Mosaic evolution occurs when the gene alleles of an organism or species evolve at different rates. Marks of mosaic evolution include the development of features within a species or organism at different times.
This type of evolution suggests that there are overall patterns between and within species. Scientists believe that the occurrence is most likely in organisms of varying development. A famous example of mosaic evolution in the fossil record includes primate predecessors to humans that had a skull resembling that of Homo sapiens and facial structure like an ape. Mosaic evolution is a part of macroevolution, and the idea was first developed by scientist Stephen Jay Gould. There is some debate about macroevolution within the scientific community regarding its application.