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The Descent of Man

The Descent of Man

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either or both sexes have been affected through<br />

sexual selection cannot fail to be complex in the<br />

highest degree.<br />

When variations occur late in life in one sex,<br />

and are transmitted to the same sex at the same<br />

age, the other sex and the young are left unmodified.<br />

When they occur late in life, but are<br />

transmitted to both sexes at the same age, the<br />

young alone are left unmodified. Variations,<br />

however, may occur at any period <strong>of</strong> life in one<br />

sex or in both, and be transmitted to both sexes<br />

at all ages, and then all the individuals <strong>of</strong> the<br />

species are similarly modified. In the following<br />

chapters it will be seen that all these cases frequently<br />

occur in nature.<br />

Sexual selection can never act on any animal<br />

before the age for reproduction arrives. From<br />

the great eagerness <strong>of</strong> the male it has generally<br />

acted on this sex and not on the females. <strong>The</strong><br />

males have thus become provided with weapons<br />

for fighting with their rivals, with organs

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