User:AdamRetchless/macro

Merge with extinction and speciation.

There is no question that these organisms are descended from the fossil species. Sequence of appearance in the fossil record, geographical distribution, molecular phylogeny all support. (macroevolution is really about common descent?)

the term macroevolution may be used to describe the large changes in morphology between extant species and ancestral species (and by extension, between existing species with shared a shared ancestral species). There is no evidence that these changes are anything more than the accumulation of the changes that are regularly observed between organisms and their descendants--microevolution. Macroevolution may be apparent in relatively large discontinuity in features between organisms represented in the fossil record. While all scientists recognize that this results from the fact fossilized organisms are a small and biased sample of all organisms (as indicated by regular discovery of fossils that fit in these gaps), some believe that this reflects historical variation in the rate of evolution, and particularly rapid evolution in small populations. Some biologists believe that the evolution of novelty is tied to the creation of new species, and therefore macroevolution can refer to the extent and distribution of species.

Occasionally "macromutations" are proposed to be behind this apparently rapid evolution. These may involve processes like homeotic mutations or evolutionary capacitance...symbiosis, horizontal gene transfer, and de novo gene creation.