The Origin of Species by Means of Natural Selection: Or, The Preservation of Favored Races in the Struggle for Life, Volumen2AMS Press, 1972 |
Dentro del libro
Resultados 1-3 de 19
Página 19
... reproductive organs in an imperfect con- dition , is a different case from the difficulty of uniting two pure species , which have their reproductive organs perfect ; yet these two distinct classes of cases run to a large extent ...
... reproductive organs in an imperfect con- dition , is a different case from the difficulty of uniting two pure species , which have their reproductive organs perfect ; yet these two distinct classes of cases run to a large extent ...
Página 26
... reproductive systems having been specially affected , though in a lesser degree than when sterility ensues . So it is with hybrids , for their offspring in successive generations are eminently liable to vary , as every experimentalist ...
... reproductive systems having been specially affected , though in a lesser degree than when sterility ensues . So it is with hybrids , for their offspring in successive generations are eminently liable to vary , as every experimentalist ...
Página 41
... reproductive system from being eminently sensitive to changed conditions of life , fails under these circumstances ... reproductive systems in any way affected , and they are not variable ; but hybrids themselves have their reproductive ...
... reproductive system from being eminently sensitive to changed conditions of life , fails under these circumstances ... reproductive systems in any way affected , and they are not variable ; but hybrids themselves have their reproductive ...
Contenido
CONTENTS OF VOL | 1 |
CHAPTER X | 48 |
CHAPTER XII | 129 |
Derechos de autor | |
Otras 2 secciones no mostradas
Otras ediciones - Ver todas
Términos y frases comunes
accumulated adapted admit adult affinity allied species ancient animals appear Archipelago arctic areas become beds believe birds breeds Cambrian changes characters classification climate closely allied continent crustaceans degree deposited difficulty distant distinct species domestic doubt embryo Europe existing extinct fact faunas fertilised fertility flowers formations formerly forms fossil fresh-water Fritz Müller Gärtner genera genus geological period geological record Glacial period groups of species habits hybrids hybrids produced important individuals inhabitants inherited insects instance intermediate intervals land larvæ less living mammals manner marine Marsupials migration modified descendants mongrels mountains natural selection naturalists nearly occur oceanic islands offspring organisation parent parent-form peculiar perfect pistil plants pollen present probably produced quadrupeds reciprocal crosses regions remains remarked reproductive resemblance rocks rudimentary organs seeds Silurian slight South America species belonging stage stamens sterility structure successive suppose terrestrial tertiary tion variations varieties whilst widely different wings