What Factors Drive Human Evolution?

Laura van Holstein of the University of Cambridge and her colleagues, according to a Cosmos Magazine study, investigated the rate of evolution of hominin species over a five million year period. Van Holstein began by compiling a database of the 385 known hominin species, and then she devised a timeframe for the rise and demise of species to complete the fragmentary fossil record.

Vertebrates, she observed, typically adapt to fill "niches" in their environment. For example, the teeth of an early human species may have evolved to eat a variety of foods. "The pattern we see across many early hominins is similar to all other mammals," Van Holstein went on to say. "Speciation rates rise and then plateau, after which extinction rates begin to rise. This shows that interspecies rivalry was a significant evolutionary element," she stated.

However, in the group Homo, she explained, this trend was reversed. "The more species of Homo there were, the higher the rate of speciation," she went on to say. "So when those niches got filled, something drove even more species to emerge." She noted that the ability to change behaviour, such as utilising tools or fire or adopting new hunting strategies, may have allowed Homo species to quickly develop new ecological niches without having to endure the evolution of new body designs.

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