Monday, May 12, 2014

Book- John Tyler Bonner- Randomness In Evolution

This book is surely worth reading. Randomness in Evolution by John Tyler Bonner. I have loved Bonner's  previous books The Evolution of Complexity and Life Cycles. This promises to be interesting too.

In Current Science Raghavendra Gadagkar gives a positive review. The main premise of the book is that morphologies of unicellular eukaryotes like radiolarians and diatoms to give two examples are neutral phenotypes. That means that the variation of size, shape, ornamentation on skeletal material did not become common because it contributed to reproductive fitness. Rather for example different shapes were selectively neutral i.e. that is they neither gave the organism any advantage over another shape nor a disadvantage. One of the shapes became common just by chance, through random genetic drift.

Size according to Bonner is an important constraint on whether natural selection or drift becomes important in shaping morphology. Randomness is more important in small organisms with relatively simple genetic controls on morphology, while natural selection is more important in larger organisms with elaborate interlocking developmental steps.

I'll reserve comments until I have read the book but just would like to point out that even small unicellular eukaryotes have very sophisticated cellular machinery for processes like photosynthesis and regulating cellular functions. These would have evolved via natural selection.

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