Introduction to evolution

A biological theory of evolution describes and explains the origin and variation of species as a result of the evolution of organisms, that is a real historical process of development which has occurred and is continuing. Jean -Baptiste de Lamarck in 1809 proposed the concept of species change; he was one of the first evolutionary theorist, but Lamarck was falsely of the inheritance of acquired properties. The anatomist Georges Cuvier supplemented by the study of fossils the realization that the blueprints of living things are related and can die that living things.

The development of the Lamarckian theory of evolution succeeded thirty years later (1838 ) Charles Darwin and another twenty years later ( 1858), Alfred Russel Wallace. Both works, which are now known as Darwin's theory of evolution arose independently, as Darwin his work for twenty years unpublished. The main differences with respect to the question of how closely the impacts of various factors of evolution and which are determinative. Biological evolution explain both by the better adaptation of organisms to their environment and, associated with a gradual increase of complexity ( higher development and building transformations ).

Darwin's theory of evolution has been supplemented by findings from various sub-disciplines of biology such as paleontology, genetics, morphology, anatomy, cell biology, biochemistry, behavioral biology, ecology, biogeography and developmental biology and on. The theory of evolution to the common origin of all life is integrated therein.

All modern disciplines of biology complement other aspects of the theory of evolution and complete the findings on the evolution of life, since this issue affects all biological disciplines. The evolutionary biologist Theodosius Dobzhansky formulated the 1973 summary with the sentence:

" Nothing in Biology makes sense, except in the light of evolution. "

"Nothing in biology makes sense except in the light of evolution. "

Identifiable individual theories

The following theories of biological evolution are distinguished from each other:

• Catastrophism ( historical ), extinction of species by disasters
• Lamarckian theory of evolution ( historical ), adjustment by use or disuse
• Darwinian theory of evolution, adaptation by selection
• Synthetic theory of evolution
• Systems theory of evolution
• Frankfurt 's theory of evolution, living organisms are considered as energy conversion, hydraulic machinery

Scientific discourse is concerned today mainly with the details and the conditions of evolution factors to which the diversity of species can be traced back. The discussed theories of evolution are based on the following common principles:

• Evolution has taken place, and continues to be explored.
• Evolution is not reversible ( Dollosches Act), that is, individual structures or services can copy old states, but the underlying genes have not the same structure ( see also the vague term re-evolution ).
• Evolution is directionless, ie, not on an end goal or final end directed ( no final cause ).
• Evolution works on all levels of organisms: from molecular structures to the ecosystem.

From the theories share the following hypotheses can be derived:

• The individual living entities (phenotype ) of a population (species ) are always well adapted differently to the environment.
• An evolution ( development ) takes place when properties of living things are heritable, that is, by a generation of parents transmitted to their offspring and are thus obtained in the population.
• Due to the constantly acting environmental influences, a selection of certain individual living beings and thus genetic blueprints ( genotypes) that prevail in a population of organisms of a species that is temporally spatially genotype and phenotype change.

While existed in the early days of the development of various explanatory theories of evolution in the 19th century on the form of conservation and the mode of transmission of phenotypic properties and the inheritance of the offspring ( acquired characteristics or heredity ) among researchers disagreements, there is now general agreement that these over the gene takes place in the nucleus and mitochondria. In addition, maternal and paternal effects are discussed. However, there are several possible locations of the selection ( "Environment" ) is different appropriate phenotypic characteristics: due to the competition of different genes already in the genome, in gene expression during embryonic development due to structural constraints in the context of predator-prey relationships and because of cultural phenomena in populations. Furthermore, the tectonic plates symbiogenesis and dynamic processes which have the evolution of organisms significantly advanced.

Historical Summary

Vague ideas about evolution, such as the common descent and the conversion of species, there were at least since the 6th century BC, where they were represented by the Greek philosopher Anaximander. A greater diversity of such concepts was developed in the 18th century, and 1809 Jean- Baptiste de Lamarck postulated that species transformation, as well as the view that this transformation of species occurs through inheritance of adaptations, which acquire the parents during their life ( Lamarckism ). These ideas were seen as a threat to the political and religious order in England and violently attacked by the scientific establishment.

These social resistances prevented Charles Darwin 1838-1858 with the publication of his findings until 1858, he presented together with Alfred Russel Wallace two different works on the theory of evolution by natural selection in the Linnean Society of London. This publication has received little attention, but in 1859 published by Darwin 's book The Origin of Species explained the theory system in great detail and resulted in the expected social and ecclesiastical dispute. Darwin's specific theories to evolution, such as gradualism and natural selection, initially met with considerable resistance. Lamarckists argued that characteristics are acquired through training and not through a selection process. However, since all experiments for the detection of " Lamarckism " failed, this theory was in favor of " Darwinism " dropped. In the following years, a growing acceptance of Darwin's theory of evolution developed.

However, Darwin could not explain how traits are passed from generation to generation and why variations of these characteristics are not mixed through inheritance. The mechanism for this was not delivered until 1865 by Gregor Mendel, whose research laid open, that certain characteristics are inherited in a well-defined and predictable manner.

Mendel's work remained more than three decades largely unnoticed. When they were rediscovered in 1900, resulted in different predictions of the first geneticists and biostatisticians in the speed of evolution to a deep rift between the Mendelian and Darwinian model of evolution, Mendel occupied experiments but an apparent constancy of inherited characteristics. This has formed an opposition to the variability of species in the Darwinian theory of evolution, which was only resolved in the 1930s, including through the work of biologists such as Ronald Fisher. The result was a combination of Darwin Wallace'schen natural selection with Mendelian inheritance rules, the synthetic theory of evolution. It is incorrectly referred to as neo-Darwinism. Ernst Mayr, inter alia, extended it to findings from other scientific areas, especially population biology. Synthetic theory has since been constantly expanded, first to the DNA as a carrier molecule of the genetic material by Oswald Avery in 1944. Nearly a decade later, James Watson and Francis Crick explained by deciphering the molecular structure of DNA in 1953, the operation and thus the physical basis of heredity. Since then, genetics and molecular biology central to evolutionary biology.

Notwithstanding the coherent addition of all biological disciplines the theory of evolution is rejected in its entirety, especially in the United States by Christian fundamentalists (see creationism ). Most Christian churches in Europe recognize the theory of evolution on the other hand (see theistic evolution ). For example, the Roman Catholic Church declared in a message from Pope John Paul II on 23 October 1996, the compatibility with the Christian faith.

Systems theory of evolution and the theory of evolution Frankfurt are alternative concepts.