Darwin Online
Publications
Manuscripts
Biography
Media
About Us
Advanced search

See page in:
1859
1860
1861
1866
1869
1872

Compare with:
1859
1860
1866
1869
1872

Comparison with 1869
.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ↑
We should bear in mind in relation to all organic beings that many genera are of very ancient origin, and the species in this case will have had ample time for dispersal and subsequent modification. There is also .. reason to believe from geological evidence, that ... within each great class the lower organisms change at a slower rate than the higher; .. consequently they .. will have had a better chance of ranging widely and of still retaining the same specific character. This fact, together with the seeds and eggs of almost all lowly organised forms being very minute and better fitted for distant transportal, probably accounts for a law which has long been observed, and which has lately been .. discussed by Alph. de Candolle in regard to plants, namely, that the lower any group of organisms stands, the more widely it ... ranges.
The relations just discussed,— namely, lower organisms ranging more widely than the higher,— some of the species of widely-ranging genera themselves ranging widely,— such facts, as alpine, lacustrine, and marsh productions being generally related to those which live on the surrounding low lands and dry lands,— the striking relationship between the inhabitants of islands and those of the nearest mainland— the still closer relationship of the distinct inhabitants of the islands in the same archipelago— are inexplicable on the ordinary view
for the conversion of its offspring, firstly into new varieties and ultimately into new species. ↑
In considering the wide distribution of certain genera, we should bear in mind that some are extremely ancient, and that the species must have branched off from a common parent at a remote epoch; so that in such cases there will have been ample time for great climatal and geographical changes and for accidents of transport; and consequently for the migration of some of the species into all quarters of the world, where they may have become slightly modified in relation to their new conditions. There is, also, some reason to believe from geological evidence that organisms low in the scale within each great class, generally change at a slower rate than the higher forms; and consequently the lower forms will have had a better chance of ranging widely and of still retaining the same specific character. This fact, together with the seeds and eggs of many low forms being very minute and better fitted for distant transportation, probably accounts for a law which has long been observed, and which has lately been admirably discussed by Alph. de Candolle in regard to plants, namely, that the lower any group of organisms is, the more widely it is apt to range.
The relations just discussed,— namely, low and slowly-changing organisms ranging more widely than the high,— some of the species of widely-ranging genera themselves ranging widely,— such facts, as alpine, lacustrine, and marsh productions being related (with the exceptions before specified) to those on the surrounding low lands and dry lands, though these stations are so different,— the very close relation of the distinct species which inhabit the islets of the same archipelago,— and especially the striking relation of the inhabitants of each whole archipelago or island to those