The Origin of Species by Means of Natural Selection: Or, the Preservation of Favored Races in the Struggle for Life, Volumen1D. Appleton, 1898 |
Dentro del libro
Resultados 1-5 de 50
Página xv
... tend to progress , in order to account for the ex- istence at the present day of simple productions , he maintains that such forms are now spontaneously gen- erated * Geoffroy Saint - Hilaire , as is stated in his ' Life , ' written by ...
... tend to progress , in order to account for the ex- istence at the present day of simple productions , he maintains that such forms are now spontaneously gen- erated * Geoffroy Saint - Hilaire , as is stated in his ' Life , ' written by ...
Página xvi
... tend to vary in some degree , and , secondly , that agri- culturists improve their domesticated animals by selec- tion ; and then , he adds , but what is done in this latter case " by art , seems to be done with equal efficacy , though ...
... tend to vary in some degree , and , secondly , that agri- culturists improve their domesticated animals by selec- tion ; and then , he adds , but what is done in this latter case " by art , seems to be done with equal efficacy , though ...
Página 5
... tend to propagate its new and modified form . This fundamental subject of Natural Selection will be treated at some length in the fourth chapter ; and we shall then see how Natural Selection almost in- evitably causes much Extinction of ...
... tend to propagate its new and modified form . This fundamental subject of Natural Selection will be treated at some length in the fourth chapter ; and we shall then see how Natural Selection almost in- evitably causes much Extinction of ...
Página 15
... more important rule , which I think may be trusted , is that , at whatever period of life a peculiarity first appears , it tends to reappear in the offspring at a corresponding age , though. CHAP . I. ] VARIATION UNDER DOMESTICATION . 15.
... more important rule , which I think may be trusted , is that , at whatever period of life a peculiarity first appears , it tends to reappear in the offspring at a corresponding age , though. CHAP . I. ] VARIATION UNDER DOMESTICATION . 15.
Página 16
... tend to appear in the offspring at the same period at which it first appeared in the parent . I believe this rule to be of the highest importance in explaining the laws of embryology . These remarks are of course con- fined to the first ...
... tend to appear in the offspring at the same period at which it first appeared in the parent . I believe this rule to be of the highest importance in explaining the laws of embryology . These remarks are of course con- fined to the first ...
Otras ediciones - Ver todas
Términos y frases comunes
adapted advantage allied analogous animals and plants appear Asa Gray beak become bees believe birds breeds caudicle cause cells characters climate closely colour common crossed cuckoo degree descendants developed difficulty distinct species disuse divergence domestic animals domestic races doubt effects eggs existence extinct extremely facts favourable females flowers forms Fritz Müller genera genus giraffe gradations greater number groups habits Hence hermaphrodites hive-bee important increase inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ large number larger genera larvæ less males manner Melipona Mivart modified natural selection naturalists nearly nest occasionally offspring organisation organs origin Origin of Species parent perfect period pigeons pollen pollen-grains present preserved prey principle probably produced progenitor quadrupeds rank rarely Red Grouse relation remarked resemble rock-pigeon seeds sexes sexual selection slight stamens striped structure struggle supposed swimbladder tend tendency tion tree variability variations varieties vary widely wings young