The elevation of the Earth’s surface has changed significantly throughout Earth’s history, due to the tireless geological processes that constantly shape it. Therefore, those coasts where once our ancestors enjoyed the best beaches, today could be submerged in the depths of the ocean or perhaps, form part of rugged mountain ranges and cliffs.
According to an article published in the journal Nature Ecology and Evolution by a team of scientists from the University of Cambridge, topographic changes have been a key evolutionary factor for speciation , that is, for the emergence of new species. This fact is due to the fact that variations in the relief, specifically in the elevation of the terrain , directly influence the creation of new habitats and the connectivity that may exist between them , giving rise to the appearance of new forms of life.
In their study, the scientists compared data on the distribution of mammal and bird species, and information on climate change and fluctuations in the elevation of the land surface over the past three million years.
The result was surprising, since they demonstrated that the geological processes of elevation of the land have much more weight in promoting the evolution of new species, than the traditionally studied macroecological and climatic gradients, such as temperature. On the contrary, erosion or loss of altitude was much less linked to the increase in speciation processes.
Dr. Andrew J. Tanentzap, co-author of the article, states that ” the highest peaks are the places where there are usually more endemic species, that is, species that are not found anywhere else.” As the elevation of the land increases, the complexity of the habitat increases, creating insurmountable barriers between populations of the same species and leaving them reproductively isolated. Over time, these disconnected groups could grow into totally different species .
Interestingly, the correlation between changes in terrain elevation and speciation processes was much more remarkable in mammals than in birds . Scientists think that this could be due to the reconnection of isolated populations by air, that is, that the birds could have flown to circumvent some of the new geographical barriers and get to mate with distant groups.
Dr. Javier Igea, first author of the study, remarks that it is precisely in the highest places and susceptible to geological changes, where the focus of conservation is worth being able to, since it is in these areas where species with a high evolutionary potential.
Reference: Igea, J., & Tanentzap, AJ (2021a). Global topographic uplift has elevated speciation in mammals and birds over the last 3 million years. Nature Ecology & Evolution. Doi: 10.1038 / s41559-021-01545-6