Spider Silk: Evolution and 400 Million Years of Spinning, Waiting, Snagging, and Mating

"In Spider Silk, Leslie Brunetta and Catherine Craig offer a history of this marvelous stuff that readers will find surprisingly compelling -- for not only the astonishing complexity of spider silk itself, but also the many uses that spiders have created over the ages. It is, in other words, the epitome of evolutionary innovation."
--Carl Zimmer, author of Parasite Rex and The Tangled Bank: An Introduction to Evolution

"This wonderful book cures arachnophobia for any lucky reader.† Brunetta and Craig combine superb scholarship with engaging writing, providing a compelling introduction to evolution in action through the lens of spiders and their silks."
--Simon Levin, Princeton University, author of Fragile Dominion

"From black widows to balloon-riders and bola-swingers, spider evolution depends critically on a few proteins in silk. Brunetta and Craig weave genetics and behavior into a silky-smooth portrait of this fascinating group."
--Richard Wrangham, Harvard University, author of†Catching Fire: How Cooking Made Us Human

"Spider Silk -- a wonderful, charismatic natural history of spiders -- will truly inspire all readers who may never before have appreciated this unique group of organisms."
--Margaret Lowman, author of Life in the Treetops: Adventures of a Woman in Field Biology and of Itís a Jungle Up There: More Tales from the Treetops

From Spider Silk:


No matter where you are at this moment, you can probably spot some spider silk. Spiders are everywhere, and they often leave evidence of their presence in the form of a strand, web, or tangle of silk. More than forty thousand spider species have been identified, making them the third most abundant type of animal after the first-place insects and second-place ticks and mites. Biologists estimate that there may be forty to a hundred thousand more spider species yet to be discovered. And all spiders make silk. They paste and drape it in every place imaginable, from caves to treetops and even under water.

Spiders are best known for using silk to build orb webs, the wheel-shaped webs that look as if they were engineered. These webs, and the spiderís ability to produce them using material generated in its own body, have fascinated humans for millennia. They have inspired weavers, civil engineers, and metaphor makers from poets to designers of computer networks. Geometrical, delicate to the point of transparency, yet super strong and super sticky, these webs can stop and hold insects hurtling with tremendous speed through the air. †Spiders build orb webs by piecing together a minimum of four types of silk, each having a different form and function. One silk provides strength, another flexibility, and still another a scaffold to aid the spider during construction. Scientists and entrepreneurs have spent millions of dollars trying to copy what spiders accomplish on a budget of dead bugs.

How could anything as complex, functional, and beautiful as an orb web result from chance changes in genes rather than by design? All adaptations to an animalís environment, including spiderwebs, are the products of natural selection, which allows certain random changes in genes to be passed on to later generations. Natural selection is the major mechanism behind evolution, the process of change in a species over time. This change results from the accumulation of gene changes. The spiderweb has evolved gradually, over millions of years. Spiders, too, have evolved over time. Spiders and spider silks are thus like all animals and all adaptations.

But unlike most other animals and adaptations, spiders and their silks allow us to understand relatively easily how small changes in genes can lead to evolution at the species level. Nonbiologists may have trouble grasping how minute genetic changes can lead to anatomical, physiological, or behavioral alterations that help an animal survive. The evolution of spiders can help elucidate the workings of natural selection -- and why Charles Darwin's phrase "descent with modification" so well describes evolution at both the genetic and the species level.† The case of spiders can also help dispel some commonly held misconceptions about evolution, such as the notion that it always leads to a better organism or aims at a perfect adaptation to the environment. Indeed, the orb web is by no means a perfect adaptation, and some shockingly messy-looking spiderwebs evolved after the orb web.

Spiders are unusual because their survival hangs on their silk...

Spider Silk Contents:


Fossils
Living Fossils
Chance and Change
Outward and Upward
Triumph over Thin Air
Small Changes, Big Benefits
Spinning, Running, Jumping, Swimming
Going Vertical
Links
Now You See It, Now You Don't
Beyond "Perfect"
Endless Forms

"...a compelling introduction to evolution in action through the lens of spiders and their silks."

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