Evidence-Based is a series where scientists and students in STEM clarify misconceptions and debunk misinformation about topics from their own field of study. In consideration of growing misinformation and questions surrounding fact and fiction, we aim to highlight and deconstruct evidence and research from science, and discuss ways to prevent science misconceptions.
The Missing Link Misconception
By Alex Daniel Velez
4th year graduate student, MA-Ph.D. in Anthropology at Binghamton University
Research area: Paleoanthropology
The missing link misconception is based on an old misunderstanding of evolution which many evolutionary scientists themselves used to have. It thinks of evolution as a linear series of forms one can discretely categorize as: primary form -> transitional form -> evolved form. This has become a source of hoaxes, the most famous example of which is the alleged hominin (human ancestor) Piltdown Man. This was an alleged “missing link” between humans and apes found in the UK that fascinated the scientific community from 1912 until 1915 when it was discovered that someone had simply attached an Orangutan jaw to the skull of a modern human. However, media headlines continue to use the term “missing link” to describe newly discovered fossils, and the term has found use across artistic mediums from novels and films to music and television. Needless to say, it’s become a source of frustration, especially to those who discover the fossils, to have the meaning of the fossils misunderstood. Seeing this term used in so many places reinforces the misconception and continues to spread the misunderstanding of evolution as unilinear, which also feeds the arguments of anti-evolution advocates; i.e: “if evolution is real, why are there still apes?”
Rather than a singular chain, research suggests that evolution should be thought of the same way you would consider a family tree. Human evolutionary history is complicated with branches ending and splitting off in unexpected ways. Some species of hominin are long lived. Homo erectus fossils date from 1.9 million years ago to 140 thousand years ago.1 While other species are quite short lived; Homo floresiensis lived from 100 thousand to 60 thousand years ago.2 Neandertals lived between 400 thousand and 40 thousand years ago.3 Our own species dates back to 300 thousand years ago, as confirmed by recent fossil finds in North Africa.4
As the graphic shows, human evolution is best represented as a branching tree where different relatives diverge and begin their own line. The fact that so much variation exists within the fossil record, both human and nonhuman, is evidence against the missing link concept. The varied nature of evolution makes it difficult to explain evolution in short sentences, especially to the general public. But, as renowned evolutionary scientist Stephen Jay Gould wrote: “…all evolutionary biologists know that variation itself is nature’s only irreducible essence.” 5
The danger in continuing to use the term “missing link” is that it continues this misunderstanding of evolution which creates difficulties in educating the general public about evolution. In a political climate which treats academia, especially fields of study historically targeted for suppression by conservative administrations, with hostility, this can have negative setbacks in science education and educational policy.
The best way to prevent this misconception is by finding better ways to relate evolution to the public, especially with concrete examples. The example of the family tree I used earlier makes it a bit easier to explain the evolutionary relationships between different species. Also, finding everyday examples, such as the reason flu vaccines change from year to year, that is the constant mutation and development of news strains of Influenza virus.
1 Indriati, E., Swisher III, C. C., Lepre, C., Quinn, R. L., Suriyanto, R. A., Hascaryo, A. T., … & Lees, W. (2011). The age of the 20 meter Solo River Terrace, Java, Indonesia and the survival of Homo erectus in Asia. PloS one, 6(6), e21562.
2 Sutikna, Thomas; Tocheri, Matthew W.; et al. (2016). Revised stratigraphy and chronology for Homo floresiensis at Liang Bua in Indonesia. Nature. 532: 366–9.
3 Trinkaus, E., Shipman, P. (1993). The Neanderthals: Changing the Image of Mankind. Knopf: New York.
4 Richter, D., Grün, R., Joannes-Boyau, R., Steele, T. E., Amani, F., Rué, M., … & Hublin, J. J. (2017). The age of the hominin fossils from Jebel Irhoud, Morocco, and the origins of the Middle Stone Age. Nature, 546(7657), 293-296.
5 Gould, S. J. (2010). The median isn’t the message. Ceylon Medical Journal, 49(4).