Foster's rule
Encyclopedia
Foster's rule is a principle in evolutionary biology stating that members of a species
get smaller or bigger depending on the resources available in the environment. This is the core of the study of island biogeography
. For example, it is known that pygmy mammoth
s evolved from normal mammoth
s on small island
s. Similar evolutionary paths have been observed in elephant
s, hippopotamus
es, boas, deer
, and human
s.
It was first stated by J. Bristol Foster in 1964 in the journal Nature
, in an article titled "The evolution of mammals on islands". In it, he studied 116 island species and compared them to their mainland varieties. He proposed that certain island creatures evolved into larger versions of themselves while others became smaller versions of themselves. For this, he proposed the simple explanation that smaller creatures get larger in the absence of the predators they had attracted on the mainland and larger creatures become smaller with the absence of food sources.
Later, that idea was expanded upon by the publication of The Theory of Island Biogeography
, by Robert MacArthur
and Edward O. Wilson. And in 1978, Ted J. Case published a much longer and more complex paper on the topic in the journal Ecology
. Case also demonstrated that Foster's original conjecture for the reason all this happened was oversimplified and not completely true.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
get smaller or bigger depending on the resources available in the environment. This is the core of the study of island biogeography
Island biogeography
Island biogeography is a field within biogeography that attempts to establish and explain the factors that affect the species richness of natural communities. The theory was developed to explain species richness of actual islands...
. For example, it is known that pygmy mammoth
Pygmy Mammoth
The Pygmy Mammoth or Channel Islands Mammoth is an extinct species of dwarf elephant descended from the Columbian mammoth . A case of island or insular dwarfism, M. exilis was only to tall at the shoulder and weighed about , in contrast to its tall, ancestor.Remains of M...
s evolved from normal mammoth
Mammoth
A mammoth is any species of the extinct genus Mammuthus. These proboscideans are members of Elephantidae, the family of elephants and mammoths, and close relatives of modern elephants. They were often equipped with long curved tusks and, in northern species, a covering of long hair...
s on small island
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...
s. Similar evolutionary paths have been observed in elephant
Elephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...
s, hippopotamus
Hippopotamus
The hippopotamus , or hippo, from the ancient Greek for "river horse" , is a large, mostly herbivorous mammal in sub-Saharan Africa, and one of only two extant species in the family Hippopotamidae After the elephant and rhinoceros, the hippopotamus is the third largest land mammal and the heaviest...
es, boas, deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...
, and human
Human
Humans are the only living species in the Homo genus...
s.
It was first stated by J. Bristol Foster in 1964 in the journal Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...
, in an article titled "The evolution of mammals on islands". In it, he studied 116 island species and compared them to their mainland varieties. He proposed that certain island creatures evolved into larger versions of themselves while others became smaller versions of themselves. For this, he proposed the simple explanation that smaller creatures get larger in the absence of the predators they had attracted on the mainland and larger creatures become smaller with the absence of food sources.
Later, that idea was expanded upon by the publication of The Theory of Island Biogeography
The Theory of Island Biogeography
The Theory of Island Biogeography is a 1967 book by Edward O. Wilson and Robert MacArthur which laid the foundations for the study of island biogeography. An edition with a new preface by Edward O. Wilson was published in 2001 ....
, by Robert MacArthur
Robert MacArthur
Robert Helmer MacArthur was an American ecologist who made a major impact on many areas of community and population ecology....
and Edward O. Wilson. And in 1978, Ted J. Case published a much longer and more complex paper on the topic in the journal Ecology
Ecology (journal)
Ecology is a scientific journal publishing research and synthesis papers in the field of ecology. It was founded in 1920, and is published by the Ecological Society of America.- External links :**...
. Case also demonstrated that Foster's original conjecture for the reason all this happened was oversimplified and not completely true.