The image below is a very popular depiction of evolution. Actually, it is known as March Of Progress.
March of Progress
March of Progress is a scientific illustration presenting 25 million years of human evolution. It is actually the short version of Road to Homo Sapiens, which depict 15 human evolutionary forebears lined up as if marching in a parade from left to right. There is no other scientific image which is so eye catching and depicts evolution like this one. But the problem is, it does not resemble with our recent understanding of life’s history. Popularity doesn’t make the image authentic, does it? What makes it wrong then? Let’s have a close look to the image. From left to right the species depicted above are -
Dryopithecus, Oreopithecus, Ramepithecus, Neandertal, Cro-Magnon and Sapiens
We evolved linearly from Dryopithecus is kind of weird. And popularity doesn't make things correct, does it? Let’s have a deep dive into the images depicted above.
Cro-Magnon, a population of early Homo sapiens dating from the Upper Paleolithic Period (c. 40,000 to c. 10,000 years ago) in Europe. Current scientific literature prefers the term European early modern humans (EEMH). It has no formal taxonomic status, as it refers neither to a species or subspecies nor to an archaeological phase or culture.
Reconstruction of a Cro-Magnon woman and child
Neanderthals were a species or subspecies of archaic humans in the genus Homo that went extinct about 40,000 years ago. Neanderthals and Sapiens were two different species of same genus Homo. And they coexisted for a period of time in the past until the former’s extinction. Even they mate together. If you are from Europe or Asia, there is a probability that you are carrying 2-4% of Neanderthal gene. It means Neanderthals were not our ancestor. They and we were in two different boats for moments. Although, we share a common ancestor with them.
Reconstruction of a Neanderthal face
By the mid-1960s, David Pilbeam of Harvard University argued that Ramapithecus, a 14 million-year-old ape from the Siwalik Mountains of Pakistan, but also found in East Africa, was the earliest member of the human line. It was even suggested that humans had split from a common ancestor with the African apes by about 30 million years ago. Molecular Clock suggested humans and gorillas had separated only around 11 million years ago, not 30 million as suggested by fossils like Ramapithecus. The Molecular Clock is a technique that uses nucleotide sequences for DNA or Amino Acid sequences of protein to evaluate the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged. Ramapithecus was considered a possible human ancestor on the basis of the reconstructed jaw and dental characteristics of fragmentary fossils. A complete jaw discovered in 1976 was clearly nonhominid. Ramapithecus is now regarded as a member of Sivapithecus, a genus considered to be an ancestor of the orangutan. So, why is it present in “March of Progress”?
In the 1950s, a Swiss paleontologist unearthed dozens of fossils, including a largely complete skeleton, belonging to an ape species named Oreopithecus bambolii. The ape’s features implied it walked upright on two legs, just like humans. This apes coexisted in Europe with Sivapithecus. This habitat and specialized diet suggest similarities between Oreopithecus and some of the early members of the human branch of the ape tree: the hominins.
Fossil of Oreopithecus
It is a genus of extinct ape that is representative of early members of the lineage that includes humans and other apes. They were found over a widespread area including Europe, Africa, and Asia. It appears probable that only a single genus is represented. Dryopithecus is found as fossils in deposits dated back 23 to 2.6 million years old, originated in Africa.
We mentioned earlier that, “March of Progress” is an abbreviated version of “Road to Homo Sapiens”. These images were first introduced on a volume “Early Man” of Life Nature Library. The book was authored by anthropologist F. Clark Howell. The book was first published in 1965. “Road to Homo Sapiens” looks like bellow-
Road to Homo Sapiens
Some species depicted in the image is not directly connected to us. The main problem with this image is here evolution is depicted as a linear process, which it is not. Even the author of the book forbid to illustrate of evolution from one species to another. Evolution doesn’t produce one species from the previous one and goes on. Evolution makes species adaptive to an environment which is called evolutionarily successful. Orangutan and Chimpanzee are examples of evolutionarily successful species which share common species with us.