Biological rules

Biological rules and laws are often developed as succinct, broadly applicable ways to explain complex phenomena or salient observations about the ecology and biogeographical distributions of plant and animal species around the world, though they have been proposed for or extended to all types of organisms.

[1][2] From the birth of their science, biologists have sought to explain apparent regularities in observational data.

In his biology, Aristotle inferred rules governing differences between live-bearing tetrapods (in modern terms, terrestrial placental mammals).

[3] Rules like these concisely organized the sum of knowledge obtained by early scientific measurements of the natural world, and could be used as models to predict future observations.

Among the earliest biological rules in modern times are those of Karl Ernst von Baer (from 1828 onwards) on embryonic development (see von Baer's laws),[4] and of Constantin Wilhelm Lambert Gloger on animal pigmentation, in 1833 (see Gloger's rule).

The pygmy mammoth is an example of insular dwarfism , a case of Foster's rule , its unusually small body size an adaptation to the limited resources of its island home.
Bergmann's rule states that body mass increases with colder climate, as here in Swedish moose . [ 7 ]
Dollo's law of irreversibility asserts that once an organism has evolved in a certain way, it will not return exactly to a previous form.
Emery's rule states that insect social parasites like cuckoo bumblebees choose closely related hosts, in this case other bumblebees .
Lack's principle matches clutch size to the largest number of young the parents can feed