Footnotes to Evolution : a Series of Popular Addresses On the Evolution of Life
The book Footnotes to Evolution : a Series of Popular Addresses On the Evolution of Life was written by author Jordan David Starr Here you can read free online of Footnotes to Evolution : a Series of Popular Addresses On the Evolution of Life book, rate and share your impressions in comments. If you don't know what to write, just answer the question: Why is Footnotes to Evolution : a Series of Popular Addresses On the Evolution of Life a good or bad book?
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,, , , ,, „, germ cells from other cells. The germ cell in the higher creatures gains characters and quali- ties of its own not possessed by the other cells of the body. As the character of double parentage is retained in the development of the higher animals and plants, it too is specialized and perfected. " Nature," says Weis- mann, " has no better way of encouraging variation than by preventing individual units from developing alone." In the germ cell of the female, known as the egg or ovum,... food yolk is deposited for the use of the young organism. This burden reduces the activity of the fe- male cell. It becomes sessile and motionless. Its cog- nate, the male germ, on the other hand, is specialized to seek the egg cell. It is made up of an almost bare nucleus to which is attached a vibratile structure which gives it the power to move. This differentiation of sex in the germ cell produces changes and reactions in the organism from which it proceeds. The egg-bearing sex becomes in comparison with the other sessile, expectant, conservative.
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