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Darwin and Evolution
On Earth, there literally exists millions of organisms of every size,
shape and habitat. The questions at hand are…How did all these
organisms get to be here in the first place? How are these
organisms related? What makes life what it is?
The scientific branch that attempts to explain these questions by
using collections of facts, observations and hypotheses is known
collectively as EVOLUTIONARY THEORY.
Evolutionary theory tries to explain the change in organisms over
time and how modern organisms descended from ancient
organisms.
The Voyage of the HMS Beagle
The individual who perhaps made the most contributions to the
field of evolution was CHARLES DARWIN.
Charles Darwin was born in England in 1809,
and after completing his college studies, he set
aboard the HMS Beagle, an English royal navy
ship, as a map maker hired to plot the coast line of
South America. Although he did not know at that
time, Darwin would soon become one of the most
influential names in the world of science.
Whenever the HMS Beagle anchored, Darwin
went ashore to collect plant and animal
specimens, which he added to an ever-growing collection. Each
piece that Darwin collected along the way served as a “puzzle
piece” in his ever-growing curiosity about this strange new world.
Darwin, being very curious about the world around him, made
many observations of what he saw in South America, a new land
that he had never seen. Darwin, wrote down his observations, as
well as made many sketches of what he saw. His information
gathered on his trip would soon serve as a basis for the theory of
evolution.
What Darwin Saw…
Back in England, Darwin was very knowledgeable about the nature
of his country. But in South America, he saw far more diverse
species that he had never seen before.
Patterns of Diversity
When looking at the new and diverse species he stumbled across, he
noticed how well many of these species were adapted to the
environment in which they were living. He was also impressed in
how many of these species reproduced and produced offspring,
many in which he had never seen or heard about before. In front of
him, a new view on how nature works was beginning to unfold.
He was also puzzled by where different species lived and did not
live. In his travels, Darwin visited Argentina in South America and
Australia, which both have similar ecosystems, yet both
ecosystems were inhabited by very different animals. This
confused Darwin because he thought that similar ecosystems should
have similar animals…which in this case, it didn’t.
He asked himself why there were rabbits in the grasslands of
Europe but not in the grasslands of Australia, which Darwin
thought would also be a perfect place for rabbits. At the same time,
why were there Kangaroos in Australia but not Europe?
Living Organisms and Fossils…
Darwin soon realized that the living organisms that he saw were
only half of the puzzle. In many places on his voyage, Darwin came
across many FOSSILS of organisms that didn’t look like any of the
living organisms in the area. This posed even more questions, like,
“Where did these species come from?” and “Where did these
species go if they’re no longer here?”
The Galapagos Islands
Of all the places in which the HMS Beagle anchored at, the
Galapagos Islands, off the coast of modern-day Ecuador,
influenced Darwin the most.
What Darwin noticed about these islands was that although they
were closely packed together, each island had a different climate
with different geological characteristics. Some were low elevation
and dry while some others had large volcanoes and were very wet.
On these islands, Darwin encountered a small brown species of bird
called a finch. Each island within the Galapagos chain had a
unique version of this finch. Some islands with an abundance of
insects had finches with long, slender beaks, whereas some islands,
which had an abundance of fruit and nuts, had finches with large
beaks, designed to break open large seeds.
Darwin found this odd, that a species that lived in such a close
proximity, had such a diverse physical characteristics. It wasn’t
until later, that the importance of these tiny birds would be noticed.
The Journey Home
On his way home back to England, Darwin pondered his results and
observations, especially the ones about the tiny little finches on the
Galapagos. Darwin began to wonder if animals living on different
islands had once been members of the same species long ago.
Darwin hypothesized that these separate species evolved from a
common South American ancestor, which later became isolated
and were forced to change to meet their environmental demands.
He thought, that if this hypothesis was possible, it would change the
world’s views of the natural world.