A recent study conducted by the Massachusetts Institute of Technology（MIT）has discovered that river erosion（侵蚀）can lead to increased biodiversity in areas with minimal tectonic（地壳构造的）activity. The researchers focused their attention on the Tennessee River Basin and examined how the erosion of various rock types by the river had led to the separation and diversification of a type of fish called the greenfin darter. As time passed, these separate fish populations evolved into distinct families with genetic differences.
Scientist Thomas Near observed that the greenfin darter was exclusively found in the southern half of the Tennessee River Basin. The researchers analyzed the genes of each fish in Near's data set and constructed an evolutionary tree. This tree helped them comprehend the evolution and differences of the greenfin darter species. They discovered that the fish within the same branch of the river were more closely related to each other than to the fish in other branches.
This study provides evidence that river erosion significantly impacts biodiversity in regions with low tectonic activity. It illustrates how changes in the landscape caused by river erosion can lead to the division and diversification of species over time, even in peaceful environments. These findings enhance our understanding of the mechanisms（机制）that drive biodiversity and evolution, even in areas that are not typically associated with intense tectonic activity.
Subsequently, the team discovered a strong correlation between the habitats of the greenfin darter and the type of rocks present. The southern half of the Tennessee River Basin consists of hard, tightly packed rocks, resulting in turbulent（湍急的）waves in the rivers that flow through it. This characteristic may be favored by the greenfin darter. As a result, the team assumed whether the distribution of greenfin darter habitats had been influenced by the changing rock types, as the rivers eroded the land over time. To test this assumption, the researchers developed a simulation model. Remarkably, the results confirmed their assumption.
