It comes as no surprise to anyone that more than a hundred years ago, some extremely smart dudes came up with some extremely outlandish theories for their time, which then got proven in this day and age. Einstein is one smart dude, and Darwin is another in a whole different genre!
So 150 years ago, Charles Darwin came up with a curious theory regarding the natural selection of finches, seed-eating songbirds with varying beak sizes that live in the Galapagos Islands. According to Darwin, the birds’ beak sizes and shapes were major components of their evolution.
In a paper published on Thursday in the journal Science, researchers found the genome responsible for finch beak sizes; it’s known as HMGA2. According to Christian Science Monitor, the study followed finches that had to fight over extremely scarce seeds after the draught on Daphne Mayor Island, next to Ecuador, about a decade ago. In the study, the researchers noticed that 2 types of finches seemed to mostly be fighting: larger ground finches, and larger beaked medium ground finches. These two large beaked species were competing with each other over large seeds. However, small beaked finches had the small seeds all to themselves. Hence, while the smaller beaked finches had better chances of survival, the larger beaked finches tended to die out more often. The HMGA2 gene is not solely responsible, but it does contribute greatly to the process of adaptation to drier environments.
The study, however, also shows that the larger beak variation of the genome hasn’t gone completely extinct. According to the scientists, different ecological pressures may give rise to the resurgence of the larger beak genome. Furthermore, the same part of the genome is responsible for stature in humans.
Last year, another study was performed that discovered the genome responsible for beak shape, named ALX1, which decided whether the beak was pointed or blunt. Beak shape and size are two important ways that Darwin’s finches evolved throughout their lineage. As birds diverged to exploit the resources available, the genomes shifted according to environmental pressures.
Scientists think that Darwin’s finches are a model of the evolutionary biodiversity on Earth. Moreover, the first finches to colonize the Galapagos Islands were only one species; however, scientists have been able to identify 18 different species on the islands today. The process of forming more species is known as speciation, while the change that takes over these birds’ genomes is known as adaptive radiation. This process is the cornerstone of evolutionary biology.