Macro evolution

from Wikipedia, the free encyclopedia

Macroevolution in the modern sense denotes evolution through selection based on inter-species variation, in contrast to evolutionary changes through selection based on intra-species variation in microevolution . This modern view contrasts with the original concept, which defined macroevolution as the evolution of taxa above the species level.

Origin and change of meaning of the term

Philipchenko differentiated between macro- and microevolution because he assumed that natural selection in the sense of Darwin could not be the cause of the larger evolutionary steps from which taxa above the species level in the Linnean taxonomy emerge. He therefore differentiated between microevolution as evolution in the Darwinian sense, which could at most lead to the formation of races or subspecies within species, and macroevolution, which crossed the species boundary through unknown evolutionary mechanisms. One explanatory model for macroevolution in this sense was the concept of the "hopeful monsters" by geneticist Richard Goldschmidt , who assumed volatile evolution through genetic changes that either affect the timing of ontogenetic development or changed the entire chromosome pattern. The latter hypothesis in particular was categorically rejected by representatives of the synthetic theory of evolution and is now considered to be refuted. In contrast, the idea of ​​volatile evolution through changes in gene regulation processes is experiencing a certain renaissance in the area of evolutionary developmental biology . As an alternative to volatile evolution, Dobzhansky suggested that the difference between macro- and microevolution is actually only a difference on a temporal scale. According to this, macroevolution is simply the sum of microevolutive changes over geological time periods. This view quickly became popular and formed the basis of a new view that used the term macroevolution as a neutral label for the study of evolution over long periods of time. The reducibility of macroevolution to the sum of microevolutive changes has been called into question since the 1970s, especially by the evolving concept of species selection, which assumes that selection based on inter-species variability is an essential evolutionary factor that acts independently and in addition to selection between organisms. The level at which selection takes place thus became the basis for a redefinition of macroevolution. Accordingly, macroevolution is the part of evolution that occurs through selection between species, as opposed to microevolution, which is based on selection between organisms of the same species.

Macroevolutionary Processes

Speciation

According to the modern definition, the evolutionary transition between mother and daughter species is microevolutive because it occurs through selection between individuals of the same species. However, speciation also has a macro-evolutionary aspect, as it creates the inter-species variation on which selection takes place in the macro-evolutionary level. Likewise, the speciation rate can be viewed as a macro-evolutionary parameter, analogous to the reproductive success on a micro-evolutionary level.

Species selection

The raw material for species selection is the inter-species variation provided by the largely random process of speciation. Species selection favors species that have a high speciation rate and exist for a long time and can therefore produce many daughter species. A distinction is made between “effect macroevolution”, which is based on organismic characteristics that have an impact on the survival time and speciation rate of species, and macroevolution in the narrower sense, which is based on emergent species characteristics, i.e. characteristics that only manifest themselves at the species level, but do not represent any organismic properties (e.g. gender ratio or geographical distribution).

Punctuated equilibrium

The theory of punctuated equilibrium (also called punctualism ) postulates that evolutionary change is concentrated in the geologically short speciation phase, followed by the evolutionary stasis of the species until they become extinct. The prevalence of evolutionary stasis during the vast majority of species' existence is a strong argument for the dominance of species selection and macroevolution in the long-term evolution of phylogenetic branches. However, punctuated equilibrium is neither a macroevolutive form of species development, as is sometimes wrongly claimed (e.g. in), nor is it a prerequisite for species selection. Ernst Mayr, as a representative of the classical synthetic theory of evolution, considers the point theory to be essentially compatible with it. One possible explanation for the finding is his own hypothesis that new species emerge above all in isolated populations on the edge of the distribution of common species, so that after they have spread from there, they would appear almost everywhere suddenly and suddenly in the fossil record.

Examples

Evolutionary Faunas

Analyzes of marine biodiversity by the Phanerozoic have shown that different higher taxa have replaced each other in their relative importance over the course of the earth's history. It could Jack Sepkoski summarize them in three groups ( "Evolutionary faunas"), followed by the time-series and distinguished by increasing equilibrium diversities and decreasing diversification rates. The study is remarkable insofar as the evolutionary success is not directly attributed to organismic properties, but to macro-evolutionary parameters.

Mass extinction events

The macroevolutive significance of environmental changes is particularly evident in global mass extinction events . Such events are mostly due to changes in the non-biological environment that occur too quickly to allow microevolutive adaptation through adaptations. Mass extinction events therefore have an effect almost exclusively through species selection, i.e. macroevolutionary. Since they are mostly highly selective, i. H. affect certain taxa more than others, they add a significant non-adaptive component to evolution. A classic example in this context is the increase in mussel diversity at the expense of the brachiopods, possibly due to a corresponding selectivity of the end-Permian mass extinction event.

Stanley's rule

Macroevolution is controlled by speciation and extinction advice. Empirical data show that both parameters are positively correlated: Taxa that show high speciation rates usually also have high extinction rates. This rule was first described by Steven Stanley, who attributed it to a number of environmental factors. However, a positive correlation between speciation and extinction rates is also a prediction of the Red Queen Hypothesis , which postulates that every increase in fitness in one species (or due to a speciation event ) causes a corresponding decrease in fitness in other species, which leads to the Extinction of species that do not adapt quickly enough. Therefore, high speciation rates must correlate with high extinction rates, at least if the premise of niche conservatism is met. Stanley's rule, which applies to almost all higher taxa and geological times, is therefore a strong argument for the importance of inter-species competition in macroevolution.

literature

Individual evidence

  1. ↑ a b c S. M. Stanley: A theory of evolution above the species level . In: Proceedings of the National Academy of Sciences . tape 72 , no. 2 , February 1, 1975, ISSN  0027-8424 , p. 646–650 , doi : 10.1073 / pnas.72.2.646 , PMID 1054846 , PMC 432371 (free full text) - ( pnas.org [accessed May 5, 2020]).
  2. ^ A b Gould, Stephen Jay: The structure of evolutionary theory . The >> Belknap Press of Harvard University Press, 2002, ISBN 0-674-00613-5 ( worldcat.org [accessed May 5, 2020]).
  3. ↑ a b c d Michael Hautmann: What is macroevolution? In: Palaeontology . tape 63 , no. 1 , January 2020, ISSN  0031-0239 , p. 1–11 , doi : 10.1111 / pala.12465 ( wiley.com [accessed May 5, 2020]).
  4. ↑ a b Philipchenko, Juri: variability and variation . Bornträger, Berlin 1927.
  5. ↑ R. Goldschmidt: SOME ASPECTS OF EVOLUTION . In: Science . tape 78 , no. 2033 , December 15, 1933, ISSN  0036-8075 , p. 539–547 , doi : 10.1126 / science.78.2033.539 ( sciencemag.org [accessed May 5, 2020]).
  6. ^ Goldschmidt, Richard: The material basis of evolution . Yale University Press, 1940, ISBN 0-300-02822-9 ( worldcat.org [accessed May 5, 2020]).
  7. ^ Günter Theißen: Saltational evolution: hopeful monsters are here to stay . In: Theory in Biosciences . tape 128 , no. 1 , March 2009, ISSN  1431-7613 , p. 43–51 , doi : 10.1007 / s12064-009-0058-z ( springer.com [accessed May 5, 2020]).
  8. ^ Rieppel, Olivier: Turtles as hopeful monsters: origins and evolution . Bloomington, Indiana, ISBN 978-0-253-02507-4 (oclc / 962141060 [accessed May 5, 2020]).
  9. ↑ Dobzhanski, T .: Genetics and the origin of species . Columbia University Press, 1937.
  10. ^ A b David Jablonski: Species Selection: Theory and Data . In: Annual Review of Ecology, Evolution, and Systematics . tape 39 , no. 1 , December 2008, ISSN  1543-592X , p. 501-524 , doi : 10.1146 / annurev.ecolsys.39.110707.173510 ( annualreviews.org [accessed May 5, 2020]).
  11. ↑ Stephen Jay Gould, Niles Eldredge: Punctuated equilibria: the tempo and mode of evolution reconsidered . In: Paleobiology . tape 3 , no. 2 , 1977, ISSN  0094-8373 , pp. 115–151 , doi : 10.1017 / S0094837300005224 ( cambridge.org [accessed May 5, 2020]).
  12. ↑ Hopi E. Hoekstra, Jerry A. Coyne: THE LOCUS OF EVOLUTION: EVO DEVO AND THE GENETICS OF ADAPTATION: THE LOCUS OF EVOLUTION . In: evolution . tape 61 , no. 5 , May 2007, pp. 995-1016 , doi : 10.1111 / j.1558-5646.2007.00105.x ( wiley.com [accessed May 5, 2020]).
  13. ^ Ernst Mayr (1989): Speciational evolution or punctuated equilibria. Journal of Social and Biological Structures 12 (2/3): 137-158. doi: 10.1016 / 0140-1750 (89) 90041-9
  14. ^ J. John Sepkoski: A kinetic model of Phanerozoic taxonomic diversity. III. Post-Paleozoic families and mass extinctions . In: Paleobiology . tape 10 , no. 2 , 1984, ISSN  0094-8373 , pp. 246-267 , doi : 10.1017 / S0094837300008186 ( cambridge.org [accessed May 6, 2020]).
  15. ↑ Stephen Jay Gould: The paradox of the first tier: an agenda for paleobiology . In: Paleobiology . tape 11 , no. 1 , 1985, ISSN  0094-8373 , pp. 2–12 , doi : 10.1017 / S0094837300011350 ( cambridge.org [accessed May 6, 2020]).
  16. ↑ Stephen Jay Gould, C. Bradford Calloway: Clams and brachiopods — ships that pass in the night . In: Paleobiology . tape 6 , no. 4 , 1980, ISSN  0094-8373 , pp. 383-396 , doi : 10.1017 / S0094837300003572 ( cambridge.org [accessed May 6, 2020]).
  17. ^ Stanley, Steven M .: Macroevolution, Pattern and Process . WH Freeman, San Francisco 1979, ISBN 0-7167-1092-7 (oclc / 5101557 [accessed May 6, 2020]).
  18. ^ Van Valen, L .: A new evolutionary law . In: Evolutionary Theory . tape 1 , 1973, p. 1 - 30 .

Web links