Microevolution
With Microevolution that is evolutionary development means of living beings, which within a biological kind takes place, and thus within a short in evolutionary terms period. It is smaller changes caused by mutations , recombinations and selection processes to an altered morphology or physiology of organisms cause. These changes are caused by the change in the allele frequencies of the population, "such a change in the genetic structure of a population is called microevolution."
Origin of the term
The term microevolution was first published by the botanist Robert Greenleaf Leavitt in the journal Botanical Gazette in 1909. In it he described how, for example, formlessness is transformed into form , which he called mystery .
... The production of form from formlessness in the egg-derived individual, the multiplication of parts and the orderly creation of diversity among them, in an actual evolution, of which anyone may ascertain the facts, but of which no one has dissipated the mystery in any significant measure. This microevolution forms an integral part of the grand evolution problem and lies at the base of it, so that we shall have to understand the minor process before we can thoroughly comprehend the more general one ...
“ ... The creation of shape from shapelessness in the individual determined by the egg, the multiplication of parts and the orderly multiplication of parts in a development of which everyone can confirm the facts, but of which no one has solved the riddle in a significant way. This microevolution is an integral part of the great problem of evolution and forms its basis. We have to understand the smaller process first before we can understand the general process more deeply ... "
Leavitt used the term for what is now called developmental biology . Only the Russian entomologist Yuri Filipchenko used the terms "macroevolution" and "microevolution" in 1927 in his German work, "Variability and Variation" by which they then acquired the modern meaning. The term was introduced to the English-speaking world by Theodosius Dobzhansky in his book Genetics and the Origin of Species (1937).
Delimitations
The use of the terms “microevolution” and “ macroevolution ” is controversial today. Some evolutionary biologists avoid both terms with the argument that they are based on the same facts: "macroevolutionary" processes are merely a temporal summation of "microevolutionary" processes, the subdivision is thus artificial and fuzzy. Others, such as Stephen Jay Gould , use the terms because they are of the opinion that, in addition to the same processes that are responsible for microevolution, selection processes at the species level are also essential for the dynamics of macroevolution . This subdivision is also used in creationism and intelligent design . Microevolution is accepted in connection with breeding or the development of resistance and thus as part of the doctrine of creation. Microevolution is seen as species formation which consists of selection and thus impoverishment of the gene pool of the basic type . Forms of mutation, which in principle expand the genetic makeup, are classified under macroevolution.
Examples
Examples of microevolution are
- the increased occurrence of a dark variant of the moth in English industrial areas, also known as industrial melanism , since the 19th century ;
- Development of resistance of microorganisms to antibiotics ;
- Changes in beak size in Darwin's finches .
See also
supporting documents
- ↑ Joachim Jaenicke / Andreas Paul (eds.), Discovering Biology Today SII, 2004 edition for secondary level II, Schroedel Verlag 2005.
- ↑ Leavitt, Robert Botanical Gazette 1909 vol. 47 no.1 January A Vegetative Mutant, and the Principle of Homoeosis in Plants http://www.jstor.org/pss/2466778