Cope's rule

The Copesche law states that there is in groups of organisms over the course of evolution, the tendency to increase in body size. The assumption is based on fossil series of diverse groups. An example of this is the size comparison between the parental forms of horse ( Hyracotherium with about 20 inches at the withers) and today's horses. Counter-examples are rare, mention would be the gradual reduction of body size within the amphibians.

Founder of the theory was the American paleontologist Edward Drinker Cope ( 1840-1897 ).

Reasons for growth in size

One of the main reasons is between - and intraspecific competition. Larger animals dominate this on smaller animals. A large body also has favorable metabolic conditions because the surface / volume ratio is smaller. Physiological processes and the heat balance therefore run in large specimens from economic (lower breathing and heart rate). Evidence of this is the size growth of species from cold areas compared to their relatives ( Bergmann rule). Many extant species are smaller than their Pleistocene ancestors. An increase in size also allows for a larger, more complex verschaltetes brain. By increasing the service life and the support and youth results in longer, individual learning processes and a buffer against variation in living conditions.

Such advantages could give individuals greater advantages in natural selection.

Criticism

The Copesche law is criticized. There are a number of counter-examples: So when the mollusks of the Cretaceous period, a reduction in size was more common than an increase in size. Growth in size in the course of evolution, however, is more common than total size decrease. The rule, however, is therefore not universally applicable.

Swell

• Wilfried West Heath, Reinhard Rieger: Systematic Zoology. Volume 2: vertebrae or skull animals. Spektrum Akademischer Verlag, Heidelberg, inter alia, 2004, ISBN 3-8274-0900-4, pp. 549-553.

• Evolution