Fig. 257: Micro- and Macroevolution. Microevolution for instance includes the formation of the different dog races out of one archetype, probably the wolf. On the other hand the formation of mammals out of reptiles and simply organized living beings would be macroevolution. In the first case only already existing structures are varied (features of the fur, muzzle form and so on), whereas in the second case totally new structures would have to be formed: hair, mammary glands, facilities of temperature regulation and whatever characterizes mammals but not reptiles or other living beings.