In the Blink of an Eye: How Vision Sparked the Big Bang of Evolution

by Andrew Parker

Book Overview

The Cambrian Explosion is universally referred to as biology's "Big Bang." About 550 million years ago, there was literally an explosion of life forms, as all the major animal groups suddenly and... This description may be from another edition of this product.

• Format: Paperback
• Language: English
• ISBN: 0465054382
• ISBN13: 9780465054381
• Release Date: April 2004
• Publisher: Basic Books
• Length: 336 Pages
• Weight: 0.84 lbs.
• Dimensions: 0.9" x 5.1" x 8.2"

Customer Reviews

Eyes Wide Open

Imagine what it must have been like to be the first creature that had eyes, that could see through the murky waters. The world is no longer just what you touch, or what chemicals drift your way. Now you can range widely to hunt for food, and your dinner can't even see you coming! From an evolutionary perspective, this must have been the nuclear scenario for many species, and the true start of the evolutionary arms race. This is Andrew Parker's thesis, presented for a general audience. At times, you might feel like he's belaboring his points, but long before the end of the book you'll wonder why something this obvious never occurred to you. On the way you run into some unique characters, some mysterious creatures, and get some fossil-digging history too. Very interesting and easy to read.

The eyes have it

What triggered the Cambrian Explosion? Starting around 543 million years ago, there was a 10-million year period (give or take 5 million years) in which the number of phyla on this planet went from three to thirty-eight. After that, no new phyla appeared. Something dramatic happened during that time period, but why? There was also a major evolution of external body parts in all phyla at that time, but what caused all this? There are some explanations that have been taken seriously for the Cambrian explosion, and Parker reviews a number of them. The first is that the Cambrian was just a great time for rapid evolution. But there is evidence from embryos of nonskeletised animals that indicates that the Cambrian was probably not a particularly hospitable time after all. The second group of explanations that Parker deals with attempt to cover not only the Cambrian explosion itself, but the Precambrian changes in internal body plans. But Parker wants to know what caused the explosion itself, and feels strongly that the Precambrian changes are not an integral part of this. The third explanation is that the physical environment changed significantly at the start of the Cambrian. That means changes in, say, oxygen, carbon dioxide, or phosphorus levels. But these levels changed at plenty of times, and the start of the Cambrian doesn't appear to be all that special. A fourth explanation is that shallow-water continental shelf areas increased at the start of the Cambrian. A fifth is that there was a "Snowball Earth" that ended just prior to the Cambrian. A sixth is that collagen was acquired by animals during the Cambrian. A seventh deals with the generation of new niches: perhaps the increased availability of free-swimming plants could create a new niche. An eighth deals not with niches, but with all feeding modes. And yes, one or more of these explanations may be pretty close. But they don't satisfy Parker, and he has an explanation that makes plenty of sense, namely that around 543 million years ago, there was a sudden development of sight among animals. That means eyes, and brains to interpret the light that reaches those eyes. By the way, one of the early species to acquire eyes may have been the box jellyfish, which has no brain! But the trilobites are the creatures that Parker dwells on: they originated at the start of the Cambrian, and they appear to have had eyes (and brains) at that time. The book covers plenty about what eyes are, what different sorts of eyes there are, how eyes evolved, and what eyes are used for. As an example, rabbits have eyes on each side of their heads. A reason is that they spend plenty of energy to avoid getting eaten. That means they want as close to 360-degree vision as they can get, since they intend to run away at top speed towards safety if they see a predator (and keep running for their lives if the predator chases them). That is a cost-effective idea! On the other hand, foxes spend

Intriguing, Persuasive Explanation for the Cambrian "Explosion" of Multicellular Animal Life

Biologist Andrew Parker's "In the Blink of an Eye", is a spirited, provocative statement of his "Light Switch" theory accounting for the dramatic burst in the evolution of metazoans (multicellular animal life) at the dawn of the Cambrian Period of the Paleozoic Era, approximately 543 million years ago. He makes a very persuasive case that it was the evolution of eyesight in metazoans which triggered a rapid adaptive radiation of metazoans - though confined mostly - to arthropods (Living representatives include shrimp, crabs, lobsters, spiders, and insects, to name but a few.) as seen most impressively in the celebrated "Burgess Shale" fauna from approximately 515 million years ago. Parker opens the book with a discussion of the Cambrian explosion and the nature of fossilization itself. Next he turns to the physics of light, and discusses how living animals use light not only for nourishment, but also as a means of defense, including - but not exclusively - mimicry to avoid detection by potential predators and prey. He also describes how sight has been lost by cave-dwelling animals, and the evolution of bioluminesence in deep sea creatures. Surprisingly, this leads next to exploring the possibility that Cambrian creatures were colorful, dressed in vibrant hues of many colors, which were quite visible in the shallow seas of the Burgess Shale fauna. The final chapters describe the evolution of sight in metazoans, and Parker alleges that a primitive ancestral trilobite has been discoverd in the uppermost occurrence of the Ediacaran (latest Precambrian) fauna with a pair of crude eyes. So why was sight necessary? Parker states that it arose as the direct consequence of some animals becoming active predators - the earliest trilobites - and this, in turn, triggered an evolutionary arms race in the development of body armor to defend from predation; which we see in the fossil record as the "Cambrian explosion". Parker has made an elegant, persuasive case on behalf of his "Light Switch" theory to account for the Cambrian explosion. It is the most consistently logical explanation I have come across, supported amply by the evidence he has presented in this book. However, like another reviewer, I wish he had offered a bibliography citing those he has mentioned in support of his theory. It's a major oversight of both Parker and his publisher, and one which lessens the overall significance of the book and the compelling ideas presented within it. Still, I recommend this book to anyone interested in paleobiology - or in general, with evolution - especially those fascinated with the Cambrian explosion. Much to his credit, Parker has written a compelling tome which comes close to the literary eloquence attained by the likes of Stephen Jay Gould, Ernst Mayr and George Gaylord Simpson.

In the Blink of an Eye from a geologist's point of view

Parker's book was extremely interesting. As a geologist, I was delighted to find a book that was not completely bogged down with scientific terminology, so that I could pass this book on to my friends and family and share my interest. For someone who is not a geologist or biologist, a few of the terms may be a bit heavy. However, I believe for any science, paleontology or geology geek, this book is a must-read. The exploration of the Cambrian life forms is fascinating, the chapter on eyes alone is amazingly informative and very interesting. The reader will be swept away by Parker's enthusiasm and honesty. Especially enjoyable were his description of the male seed shrimp's attempts to court a female, and the descriptions of the predators and prey of the Cambrian. I have become enamored of Trilobites after reading this book, creatures I had previously not given a lot of thought.

What Caused the Big Bang in Animal Evolution

There have been living creatures on Earth for about four billion years, but most of that time they were blind. Most of that time, also, they were very simple (single cell animals, sponges, and soft-bodied animals). The famous Cambrian explosion was the sudden boom in animal diversity that happened between 543 and 538 million years ago. It is when teeth and armor appeared. It is also when eyes appeared. It is easy for us to imagine the drama of, say, the destruction of the dinosaurs 65 million years ago, but according to Andrew Parker the Cambrian explosion is "the most dramatic event in the history of life." Other dramatic events have their explanations (an asteroid wiping out the dinosaurs, for instance), but there has not been a satisfactory explanation of the Cambrian boom. Until now, according to Parker, and he has come up with it. _In the Blink of an Eye_ (Perseus Publishing) is a convincing explanation that he first announced seven years ago: the Cambrian explosion was caused by the evolution of vision.What happened in the explosion is that animals acquired armor, hard body parts, and a huge variety of different shapes. Parker explains that the shapes and armor came along because eyes came along. In the blind pre-Cambrian world, creatures took in sensation by smell / taste, sound, or touch. It did not matter what the creatures looked like, because no other creature could see them. It didn't matter if creatures had no armor, because predators weren't chasing them. Creatures scavenged upon dead animals, but did not need claws or jaws to catch those; catching prey was unlikely for a creature that was blind, so predation was not the rule. And then there was light! Parker thinks that a soft-bodied ancestor of the trilobite was the first creature to get a light sensitive patch that eventually differentiated into different units of an eye. The trilobite that could gradually see better could gradually become a better predator. Not only does vision power a diversity of the trilobite itself, into such skills as agility and efficient use of muscular propulsion, it powers changes in prey. In the dark, an animal has no need to care what it looks like. Pursued by creatures that can see, an animal has many avenues of change that it might follow, like making camouflage, developing its own armor, swimming faster, growing bigger, or gaining its own eyesight. And then the predators can become modified to overcome those tactics, and the familiar evolutionary battle is enjoined in earnest. Vision started diversity, and has powered it ever since.Parker's book is a rich account of how he came to these conclusions, with a wide-ranging gathering of supportive evidence. He writes clearly, and with a witty understatement. When, for example, he describes examining seed-shrimps and dissecting them under the microscope, he says, "The seed-shrimps tend to roll around and fall in exactly the positions that are not required of them." Any scientific