The Tree of Life is Really a Network. Link to original article.
Central to Darwin's Theory is the "Tree of Life". The massive tree trunk represents simpler life forms such as amoebas, protozoans, and one-celled organisms, etc. The more complex organisms such as fish, birds and land mammals are represented by smaller branches at the top of the tree.
According to Graham Lawton in a 2009 article in New Scientist, Why Darwin was wrong about the tree of life, this "iconic concept of evolution, has turned out to be a figment of our imagination." Darwin's tree has been rendered obsolete by the discovery of Horizontal Gene Transfer. Instead of a tree, we have a new model represented by a network of inter-related life forms.
This isn't the only flaw in Darwin's theory. Since 1859 when Darwin wrote his theory evolution, there has been considerable progress in molecular biology. In 1953, the double-helix structure of DNA was elucidated by Watson and Crick. In 2003, the genetic code for the entire human genome was sequenced. These advances provoked a paradigm shift in thinking about evolution. Darwin's simple 19th-century Theory of Evolution required drastic revision in order to incorporate all this new knowledge.
The Evolution From Simple to More Complex
The idea of evolution of life from the simple to more complex is an old idea and can be found in ancient writings. Darwin's theory started with this concept and sought to explain the mechanism of evolution. Darwin's theory of evolution is the idea that over many generations, small incremental changes lead to emergence of entirely new species. This idea seemed plausible to professional animal breeders with extensive experience "breeding-in" desirable traits in their dogs, horses or livestock.
Darwin's idea was that "Mother Nature" would act in place of the professional animal breeder. Nature would select traits that provided survival advantage, and reject traits that impaired survival. Animals with better survival advantages would win the battle for reproduction. This is called "Natural Selection". In 1859, Charles Darwin then took the next step. He proposed Natural Selection as the mechanism for evolution.
To summarize Charles Darwin's theory of Evolution:
1) Random genetic mutations in the herd provide variation.
2) The genetic variants most adapted for survival will survive, while less adapted will not. This is called Natural Selection.
Questioning Natural Selection as the MechanismNatural Selection Replaced by Genetic Engineering
James A Shapiro at the University of Chicago proposes Genetic Engineering as the new mechanism for evolution. He says that genome change is a regulated biological function, and natural genetic engineering processes are subject to biological feedback at multiple levels. Here is his slide show about Natural ENGINEERING OF GENOME STRUCTURE by James A Shapiro.
Dr Shapiro says: "Cells have a large toolbox of biochemical systems that carry out genome restructuring at all levels of complexity."
James A Shapiro is author of the book, Evolution: A View from the 21st Century (left image cover)
Common Questions Raised by Darwin Dissenters: