Overview

Neoteny is the retention of adolescent traits into adulthood (Somel, 2016). The physical similarities between an adult and a child can be accredited to neoteny. This study highlights the now cutting-edge hypothesis that the characteristics of certain species may be due to a generational form of neoteny. How the theory goes, certain individuals of a species are stricken with dwarfism. This forces them to retain their juvenile traits throughout their life. Unexpectedly, this dwarf state actually allows them to capitalize on another niche in the environment. Due to their isolation and the hereditary nature of their dwarfism, they branch off and make their own species. 

The supposed evidence for this hypothesis is the visual and genetic similarities between certain types of organisms. A bird’s skull, for example, is very similar to a baby reptile’s skull, and since they share a close common ancestor, it is theorized that birds started as a dwarf reptile. Likewise with humans. A baby chimpanzee skull is far more similar to an adult human skull than it is to an adult chimpanzee. This may have kick-started the evolution of modern humans (Shea, 1989).

It is important to note that this hypothesis is currently being debated, and these similarities could either be due to coincidence or convergent evolution, like bats and birds’ wings. As with all budding studies, it is difficult to currently discern the truth (Stern, 2013).

References

Stern, D. L. (2013). The genetic causes of convergent evolution. Nature Reviews Genetics, 

14(11), 751-764. https://doi.org/10.1038/nrg3483

Somel, Mehmet. (2016). “The Role of Neoteny in Human Evolution: From Genes to the Phenotype | SpringerLink.” 

SpringerLink, https://link.springer.com/chapter/10.1007/978-4-431-54011- 3_3#:~:text=3.2%20The%20Neoteny%20Hypothesis%20of%20Human%20Evolution&text=A%20specific%20type%20of%20heterochrony,Gould%201977%3B%20Alberch%20et%20al. Accessed 16 Mar. 2021.

Shea, B. T. (1989). Heterochrony in human evolution: The case for neoteny reconsidered. American Journal of Physical Anthropology, 32(S10), 69-101. https://doi.org/https://doi.org/10.1002/ajpa.1330320505