| → mammals 1859 1860 1861 1866 1869 |
| new species of mammals 1872 |
|
| → of the same 1859 1860 1861 1866 |
| OMIT 1869 1872 |
|
| → through natural selection 1859 1860 1861 1866 |
| OMIT 1869 1872 |
|
| ↑ 1 blocks not present in 1859 1860 1861 1866; present in 1869 1872 |
| Another interesting relation exists, namely between the depth of the sea separating islands from each other or from the nearest continents,
and the degree of affinity of their mammalian inhabitants.
|
|
|
for the creation of mammals; many volcanic islands are sufficiently ancient, as shown by the stupendous degradation which they have
and by their tertiary strata: there has also been time for the production of endemic species belonging to other classes; and on continents it is
that
→mammals
appear and disappear at a quicker rate than other and lower animals.
terrestrial mammals do not occur on oceanic islands,
mammals do occur on almost every island. New Zealand possesses two bats found nowhere else in the world: Norfolk Island, the Viti Archipelago, the Bonin Islands, the Caroline and Marianne Archipelagoes, and Mauritius, all possess their peculiar bats. Why, it may be asked, has the supposed creative force produced bats and no other mammals on remote islands? On my view this question can easily be answered; for no terrestrial mammal can be transported across a wide space of sea, but bats can fly across. Bats have been seen wandering by day far over the Atlantic Ocean; and two North American species either regularly or occasionally visit Bermuda, at the distance of 600 miles from the mainland. I hear from Mr. Tomes, who has specially studied this family, that many
→of the same
species have enormous ranges, and are found on continents and on far distant islands. Hence we have only to suppose that such wandering species have been
→through natural selection
in their new homes in relation to their new position, and we can understand the presence of endemic bats on
with the absence of all
mammals. ↑
|
| Besides the absence of terrestrial mammals in relation to the remoteness of islands from continents, there is also a
to a certain extent independent of distance, between the depth of the sea separating an island from the neighbouring mainland, and the
|
