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 16-20 de 100
Página 109
... modification to be more numerous or greater in amount , to convert these three forms into well - defined species : thus the diagram illustrates the steps by which the small differences distinguishing varieties are increased into the ...
... modification to be more numerous or greater in amount , to convert these three forms into well - defined species : thus the diagram illustrates the steps by which the small differences distinguishing varieties are increased into the ...
Página 110
... modification , represented in the diagram , another of our principles , namely that of extinction , will have played an important part . As in each fully stocked country natural selection neces- sarily acts by the selected form having ...
... modification , represented in the diagram , another of our principles , namely that of extinction , will have played an important part . As in each fully stocked country natural selection neces- sarily acts by the selected form having ...
Página 111
... commencement of the process of modification , will be widely different from the other five species , and may constitute a sub - genus or even a distinct genus . The six descendants from ( I ) will form two NATURAL SELECTION 111.
... commencement of the process of modification , will be widely different from the other five species , and may constitute a sub - genus or even a distinct genus . The six descendants from ( I ) will form two NATURAL SELECTION 111.
Página 112
... modification , from two or more species of the same genus . And the two or more parent - species are supposed to have descended from some one species of an earlier genus . In our diagram , this is indicated by the broken lines , beneath ...
... modification , from two or more species of the same genus . And the two or more parent - species are supposed to have descended from some one species of an earlier genus . In our diagram , this is indicated by the broken lines , beneath ...
Página 113
... modification , as now explained , to the formation of genera alone . If , in our diagram , we suppose the amount of change represented by each successive group of diverging dotted lines to be very great , the forms marked a 14 to p14 ...
... modification , as now explained , to the formation of genera alone . If , in our diagram , we suppose the amount of change represented by each successive group of diverging dotted lines to be very great , the forms marked a 14 to p14 ...
Otras ediciones - Ver todas
On the Origin of Species by Means of Natural Selection: or the Preservation ... Charles Darwin Vista previa limitada - 2023 |
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