change. Indeed, they can be deliberately changed. Darwin quoted a famous
breeder of pigeons, Sir John Sebright, who boasted that “he would produce
any given feather in three years, but it would take him six years to obtain
head and beak” (Christian, Maps of Time, p. 87).
By the 19th century, growing evidence that species really did change made it
necessary to explain how. In 1809, French naturalist Jean-Baptiste Lamarck
proposed that species change, in effect, because they want to change. Thus,
in an environment where the tastiest leaves were high up, browsing animals
would naturally stretch, and over time they might even lengthen their necks.
Over many generations, they might even turn into giraffes!
Unfortunately, any animal breeder could point out what was wrong
with this argument. Qualities acquired during one’s lifetime (“acquired
characteristics”) are not passed on to one’s offspring. Only “inherited
characteristics” are passed on. A fattened pig will not necessarily produce fat
piglets, but a pig with fat parents may.
We have seen that life represents a new level of complexity with three critical
emergent properties: control of energy, the capacity to reproduce, and the
ability to adapt to changing environments. We have also seen that, in the
middle of the 19th century, the riddle of adaptation—the key to understanding
what made life different from non-life—remained unsolved. Charles Darwin
solved the riddle in a book published in 1859. What was his answer? Ŷ
Christian, Maps of Time, chap. 4.
Delsemme, Our Cosmic Origins, chap. 5.
Chaisson, Epic of Evolution, chap. 6.
Maynard Smith and Szathmáry, The Origins of Life.
Essential Reading
Supplementary Reading