Overview

It was in his theory of evolution that Charles Darwin first presented the concept of Speciation. It explains that, if isolated from the main species, a population will evolve differently in response to the environment it is exposed to. It might be a tricky concept to grasp, but if you are looking for Speciation manifesting in real life, look no further than frogs in Chernobyl, Ukraine.

Scientists studying the effects of radiation on — and the evolution of — wildlife in the Chernobyl Exclusion Zone have discovered “black” specimens of an otherwise bright, green-colored Eastern Tree Frog. Their occurrence, scientists believe, is an expedited evolutionary response to excessive radiation in the area and a key survival response that has enabled the species to persevere. 

Science and Other Stuff to know

The Chernobyl Exclusion Zone came into being in 1986 in the wake of the biggest nuclear accident in human history. But over the three decades, the zone has become a thriving haven for wildlife. Scientists Germán Orizaola and Pablo Burraco first began studying the effects of radiation on wildlife in Chernobyl in 2016, noticing darker, almost black colored, frogs in areas close to a damaged reactor. 

With their curiosities piqued, the two expanded on their study and examined several hundred frogs between 2016 and 2019. The frogs were collected from areas within and around the zone that had varying degrees of radiation exposure. What they discovered was that the dark pigmentation was a result of Melanin and was the most dominant in frogs found closest to the damaged reactor, the frogs’ shades lightening as researchers moved away from the exclusion zone. 

Melanin is what makes many organisms, including humans, appear darker in complexion. But it is also known for being responsible for reducing the negative effects of ultraviolet radiation, including ionization of radiation. Melanin’s ability to absorb radiation means that species having more of it will stand a better chance of surviving and absorbing the harmful effects of radiation exposure. 

What surprised the scientists was that the dark pigmentation of frogs was not a result of recent radiation exposure, but a likely evolutionary response by the species to survive in an environment having the highest levels of radiation contamination.

So what? 

The study of frogs is a major insight into species’ evolutionary ability to survive against odds. The researchers opined that the Chernobyl frogs underwent rapid evolution to survive radiation. They believe that when the accident occurred, frogs with darker skins (more melanin) likely suffered limited damage than their greener brethren and reproduced more successfully.

In today’s age where skin lightening has become the norm, while ozone depletion is making the ultraviolet radiation evermore stronger, the study could form the basis of awareness campaigns that inform people against dangerous trends and procedures they keep pursuing all for the sake of social acceptance.

What’s next? 

Although further studies are needed to determine the causes of darker pigmentation in contaminated environments, the findings do look promising. In the future, this study of evolution could help scientists find cures to various skin conditions, like cancer, that are caused by exposure to radiation of various sorts. Besides, it could offer insight into the role melanin can play in radioactive and nuclear waste management, an issue we would be facing increasingly in the decades ahead.