charles_darwin

134
Primary Documents Relating to Darwin and Darwinism
varieties or sub-species or true species. And it follows, I think,
from the foregoing facts that the varying offspring of each species
will try (only a few will succeed) to seize on as many and
as diverse places in the economy of nature, as possible. Each
new variety or species, when formed will generally take the
places of and so exterminate its less well-fitted parent. This, I
believe, to be the origin of the classification or arrangement of
all organic beings at all times. These always seem to branch and
sub-branch like a tree from a common trunk; the flourishing
twigs destroying the less vigorous—the dead and lost branches
rudely representing extinct genera and families.
This sketch is most imperfect; but in so short a space I
cannot make it better. Your imagination must fill up many wide
blanks. Without some reflection it will appear all rubbish; perhaps
it will appear so after reflection.
C. D.
P.S.—This little abstract touches only on the accumulative
power of natural selection, which I look at as by far the most
important element in the production of new forms. The laws
governing the incipient or primordial variation (unimportant
except as to groundwork for selection to act on, in which
respect it is all important) I shall discuss under several heads,
but I can come, as you may well believe, only to very partial &
imperfect conclusions.
Source: Francis Darwin, ed., The Life and Letters of Charles Darwin,
Including an Autobiographical Chapter (London: John Murray, 1887),
I: 122–125.
Document 7: Darwin on Writing
The Origin of Species
Although Darwin had begun sketching his ideas about natural
selection in written form since 1842, he did not begin to write a book
on the subject until 1856. In the 1850s, his friends Charles Lyell and
Joseph Hooker urged Darwin to publish his theory as soon as possible:
Lyell and Hooker were worried that another naturalist might preempt
Darwin. The popular success of Vestiges of the Natural History of Creation
demonstrated that many people were thinking about and interested
in evolution. By June 1858, Darwin had written eleven chapters
but not completed his (untitled) book about natural selection.
Darwin’s shock at receiving Alfred Russel Wallace’s essay on natural
selection—Wallace would eventually entitle the essay ‘‘On the Tendency
of Species to Form Varieties’’—prompted Darwin to write a series
of letters to Lyell. Darwin was distraught: he could hardly believe that