"As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequen…"

"Although much remains obscure, and will long remain obscure, ... I am convinced that Natural Selection has been the m…"

"When we look to the individuals of the same variety or sub-variety of our older cultivated plants and animals, one of…"

"Pigeons can be mated for life, and this is a great convenience to the fancier, for thus many races may be kept true, …"

"[I]t will be seen that I look at the term species, as one arbitrarily given for the sake of convenience to a set of i…"

"And thus, the forms of life throughout the universe become divided into groups subordinate to groups."

"Owing to this struggle for life, any variation, however slight and from whatever cause proceeding, if it be in any de…"

"We will now discuss in a little more detail the struggle for existence."

"We behold the face of nature bright with gladness, we often see superabundance of food; we do not see, or we forget, …"

"When on board H.M.S. Beagle, as naturalist, I was much struck with certain facts in the distribution of the inhabitan…"