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Macroevolution is a scale of analysis of evolution in separated gene pools.[1] Macroevolutionary studies focus on change that occurs at or above the level of species, in contrast with microevolution,[2] which refers to smaller evolutionary changes (typically described as changes in allele frequencies) within a species or population.[3]
The process of speciation may fall within the purview of either, depending on the forces thought to drive it. Paleontology, evolutionary developmental biology, comparative genomics and genomic phylostratigraphy contribute most of the evidence for the patterns and processes that can be classified as macroevolution. An example of macroevolution is the appearance of feathers during the evolution of birds from theropod dinosaurs.
Abrupt transformations from a biologic system to another, for example the passing of life from water into land or the transition from invertebrates to vertebrates, are rare. Few major biological types have emerged during the evolutionary history of life and most of them survive till today. When lifeforms take such giant leaps, they meet little to no competition and are able to exploit a plethora of available niches, following a pattern of adaptive radiation. This can lead to convergent evolution, where unrelated populations display similar adaptations.[4]
The evolutionary course of Equidae (wide family including all horses and related animals) is often viewed as a typical example of macroevolution. The earliest known genus, Hyracotherium (now reclassified as a palaeothere), was a herbivore animal resembling a dog that lived in the early cenozoic. As its habitat transformed into an open arid grassland, selective pressure required that the animal become a fast grazer. Thus elongation of legs and head as well as reduction of toes gradually occurred, producing the only extant genus of Equidae, Equus.[4]
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Russian entomologist Yuri Filipchenko (or Philipchenko, depending on the transliteration) first coined the terms "macroevolution" and "microevolution" in 1927 in his German language work, "Variabilität und Variation". Since the inception of the two terms, their meanings have been revised several times and the term macroevolution fell into limited disfavour when it was taken over by such writers as the geneticist Richard Goldschmidt (1940) and the paleontologist Otto Schindewolf to describe their orthogenetic theories.[5]
As a result, apart from Dobzhansky, Bernhard Rensch and Ernst Mayr, very few neo-Darwinian writers used the term, preferring instead to talk of evolution as changes in allele frequencies without mention of the level of the changes (above species level or below). Those who did were generally working within the continental European traditions (as Dobzhansky, Ernst Mayr, Bernhard Rensch, Richard Goldschmidt, and Otto Schindewolf were) and those who didn't were generally working within the Anglo-American tradition (such as John Maynard Smith and Richard Dawkins). Hence, use of the term "macroevolution" is sometimes wrongly used as a litmus test of whether the writer is "properly" neo-Darwinian or not.[5]
Within the Modern Synthesis school of thought, macroevolution is thought of as the compounded effects of microevolution.[6] Thus, the distinction between micro- and macroevolution is not a fundamental one – the only difference between them is of time and scale; as Ernst W. Mayr observes, "transspecific evolution is nothing but an extrapolation and magnification of the events that take place within populations and species...it is misleading to make a distinction between the causes of micro- and macroevolution”.[6] However, it should be noted that time is not a necessary distinguishing factor – macroevolution can happen without gradual compounding of small changes; whole-genome duplication can result in speciation occurring over a single generation - this is especially common in plants.[7]
Changes in the genes regulating development have also been proposed as being important in producing speciation through large and relatively sudden changes in animals' morphology.[8][9]
Some examples of subjects whose study falls within the realm of macroevolution:
The term "macroevolution" frequently arises within the context of the evolution/creation debate, usually used by creationists alleging a significant difference between the evolutionary changes observed in field and laboratory studies and the larger scale macroevolutionary changes that scientists believe to have taken thousands or millions of years to occur. They may accept that evolutionary change is possible within species ("microevolution"), but deny that one species can evolve into another ("macroevolution").[1] Contrary to this belief among the anti-evolution movement proponents, evolution of life forms beyond the species level ("macroevolution", i.e. speciation in a specific case) has indeed been has been observed multiple times under both controlled laboratory conditions and in nature.[10]
The criticism is rejected by the scientific community, which holds that there is ample evidence that macroevolution has occurred in the past.[5][11] The terms macroevolution and microevolution as used in mainstream science relate to the same processes operating at different scales, but creationist claims misuse the terms in a vaguely defined way which does not accurately reflect scientific usage, acknowledging well observed evolution as "microevolution" and denying that "macroevolution" takes place.[5][12] Evolutionary theory (including macroevolutionary change) remains the dominant scientific paradigm for explaining the origins of Earth's biodiversity. Its occurrence is not disputed within the scientific community.[13] While details of macroevolution are continuously studied by the scientific community, the overall theory behind macroevolution (i.e. common descent) has been overwhelmingly consistent with empirical data. Predictions of empirical data from the theory of common descent have been so consistent that biologists often refer to it as the "fact of evolution".[14][15]
Nicholas Matzke and Paul R. Gross have accused creationists of using "strategically elastic" definitions of micro- and macroevolution when discussing the topic.[1] The actual definition of macroevolution accepted by scientists is "any change at the species level or above" (phyla, group, etc.) and microevolution is "any change below the level of species." Matzke and Gross state that many creationist critics define macroevolution as something that cannot be attained, as these critics describe any observed evolutionary change as "just microevolution".[1]
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Macroevolution refers to large-scale evolution. For some, this means the origin of species. For others, it means the large-scale changes seen in the fossil record. It is a term of convenience: for most biologists it does not suggest any change in the process of evolution.
Some biologists use the term for evolution in already separated gene pools.[1] Macroevolutionary studies focus on change that occurs at or above the level of species.
Microevolution,[2] on the other hand, refers to smaller evolutionary changes within species or populations. Microevolution can typically be described as changes in allele frequencies.
Paleontology, evolutionary developmental biology, and sequence analysis contribute much evidence for the patterns and processes that can be classified as macroevolution. An example of macroevolution is the appearance of feathers during the evolution of birds from one group of dinosaurs.
Within the modern evolutionary synthesis school of thought, macroevolution is thought of as the compounded effects of microevolution. Thus, the distinction between micro- and macroevolution is not a fundamental one – the only difference between them is of time and scale.[3][4]
Some creationists have also adopted the term 'macroevolution' to describe the form of evolution that they reject. They may accept that evolutionary change is possible within species (microevolution), but deny that one species can evolve into another (macroevolution).[1] These arguments are rejected by biologists, who hold that there is ample evidence that macroevolution has occurred in the past.[5][6]
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Some examples of subjects whose study falls within the realm of macroevolution:
Russian entomologist Yuri Filipchenko (or Philipchenko, depending on the transliteration) first coined the terms 'macroevolution' and 'microevolution' in 1927 in his German language work, Variabilität und Variatio.[5]
Since then, their meanings have been revised several times and fallen into disfavour with many, who prefer to speak of biological evolution as one process.[5]
Evolution as a whole is strongly supported by many kinds of evidence.[7][8][9]. The issue for biologists is whether there is any sense in having the special term macroevolution.[10] The answer is yes for a few biologists who proposed one or more evolutionary mechanisms which worked above the species level. The ideas of punctuated equilibrium and species selection were suggested, but in each case most biologists felt they could be explained by the usual small-scale changes. This explains why 'macroevolution' is perhaps a term biologists do not need to use.
When discussing the topic, creationists use "strategically elastic" definitions of micro- and macroevolution.[1] Macroevolution, by their definition, cannot be attained. Any observed evolutionary change is described by them as being "just microevolution".[1]
   | "29+ Evidences for Macroevolution" - 29+ Evidences for Macroevolution: the Scientific Case for Common Descent |
| | Macroevolution FAQ - Macroevolution: Its definition, Philosophy and History |
 | news-links and resources - AAAS - Evolution Resources |
| | "A Critique of 29+ Evidences for Macroevolution" - - A Critique of ''29 Evidences for Macroevolution'' - Intro - |
| | Evolution is a Fact and a Theory - Evolution is a Fact and a Theory |
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