Most biologists feel that adaptation
occurs through the accumulation of small mutations. However an alternative that has been suggested for this process is macromutation, essentially when a large scale mutation produces a characteristic. This theory has generally been disregarded as the major explanation for adaptation, since a mutation on this scale is regarded as more likely to be detrimental then beneficial. However beneficial macromutations have been known to occur. For example the addition of body segments among arthropods
may be regarded as a macromutation.
See also; mutation evolution adaptation