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according action adapted admit allied America amount animals appear become believe belonging birds breeds called cause certain characters climate closely colour common considered continued crossed descendants developed difficulty distinct domestic doubt effects existing extinct extremely facts families favourable fertility flowers follow formations forms genera genus give given greater groups habits hand Hence hybrids important increase individuals inhabitants inherited insects instance instincts intermediate islands kind known laws less living look male manner means modified namely natural selection naturalists nearly never observed occur offspring organs origin parent perfect period plants points present preserved principle probably produced range ranked reason remarked resemblance respect seeds seems seen separated shown side similar single slight sometimes species stage sterility structure successive supposed tend theory variability variations varieties various vary whole widely young
Síđa 428 - In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation. Light will be thrown on the origin of man and his history.
Síđa 322 - Every species has come into existence coincident both in space and time with a pre-existing closely allied species.
Síđa 23 - ... that which enables the agriculturist, not only to modify the character of his flock, but to change it altogether. It is the magician's wand, by means of which he may summon into life whatever form and mould he pleases.
Síđa 63 - If such do occur, can we doubt (remembering that many more individuals are born than can possibly survive) that individuals having any advantage, however slight, over others, would have the best chance of surviving and of procreating their kind? On the other hand, we may feel sure that any variation in the least degree injurious would be rigidly destroyed.
Síđa 426 - ... when we regard every production of nature as one which has had a long history; when we contemplate every complex structure and instinct as the summing up of many contrivances, each useful to the possessor...
Síđa 50 - Two canine animals, in a time of dearth, may be truly said to struggle with each other which shall get food and live. But a plant on the edge of a desert is said to struggle for life against the drought, though more properly it should be said to be dependent on the moisture.
Síđa 3 - As many more individuals of each species are born than can possibly survive; and as, 'consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected.
Síđa 63 - Several writers have misapprehended or objected to the term Natural Selection, Some have even imagined that natural selection induces variability, whereas it' implies only the. preservation of such variations as arise and are beneficial to the being under its conditions of * life.
Síđa 388 - In my possession are two little embryos in spirit, whose names I have omitted to attach, and at present I am quite unable to say to what class they belong. They may be lizards or small birds, or very young mammalia, so complete is the similarity in the mode of formation of the head and trunk in these animals.