Origin of Species Variorum

Comparison with 1866

exposed to great changes of climate and have migrated over great distances; whereas, in Egypt, during the last 3000 years, the conditions of life, as far as we know, have remained absolutely uniform. The fact of little or no modification having been effected since the glacial period would be of some avail against those who believe in the existence of an innate and necessary law of development, but is powerless against the doctrine of natural selection, which implies only that variations occasionally occur in single species, and that these when favourable are preserved; but this will occur only at long intervals of time after changes in the conditions of each country. As Mr. Fawcett has well asked, what would be thought of a man who argued that because he could show that Mont Blanc and the other Alpine peaks had exactly the same height 3000 years ago as at present, consequently that these mountains had never been slowly upraised, and that the height of other mountains in other parts of the world had not recently been increased by slow degrees?

It has been objected, if natural selection be so powerful, why has not this or that organ been recently modified and improved? Why has not the proboscis of the hive-bee been lengthened so as to reach the nectar in the flower of the red-clover? Why has not the ostrich acquired the power of flight? But granting that these organs have happened to vary in the right direction, granting that there has been time sufficient for the slow work of natural selection, checked as it will be by intercrossing and the tendency to reversion, who will pretend that he knows the natural history of any one organic being sufficiently well to say whether any particular change would on the whole be to its advantage? Can we feel sure that a long proboscis would not be a disadvantage to the hive-bee in sucking the innumerable small flowers which it frequents? Can we feel sure that a long proboscis would not, by correlation of growth, almost necessarily give increased size to other parts of the mouth, perhaps interfering with the delicate cell-constructing work? In the case of the ostrich a moment's reflection will show that an enormous supply of food would be necessary in this bird of the desert, to supply force to move its huge body through the air.

It has been objected, if natural selection be so powerful an agent, why has not this or that organ been .. modified and improved? Why has not the proboscis of the hive-bee been lengthened so as to reach the nectar of the ... red-clover? Why has not the ostrich acquired the power of flight? But granting that these parts and organs have varied in the right direction— granting that there has been time sufficient for the slow work of natural selection, the effects being often checked as they will be by intercrossing and the tendency to reversion, who will pretend that he knows the life-history of any one organic being sufficiently well to say that any particular change would be on the whole to its advantage? Can we feel sure that a long proboscis would not be a disadvantage to the hive-bee in sucking the innumerable small flowers which it frequents? Can we feel sure that a long proboscis would not, by correlation, .. almost necessarily give increased size to other parts of the mouth, perhaps interfering with the delicate cell-constructing work? In the case of the ostrich, a moments reflection will show what an enormous supply of food would be necessary to supply force for this bird of the desert to ... move its huge body through the air.