Island Life; Or, The Phenomena and Causes of Insular Faunas and FlorasWallace, Alfred Russel
Science
Island Life; Or, The Phenomena and Causes of Insular Faunas and Floras
Wallace, Alfred Russel
Biogeography; Glacial epoch; Island ecology
The Japanese Islands occupy a very similar position on the eastern shore of
the great Euro-Asiatic continent to that of the British Islands on the
western, except that they are about sixteen degrees further south, and
having a greater extension in latitude enjoy a more varied as well as a
more temperate climate. Their outline is also much more irregular and their
mountains loftier, the volcanic peak of Fusiyama being 14,177 feet high;
while their geological structure is very complex, their soil extremely
fertile, and their vegetation in the highest degree varied and beautiful.
Like our own islands, too, they are connected with the continent by a
marine bank less than a hundred fathoms below the surface--at all events
towards the north and south; but in the intervening space the Sea of Japan
opens out to a width of six hundred miles, and in its central portion is
very deep, and this may be an indication that the connection between the
islands and the continent is of rather ancient date. At the Straits of
Corea the distance from the main land is about 120 miles, while at the
northern extremity of Yesso it is about 200. The island of Saghalien,
however, separated from Yesso by a strait only twenty-five miles wide,
forms a connection with Amoorland in about 52deg N. Lat. A southern warm
current flowing a little to the eastward of the islands, ameliorates their
climate much in the same way as the Gulf Stream does ours, and added to
their insular position enables them to support a more tropical vegetation
and more varied forms of life than are found at corresponding latitudes in
China.
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[Illustration: MAP OF JAPAN AND FORMOSA (with depths in fathoms).
Light tint, sea under 100 fathoms. Medium tint, under 1,000 fathoms. Dark
tint, over 1,000 fathoms. The figures show the depth in fathoms.]
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_Zoological Features of Japan._--As we might expect from the conditions
here sketched out, Japan exhibits in all its forms of animal life a close
general resemblance to the adjacent continent, but with a considerable
element of specific individuality; while it also possesses some remarkable
isolated groups. Its fauna presents indications of there having been two or
more lines of migration at different epochs. The majority of its animals
are related to those of the temperate or cold regions of the continent,
either as identical or allied species; but a smaller number have a tropical
character, and these have in several instances no allies in China but occur
again only in Northern India or the Malay Archipelago. There is also a
slight American element in the fauna of Japan, a relic probably of the
period when a land communication existed between the two continents over
what are now the shallow seas of Japan, Ochotsk, and Kamschatka. We will
now proceed to examine the peculiarities and relations of the fauna.
Public-domain text, read in full here on John Shaqi.
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