Ancient ape remains "suspected" of being a missing link in human evolution
Merit Sloin
From Galileo, issue 7 November/December 1994
If Darwin were alive today, he would certainly have been satisfied with the latest findings that were discovered in the vast savannahs of Ethiopia, and which confirmed his assumption about the origin of man. In his book "The Origin of Species" published in 1859, Charles Darwin stated that the earliest roots of the human race are found in Africa. Since then, many fossils have been found in Africa, which, together with evidence from the field of molecular inheritance, testify to the great closeness between man and the African ape.
About seventy years ago, the researcher Raymond Dart found a strange skull in South Africa that did not resemble the skull of any human being, not even that of a monkey. Its general structure corresponded to that of a young monkey, but the way the spine entered the skull corresponded to a state of upright standing. This was the first evidence of our ancient ancestors - the hominids. Dart called the creature the Mozeraustralopithecus (southern monkey) africanus
Australopithecus), until 1978 he was considered the most primitive human being. In this year, "Lucy" was discovered in Ethiopia - an earlier skeleton of a hominid, 3.2 million years old - in this case a female, called Australopithecus afarensis. Lucy was blessed with a distinctly human trait - she walked on two legs, but the remains of her skull and teeth resembled those of monkeys. In doing so, Lucy earned the honor of finding close to the point of divergence between the apes and man, which occurred, according to the calculations of molecular geneticists, four to six million years ago. Paleoanthropologists (researchers of human origin) knew that somewhere in Africa there was the "missing link" - the common ancestor of monkeys and human beings.
It was Jen Suwa from the University of Tokyo, a member of the excavation expedition in Ethiopia, who noticed the glint of fossilized teeth that were hidden in the rocky soil, about 30 km south of the site where Lucy was found. "I knew right away that these were hominid teeth," he says excitedly, "and I had the feeling that in front of me were the remains of one of the earliest hominids."
Jen Sue was not wrong, and what's more - he found the most ancient human link - a human-like creature that walked the earth 4.4 million years ago. This creature is considered to represent a new species of hominids, which the scientists named Australopithecus ramidus (ramidus Australopithecus); Ramidos means root in the Ethiopian language. The findings indicated that the height of this creature was one meter twenty, and its weight was about thirty kilograms - it was heavier than Lucy, and possibly even bigger than her. "We know that the arm bones we found belong to the larger specimen from Lucy, but we are not clear if it was male or female," notes Tim White, who headed the expedition. The researchers' findings, published in the journal Nature last September, received reactions from the academic community. The majority agreed that Ramidos is indeed located very close to the point of split between the human race and the apes, and some said that he represents the same "missing link" from which the human family and the great ape family split.
Ramidos lacked a number of human features that characterized Lucy: his teeth resembled monkey teeth more than human teeth, and as for walking on two legs - a feature that clearly represents man - there is still no clear answer. Most experts believe that Ramidos did indeed walk on two feet, this is based on evidence based on the way the spine is connected to the skull, which probably indicates an upright body position. The structure of his arm bones is also different from those of the monkeys, who use their arms to walk, and it is possible that these also indicate upright walking.
The accepted opinion holds that the upright walk is the one that hastened the development of the human race. Freeing the hands enabled the development of human qualities, such as the use of tools, which led to the development of thinking and the brain. Our ancient ancestors carried their food and their offspring in their hands, and this is how the family framework developed. From Lucy's skeleton, which was upright but had the structure of a monkey's skull, it was clear that walking on two legs preceded the development of the brain. But what was the factor that pushed the transition to walking on two?
The accepted theory holds that the climate changes that occurred at the time caused the drying of the forests in East and South Africa, and the flat savannas gave an advantage to those monkeys that walked upright. They could spot predators from a distance and even walk long distances and carry food in their hands for their offspring.
However, it turns out that Ramidos does not live in the savanna but in the forest. Among the findings uncovered in the excavations along with his bones were thousands of fossilized tree seeds and fossilized tree trunks. In addition, hundreds of species of forest-dwelling animals were found there. If indeed Ramidos lived in the forest, a new explanation must be found for the process of the apes standing upright.
One of the theories holds that standing upright and walking on two feet in the savannas does not confer a biological advantage, on the contrary - creatures that learn to walk upright are exposed to the risk of predation in an exposed area to a greater extent than in a forested area. The stable position, then, provided Ramidos with another advantage. What is that advantage? The clue to this, the supporters of the theory believe, lies in his teeth. "The pointed fangs in monkeys are used as an intimidating weapon and as an ostentatious means of finding a suitable mate," explains White. Ramidos had small fangs, lacking intimidation potential, that had no role in sex play either. The females therefore looked for partners with another advantage, such as those capable of taking care of the offspring, and these were the apes that walked upright, their hands were free to carry their offspring and the food for them. It is these details that survived during evolution and from which man developed.
Whether this theory is true or not, many questions still remain unsolved: is the new hominid the first species that appeared in the human trajectory after the split from the apes, or perhaps there are several other types between it and the apes - types that have not yet been found. The solution to these basic questions will only be found with the disclosure of additional findings. As of today, humanity has added half a million years to its history.
May 2009: The missing link between the apes and the apes (and with them, of course, the humans as well)
