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The Theory of Evolution

The Theory of Evolution

Introduction: Evolution is the theory of how organisms change over time. While some may say that it is "only a theory," in science, a theory is pretty much accepted as fact. The term is not attached to an idea unless there is significant evidence to support it. Ever since Charles Darwin first presented the idea in 1859, there has yet to be a single piece of evidence that disputes what he said.

Evolution takes time, which is why scientists need evidence to support it. Fossils, homologous structures, vestigial organs, and even DNA evidence all work to show that it is possible that one species can evolve into another. This does not mean that chimpanzees turned into humans, but rather they share a common ancestor. Those intermediate species that were not successful in the environment died out, taking their genes with them. Those species that were successful, survived to reproduce and move forward.

Evolution shows how species are related and, even more, that all life on Earth shares a common ancestor.

The finches of the Galapagos Islands provide strong evidence for Darwin's ideas. The beaks of these birds are specially adapted for the island on which they live and the food they eat, but there is no doubt these birds are related to each other.

Directions for this Lesson: Answer the practice questions and then watch the video to learn more about the evidence that supports the Theory of Evolution.

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