Potential explanations have included rising levels of atmospheric oxygen because of photosynthesis, allowing for the development of more complex animals; the rise in carnivorous species and new predatory tactics, such as the flat and segmented, armor - crushing creatures known as anomalocaridids; and the breakup of the supercontinent Rodinia, which may have created new ecological niches and isolated populations as the continents drifted apart. (sciencemag.org)
Or the wild creatures exploited new ecological niches created by humans, gradually habituating themselves to people and, in essence, domesticating themselves. (sciencenews.org)
Some scientists had previously proposed a causal link between the two events: Raining debris from an asteroid breakup (SN: 7/23/16, p. 4) drove evolution by upsetting ecosystems and opening new ecological niches. (sciencenews.org)