Chris' Original Blogbeque

A fresh, vinegar-based examination of life

Darwin’s Tree of Life Diagram

Posted by Chris on April 18, 2010

Before reading, you may want to read my introduction which includes why I’m reading The Origin of Species, my scientific beliefs about evolution, and my theological beliefs about creation.  Also, click the category listed below the post for related posts.


The accompanying diagram will aid us in understanding this rather perplexing subject.  Let A to L represent the species of a genus large in its own country; these species are supposed to resemble each other in unequal degrees, as is so generally the case in nature… The little fan of diverging dotted lines of unequal lengths proceeding from (A) may represent its varying offspring [Chris’ note: those going from bottom to top of the diagram]… When a dotted line reaches one of the horizontal lines, and is there marked by a small numbered letter, a sufficient amount of variation is supposed to have been accumulated to have formed a fairly well-marked variety.

OK.  This post is going to be all technical, not philosophical, because one of my primary intellectual reasons for reading the book was addressed by Darwin in this section and diagram.  This diagram shows how 11 unique species, over time, would evolve into 15 species (all different from the first 11).  Darwin believed extinction was an inevitable byproduct of natural selection.

In my introduction, I said that one of my intellectual obstacles with macro-evolution is how life evolved not within a genus into different species but within kingdoms and even the development from one-celled organisms to more complex creatures.  This chart and Darwin’s writing sort of helped answer that question.  The visual was helpful for grasping inter-genus evolution… but I already said that I could buy that– now I could explain it better.

Darwin says that scale is the key.  Let each horizontal line equal 1000 generations and at each line perhaps you have new varieties of a species, or even new species. After 14,000 generations “species are multiplied and genera are formed.”

Darwin also believes that the most distinct varieties survive.  Thus, it is not a coincidence that he chose the species that were at the extreme ends of the diagram to have the most evolved descendants.  If the extremes are selected and then their extremes selected and etc… that would speed up evolution and help explain incomprehensible changes.  These new species at the end of 14,000 generations differ much more from one another than the original 11, therefore meriting classification as more than one genus.

In this chapter, Darwin does not yet make the jump to large-scale evolution apologetics which I am expecting.  If this is it, I will be disappointed– I understand that he believes it’s the same idea, just taken to scale– but it’s so hard to believe!  I mean, seriously– it takes a lot of imagination.  Not in the sense that evolution is “made up”, but it is so beyond the human mind.  It would take faith for me at this point, something I’m not willing to give to this theory.

Yet in the summary following the chapter, Darwin sort of makes the jump– but with little explanation.  From a literary perspective, I was really surprised– had I missed something in his argument? From the summary:

It is a truly wonderful fact… that all animals and all plants throughout all time and space should be related to each other in group subordinate to group.

Wwww-wh-what?  He is very confident.  I expected a lot of sincere appeal and intellectual argumentation to precede this assertion in the book.  After all, wouldn’t most people at that time have rejected his findings?  Didn’t he expect intellectual attack?  I’ll have to assume that more explanation follows.


One Response to “Darwin’s Tree of Life Diagram”

  1. […] (RSS) « Darwin’s Tree of Life Diagram Bonhoeffer on Darwinism […]

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