Evolution Theory
章节目录
共 44 段- In the course of these lectures, we shall find at every step
- Christianity was in part responsible for this, because it re
- In the same way the long legs of the wading birds have been,
- I need not linger over any detailed account of his travels;
- Among pigeons, as well as among other domesticated animals,
- But even this prodigality of seeds is not the greatest reach
- We cannot, however, directly observe this process of natural
- But all attempts at any other explanation are even more deci
- In all the nocturnal Lepidoptera it is the _upper_ side of t
- It is not without a purpose that I have lingered so long ove
- I do not know how any one can put any other construction on
- In this connexion Poulton has brought forward interesting fa
- But even in single species of butterflies immune through unp
- Very well known are the stinging-hairs of the Urticaceæ, lon
- The marshes of European countries, and also those of warmer
- The hermit-crab (Fig. 34, p. 163), which conceals its soft a
- If we inquire how this instinct of fluttering, careless flig
- We owe our understanding of this adaptive change in the sea-
- This alone would not suffice to protect the tree against the
- By far the greater number of the phanerogams, however, espec
- In the ancestors of those which carry pollen on the abdomen
- [Illustration: FIG. 52. The fertilization of the Yucca. _A_,
- No one can seriously believe this in regard to butterflies w
- Butterflies are by no means the only creatures that produce
- Finally, when in an enormous number of cases we find in addi
- To conclude this section, I should like once again to call a
- In many-celled organisms, however, we must admit that there
- The little flagellated cells just described serve not only f
- To an understanding of the process even in its most general
- It is remarkable how different the sperm-cells sometimes are
- These pieces or chromosomes become shorter by slowly contrac
- The process of fertilization is now known in all its details
- From all these results we can at least infer so much, that c
- The most primitive form of conjugation is undoubtedly the co
- I shall return later to the problem of the meaning of 'sexua
- Attempts have recently been made to prove that parthenogenes
- That this conclusion is correct is obvious from the fact tha
- There are human families in which individuals occur repeated
- This example seems to me to be preferable to that of the win
- But if the determinants must separate from each other in the
- All living processes, therefore, both those of growing and o
- For it is undoubtedly a very different matter whether a cell
- The botanist Reinke has recently called attention once again
- This splitting up of the substance of the ovum into a somati