The rate of evolution is consistent across many fossil lineages, even if some show little physical change.

Such seemingly unchanged fossils — described as being in stasis — have often been interpreted as evidence for slow evolution. Kjetil Lysne Voje at the University of Oslo analysed published data on 450 fossil lineages, calculating the rate of evolution and morphological change. In lineages in stasis, he found that traits constantly fluctuated, but these shifts did not lead to large evolutionary changes in a particular direction. However, the traits still evolved just as much as those in lineages that saw major directional changes.

Long periods of stasis in the fossil record are evidence for stable environmental conditions that allowed ecological niches to persist for millions of years, Voje suggests.

Evolution http://doi.org/br3n (2016)