We explain what the evolution of man is and when this process began. Also, the different stages of human evolution.
What is the evolution of man?
Human evolution or hominization is the name given to the process gradual and historical biological change of the most primitive ancestors (Australopithecus sp.) of human being until the appearance of our species as we know it todayHomo sapiens).
This process began 5 to 7 million years ago in the African continent, with the emergence of the common ancestor between the human being (the species of the hominid lineage) and chimpanzees (Pan troglodytes).
Strictly speaking, when we speak of human beings we refer exclusively to the Homo sapiens, although we have not been the only members of the genre Homo.
Before us (during our prehistory) there were numerous species that are now extinct but that presented numerous physical, biological and behavioral similarities.
Human evolution had its starting point when a population of primates from northwest Africa was divided into two lineages that evolved independently: one of them remained in the trees, while the other adapted to the plain.
Due to environmental pressures, subsequent generations of this last lineage developed bipedalism, that is, the ability to walk on the two lower limbs, thus freeing the upper limbs that would later become hands, to manipulate tools.
The study of this process was made thanks to the archeology, paleontology, geology and others Sciences similar, but above all thanks to the emergence of the studies of Charles Darwin and the Theory of the origin of species, who came to supplant the creationism or to spontaneous generation as the greatest human explanation regarding its origins.
Stages of human evolution
Human evolution includes the emergence of the following main species (there were other minor species that were not a vital part of the evolutionary tree):
- Ardipithecus. It lived in East Africa between 4 and 6 million years ago. The Ardipithecus it is close to the "root" of the human family tree. The shape of the bones Toe fossils suggest he walked upright. The Ardipithecus gave rise to Australopithecus, a genus that includes several species that lived between 4 million years and 1 million years ago. As he Ardipithecus As the Australopithecus they have longer arms, shorter legs, and smaller brains compared to modern humans.
- Australopithecusanamensis. It existed between 4.2 and 3.9 million years ago. This species, which has a mixture of ape-like and human-like characteristics, evolved from the Ardipithecus. A comparison of the body sizes and canine teeth of male and female of the A. anamensis reveals sexual dimorphism, notable differences between the two sexes of the same species. A fossil of the leg bone, the tibia, indicates that the A. anamensis it was erect and bipedal, though perhaps it also foraged in the trees. Thus, bipedalism occurred early in human evolution and may also have been the first human adaptation.
- Australopithecus afarensis. It probably evolved directly from Australopithecus anamensis. Many fossils of skeletal remains from this group have been discovered in Africa, including a remarkably complete 3.2 million-year-old skeleton named Lucy. The skull had a relatively small brain, pronounced brow ridges, and a protruding jaw with large canine teeth. They were a diverse and successful group of species that faced a climate change intense in the bed sheet of his time.
- Homo habilis. It is the first hominin that had enough uniquely human characteristics to be able to be placed in the same genus as modern humans. The gender Homo It is characterized by its ability to develop stone tools, and the first of them existed in Africa 2.2 million years ago. Its cranial capacity did not exceed 800 cm3 and it had smaller premolars and molars than those of australopithecines. I would have shared time with him Homo rudolfensis, u are often considered the same species.
- Homo ergaster. It is believed to have evolved from habilis. Homo ergaster was the first human species to leave Africa 1.8 million years ago and colonize other territories, thanks to which it in turn served as a link between two other future species: the Homo erectus (in China and the Far East) and Homo cepranensis or Homo antecessor (in Europe).
- Homo erectus. Initially the fossils that are now classified as Homo ergaster were considered by some scientists as Homo erectus Dwelt in Asia 1.8 million years ago, until its extinction 300,000 years ago. He covered himself with animal skins and made various stone tools, in addition to firing his foodbecause it would have tamed the fire. This would print profound changes in his musculature and his digestive system, as well as more complex forms of socialization which would then have required a language articulate. The Homo erectus it is the first hominid that has the fewest differences between the sexes.
- Homo antecessor. Taller and still small in brain compared to Homo sapiens, were the first European human link, which served as a step between the Homo ergaster and the Homo heidelbergensis, and perhaps the only common ancestor between modern humans and the Homo neardenthalensis. It existed from about 1.2 million years ago to 800,000 years ago. The sites where fossils of antecessor show numerous cuts on human bones, suggesting that these early humans practiced cannibalism.
- Homo heidelbergensis. It appeared about 600,000 years ago and existed until about 300,000 years ago, perhaps it descended from Homo antecessor. It had large 1,200 cm3 skulls and protruding jaws, larger nasal opening, and possibly early symbolic language. Its first fossils were found near the town German Heidelberg, and hence its name.
- Homo rhodesiensis. It emerged 600,000 years ago in Africa, it had a higher cranial capacity, between 1280 and 1325 cm3, and common features with the Homo erectus, Homo ergaster Y antecessor. However, his features already point more to the future H. sapiens than to the species that were contemporaneous, so it would be our direct ancestor.
- Homo neanderthalensis. The famous "Neanderthal man" inhabited Europe, the Middle East and Central Asia more or less between 250,000 and 28,000 years ago, and its extinction was due to unknown causes. However, having shared time with him Homo sapiens, it is thought that the natural selection and competition would have favored the latter. Even so, many humans today possess genetic indices of Homo neanderthalensis, so the cross between species should not have been unusual. Neanderthals had stocky, short builds. Their faces protruded slightly, their chins and foreheads receded, and they had pronounced brow ridges and heavy jaws; their brains and front teeth were larger than those of modern humans and they had large nasal cavities. The existence of skeletons of the elderly and of some with healed fractures may show that Neanderthals cared for the old and the sick, an indication of advanced social cooperation. They apparently had rituals, possibly of religious significance, and sometimes buried their dead.
- Homo sapiens. It is the human being as we know it and it emerged in two batches. Premodern humans, whose skulls were not yet fully spherical, had a vertical forehead and a high vault, and inhabited Africa (mainly Ethiopia, Israel, Morocco, and South Africa) between 315,000 and 100,000 years ago. Modern humans were endowed with modern behavior and physiognomy, with the earliest remains dating from 195,000 to 140,000 years ago. About 30,000 years ago, anatomically modern humans were the only members of the genus Homo that remained. This species would have conquered the entire world, actively or accidentally extinguishing the rest of the species of the genus Homo and becoming the humanity that we know today.