Humans have had a definite effect upon a diverse array of species. In his paper entitled, “Loss of speciation rate will impoverish future diversity”, Michael Rosenzweig discusses the effects of human presence upon the macroevolution of species. One of the papers arguments is rooted in the idea that human intervention and development is directly contributing to a lower speciation rate. Rosenzweig claims that this can be traced to the reduction of natural areas which has caused species with naturally wide geographical ranges to consolidate into smaller areas, reducing isolation due to potential geographical barriers, and genetic variability. Both of these factors contribute to speciation events, and when disrupted due to human activity their absence could severely limit such diversification events.
However, the very notion that humans act as the world’s greatest evolutionary force in one of swollen egocentrism.
Life on earth has been estimated to have been developing for the last 3.7 billion years. Humans reached full behavioral modernity merely 50,000 years ago. The majority of the human impact upon nature has occurred within the past 150 years with the advent of technology. Currently, the extinction rates are 100 to 1000 times the background extinction rates previously observed in earth’s evolutionary history.
While this is obviously no small feat, it encompasses a minute dimple in the time scale of the earth and it’s biological diversity; compared to the Permian- Triassic extinction event which is believed to have caused the extinctions of approximately 96% of all marine species and over 70% of all land species, human influence pales in comparison.
While the human impact upon evolution is certainly grandiose in our own eyes, it is by no means the greatest force to hold sway over the intricacies of evolution.
For more information regarding the human impact on evolution, please refer to: Rosenzweig, M., 2001. Loss of speciation rate will impoverish future diversity. PNAS. 98(10): 5404-5410.