Ecological Dominance

 Though all organisms modify their environment, humans stand out from other species and our closest living relatives in our degree of ecological dominance, or our ability to not only be successful in our environment but to have relative control over it. Beyond just the areas that are inhabited or used for resources, modern humans have successfully impacted all areas and ecosystems of the Earth’s environment. Human activity has altered the land, ocean, air, and biochemical cycles of the entire planet. Human ecological dominance originated before or concurrently with other notable human-specific attributes, including an increased brain size, prolonged immaturity, and most complex social cognitive abilities. Evidence from fossils suggests that human ecological dominance emerged in homo erectus, 1.8 MYA. As our hominin ancestors increased their ability to control forces of nature, competition among conspecifics gained importance. Therefore, ecological dominance allowed more resources to be devoted to within-species competition, thus driving the need for increased social competency. Though chimpanzees and other nonhuman primates also use tools and hunt, there is less evidence for competition among conspecifics during hunting (e.g., there is evidence that chimps throw things at conspecifics, but not during hunting), suggesting that for chimpanzees, the ecological environment is still the biggest source of selection pressure. This is true for other species as well, given that phenotypes are primarily altered by selection from the external forces of their environment rather than by interspecies competition. This difference in relationship to the environment in comparison with all other species demonstrates human uniqueness and demonstrates one possible mechanism driving other important social-cognitive changes that emerged in homo erectus.