Can we predict the path of evolution? Science says maybe

In the television series Psych (now streaming on Peacock!), Shawn Spencer uses keen observation skills and an eidetic memory to solve crimes others are incapable of cracking. In the process of doing so, he finds himself a suspect of various crimes and has to cook up a story about being a psychic in order to avoid prosecution. As far as we know, psychic abilities aren’t real, they certainly don’t have any reliable scientific evidence to back them up, but that doesn’t mean we can’t make predictions about the natural world.

In fact, the process of science largely depends on making predictions and using experimentation to validate our hypotheses. That said, some fields of science are a little harder to predict than others. When it comes to evolution, we’re able to make wide-ranging predictions about processes, but knowing exactly how a species will change over time has largely evaded our grasp. That might be primed to change.

Now, an international team of scientists have described the ways in which a family of plants in Central and South America have changed over time and determined that evolutionary changes might actually be predictable. Their findings were published in the journal Nature Ecology & Evolution.

Researchers studied a genus of flowering plants known as Viburnum which made its way from Mexico into Central and South America roughly 10 million years ago. Previous research involving the same plants determined that their smooth leaves and hair-covered leaves evolved around the same time and were subsequently distributed throughout 11 different regions by birds. That was some 40 years ago and advances in genetics techniques allowed for a new analysis which challenged that original conclusion.

Analyzing both the genetics and morphology of Viburnum plants, researchers found the presence of both smooth and hairy leaves in 9 of the 11 studied regions. Rather than coming from a single ancient source which was later distributed, the new paper concludes that the various leaf types evolved independently in each region through a phenomenon known as replicated radiations. If that’s the case, it would suggest that evolution of the genus has followed a sort of track with predictable outcomes, rather than the more random distribution of traits we might have expected.

Moreover, in the remaining regions where hair-covered leaves aren’t present, the genus arrived relatively recently on evolutionary timescales. The team suspects that, given enough time, they will evolve large hairy leaves as well. If that happens, it would go a long way to confirming this new interpretation, but we’ll likely have to wait a long time to find out.

A similar phenomenon has been observed previously in some animals, with disparate populations in similar environments evolving convergent traits. Large headed theropods adapting smaller arms over time is one notable example of traits converging even in unrelated species. Now that it has been observed in plants as well, the team suggests evolution might become a more predictable science, one in which we can look at the current state of an organism as well as its environment to glean clues about what it might become in the future.

As with all things in science, our predictions are only as good as the quality of factors and evidence we have at hand. Prior gaps in our ability to predict future changes in a population might have been an artifact of lacking critical information. As we continue to learn and fill in the biological puzzle pieces, a clearer picture of the tree of life is emerging. Of course, we’ll likely never have the full picture and nature will continue to surprise us with species radiating into various unexpected forms even within similar environments. Scientists now hope to understand the necessary conditions under which we can make reliable predictions to further refine our understanding of how natural selection shapes organisms.

We can’t help but wonder what we might evolve into down the line, and if we’ll be able to see it coming in advance.