Conventional wisdom holds that complex structures evolve from simpler ones, step-by-step, through a gradual evolutionary process, with Darwinian selection favoring intermediate forms along the way.
But recently some scholars have proposed that complexity can arise by other means—as a side effect, for instance—even without natural selection to promote it.
Studies suggest that random mutations that individually have no effect on an organism can fuel the emergence of complexity in a process known as constructive neutral evolution.
Read the full article here: The Surprising Origins of Life’s Complexity