 The intermixture of distinct species is guarded against by the aversion of the individuals composing them to sexual union, or by the sterility of the mule offspring. It does not appear that true hybrid races have ever been perpetuated for several generations,...  Life on the Earth: Its Origin and Succession - الصفحة 186بواسطة John Phillips - 1860 - عدد الصفحات: 224عرض كامل - لمحة عن هذا الكتاب
 | Sir Charles Lyell - 1832 - عدد الصفحات: 368
...beyond the defined limits being fatal to the existence of the individual. Sthly. The intermixture of distinct species is guarded against by the aversion...and not to the intermixture of hybrid with hybrid. 6thly. From the above considerations, it appears that species have a real existence in nature, and... | |
 | Benjamin Godwin - 1834 - عدد الصفحات: 314
...beyond the defined limits being fatal to the existence of the individual. " oth ly, The intermixture of distinct species is guarded against by the aversion...and not to the intermixture of hybrid with hybrid. "6thly, From the above considerations, it appears that species have a real existence in nature, and... | |
 | Benjamin Godwin - 1835 - عدد الصفحات: 408
...beyond the defined limits being fatal to the existence of the individual. " 5thly. The intermixture of distinct species is guarded against by the aversion...mules with individuals of pure species, and not to the intermixure of hybrid with hybrid. " 6thly. From the above considerations, it appears that species... | |
 | Sir Charles Lyell - 1837 - عدد الصفحات: 570
...beyond the defined limits being fatal lo the existence of the individual. Sthly. The intermixture of distinct species is guarded against by the aversion...perpetuated for several generations, even by the assistance * E. R- A. Serres, Anatomic Compare du Cerveau, illustrated by numerous plates, tome i., 1824. of man... | |
 | 1850 - عدد الصفحات: 600
...beyond the defined limits being fatal to the existence of the individual. " 5th. The intermixture of distinct species is guarded against by the aversion...relate to the crossing of mules with individuals of the pure species, and not to the intermixture of hybrid with hybrid. " 6th. From these considerations... | |
 | 1850 - عدد الصفحات: 608
...beyond the defined limits being fatal to the existence of the individual. '_5th. The intermixture of distinct species is guarded against by the aversion...relate to the crossing of mules with individuals of the pure species, and not to the intermixture of hybrid with hybrid. ' 6th. From these considerations... | |
 | John Holmes Agnew, Walter Hilliard Bidwell - 1850 - عدد الصفحات: 604
...beyond the defined limits being fatal to the existence of the individual. " 5th. The intermixture of distinct species is guarded against by the aversion...sterility of the mule offspring. It does not appear tiiat true hybrid races have ever been perpetmted for several generations, even by the assistance of... | |
 | 1857 - عدد الصفحات: 520
...beyond the defined limits being fatal to the existence of the individual. " 5thly. The intermixture of distinct species is guarded against by the aversion...and not to the intermixture of hybrid with hybrid. "6thly. From the above considerations, it appears that species have a real existence in nature ; and... | |
 | Thomas Ragg - 1858 - عدد الصفحات: 458
...beyond the defined limits being fatal to the existence of the individual. "5thly. The intermixture of distinct species is guarded against by the aversion...of man ; for the cases usually cited relate to the crossings of mules with individuals of pure species, and not to the intermixture of hybrid with hybrid.... | |
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