2020-08-07 14:06:59  来源:人民网-人民日报海外版


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    I was going out at my door on the morning after that deplorable day of headache, sickness, and repentance, with an odd confusion in my mind relative to the date of my dinner-party, as if a body of Titans had taken an enormous lever and pushed the day before yesterday some months back, when I saw a ticket-porter coming upstairs, with a letter in his hand. He was taking his time about his errand, then; but when he saw me on the top of the staircase, looking at him over the banisters, he swung into a trot, and came up panting as if he had run himself into a state of exhaustion.


   As we see that those variations which under domestication appear at any particular period of life, tend to reappear in the offspring at the same period; for instance, in the seeds of the many varieties of our culinary and agricultural plants; in the caterpillar and cocoon stages of the varieties of the silkworm; in the eggs of poultry, and in the colour of the down of their chickens; in the horns of our sheep and cattle when nearly adult; so in a state of nature, natural selection will be enabled to act on and modify organic beings at any age, by the accumulation of profitable variations at that age, and by their inheritance at a corresponding age. If it profit a plant to have its seeds more and more widely disseminated by the wind, I can see no greater difficulty in this being effected through natural selection, than in the cotton-planter increasing and improving by selection the down in the pods on his cotton-trees. Natural selection may modify and adapt the larva of an insect to a score of contingencies, wholly different from those which concern the mature insect. These modifications will no doubt affect, through the laws of correlation, the structure of the adult; and probably in the case of those insects which live only for a few hours, and which never feed, a large part of their structure is merely the correlated result of successive changes in the structure of their larvae. So, conversely, modifications in the adult will probably often affect the structure of the larva; but in all cases natural selection will ensure that modifications consequent on other modifications at a different period of life, shall not be in the least degree injurious: for if they became so, they would cause the extinction of the species.Natural selection will modify the structure of the young in relation to the parent, and of the parent in relation to the young. In social animals it will adapt the structure of each individual for the benefit of the community; if each in consequence profits by the selected change. What natural selection cannot do, is to modify the structure of one species, without giving it any advantage, for the good of another species; and though statements to this effect may be found in works of natural history, I cannot find one case which will bear investigation. A structure used only once in an animal's whole life, if of high importance to it, might be modified to any extent by natural selection; for instance, the great jaws possessed by certain insects, and used exclusively for opening the cocoon or the hard tip to the beak of nestling birds, used for breaking the egg. It has been asserted, that of the best short-beaked tumbler-pigeons more perish in the egg than are able to get out of it; so that fanciers assist in the act of hatching. Now, if nature had to make the beak of a full-grown pigeon very short for the bird's own advantage, the process of modification would be very slow, and there would be simultaneously the most rigorous selection of the young birds within the egg, which had the most powerful and hardest beaks, for all with weak beaks would inevitably perish: or, more delicate and more easily broken shells might be selected, the thickness of the shell being known to vary like every other structure.Sexual Selection

 She rubbed her eyes with her handkerchief until they looked quite red. After which she got up and went out of the room, without venturing to say another word. When her older sister looked and spoke as she had done just now, the wisest course to pursue was to obey orders without any comment. Miss Minchin walked across the room. She spoke to herself aloud without knowing that she was doing it. During the last year the story of the diamond mines had suggested all sorts of possibilities to her. Even proprietors of seminaries might make fortunes in stocks, with the aid of owners of mines. And now, instead of looking forward to gains, she was left to look back upon losses.










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    At such time as Octavius Caesar (not as yet named Augustus, but onlyin the office called Triumveri) governed the Romane Empire, theredwelt in Rome a Gentleman, named Publius Quintus Fulvius, a man ofsingular understanding, who having one son, called Titus QuintusFulvius, of towardly yeares and apprehension, sent him to Athens tolearne Philosophy, but with letters of familiar commendations, to aNoble Athenian Gentleman, named Chremes, being his ancient friend, oflong acquaintance. This Gentleman lodged Titus in his owne house, ascompanion to his son, named Gisippus, both of them studyingtogether, under the tutoring of a Philosopher, called Aristippus.These two yong Gentlemen living thus in one Citty, House, and Schoole,it bred betweene them such a brother-hoode and amity, as they couldnot be severed from one another, but only by the accident of death;nor could either of them enjoy any content, but when they were bothtogether in company.




如何降低返程高峰疫情传播风险?交通运输部回应和中俄打世界大战 美国要增加多少兵力   "Then I saw Chloris, whom Neleus married for her beauty, havinggiven priceless presents for her. She was youngest daughter to Amphionson of Iasus and king of Minyan Orchomenus, and was Queen in Pylos.She bore Nestor, Chromius, and Periclymenus, and she also bore thatmarvellously lovely woman Pero, who was wooed by all the countryround; but Neleus would only give her to him who should raid thecattle of Iphicles from the grazing grounds of Phylace, and this was ahard task. The only man who would undertake to raid them was a certainexcellent seer, but the will of heaven was against him, for therangers of the cattle caught him and put him in prison; neverthelesswhen a full year had passed and the same season came round again,Iphicles set him at liberty, after he had expounded all the oracles ofheaven. Thus, then, was the will of Jove accomplished.【详细】

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