Darwin's Password Generator

...he shape of their kidneys. Others believe that the shape of the pelvis in the human mother influences by pressure the shape of the head of the child. In snakes, according to Schlegel, the shape of the body and the manner of swallowing deter...

...d much longer; for instance, ripe hazel-nuts sank immediately, but when dried, they floated for 90 days and afterwards when planted they germinated; an asparagus plant with ripe berries floated for 23 days, when dried it floated for 85 days...

...ned by several curious and complex laws. It is generally different, and sometimes widely different, in reciprocal crosses between the same two species. It is not always equal in degree in a first cross and in the hybrid produced from this c...

... and the production of a number of allied forms must be slow and gradual,—one species giving rise first to two or three varieties, these being slowly converted into species, which in their turn produce by equally slow steps other species, a...

...es in large genera being closely allied to others, 57. on the tarsi of Engidæ, 157. on the antennæ of hymenopterous insects, 416. Whales, fossil, 303. Wheat, varieties of, 113. White Mountains, flora of, 365. Wings, reduction of size, 1...

...stence of groups would have been of simple signification, if one group had been exclusively fitted to inhabit the land, and another the water; one to feed on flesh, another on vegetable matter, and so on; but the case is widely different in...

...ent, that I should without hesitation adopt this view, even if it were unsupported by other facts or arguments. CHAPTER XIV. RECAPITULATION AND CONCLUSION. Recapitulation of the difficulties on the theory of Natural Selection. Recapit...

...t surfaces, according as the cell adjoins two, three or more other cells. When one cell comes into contact with three other cells, which, from the spheres being nearly of the same size, is very frequently and necessarily the case, the three...

...d measures, would find it very difficult to make cells of wax of the true form, though this is perfectly effected by a crowd of bees working in a dark hive. Grant whatever instincts you please, and it seems at first quite inconceivable how ...

...y far the predominant Power. CHAPTER II. VARIATION UNDER NATURE. Variability. Individual differences. Doubtful species. Wide ranging, much diffused, and common species vary most. Species of the larger genera in any country vary more t...

...or the more ancient a form is, the more nearly it will be related to, and consequently resemble, the common progenitor of groups, since become widely divergent. Extinct forms are seldom directly intermediate between existing forms; but are ...

...s; it seems to me that we may well be permitted to doubt whether many other species are really so sterile, when intercrossed, as Gärtner believes. It is certain, on the one hand, that the sterility of various species when crossed is so di...