Panorama of Fractals and Their Uses

Ammonite Sutures

Another explanation has been put forward by Stephen Jay Gould. Gould noted some complications with the standard interpretation.

*	Most lineages of ammonites contain species with low-dimensional sutures throughout their histories.
*	Examining the descendants of a given ancestor, no bias to higher suture dimension was observed.
*	No correlation was observed between the suture dimension and the longevity of a species.

Gould asserts the drift to higher dimensions is a left wall phenomenon.

Because the dimension of a curve is at least 1, random genetic drift cannot push the suture dimension lower; all it can do is increase (or stay the same).

Gould carries this point further and argues the controversial view that

there is no evolutionary drive to greater complexity, that the effects we observe are all left wall phenomena.

How does Gould support this view?

The first life on Earth was bacteria. Click for the next picture.

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