Daily Newsletter
September 7, 2012 Evolution Friday
As with most scientific thought, the theory of evolution has been fefined since it's first conception. This occurs as we learn more about organisms. For instance, Darwin did not have a valid hypothesis regarding how inheritence of characteristics occurred. He knew that we inherited characteristics from our parents (phenotypes), but not how this occurred. In his own words "[t]he laws governing inheritance are quite unknown...."1 This is not unusual. We may see a pattern in nature, but we are not yet be able to explain it. The observed pattern is a model that we can start with, but ultimately, we want to find a way of understanding the pattern.
In 1866, Gregor Mendel published his work on plant hybridization, which included his mathematical descriptions of inheritence. Historians have shown that Darwin was not aware of this work, and it did not have a significant impact at the time. His work was 'rediscovered' during the 1890's, and a publication by Hugo de Vries of his own work and subsequent credit to Mendel's initial work led people to being looking at the science we know know as genetics.
There was actually a vigous debate between Darwinians and Mendelians as to which system best represented evolution. This debate would continue for years. The work of Sir Ronald Aylmer Fisher, a British biologist and statistician, would be instrumental in combining the work of Darwin and Mendel, and their intellectual descendents, into a new system. Sir Fisher was also one of the pioneers of population genetics, a field of study instrumental in modern evolutionary thought. His book, The Genetical Theory of Natural Selection, published in 1930, is considered one of the foundations of modern evolutionary thought. (NOTE: There were other's working at this time on this issue, including Ernst Mayer, Theodosius Dobzhansky, and George Gaylord Simpson. Fisher is discussed in detail here as his work became a turning point in the discussion of evolution).
So, what is this modern evolutionary view?
Here are a few brief articles to look at:
- The Modern Synthesis of Genetics and Evolution
- The Modern Synthesis: A Historical Approach
- Evolution Is Change in the Inherited Traits of a Population through Successive Generations
Daily Challenge
Read the articles above, and discuss the formation and refinement of scientific theories, specifically as it relates to evolution. One a hypothesis becomes a theory, is it set in stone? If we learn something new, does it over turn a theory, or could it explain something we previously didn't know? Is debate among experts useful in refining theories? Are we still refining the theory of evolution?Additonally, what are the "main" points (concepts) of the modern theory of evolution?
Link to Forum
Reference
The reference below is linked to an online copy of the book. While not required, it is a book all biology students are encouraged to read at some point.1. Darwin, C. R. 1859. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. [1st edition]
