Travel Reference
In-Depth Information
I was much struck with the marked dif erence between the vegetation of these eastern valleys
and those on the Chilian side: yet the climate, as well as the kind of soil, is nearly the same, and
the dif erence of longitude very trifl ing. The same remark holds good with the quadrupeds,
and in a lesser degree with the birds and insects. I may instance the mice, of which I obtained
thirteen species on the shores of the Atlantic, and fi ve on the Pacifi c, and not one of them is
identical.
Although Darwin knew nothing of the tectonic plate movements that
had caused the earthquake, his direct encounter with the Earth's unstable
crust and the many other geological observations that he made during the
Beagle
's voyage reinforced what he had earlier absorbed from his intensive
reading of Lyell's topics. On his trip he gathered further proof that our planet
has had a long history, far longer than the cramped chronology still insisted
upon by believers in the literal interpretation of the Bible. He also realized
that small geological events can have mighty consequences when they are
repeated many times. And, central to his growing conviction that species
were not immutable and had evolved, he saw at fi rst hand how the gradual
emergence of the geographical barrier of the Andes had led to the formation
of dif erent species on the mountains' eastern and western slopes.
The origins of Indonesia—a collision of worlds
My relatively minor earthquake experience and Darwin's more substantial
one are the kinds of geological changes that many people encounter during
their lifetimes. Summed over a span of hundreds of millions of years, such
small, medium, and large earthquakes and eruptions have led to dramatic
rearrangements of the crust of our planet. One of the most impressive of
these rearrangements is a vast slow-motion collision at the junction of the
Pacifi c and Indian Oceans, a geological maelstrom that has led to the forma-
tion of Indonesia and the Philippines.
This collision is bringing together animals and plants that have followed
separate evolutionary paths for two hundred million years. In this and in
subsequent chapters we will follow the consequences of that collision.
