p.16 At the basis of all this ferment lies nature's irreducible
complexity. Organisms are not billiard balls, propelled by simple and measurable external forces to predictable new positions
on life's pool table.
p.20 ideal design is a lousy argument for evolution, for it mimics the postulated
action of an omnipotent creator. Odd arrangements and funny solutions are the proof of evolution - paths
that a sensible God would never tread but that a natural process, constrained by history, follows perforce.
p.22 The panda's "thumb" is not, anatomically, a finger at all.
It is constructed from a bone called the radial sesamoid, normally a small component of the wrist. In pandas, the
radial sesamoid is greatly enlarged and elongated until it almost equals the metapodial bones of the true digits in length...
The panda's thumb comes equipped not only with a bone to give it strength but also with muscles to sustain its agility...
they are familiar bits of anatomy remodeled for a new function.
p.24 The panda's true thumb is committed to another role,
too specialized for a different function to become an opposable, manipulating digit. So the panda must use parts on
hand to settle for an enlarged wrist bone and a somewhat clumsy, but quite workable, solution.
The sesamoid thumb wins no prize in an engineer's derby. It is, to use Michael Ghiselin's
phrase, a contraption, not a lovely contrivance.
p.26 All these adaptations [of the orchid] have
been built from a part that began in some ancestral form. Yet nature can do so much with so little
that it displays, in Darwin's words, "a prodigality of resources for gaining the very same end, namely, the fertilization
of one flower by pollen from another plant."
p.29 The panda's thumb demonstrates evolution because it is
clumsy and built from an odd part, the radial sesamoid bone of the wrist. The true thumb had been so shaped
in its ancestral role as the running and clawing digit of a carnivore that it could not be modified into an opposable grasper
for bamboo in a vegetarian descendant.
p.64-65 The theory of natural selection arose neither as
a workmanlike introduction from nature's facts, nor as a mysterious bolt from Darwin's subconscious, triggered by an accidental
reading of Malthus. It emerged instead as the result of a conscious and productive search, proceeding
in a ramifying but ordered manner, and utilizing both the facts of natural history and an astonishingly broad range of insights
from disparate disciplines far from his own.
p.65 Silvan S. Schweber... argues that the final pieces [of Darwin's
theory] arose not from new facts in natural history, but from Darwin's intellectual wanderings in distant
fields.
p.66 In reading Schweber's detailed account of the moments preceding
Darwin's formulation of natural selection, I was particularly struck by the absence of deciding influence from his own field
of biology. The immediate precipitators were a social scientist, an economist, and a statistician. If genius has any
common denominator, I would propose breadth of interest and the ability to construct fruitful analogies between fields.
p.67 The theory of natural selection is a creative transfer to biology
of Adam Smith's basic argument for a rational economy: the balance and order of nature does not arise from a higher,
external (divine) control, or from the existence of laws operating directly upon the whole, but from struggle among individuals
for their own benefits
p.76 The world, unfortunately, rarely matches our hopes
and consistently refuses to behave in a reasonable manner.
p.78 Darwin's theory of natural selection is more complex than Lamarckism because it requires two
separate processes, rather than a single force.
p.79 Darwinism, on the other hand, is a two-step
process, with different forces responsible for variation and direction... variation occurs with no preferred orientation
in adaptive directions... Selection, the second step, works upon unoriented variation and changes a population by
conferring greater reproductive success upon advantageous variants.
p.189 Even though we have no direct evidence for smooth transitions, can
we invent a reasonable sequence of intermediate forms - that is, viable, functioning organisms - between ancestors and descendants
in major structural transitions? ...The concept of preadaptation provides the conventional answer by permitting us
to argue that incipient stages performed different functions... I regard preadaptation as an important, even an indispensable,
concept.
p.190 The essence of Darwinism lies in a single phrase: natural
selection is the major creative force of evolutionary change. No one denies that natural selection will play a negative
role in eliminating the unfit. Darwinian theories require that it create the fit as well. Selection must
do this by building adaptations in a series of steps, preserving at each stage the advantageous part in a random spectrum
of genetic variability.
