Mosaic evolution

In mosaic evolution some characters in a transitional form are basal, while others are remarkably advanced.

Apparently, evolutionary change takes place rapidly in some body parts or systems without simultaneous changes in other parts.^[1] Another definition is the "evolution of characters at various rates both within and between species".^[2]408 Its place in evolutionary theory comes under long-term trends or macroevolution.^[2]

Evolution from a basal (early) form to a derived (later) form takes place in stages. Modules (groups of characters) change semi-independently of each other. They change at different times, so producing a mosaic of primitive and derived traits.

These changes play a leading role in major evolutionary transitions. It may involve speciations producing a series of species, only a few of which would be found as fossils.

By its very nature, the evidence for this idea comes mainly from palaeontology. It is not claimed that this pattern is universal, but it is common. There are now a wide range of examples from many different taxa.

1. ↑ King R.C. Stansfield W.D. & Mulligan P.K. 2006. A dictionary of genetics. 7th ed, Oxford University Press. p286 ISBN 0-19-530761-5
2. ↑ ^{2.0 2.1} Carroll R.L. 1997. Patterns and processes of vertebrate evolution. Cambridge University Press. ISBN 0-521-47809-X