ii. pp. 231,
275, 330.]
[Footnote 33: See Darwin's _Animals and Plants under Domestication_,
vol. i. pp. 40-42.]
[Footnote 34: Mr. Brent in _Journal of Horticulture_, 1861, p. 76;
quoted by Darwin, _Animals and Plants under Domestication_, vol. i. p.
151.]
[Footnote 35: This account of domestic pigeons is greatly condensed from
Mr. Darwin's work already referred to.]
[Footnote 36: _Animals and Plants under Domestication_, vol. ii. pp.
307-311.]
CHAPTER V
NATURAL SELECTION BY VARIATION AND SURVIVAL OF THE FITTEST
Effect of struggle for existence under unchanged conditions--The
effect under change of conditions--Divergence of character--In
insects--In birds--In mammalia--Divergence leads to a maximum of
life in each area--Closely allied species inhabit distinct
areas--Adaptation to conditions at various periods of life--The
continued existence of low forms of life--Extinction of low
types among the higher animals--Circumstances favourable to the
origin of new species--Probable origin of the dippers--The
importance of isolation--On the advance of organisation by
natural selection--Summary of the first five chapters.
Pages:
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