VOICE ONE:
This is SCIENCE IN THE NEWS in VOA Special English. I'm Bob Doughty.
VOICE TWO:
And I'm Doug Johnson. November twenty-fourth marked the one hundred fiftieth anniversary of one of the most influential books ever written. Naturalist Charles Darwin published "On the Origin of Species" in eighteen fifty-nine. The book was an immediate success in the scientific community. Today, evolution forms the basis for the modern science of biology.
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VOICE ONE:
Evolution can be defined as change in groups of living things over time. Small changes take place in each generation of organisms. Those with useful changes survive to reproduce. Changes that do not aid survival disappear. This is the idea of natural selection. Over long periods of time, these small changes result in the creation of new species. They are the reason for the many different kinds of life on Earth.
The idea that species change was not new even in Darwin's time. The idea dates back to ancient Greece. In the late eighteenth century, Darwin's grandfather, Erasmus Darwin, suggested that species evolved from their ancestors. He even thought that competition helped drive change.
At the beginning of the nineteenth century, Jean-Baptiste Lamark attempted a fuller explanation. He suggested that individual organisms changed in reaction to their environment and passed on these traits to the next generation.
VOICE TWO:
Darwin had been working on his theory for over twenty years when he published "On the Origin of Species." Yet it was the work of naturalist Alfred Russel Wallace that pushed Darwin to finally release his theory. Wallace had studied plants and animals in South America and the South Pacific. In eighteen fifty-eight, he sent Darwin a short study he had written containing ideas about evolution. Darwin was shocked by its similarity to his own work.
In July of that year, Darwin's friends Charles Lyell and Joseph Hooker had studies by both men presented to the scientific group called the Linnean Society of London. But the first explanation of evolution in public caused little reaction.
A year later, Darwin would complete his detailed study of evolution through natural selection. With its publication, Darwin gained important supporters like Thomas Huxley who were willing to defend his ideas.
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VOICE ONE:
Evolution, however, did not explain everything about how species evolved. It is important to remember that many of the greatest biological discoveries had yet to be made when Darwin published "On the Origin of Species."
WARREN SCHMAUS: "When Darwin first proposed his theory in eighteen fifty-nine, he had no concept of a gene, no concept of a chromosome, no concept of mutation, and certainly no concept of things like DNA and RNA."