On the Origin of Species by Means of Natural Selection: Or The Preservation of Favoured Races in the Struggle for LifeHumphrey Milford, Oxford University Press, 1923 - 454 páginas |
Dentro del libro
Resultados 1-5 de 100
Página 8
... period of life the causes of variability , whatever they may be , generally act ; whether during the early or late period of development of the embryo , or at the instant of conception . Geoffroy St. Hilaire's experiments show that ...
... period of life the causes of variability , whatever they may be , generally act ; whether during the early or late period of development of the embryo , or at the instant of conception . Geoffroy St. Hilaire's experiments show that ...
Página 13
... period of life a peculiarity appears , it tends to appear in the offspring at a corresponding age , though sometimes earlier . many cases this could not be otherwise : thus the inherited peculiarities in the horns of cattle could appear ...
... period of life a peculiarity appears , it tends to appear in the offspring at a corresponding age , though sometimes earlier . many cases this could not be otherwise : thus the inherited peculiarities in the horns of cattle could appear ...
Página 21
... period at which the perfect plumage is acquired varies , as does the state of the down with which the nestling birds are clothed when hatched . The shape and size of the eggs vary . The manner of flight differs remarkably ; as does in ...
... period at which the perfect plumage is acquired varies , as does the state of the down with which the nestling birds are clothed when hatched . The shape and size of the eggs vary . The manner of flight differs remarkably ; as does in ...
Página 31
... periods of English history choice animals were often imported , and laws were passed to prevent their exportation : the ... period attended to . Savages now sometimes cross their dogs with wild canine animals , to improve the breed , and ...
... periods of English history choice animals were often imported , and laws were passed to prevent their exportation : the ... period attended to . Savages now sometimes cross their dogs with wild canine animals , to improve the breed , and ...
Página 61
... period of life . familiarity with the larger domestic animals tends , I think , to mislead us : we see no great ... period of life ; and this period in the great majority of cases is an early one . If an animal can in any way protect its ...
... period of life . familiarity with the larger domestic animals tends , I think , to mislead us : we see no great ... period of life ; and this period in the great majority of cases is an early one . If an animal can in any way protect its ...
Otras ediciones - Ver todas
Términos y frases comunes
accumulated adapted affinities allied species America amount analogous ancient appear Archipelago become bees believe birds breeds cause cells characters cirripedes climate closely allied colour common parent continuous crossed crustaceans degree difficulty distinct species divergence doubt embryo endemic Europe existing exterminated extinct extremely facts favourable fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hermaphrodites hybrids hybrids produced important individuals inhabitants inherited insects instance instincts intercrossing land larvæ less living male mammals manner Marsupials migration modification modified descendants natural selection naturalists nearly nest oceanic islands offspring organisation perfect pigeons pistil plants pollen present principle probably produced progenitor ranked reciprocal crosses remarked resemble rock-pigeon rudimentary organs seeds sexual selection Silurian slight South America sterility structure struggle successive suppose swimbladder tend theory tion trees variability variation vary whole widely