Hike in the Jungle

A Hike in the Jungle

Current Step:

Welcome to Another Hike!

Today we are going to take an exciting hike into the jungle of the Galapagos Islands in the Pacific Ocean. Everywhere we peer into the jungle mists we see unusual plants and glimpse strange animals. Calls of exotic birds fill the warm, moist air.

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We are retracing some of the steps of Charles Darwin on his five-year voyage around the world.

In South America, Darwin found fossils of extinct animals that were similar to modern species. And, in the area where we are hiking in the Galápagos islands, he noticed many variations among plants and animals of the same general type as those in South America.

From 1831 to 1836 Darwin served as naturalist aboard the H.M.S. Beagle on a British science expedition around the world.

For example, we find Galápagos tortoises that have been living throughout the world for the last 30 million years.

Since they arrived in the Galápagos Islands from the South American continent, they have evolved in isolation on the islands and volcanoes of the archipelago.

We note that this highly successful animal possesses special features that enable it to survive harsh environmental conditions on the Galapagos Islands.

How can we explain the intricacy and adaptedness of the Galápagos tortoise and the many other unusual creatures that we encounter in the Galápagos?

Ancient Greek philosophers like Anaximander had speculated that living beings had developed from non-living ones and that humans had somehow descended from the brute animals. But those early thinkers offered no plausible explanation for such development. Aquinas, Paley, and other observers before Darwin held that the intricacy and adaptedness of organisms can be explained only as the products of intelligent design.

But the modern Theory of Evolution, originating with Charles Darwin (1809-1882) in his book The Origin of Species, explains the intricacy and adaptedness of organisms through a process called natural selection.

In the hard sciences, a theory is a model or framework for understanding. The word theory, in the context of science, means "a coherent group of general propositions used as principles of explanation for a class of phenomena" (Barnhart 1948).An example would be "electromagnetic theory", which is usually taken to be synonymous with classical electromagnetism, the specific results of which can be derived from Maxwell's equations.

Darwin's theory of evolution contains two main hypotheses:

Theory of Evolution

Current Scientific Status

Darwin Hypothesis₁All living beings today are related through family trees that extend into the distant past.

Not controversial in the scientific community—a well-established hypothesis.

There is no question about whether living beings have evolved.

Darwin Hypothesis₂The processes of natural selection accounts for why new characteristics appear in species and why some old characteristics disappear.

Somewhat controversial in the scientific mmunity—but by far the majority view today.

There are questions about why living beings evolved in the way they did.