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In 1847, Carl Bergmann published his observations that endothermic body size (i.e. mammals) increased with increasing latitude, commonly known as Bergmann's rule. [9] His rule postulated that selection favored within species individuals with larger body sizes in cooler temperatures because the total heat loss would be diminished through lower surface area to volume ratios. [8]
In other words, the maximum size increases, but the minimum size does not; this is usually a result of size varying pseudo-randomly rather than directed evolution. This does not fall into Cope's rule sensu stricto , but is considered by many workers to be an example of "Cope's rule sensu lato ". [ 15 ]
Size comparison of the giant gymnure (moonrat) Deinogalerix from the Late Miocene of Gargano, Italy, with a European hedgehog. Island gigantism, or insular gigantism, is a biological phenomenon in which the size of an animal species isolated on an island increases dramatically in comparison to its mainland relatives.
Garganornis ballmanni, a very large fossil goose from the Gargano and Scontrone islands of the Late Miocene. Foster's rule, also known as the island rule or the island effect, is an ecogeographical rule in evolutionary biology stating that members of a species get smaller or bigger depending on the resources available in the environment.
Many factors go into the determination of body mass and size for a given animal. These factors often affect body size on an evolutionary scale, but conditions such as availability of food and habitat size can act much more quickly on a species. Other examples include the following: Physiological design
At small spatial scales (e.g. a dozen hectares or a local community) the body size-species richness pattern dissolves and the number of species per body size class is almost uniform (i.e. there is an equal number of small and large bodied species in the community (see fig. 2 b)).
The species–area relationship or species–area curve describes the relationship between the area of a habitat, or of part of a habitat, and the number of species found within that area. Larger areas tend to contain larger numbers of species, and empirically, the relative numbers seem to follow systematic mathematical relationships. [ 1 ]
Much of past debate have focused on two particular types of mechanisms. [16] One of these assumes energy or resource transport across the external surface area of three-dimensional organisms is the key factor driving the relationship between metabolic rate and body size. The surface area in question may be skin, lungs, intestines, or, in the ...