Editing Macroevolution (section)

== Microevolution vs Macroevolution ==

The fact that both micro- and macroevolution (including common descent) are supported by [[Evidence_of_common_descent|overwhelming evidence]] remains [[Level_of_support_for_evolution#Scientific|uncontroversial within the scientific community]]. However, there has been considerable debate over the past 80 years regarding causal and explanatory connection between microevolution and macroevolution.<ref name="Saupe2021a"></ref>

The '''‘Extrapolation’''' view holds there is no fundamental difference between the two aside from scale; i.e. macroevolution is merely cumulative microevolution. Hence, the patterns observed at the macroevolutionary scale can be explained by microevolutionary processes over long periods of time. 

The '''‘Decoupled’''' view holds that microevolutionary processes are decoupled from macroevolutionary processes because there are separate macroevolutionary processes that cannot be sufficiently explained by microevolutionary processes alone.  

<blockquote>" ... macroevolutionary processes are underlain by microevolutionary phenomena and are compatible with microevolutionary theories, but macroevolutionary studies require the formulation of autonomous hypotheses and models (which must be tested using macroevolutionary evidence). In this (epistemologically) very important sense, macroevolution is decoupled from microevolution: macroevolution is an autonomous field of evolutionary study."
      &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Francisco J. Ayala (1983)<ref>{{cite book |last=Ayala Francisco J |date=1983|name-list-style= and |editor-last1 = Asquith | editor-first1= Peter D|  editor-last2=Nickles|editor-first2= Thomas |title=PSA 1982 |volume=2|publisher=Philosophy of Science Association |pages=118–132 |chapter=Beyond Darwinism? The Challenge of Macroevolution to the Synthetic Theory of Evolution |isbn=}}</ref></blockquote>

Many scientists see macroevolution as a field of study rather than a distinct process that is similar to the process of  microevolution. Thus, macroevolution is concerned with the history of life and macroevolutionary explanations encompasses ecology, paleontology, mass extinctions, plate tectonics, and unique events such as the Cambrian explosion.<ref name = Levinton2001>{{ cite book | vauthors = Levinton Jeffrey S | date = 2001 | title = Genetics, Paleontology, and Macroevolution 2nd edition | publisher = Cambridge University Press | place = Cambridge, UK | isbn = 0-521-80317-9}}</ref><ref name="Rolland2022a"></ref><ref name="Simons2002a">{{cite journal |last1=Simons |first1=Andrew M. |title=The continuity of microevolution and macroevolution |journal=Journal of Evolutionary Biology |date=August 21, 2002 |volume=15 |issue=5 |pages=688–701 |doi=10.1046/j.1420-9101.2002.00437.x}}</ref><ref name="Erwin2001a">{{cite journal |last1=Erwin |first1=Douglas H. |title=Macroevolution is more than repeated rounds of microevolution |journal=Evolution & Development |date=December 24, 2001 |volume=2 |issue=2 |pages=78–84 |doi=10.1046/j.1525-142x.2000.00045.x|pmid=11258393 }}</ref><ref name="Adams1990a">{{cite journal |last1=Adams |first1=Mark B |title=Filipchenko [Philiptschenko], Iurii Aleksandrovich. |journal=Dictionary of Scientific Biography |date=1990 |volume=17 |issue=297–303 |url=https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/filipchenko-philiptschenko-iurii-aleksandrovich}}</ref><ref name="DAOAL1"></ref><ref name="Moran2022a">{{cite web |last1=Moran |first1=Laurence A. |title=Macroevolution |url=https://sandwalk.blogspot.com/2022/10/macroevolution.html |website=Sandwalk Blog |date=October 13, 2022}}</ref>

Within microevolution, the evolutionary process of changing heritable characteristics (e.g. changes in allele frequencies) is described by [[population genetics]], with mechanisms such as [[mutation]], [[natural selection]], and [[genetic drift]]. However, the scope of evolution can be expanded to higher scales where different observations are made. Macroevolutionary mechanisms are provided to explain these.<ref name=":0"></ref> For example, [[speciation]] can be discussed in terms of the ‘mode’, i.e. how speciation occurs. Different modes of speciation include [[sympatric]] and [[allopatric]]). Additionally, scientists research the 'tempo' of speciation, i.e. the rate at which species change genetically and/or morphologically. Classically, competing hypothesis for the tempo of specieation include [[phyletic gradualism]] and [[punctuated equilibrium]]). Lastly, what are the causes of speciation is also extensively researched.<ref name="Saupe2021a"></ref> 

More questions can be asked regarding the evolution of species and higher taxonomic groups ([[genera]], [[Family_(biology)|families]], [[Order_(biology)|orders]], etc), and how these have evolved across geography and vast spans of [[geological time]]. Such questions are researched from various fields of science. This makes the study of 'macroevolution' [[Interdisciplinarity|interdisciplinary]]. For example: 

* How different species are related to each other via common ancestry. This topic is researched in the field of [[phylogenetics]].
* The rates of evolutionary change and across time in the [[fossil record]].<ref name="Rolland2022a"></ref> Why do some groups experience a lot of change while others remain morphologically stable? The latter case are often called '[[living fossils]]'. However, this term is criticized for wrongly implying that such species have not evolved. The term 'stabilomorph' has been proposed instead.<ref name="Kin2014a">{{Cite journal|last1=Kin|first1=Adrian|last2=Błażejowski|first2=Błażej|date=2014-10-02|title=The Horseshoe Crab of the Genus Limulus: Living Fossil or Stabilomorph?|journal=PLOS ONE|language=en|volume=9|issue=10|pages=e108036|doi=10.1371/journal.pone.0108036|issn=1932-6203|pmc=4183490|pmid=25275563|bibcode=2014PLoSO...9j8036K|doi-access=free}}</ref>
* The impacts and causes of major events in [[palaeontological]] history, including [[mass extinctions]] and [[adaptive radiation|evolutionary diversifications]].<ref name="GEOL331a"></ref> Prominent examples of mass extinctions are the [[Permian-Triassic]] and [[End Cretaceous|Cretaceous-Paleogene]] events. In contrast, famous evolutionary radiations include the [[Cambrian Explosion]] and [[Cretaceous Terrestrial Revolution]].
* Why different species or high taxonomic groups (even in spite of having similar ages) exhibit different survival/extinction rates, [[species diversity]], and/or [[Phenotypic_disparity|morphological disparity]]. 
* The observation of long-term trends in evolution. Evolutionary trends can be passive (resembling diffusion) or driven (directional). A related question is whether these trends are directed in some way, e.g. towards complexity or simplicity.<ref name="Gregory2008a">{{cite journal |last1=Gregory |first1=T.R. |title=Evolutionary Trends |journal=Evo Edu Outreach |date=June 25, 2008 |volume=1 |issue=3 |pages=259–273 |doi=10.1007/s12052-008-0055-6 |issn=1936-6434|doi-access=free }}</ref> 
* How the distinctive and of complext traits, which differentiate species and higher taxa from another, have evolved. Examples of this include [[gene duplication]], [[heterochrony]], [[Evolutionary_developmental_biology#The_origins_of_novelty|novelty in evodevo]] from [[facilitated variation]], and [[constructive neutral evolution]].