It has been observed that the gene structure in a particular species undergoes a small-scale evolutionary change, over time. This may be due to sexual mating that is not random, natural selection, genetic mutation due to environmental effects and lifestyle, gene flow, or genetic drift. That is the reason we find different races in human beings or different breeds in dogs. This phenomenon is called microevolution.
Human beings have used this concept to create new breeds of dogs, or in crossbreeding of plants or animals in general. In microevolution, genetic information that already exists is put in a new arrangement, altered, or lost. It is also believed that microevolution is better referred to as ‘variation’ or ‘adaptation’, that occurs within a population or species.
Biologists believe that this process over a much larger time scale can lead to so much of genetic change that it may give rise to a new species. This theory is the extrapolation of microevolution over very long time scales. It is termed as macroevolution. The proponents of Darwin’s theory believe in this concept.
Contrary to microevolution, this theory assumes the addition of new genetic information to the existing genetic structure. In other words, it is the evolutionary changes that occur past the species level. However, so far such a thing has not been observed. Moreover, the difficulty to conduct such experiments is that macroevolution proposes a much longer timescale for species change when compared to a human being’s lifetime.
|Intra-species genetic change||Change leads to formation of a completely new species.|
|Occurs over small-time scales||Occurs over large-time scales|
|Genetic information that already exists is put in a new arrangement, altered, or lost.||New information is added to the existing genetic structure.|
|Can be experimentally proven||Difficulty in providing experimental proof|
|Example: New breeds of dogs or other living species||Example: Amphibians undergoing evolution to form reptiles or reptiles undergoing evolution to form birds|
|Creationists support this.||Creationists do not support this.|