Evolution and Animal Life: An Elementary Discussion of Facts, Processes, Laws and Theories Relating to the Life and Evolution of AnimalsD. Appleton, 1907 - Всего страниц: 489 |
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Стр. 4
... varying climate , differing lines of descent are brought into existence . The fact of descent with modification large or small is a matter of common knowledge in the biology of to - day , veri- fied in the hundreds of thousands of ...
... varying climate , differing lines of descent are brought into existence . The fact of descent with modification large or small is a matter of common knowledge in the biology of to - day , veri- fied in the hundreds of thousands of ...
Стр. 5
... varying conditions . It could not be the same under the tropical sun as under the arctic cold , and the individuals adapted to either would tend to reproduce individuals likewise adapted . There must , then , exist in all things a ...
... varying conditions . It could not be the same under the tropical sun as under the arctic cold , and the individuals adapted to either would tend to reproduce individuals likewise adapted . There must , then , exist in all things a ...
Стр. 16
... varying needs of changing environment . This Of these extinct forms of animals and plants we know. FIG . 5. - Diamond rattlesnake , Crotalus adamanteus . ( Photograph by W. K. Fisher . ) FIG . 7. - Common lizard or swift , Sceloporus. 16 ...
... varying needs of changing environment . This Of these extinct forms of animals and plants we know. FIG . 5. - Diamond rattlesnake , Crotalus adamanteus . ( Photograph by W. K. Fisher . ) FIG . 7. - Common lizard or swift , Sceloporus. 16 ...
Стр. 28
... varies in its physical make - up at different times or in different cells . We also find that the difficulties of interpreting just what one sees when using the highest microscopic powers make it impossible to be really certain of ...
... varies in its physical make - up at different times or in different cells . We also find that the difficulties of interpreting just what one sees when using the highest microscopic powers make it impossible to be really certain of ...
Стр. 52
... varying . The unfit and the less fit are assumed to com- pose the thousands and hundreds of thousands who must die where only tens or hundreds can live at one time . But if natural selection , which is , so far , obviously one of but ...
... varying . The unfit and the less fit are assumed to com- pose the thousands and hundreds of thousands who must die where only tens or hundreds can live at one time . But if natural selection , which is , so far , obviously one of but ...
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actual adaptation adult animals and plants ants appear artificial selection become bees beetles biologists birds body breeding Burbank butterfly called causes centrosome changes characters chromatin chromosomes color and pattern common crab Darwin degeneration degree division egg cell embryo environment evolution existence fact factors fauna feeding female fertilized fishes forms fossils gastrula genus germ cells habit hatched heredity honeybee host hybrid individuals influence inheritance insects instinct islands isolation kinds of animals larva larvæ legs live lower male mammals ment modified mutations natural selection naturalists nest nucleus offspring organs Origin of Species original parasites parent phenomena plasm produced protoplasm Protozoa rabbit race relation reproduction resemblance rocks Sacculina sea anemone sexual sexual selection sheep simple species species-forming sperm spines stage structure tail tetrads theory tion traits tree variation various vertebrates Vries Weismann wings workers worm young
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Стр. 466 - There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.
Стр. 424 - ... duty of each and all of us is to try to make the little corner he can influence somewhat less miserable and somewhat less ignorant than it was before he entered it. To do this effectually it is necessary to be fully possessed of only two beliefs: the first, that the order of nature is ascertainable by our faculties to an extent which is practically unlimited; the second, that our volition counts for something as a condition of the course of events.
Стр. 23 - ... x's and y's with which he works his problems, for real entities — and with this further disadvantage, as compared with the mathematician, that the blunders of the latter are of no practical consequence, while the errors of systematic materialism may paralyse the energies and destroy the beauty of a life.
Стр. 466 - To my mind it accords better with what we know of the laws impressed on matter by the Creator, that the production and extinction of the past and present inhabitants of the world should have been due to secondary causes, like those determining the birth and death of the individual.
Стр. 424 - We live in a world which is full of misery and ignorance, and the plain duty of each and all of us is to try to make the little corner he can influence somewhat less miserable and somewhat less ignorant than it was before he entered it.
Стр. 61 - Near villages and small towns I have found the nests of humble-bees more numerous than elsewhere, which I attribute to the number of cats that destroy the mice.
Стр. 135 - Our ignorance of the laws of variation is profound. Not in one case out of a hundred can we pretend to assign any reason why this or that part has varied.
Стр. 455 - Thus, whatever system of organs be studied, the comparison of their modifications in the ape series leads to one and the same result — that the structural differences which separate man from the gorilla and the chimpanzee are not so great as those which separate the gorilla from the lower apes.
Стр. 118 - Given any species in any region, the nearest related species is not likely to be found in the same region, nor in a remote region, but in a neighboring district, separated from the first by a barrier of some sort, or at least by a belt of country the breadth of which gives the effect of a barrier.