On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeEaston Press, 1976 - 470 páginas |
Dentro del libro
Resultados 1-3 de 77
Página 285
... formation , the deposit must have gone on continuously accumulating during a long period , sufficient for the slow process of modification ; hence the deposit must be a very thick one ; and the species undergoing change must have lived ...
... formation , the deposit must have gone on continuously accumulating during a long period , sufficient for the slow process of modification ; hence the deposit must be a very thick one ; and the species undergoing change must have lived ...
Página 286
... formation . Many cases could be given of the lower beds of a formation having been upraised , denuded , submerged , and then re - covered by the upper beds of the same formation , - facts , showing what wide , yet easily overlooked ...
... formation . Many cases could be given of the lower beds of a formation having been upraised , denuded , submerged , and then re - covered by the upper beds of the same formation , - facts , showing what wide , yet easily overlooked ...
Página 322
... formation , and in a succeeding formation there be six other allied or representative genera each with the same number of species , then we may conclude that generally only one species of each of the older genera has left modified ...
... formation , and in a succeeding formation there be six other allied or representative genera each with the same number of species , then we may conclude that generally only one species of each of the older genera has left modified ...
Contenido
VARIATION UNDER NATURE | 30 |
STRUGGLE FOR EXISTENCE | 45 |
NATURAL SELECTION | 59 |
Derechos de autor | |
Otras 13 secciones no mostradas
Otras ediciones - Ver todas
Términos y frases comunes
accumulated adapted admit affinities allied species America ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour common progenitor continuous crossed crustaceans degree developed difficulty distinct species divergence doubt effects eggs embryo existing exterminated extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological geological period gradations greater number groups of species habits Hence hybrids hybrids produced important increase individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living male mammals manner marsupials migration modified descendants natural selection naturalists nearly nest occasionally offspring organisation organs Origin of Species parent peculiar perfect pigeons pistil plants pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds slight South America stamens sterility structure struggle successive supposed swimbladder theory variability variations varieties vary whilst whole wings young