Wednesday, June 2, 2010

Does the World Need Another Book on Evolution?

Does the world need another book on evolution? Absolutely.

Some notes below on why, and some points working their way into my book-in-progress, The Fact of Evolution (Prometheus, slated for release in late 2010 / early 2011). These are notes to myself and much of this has to be translated into the prose of popular science.

First, most people still do not, deep down, believe that evolution occurs. We execute and exonerate prisoners based on DNA evidence, and yet most Americans still don't believe in evolution.

Second, science is a cumulative endeavor, and our understanding of biology continues to grow; so yes, this book is needed, and more will be needed after it, and more after those.

"We make our world significant by the courage of our questions,
and the depth of our answers." -- Carl Sagan

New material to be incorporated into the book:

* Horizontal Gene Transfer: microbial species can acquire new DNA from other, genetically-distant species, during a lifetime, and that newly-acquired DNA can be pased on to the next generation. Since there are almost certainly more microbial than macroscopic species, we can say that most of evolution is, in fact, Lamarckian.

* Mutagenesis: we now know that mutations aren't unusual, and that most of them don't result from 'zap'-like mechanisms such as cosmic ray strike. Rather, mutation occurs almost continuously, but the greater part of it is repaired by DNA repair systems. Thus, we completely overturn the concept of mutation from it's being an unusual occurence to a failure of DNA repair mechanisms.

* Symbiosis: it is now clear that no species exists alone; species continuously co-evolve with many other species. Thus, coevolution, symbiopsis, and parasitism take on new significance.

* Continuous New Discoveries of Instances of Speciation: instances of speciation continue to be observed both in the wild (e.g. cichlid fishes in Malawi) and the lab (e.g. E. coli evolution of citrate metabolism in Lenski's lab at Michigan State).

* Reworking the Question 'What is Biology For'?: Carl Woese has recently pointed out that with so much biological research funding coming from biotech companies, we must decide as a civilization what biology is for; is it to learn from, or to engineer?

* Re-investigating Basic Concepts: With new understanding from genomic studies, even basic concepts in evolution--such as species, gene, protein, and even the definition of life--continue to be refined.

* Mechanisms of Constraint on Variation: we now know mutations don't just come up from nowhere; Gould's point that there is an evolutionary heritage that constrains potential variation has largely been confirmed and widely supported with new genome data.

* Life Histories from Genetic Clocks: we have developed methods of tracking genome evolution over time, vastly increasing the resolution of taxonomic understanding.

* The Fallacy of 'Junk DNA': it has been shown that DNA once considered to have no phenotypic effect often does indeed have phenotypic effects, and that what was just a decade ago called 'Junk DNA' may often have important functions; this should be a strong caution for those working in the field of genetic engineering.

* Discoveries of Ancient Gene Function: powerful genome-mapping methods have revealed startling insights into gene functions and history; for example, the Pax-6 gene, widely distrivuted in animal life, controls the growth of photoreceptors, including eyes; the tinman gene regulates the circulatory pump (heart), and the Hox genes control the differentiation of anterior and posterior elements of the body.

* The Development of Synthetic Life: American scientists have recently claimed to have developed a synthetic genome; the implications demand a thorough philosophical debate that is informed by the must up-to-date understanding of evolution.

* The Recognition of Cultural Evolution: the fact that culture is an evolving information system has been established by various anthropologists and archaeologists (William H. Durham has been central to the study); the implications are not just for the field of anthropology, but for all the life sciences because it is the discovery of a second, parallel, largely-Lamarckian variety of evolution.

1 comment:

Anonymous said...

Liking this list. If you can make these complicated ideas tangible for the pop science reader you are onto something.