| → period— Alternate Glacial periods in the North and South. 1869 1872 |
| period co-extensive with the world. 1859 1860 1861 1866 |
|
| → arctic and northern temperate parts, 1872 |
| northern parts where the circumpolar land is almost continuous, 1859 1860 1861 1866 1869 |
|
| → No doubt 1869 1872 |
| for it is a most rare case to find a group of organisms confined to any small spot, having conditions peculiar in only a slight degree; for instance, 1859 1860 1861 1866 |
|
| → can 1869 1872 |
| in the Old World could 1859 1860 |
| in the Old World can 1861 1866 |
|
| → OMIT 1869 1872 |
| hotter than any 1859 1860 1861 1866 |
|
| → hotter than any in the New World; but 1872 |
| yet 1859 1860 1861 1866 |
| hotter than any in the New World, but 1869 |
|
| → different from that of the surrounding districts; for it is rare to find a group of organisms confined to a small area, of which the conditions are peculiar in only a slight degree. 1872 |
| or flora. 1859 1860 1861 1866 |
| different from that of the surrounding districts; for it is very rare to find a group of organisms confined to a small area, having conditions peculiar in only a slight degree. 1869 |
|
|
CHAPTER
|
| GEOGRAPHICAL DISTRIBUTION. |
| Present distribution cannot be accounted for by differences in physical conditions— Importance of barriers— Affinity of the productions of the same continent— Centres of creation— Means of
by changes of climate and of the level of the land, and by occasional means— Dispersal during the Glacial
→period— Alternate Glacial periods in the North and South.
|
| IN considering the distribution of organic beings over the face of the globe, the first great fact which strikes us is, that neither the similarity nor the dissimilarity of the inhabitants of various regions can be
for
climatal and other physical conditions. Of late, almost every author who has studied the subject has come to this conclusion. The case of America alone would almost suffice to prove its
for if we exclude the
→arctic and northern temperate parts,
all authors agree that one of the most fundamental divisions in geographical distribution is that between the New and Old Worlds; yet if we travel over the vast American continent, from the central parts of the United States to its extreme southern point, we meet with the most diversified conditions;
humid districts, arid deserts, lofty mountains, grassy plains, forests, marshes, lakes, and great rivers, under almost every temperature. There is hardly a climate or condition in the Old World which cannot be paralleled in the New— at least as closely as the same species generally
→No doubt
small areas
→can
be pointed out
→OMIT
in the
→hotter than any in the New World; but
these are not inhabited by a
fauna
→different from that of the surrounding districts; for it is rare to find a group of organisms confined to a small area, of which the conditions are peculiar in only a slight degree. Notwithstanding this
in the conditions of the Old and New Worlds, how widely different are their living productions! |
|
| In the southern hemisphere, if we compare large tracts of land in Australia, South Africa, and western South America, between latitudes
and
we shall find parts extremely similar in all their
|
