates rivers) and the Egyptian civilization (along the banks of River Nile, northeastern Africa).
Conclusion: Unlike animals that have always lived at ease in a symbiotic relationship with Nature, survival and development for humans required an emancipation from it. The use of instruments, made of stone was the first act towards freedom.
Fr. Jorge Amaro, IMC
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