What makes up modern synthesis

The growth of biological thought. Diversity, evolution, and inheritance. A synthetic work of intellectual history placing Darwin, his theory, and evolutionary biology at the center of the biological sciences by one of the major figures in the modern synthesis of evolution. Ruse, Michael. Monad to man. The concept of progress in evolutionary biology. Examines how evolutionary progress has undergirded evolutionary theory from Darwin to more recent evolutionary thinkers.

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For more information or to contact an Oxford Sales Representative click here. Not a member? Sign up for My OBO. Already a member? Publications Pages Publications Pages. Subscriber sign in You could not be signed in, please check and try again. Username Please enter your Username. Password Please enter your Password. Forgot password? Don't have an account? Sign in via your Institution. Dobzhansky noted the arrangements of chromosomes in different Drosophila species as well as their mutation rates.

In his book Genetics and the Origin of Species , published in , Dobzhansky argued that genetic mutations were sources of variability that, through natural selection, could lead to evolutionary change, and he suggested that these processes could lead to speciation of populations that are isolated long enough.

Dobzhansky published updated versions of his book for decades; the last version, released in , bore the title Genetics of the Evolutionary Process. By then the structure of DNA had been discovered, and he was able to revise his ideas to include the molecular basis of genetic mutations.

C hia-Yi Hou is a freelance science writer. COM, stockstudioX W hen Charles Darwin published On the Origin of Species in , he suggested that traits could be inherited, and that natural selection could affect which traits were passed down. Haldane , and Sewall Wright provided critical contributions. In Fisher produced the paper The Correlation Between Relatives on the Supposition of Mendelian Inheritance , [9] which showed how the continuous variation measured by the biometricians could be the result of the action of many discrete genetic loci.

In this and subsequent papers culminating in his book Genetical Theory of Natural Selection Fisher was able to show how Mendelian genetics was consistent with the main elements of neo-Darwinism.

Haldane applied mathematical analysis to real world examples of natural selection such as the evolution of industrial melanism in peppered moths. Sewall Wright focused on combinations of genes that interacted as complexes, and the effects of inbreeding on small relatively isolated populations, which could exhibit genetic drift.

In a paper he introduced the concept of an adaptive landscape in which phenomena such as cross breeding and genetic drift in small populations could push them away from adaptive peaks, which would in turn allow natural selection to push them towards new adaptive peaks.

This is the precursor of the modern synthesis, which is an even broader coalition of ideas. Theodosius Dobzhansky , a Russian emigre who had been a postdoctoral worker in Morgan's fruit fly lab, was one of the first to apply genetics to natural populations. He worked mostly with Drosophila pseudoobscura. He says pointedly: "Russia has a variety of climates from the Arctic to sub-tropical Exclusively laboratory workers who neither possess nor wish to have any knowledge of living beings in nature were and are in a minority".

His work Genetics and the Origin of Species was a key step in bridging the gap between population geneticists and field naturalists. It presented the conclusions reached by Fisher, Haldane, and especially Wright in their highly mathematical papers in a form that was easily accessible to others. It also emphasized that real world populations had far more genetic variability than the early population geneticists had assumed in their models, and that genetically distinct sub-populations were important.

Dobzhansky argued that natural selection worked to maintain genetic diversity as well as driving change. Dobzhansky had been influenced by his exposure in the s to the work of a Russian geneticist named Sergei Chetverikov who had looked at the role of recessive genes in maintaining a reservoir of genetic variability in a population before his work was shut down by the rise of Lysenkoism in the Soviet Union.

Ernst Mayr 's key contribution to the synthesis was Systematics and the Origin of Species , published in Mayr emphasized the importance of allopatric speciation , where geographically isolated sub-populations diverge so far that reproductive isolation occurs. He was sceptical of the reality of sympatric speciation believing that geographical isolation was a prerequisite for building up intrinsic reproductive isolating mechanisms.

Mayr also introduced the biological species concept that defined a species as a group of interbreeding or potentially interbreeding populations that were reproductively isolated from all other populations. In the s Rensch, who like Mayr did field work in Indonesia, analyzed the geographic distribution of polytypic species and complexes of closely related species paying particular attention to how variations between different populations correlated with local environmental factors such as differences in climate.

In Rensch would write a book, eventually translated into English under the title Evoluton above the species level , that looked at how the same evolutionary mechanisms involved in speciation might be extended to explain the origins of the differences between the higher level taxa. His writings contributed to the rapid acceptance of the synthesis in Germany. George Gaylord Simpson was responsible for showing that the modern synthesis was compatible with paleontology in his book Tempo and Mode in Evolution published in Simpson's work was crucial because so many paleontologists had disagreed, in some cases vigorously, with the idea that natural selection was the main mechanism of evolution.

It showed that the trends of linear progression in for example the evolution of the horse that earlier paleontologists had used as support for neo-Lamarckism and orthogenesis did not hold up under careful examination. Instead the fossil record was consistent with the irregular, branching, and non-directional pattern predicted by the modern synthesis. The botanist G. Ledyard Stebbins was another major contributor to the synthesis.

His major work, Variation and Evolution in Plants , was published in