Tree of Life & Verge of Taxonomy
1859 was a golden year for biogenesis. Apart from Pasteur undermining “Spontaneous Generation”, Charles Darwin also published his groundbreaking book “On the Origin of Species”. The piece was successful at conceptualizing biogenesis into “Theory of Evolution”. According to evolutionary theory, the current diversity of life was generated by the living ancestors of the past. In the book, Darwin suggested that small variation in a species’ individuals’ distinguishing traits may be selected to diverge under different conditions. The divergence of traits may lead to the generation of new species or new groups of species (genus). Darwin illustrated the mode of life’s divergence as a branching tree of life (ToL) in his book.
This illustration of the branching tree of life which shows how life diversified, was the only illustration in The Origin of Species, Darwin, 1859
A classic example of natural selection’s capacity to shape different morphologies that also quite helped Darwin to establish his evolutionary theory came from Finches of Galapagos Islands during Darwin’s trip there. The morphological diversity of finches caused Darwin to not initially classify all finches that he collected during his trip as finches. Nevertheless, understanding that morphological differences of finches’ beaks were adaptations to different food sources on different Galapagos Islands led Darwin to think that all finches arose from a common ancestor that adapted to different food sources in different environments. The success of Darwin’s theory led other people to fizz with ideas to classify living organisms according to common morphological and behavioural traits or establishing novel ToLs. Classifying organisms according to common traits or similarities was an idea that was established by Carl Linnaeus in 1735, well before Darwin. Although the clades; animals, plants and minerals, where Linnaeus classified living are currently invalid, we still use the taxonomic ranking scale that he has once limited to kingdom, class, order, genus and species.
Darwin’s or Galapagos Finches, from The Voyage of Beagle, Darwin, 1845
