Cradle of Life: Chapter 8

Chapter 8 of Cradle of Life might seem complicated at first, with a lot of names and concepts. It is not like that: once you start reading through its pages, you will soon understand that the whole chapter is centered around the concept of the very slow rate of evolution of Cyanobacteria.

What is the best way to approach this chapter? Here are some guidelines:

The first section, "Modes and Tempos in the Evolution of Life", introduces the student to the concepts of Neo-Darwinism and Standard Evolution. These pages outline the different speeds at which distinct species evolved during the Phanerozoic, as explained in the theories of G. G. Simpson
Among other things, Dr. Schopf points out that Simpson was not aware of the existence of the Precambrian record. He also outlines the differences between Simpson's time and today.
You need to know, among other things, what Simpson said, and what Schopf added to his ideas.
Dr. Schopf then explains why a new concept, hypobradytelism, needs to be introduced.
The discussion of this idea occurs mainly in the central pages of the chapter ("The Status Quo Evolution of Cyanobacteria", pages 215-231).
Read these pages in order to understand the scientific reasoning behind them. I will never ask you the name of the species, or the biological classification, as for instance the list of names of Fig. 8.3, p. 215. But you need to know what these pages are about. While the quiz on Chapter 8 and any question on the final exam will be focused on the previous and on the next section (numbered 1 and 3 in this list), expect a question out of this one too (number 2 in this list).
The third and last section, "Evolution's Most Successful Ecologic Generalists", completes the chapter. It explains how asexual reproduction adds to the two other reasons Simpson used to explain bradytelism (low rate of evolution), while still maintaining the idea that versatility is the most important cause for the lack of change in cyanobacteria. All this would explain hypobradytelism in cyanobacteria.
While you do not need to know the details of Fig. 8.14, p. 233, be sure to know this whole section well. Think of it as a summary of how cyanobacteria slowly took over and expanded throughout the world.

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