Cope's Law

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The Copesche law states that there is in groups of living things in the course of evolution the tendency to increase in height. The assumption is based on fossil series from various groups. An example of this is the size comparison between the ancestral forms of horses (such as Hyracotherium with 20 centimeters shoulder height) and today's horses. Counterexamples are rare, the gradual reduction in height within amphibians should be mentioned .

The theory was founded by the American paleontologist Edward Drinker Cope (1840-1897).

Reason

One of the main reasons is inter- and intra-species competition. Larger animals dominate here over smaller animals. A large body also has more favorable metabolic conditions because the surface / volume ratio is smaller. Physiological processes and the heat balance are therefore more economical in large specimens (lower breathing and heart rates). Proof of this is the growth in size of species from cold areas compared to their relatives ( Bergmann's rule ). Many recent animal species are smaller than their Ice Age ancestors. An increase in size also enables a larger, more complex, interconnected brain. By increasing the lifespan and the gestation and youth, longer, individual learning processes and a buffer against fluctuations in living conditions arise.

Such advantages could provide advantages in natural selection for larger individuals .

Occupancy

A study of 17,208 species of marine animals over the last 542 million years showed that biomass has increased by a factor of around 150 since the Cambrian . During the same period, the minimum biomass decreased by a factor of less than 10, while the maximum biomass increased by a factor of more than 100,000. Neutral (undirected) drift from original small forms cannot explain this development.

criticism

The Copesche law was partially criticized. There are a number of counterexamples: for example, a decrease in size was more common than an increase in the mollusks of the Cretaceous , as was the case with some mammal genera during the strong warming phase of the Paleocene / Eocene temperature maximum . However, overall growth in size in the course of evolution is more frequent than decrease in size.

Conclusion

Although Cope's law is not generally applicable, it applies to most epochs of the development of marine animals.

See also

swell

Individual evidence

  1. ↑ Noel A. Heim, Matthew L. Knope, Ellen K. Schaal, Steve C. Wang, Jonathan L. Payne: Cope's rule in the evolution of marine animals . In: Science , Volume 347, No. 6224, February 20, 2015, pp. 867-870, doi : 10.1126 / science.1260065 .
  2. ↑ David WE Hone, Michael J. Benton : The evolution of large size: how does Cope's Rule work? . In: Trends in ecology and evolution . 20, No. 1, 2005, pp. 4-6. doi : 10.1016 / j.tree.2004.10.012 . PMID 16701331 .
  3. ↑ Stephen Jay Gould : Cope's rule as psychological artefact . In: Nature . 385, 1997, pp. 199-200. doi : 10.1038 / 385199a0 .
  4. ↑ D. Jablonski : Body-size evolution in Cretaceous molluscs and the status of Cope's rule. In: Nature. 385, 1997, pp. 250-252.
  5. ↑ Stephen GB Chester, Jonathan I. Bloch, Ross Secord, Doug M. Boyer: A New Small-Bodied Species of Palaeonictis (Creodonta, Oxyaenidae) from the Paleocene-Eocene Thermal Maximum . (PDF) In: Journal of Mammalian Evolution . 17, No. 4, December 2010, pp. 227-243. doi : 10.1007 / s10914-010-9141-y .