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the tree of life I have seen several versions of the tree of life, some of them visually appealing, some rather elaborated (like in The Variety of Life by Colin Tudge, 2000). True, until recently, I was only glancing at them but when I engaged myself into ‘reading’ them - the circular phylogenetic tree I found the easiest to follow. As an example, below is a some- what limited circular tree, for the major groups of life species only, from Paleontology, A Brief History of Life by Ian Tattersall (2010); as I understand the diagram is originally published in Human Origins by R. DeSalle and I. Tattersall (2008). Additionally, I’ve traced the evolutionary path for mammals on the rollover image. The more detailed circular tree of life you can see, for instance, at |
from Paleontology by Ian Tattersall (2010) Because of the branching nature of evolution, the history of life can be represented by a tree-like diagram, in which every species, living and extinct, takes its place at the tip of a peripheral twig. Those twigs are in turn assembled into ever-larger branches that reflect the descent of increasingly inclusive groups from ever-more-remote common ancestors. Diagrams of this kind do not have to take the form of a typical slen- der tree, with a central trunk soaring toward its highest tip. Indeed, they should not. It turns out that one of the most economical ways of representing an evolutionary tree is in form of a circle, as in the figure below, which shows the relationship between the great sub- divisions of life as they are understood today. Here the hypothetical ancestor lies in the center, and the individual branch tips are all of equal importance - emphasizing that, while evolution promotes diversity. it does not inexorably lead toward more complex states, and certainly not at uniform rates. |
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