In a study published this week in Science Advances, an international team of researchers from Arizona State University’s Institute of Human Origins and School of Human Evolution and Social Change, New York University, University of Kent, and the Max Planck Institute for Evolutionary Anthropology found that a simple, straightforward developmental rule — the “patterning cascade” — is powerful enough to explain the massive variability in molar crown configuration over the past 15 million years of ape and human evolution.
“Instead of invoking large, complicated scenarios to explain the majors shifts in molar evolution during the course of hominin origins, we found that simple adjustments and alterations to this one developmental rule can account for most of those changes,” says Alejandra Ortiz, a postdoctoral researcher at Arizona State University’s Institute of Human Origins and lead author of the study.Paper. (public access) – Alejandra Ortiz, Shara E. Bailey, Gary T. Schwartz, Jean-Jacques Hublin, Matthew M. Skinner. Evo-devo models of tooth development and the origin of hominoid molar diversity. Science Advances, 2018; 4 (4): eaar2334 DOI: 10.1126/sciadv.aar2334
“That all of this precise, detailed information is contained deep within teeth,” continued Schwartz, “even teeth from our long-extinct fossil relatives, is simply remarkable.”
“Our research, demonstrating that a single developmental rule can explain the countless variation we observe across mammals, also means we must be careful about inferring relationships of extinct species based on shared form,” said Shara Bailey, a coauthor and paleoanthropologist at New York University. “It is becoming clearer that similarities in tooth form may not necessarily indicate recent shared ancestry,” added Bailey. More.
If we are talking about guiding developmental rules rather than individual fitness scenarios, we are talking about structuralism, not Darwinism. Funny that such a ruling pattern should exist…
See also: Ancient teeth don’t rewrite human history after all