Scientific American Frontiers, Season 10 - Episode 1 - Voyage to the Galapagos

"VOYAGE TO THE GALAPAGOS"
SHOW 1001
Episode Open
Darwin's Eden
Evolving Beaks
Lizards of the Sea
Masked Killers
Paradise Lost?
EPISODE OPEN
ALAN ALDA: Charles Darwin once rode on one of these. And it was something
about their shells that gave him the first clue that living creatures change over
time.
ALAN ALDA (Narration): The giant tortoises of the Galapagos Islands are among
the many unique animals here…
ALAN ALDA: OK, I'm sorry, I'm sorry.
ALAN ALDA (Narration): …that got Darwin to thinking about how new species
come into being. Today, the islands' creatures still amaze their visitors…and
provide insights into how evolution works.
ALAN ALDA: I'm Alan Alda. Join me, and the creatures that inspired Darwin, as
we Voyage to the Galapagos.
back to top
DARWIN'S EDEN
ALAN ALDA: In 1831, at the age of 22, Charles Darwin set off on a voyage that
would change not only his life but ours as well. The naturalist on the British Naval
ship The Beagle, Darwin traveled around South America and beyond. What he
saw on an isolated group of islands out here in the Pacific began an intellectual
voyage that would last some 20 years, and would culminate in the then shocking
idea that living things are not designed according to an unchangeable plan, butinstead are shaped by the world around them. When the Beagle finally anchored
here in the Galapagos in September of 1835, Darwin was very excited about
coming here. He was really fascinated with the geology of the place, particularly
the volcanic origin of these islands. But when he actually set foot on the shore,
he was very disappointed in this place. In fact, this is what he wrote: "Nothing
could be less inviting than the first appearance. A broken field of black basaltic
lava is everywhere covered by a stunted brushwood, which shows little signs of
life. The dry and parched surface, having been heated by the noonday sun, gave
the air a close and sultry feeling, like that from a stove."
ALAN ALDA (Narration): Six hundred miles off the South American coast, the
Galapagos Islands are actually the tips of volcanoes that have pushed their way
above the ocean surface. The oldest islands were formed some 2 - 3 million
years ago. The youngest -- including the biggest, Isabela -- are a few hundred
thousand years old -- with volcanoes that still erupt. My visit to the Galapagos is
to take me to over half the dozen or so major islands -- including one whose
volcanic origins are only too apparent.
ALAN ALDA: These rocks look like they're laid out in a circle.
LYNN FOWLER: Yeah, this is Devil's Crown. It's an old eroded crater that's very
shallow here in the middle.
ALAN ALDA: We're in the middle of a crater, a volcanic crater?
LYNN FOWLER: Yeah, it's not going to erupt though, don't worry.
ALAN ALDA: How do you know?
LYNN FOWLER: It's old. It's all eroded.
ALAN ALDA: A lot of old things erupt. Me! I'm really surprised at how lush it is…
ALAN ALDA (Narration): My guide on the trip is Lynn Fowler, a biologist who has
spent much of her life in the islands.
ALAN ALDA: What is this trail?
LYNN FOWLER: Oh, that's a land iguana trail.
ALAN ALDA: So at the end of this trail we might find an iguana?
LYNN FOWLER: We might find one. Let's see…ALAN ALDA (Narration): And here, as if waiting patiently for our arrival, is a
creature that Darwin was not immediately impressed by.
ALAN ALDA: When Darwin first saw these land iguanas, he thought they looked
slow and stupid. In fact, there's a funny story he tells about that. Darwin was
watching a land iguana burrow, making a hole somewhat like this one. And
Darwin gave the tail a little yank. And the iguana backed out of the hole and
looked at him, as if to say, "What did you do that for?"
ALAN ALDA (Narration): What Darwin interpreted as stupidity in the islands' land
iguanas is in fact an extraordinary indifference to humans that's shared by all the
Galapagos animal life -- and that Darwin repeatedly noted in his account of his
voyage. He took advantage of it in his several encounters with the Galapagos
Islands' most famous residents, the giant tortoises.
ALAN ALDA: "As I was walking along I met two large tortoises, each of which
must have weighed at least two hundred pounds. These huge reptiles,
surrounded by the black lava, the leafless shrubs, and large cacti, seemed to my
fancy like some antediluvian animals. I was always amused when overtaking one
of these great monsters, as it was quietly pacing along, to see how suddenly, the
instant I passed, it would draw in its head and legs, and uttering a deep hiss fall
to the ground with a heavy sound, as if struck dead. I frequently got on their
backs, and then giving a few raps on the hinder part of their shells, they would
rise up and walk away; -- but I found it very difficult to keep my balance".