[Animal Modeling]-Human hands may be more primitive than chimpanzee hands

  Compared with apes, the length ratio of the human thumb to the index finger is one of the most typical characteristics of humans, and is generally considered to be one of the reasons for human success, but the human hand is about its changes over time. There are also various theories under development.

  Recently, an article was published in "Nature" magazine "The evolution of the ratio of human hands to monkey hands", human hands may be more primitive than chimpanzee hands. Became clear.

  This research was conducted by three scholars (Sergio Almecija, Jeroen Smaers and William Jungers) from Stony Brook University in New York.

  The ratio of the hand of the chimpanzee to the hand of the last ancestor of man (LCA) hardly changed. These findings indicate that, in essence, the structure of modern human hands is largely primitive, which is not the result of selective pressure in the context of context machine manufacturing.

  The ratio of the thumb to the index finger of a human hand is very large. Compared with apes, this is one of the most unique characteristics of human beings and is generally considered one of the reasons for human success, but human hands have evolved over time. There are several different theories. The researchers in this article measured the proportions of human palms, living apes, fossil apes and fossils of human ancestors (such as Ardipithecusamidus and Australopithecus sediba), which helps to understand the gradual evolution of the palm. The results of the study showed that chimpanzees and orangutans showed a convergent evolution in finger elongation, while the finger elongation of humans, human ancestors and gorillas did not change much.

  These results support the previous hypothesis. The proportions of human palms, thumbs and fingers are the same as those of other highly dexterous apes. This discovery challenges another hypothesis of scientists: They think it resembles a chimpanzee. I will. Palm is just the starting point for the evolution of palm, the common ancestor of chimpanzees and humans.