Endless Forms Most Beautiful: The New Science of Evo Devo and the Making of the Animal Kingdom

by Sean B. Carroll

Hardcover, 2005




New York : Norton, 2005.


For over a century, opening the black box of embryonic development was the holy grail of biology. Evo Devo -- Evolutionary Developmental Biology -- is the new science that has finally cracked open the box. Within the pages of his rich and riveting book, Sean B. Carroll explains how we are discovering that complex life is ironically much simpler than anyone ever expected. Perhaps the most surprising finding of Evo Devo is the discovery that a small number of primitive genes led to the formation of fundamental organs and appendages "in all animal forms." The gene that causes humans to form arms and legs is the same gene that causes birds and insects to form wings, and fish to form fins; similarly, one ancient gene has led to the creation of eyes across the animal kingdom. Changes in the way this ancient tool kit of genes is used have created all the diversity that surrounds us. Sean Carroll is the ideal author to lead the curious on this intellectual adventure -- he is the acknowledged leader of the field, and his seminal discoveries have been featured in Time and The New York Times.… (more)

Media reviews

Although Endless Forms Most Beautiful is a lucid and valuable summary of evo–devo, it does proclaim a clever but still unproved hypothesis as central to the evolutionary process. As Carroll himself notes: "Simplification may indeed be necessary for news articles, but it can distort the more
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complex and subtle realities of evolutionary patterns and mechanisms."
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User reviews

LibraryThing member gregfromgilbert
A really nice introduction to the genetics of development. Not only does all life share DNA, but most higher life forms share a similar set of genes, called homeotic or Hox genes, that control the placement and development of the major body segments in the developing embryo. From flies to mice to
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humans, the same groups of Hox genes work in roughly the same fashion, once again showing the connectedness of all living things.

The author gives an introduction to DNA and proteins and then builds up to what Hox genes are and how they work with other proteins to form a genetic tool kit (hormones, cell-type regulators, signaling proteins, Hox proteins, etc.). He shows how the tool kit determines the physical characteristics of many animals, including the size and placement of butterfly wing stripes and spots. In fact many of the specialized organs (lungs, wings, the spider’s spinneret) are modifications to the basic appendage.

The author’s excitement shows throughout the book and he excels at making some of the more complicated ideas understandable. The book has beautiful color plates of protein expression in embryos and butterfly wings. The ”Further Reading” section at the end was nicely done and not just a quick afterthought. If you have a biology background you will probably be familiar with large parts of this book. There were several areas where I would have liked the author to go deeper, but each book has an audience and this book does a great job at the level its aimed at.

Some quotes:

“But the building of an entire animal is complicated. The complexity arises from the parallel and sequential action of tool kit genes – dozens of genes acting at the same time and place, many more genes acting in sequence as development progresses. The chain of parallel and successive operations is what builds complexity” pg. 106

“It is a small leap from understanding how switches control development to anticipating how they have shaped evolution. Switches enable the same tool kit genes to be used differently in different animals. Because individual switches are independent information-processing units, evolutionary changes in one switch of a tool kit gene or in a switch controlled by a tool kit protein can alter the development of one structure or pattern without altering other structures or patterns. This is the key to the evolution of modular bodies and body parts…” pg. 131

“…everything about a tool kit protein’s action depends on context. Distal-less carries out its limb-building role in specific places and times; its job in the wing spots is in another place and time. And controls an altogether different pattern.” Pg. 208

“Evo Devo has revealed the continuity among forms that was masked or about which there were uncertainties based on appearance alone. By revealing the developmental similarities among structures, Evo Devo presents a wholly new kind of evidence that is far more objective than morphology alone.” Pg. 288
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LibraryThing member gardengallavant
A great introduction and review of the work linking the developmental impact of reusing the master regulatory proteins to control a changing galaxy of specific proteins to alter the final organisms form to fit its habitat.
He details the emergence of the body axes under the Hox proteins and how they
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work to isolate the expression of genes to promote modularity. Isolation makes regional use of bone, collagen, epithelium etc independent of other modules that also use the same genes. This allows constant tinkering without pleiotropic disruption.
The final result is:
1 Hox mapping regulation proteins. Body axis planers.
2 Master body specializing regulators. Eye, limb bud, heart. Look up Pax6, Dll, Tinman for examples of DNA binding regulatory proteins.
3 Regulators at the cell level to keep the life process going. Cellular housekeeping genes

1 - reuse what is already there – modify preexisting systems.
2 – multifunctionality & redundancy. If the systems do overlapping jobs there is space to separate and specialize. Division of labor => niche adaptation
3 – modularity to allow modification of isolated regions independent of other modules that also use the same genes.

Modular architecture - Isolate the control to the geographic position.
Master genes for mapping and local master organizers- expressed homeobox proteins
The physical geography
Complex DNA regulatory patterns to provide regulatory combinations of switch settings. Allows reuse in time and specify cell type expression.

This one combines well with "Your Inner Fish"
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LibraryThing member DoingDewey
Evo Devo stands for Evolutionary Developmental Biology and is a field which looks at both the way a fertilized egg becomes a living creature and the way changes in that process drive evolution. In Endless Forms Most Beautiful, the author/scientist Sean Carrol describes exciting new developments in
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the field (as of 2005), starting with clear, illustrated explanations of some basic concepts necessary to understand the rest of the book. As someone who does at least know the basics, this made the book drag (even more) for me, but I think it would be really helpful to someone with little to no background in biology. The second half of the book was by far my favorite part and focused on some pretty cool examples of the concepts explained in the first half of the book.

What most recommends this book is the author’s enthusiasm for his topic. Through his perspective, I thought about how incredible it is that a single cell can become a whole organism and how strange it is that the DNA shared by all organisms is so similar, yet encodes instructions for so many different creatures. As someone in a different field, I did think it was a bit presumptuous for him to declare understanding of this process the “holy grail of biology”. Also, by the time I started undergrad, a lot of the “new” research he describes was being taught in the classroom. For instance, that fact that most of the genome is non-coding and that a lot of the differences between species are caused by regulatory regions is genetics 101 these days.

My least favorite part of this book was the wordiness. Especially when describing the basics, the author came across as very pedantic. And he almost always included more detail than even I, another biologist, cared about (lists of gene names for example). I do think the book would fell less wordy to someone with less of a biology background, but most other reviews I’ve looked at also said the book could have been condensed a lot. Unfortunately, the excessive length made it harder to focus on the cool facts and as a result, the book felt kind of dry to me. To be fair, I have been a little more in the mood for fiction lately, but it’s also true that really good non-fiction can usually pull me in anyway.
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LibraryThing member vonChillan
Sean Carroll does a masterful job in putting together some of the recent advances on molecular biology (about the control of expression of different genes) and linking them to the evolution and phylogeny of animals.
A very lucid discussion on how changes in animal morphology can come around just by
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changes in timing, spatial distribution and "dose" of genes, switches and modifiers helps in really unifying the understanding of DNA activity, macroscopic morphology and evolution. I really think if you don't understand evolution of form after reading this book, there are some basic problems with accepting reasoned arguments. Brilliant!
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LibraryThing member gulley
Sean Carroll is on the leading edge of a revolution in understanding biology. It's great to have the story explained to you by one of the chief participants.
LibraryThing member name99
Yet another book on the new biology, but this time focussed on embryology and, more ambitiously, on how the regulatory mechanisms that guide embryology can fairly easily be modified to allow for apparently large-scale restructuring of organisms via fairly trivial low-level changes.

As the first pop
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book of its kind (at least the first I know of) I applaud the author's sentiments.
For the first half, focussed on embryology, I think he did a pretty good job.
Sadly I found the second half, focussed on evolution, frustrating because it lacks the details and mechanisms of the first half; I'm not sure if this is because the science is not yet worked out or if the author simply doesn't care as much about this area.
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LibraryThing member co_coyote
I started this book awhile ago, and got bogged down in some of the details. But after David Quammen's wonderful introduction to Mr. Darwin's ideas (see below) I couldn't wait to get back to it. Sure enough, this time I was more attuned to the larger ideas, and found this to be an amazing
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introduction to Evolutionary Development (Evo Devo). Carroll calls Evo Devo the third revolution behind Darwin's theory of natural selection and the Modern Synthesis of evolutionary development. The main point is that the basic plan for animal development has been in place for millions of years and that the generation of dfferent forms is not related to new gene development, but to the use of old genes in new ways. Evo Devo gives us the tools and the vocabulary to make sense of evolutionary development and to see the similarities in totally dissimilar forms. If it has been over 20 years since you studied biology, you better get hold of this book and get back up to speed!
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LibraryThing member larrycam
"Evo devo" might sound like an 80's rock band, but this book is one of those few that really does open the door to a new world of wonder -- evolutionary developmental biology, or the new and rapidly growing understanding of how a single cell is able to unfold itself, step by step, into enormously
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complex trillion-celled systems like us. And it's a story told here first hand, by a leading investigator of this new world, with warmth, passion, and humor.
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LibraryThing member ddowell
This is a wonderful exposition of the relatively new science of evolutionary development. It is very readable and very fascinating. Highly recommended for those interested in evolution. Explains how the "dark matter" of the genome is actually extremely important in evolution and how a great deal of
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evolution may not involve new genes at all! Fascinating.
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LibraryThing member danielroseman
An excellent and clear introduction to the science of evo-devo.

Caroll lays out beautifully what he and colleagues are learning through combining embryology with evolution, and shows how the union solves a number of mysteries that have been puzzling scientists for decades.

Although this is very
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definitely a layman's introduction, it does get quite deep into the science, to the point that I found myself a bit confused by all the different concepts - switches, toolkits, etc.

I also couldn't help feeling that he allows his enthusiasm - and his bias as one of the leaders in the field - to get the better of him, leaving the impression that not only is evo-devo the best thing since sliced bread, but that no-one had ever made any progress in studying evolution until it came along.

Pity, because the science clearly has had a major impact, but there's still plenty of interesting things going on outside of the field and Carroll doesn't do himself any favours by implying otherwise.
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LibraryThing member breic2
This book is quite clear and readable. It sometimes overreaches in its claims, and starts out very slowly. Instead of the high-school level exposition of genetics, it would have been more useful to talk about modern experimental setups. The book is almost entirely missing any discussion about how
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the research is done. This important missing aspect is the main flaw. However, the conclusions are presented well, with many examples from different species.

There are few very nice ideas that it explains well. For example,
* The same tool kit proteins are used to guide development across all sorts of animals, and portions of it predate the Cambrian explosion. Changes in control switches and "circuits" (combinations of switches) in the DNA modify how these proteins are used. There is strong pressure to leave the homeotic (Hox) genes the same, though.
* Complexity in form is often enabled by duplication of modular structures, followed by specialization. (A perfect example are the many specialized structures in arthropods.) For this reason, the same tool kit proteins to place many structures that now seem quite different. One can guess that without modular structures, allowing for this kind of evolution, animals could not have been so successful.
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LibraryThing member Devil_llama
As always, the author writes in a lucid, interesting style about the new science of evolutionary development. This is a must read for anyone who is interested in understanding this field.
LibraryThing member Sovranty
Furthering the evidence of evolution, this book is a great introductory crash course to "the new science of evo devo". There are plenty of illustrations and examples to assist a reader that is less familiar with the sciences, yet gives plenty of reading suggestions for anyone wishing to delve
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further into the details and methods of this exciting field.
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LibraryThing member jjwilson61
Interesting but not as much as I'd hoped. The discussion centered on hox genes and their switches but never satisfactorily explained how they were activated in different areas of the developing embryo.
LibraryThing member GlennBell
Interesting book. The author is highly knowledgeable and does a good job explaining the impact of advances in evoltionary development. Some of it gets a bit technical but is still interesting.
LibraryThing member Cheryl_in_CC_NV
The introduction here, and various summaries I've seen elsewhere, gave me all the content I wanted.  I skimmed the rest a bit, but nothing made me want to actually read it.  Besides which, it is actually already pretty old.


LA Times Book Prize (Finalist — Science & Technology — 2005)
Society of Midland Authors Award (Nominee — Adult Nonfiction — 2006)



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