The Beak of the Finch: A Story of Evolution in Our Time
by Jonathan Weiner
http://www.amazon.com/exec/obidos/t...p_ln_b_1/102-9531079-7608134?v=glance&s=books
The book is the convergence of three nice but unfortunately rare events:
first, a well written and interesting book.
second, good structured and well executed science.
third, the rarest of the three, good explanation at the layman's level of specific science and it's wider implications.
The book is primarily about the specific research done on Daphne Major, a small uninhabited island in the Galapagos Islands, by Peter and Rosemary Grant, concerning the measurements of beaks of Darwin's finches. Expertly woven into this discussion is a good understanding of evolutionary processes, a nice description of how science really works and why, along with enough human interest that it captivates the reader's interest and rightfully garnered the book a pulitzer prize. It's structure is primarily chronological as we are introduced to the Grant's now 20 years plus research project, the people who did it and the science underlying the effort. Other research is introduced as necessary to make or expand the point, so you learn a little about guppies, Darwin's particular studies, Hawaiian fruit flies, sticklebacks in BC; but mostly the details are taken from, are about the 13 species of Darwin's finches, what they eat, and the last 20 years of weather on these islands described as Nature's own biological laboratory: unique, simple enough to study, yet persuasive in the theories formed by people enchanted by their biological diversity stemming from just a few individuals lucky enough to cross the Pacific from South America.
The take home message is simple enough. Through 20 generations of finches, data has been carefully collected concerning the beaks, the food, the offspring, the blood and from this mass of data has emerged the proof that populations evolve in response to their environment; that is, natural selection(NS) is seen, not just in the propositions concerning fossils, but in the time frame of a PhD thesis, evolution happens. Like an often heard mantra, the phrase, "speciation has never been seen to occur" emerges from the writings of the Young Earth Creationists(YEC). This book is a direct reply to this idea, look and listen the author (and the Grants) seem to say to their most vocal opponents, evolution and NS happen all around us, it is just too complex to be clearly proven outside of the unique environment of the Galapagos.
If you have any interest in the topic of creation-evolution-design this ought to be one of the first 10 books on your to-be-read list.
thanks for reading this short review.
richard williams
This is one of those extraordinary books that you wondered how you missed it for so long. Of course, in my reading i had seen the title, but i did not understand how significant and well written the book is.
One of the important big issues for the YEC and for most OEC is the process of speciation.
It is curious to me that the issue is not front and center in criticisms of the YEC, for their 'science' has a critical founders effect in Noah, and another serious bottleneck in Adam's time. If Noah's flood was universal, then the best you could logically hope for on the ark was the progenitor of 'kinds'. There is simply no room for just the beetles but species. But in the 6K to 10K years intervening that prime kind pair must give rest to the entire kind domain species by normal speciation events. Extraordinary, for the YEC would thereby propose a speciation of many many times faster than any atheistic materialist evolutionist if Noah's ark was to populate the world as we see it. Truely Weird Science. But even ignoring all this, the big difference between OEC and TE is the concept of kinds, hence speciation. this book is all about speciation, the how, and why, and what drives it.
It is also painless introduction to several of the key elements of evolutionary theory. I will try to use the proper technical terms and point these ideas out in the following.
Chapter 1 "Daphne Major"
"Taken together, these new studies suggest that Darwin did not know the strength of his own theory. He vastly underestimated the power of natural selecton. Its action is neither rare nor slow. It leads to evolution daily and hourly, all around us, and we can watch" ... "This is one of the most intensive and valuable animal studies ever conducted in the word; zoologists and evolutionists already regard is as a classic. It is the best and most detailed demonstration to date of the power of Darwin's process." pg 9
Chapter 2 "What Darwin Saw"
Volcanic islands, recently formed above the waves, far from shore, provide a unique laboratory for the observation of the evolution by radiation from a few founders who find their way to these islands. Honeycreepers and fruit flies in Hawaii, Darwin's finches in the Galapagos are just a few examples out of numerous. The critical item to realize is that the finches provide what is a speciation event, there are 13 species of Darwin's finches in the Galapagos, each island has a subset of the 13, each with markers that like the tortises show exactly which island they are from. "But the Grants are the first scientists equipped with enough patience, stubborness, ground support and sea support, enough computer power, airplane power, and staying power, to watch the process actually happen."
Chapter 3 "infinite variety"
hypervariable Two ways, an attribute or feature like the beak of the finch, or a population where this attribute is found.
"'Hard facts' are those rare details in this confusing world that have been recorded so clearly and unambiguously that everyone can agree on them. The shape of the finch's beak is a hard fact."..."That is one of the most variable characters ever measured in a bird. And Darwin's finches are extraordinarily variable not only in the depth, length, and width of each mandible, and in the relative leghts of the upper and lower mandibles, but also in......." pg 67
This is the key thing that the Grants did, they measured: beaks, seed size, rainfall over a 20+ year period. Note the phrase, "everyone can agree on them" this is the key idea of public knowledge in science and the role the empirical must play in an objective reference point in the adjudication between competing theories.
Chapter 4 "Darwin's Beaks"
The details about the beaks and the seeds the birds eat. Attention was very carefully paid to types, how many, size of seeds and especially hardness, it is these numbers that make the research so valuable. The underlying driving force is energy budgets derived from the seeds, big birds can crack and eat big seeds but their size requires higher energy expenditures. A good side discussion was the divergence of beak sizes within the species if several species shared an island compared to the size of the beaks on islands that the species where without as much competition.
Chapter 5 "A Special Providence"
The weather, 1 in 7 finches made it through the drought.The larger birds were able to eat the larger harder seeds, males being 5% larger than females survived in greater numbers. Only 200 birds left on the island.
Chapter 6 "Darwin's forces"
Selection at different levels. First young birds are better off smaller, less energy, older birds are better off larger, so NS changes during the lifetime of the bird. Sexual selection is important, with the odd sex ratio as a result of the drought, only the largest best conditioned males bred, all the females bred, some several times. Size is inheritable, during this time 1978, all the birds and young where banded, effectively making the island into a very measured laboratory, a unique event in science, up to now. Guppies in south America introduced as another example of sexual selection and predator on prey population changes.
Chapter 7 "25K Darwins"
Then El Nino caused it to rain, and rain ....And like the switch from drought to rain, the selection on the beaks switched, now the larger birds were dying and the smaller living. why? lots of seeds to eat, so the larger energy cost of being big is factored into the survival rates. surprise surprise. selection pressures may oscillate wildly during the lifetime of a creature. jittering, wobbles, oscillations.