阅读与表达。

    November 24, 1859 was a special day in London. On the day, many Londoners rushed to a bookstore

to buy a book that was just published. The first printing of 1,250 copies sold out on the first day.

    The popular book was The origin of Species (《物种起源》) by British naturalist Charles Darwin

(1809-1882). In the book, Darwin argued that different forms of life could change over time because of

natural selection. This means that only those who are best suited to their environment will live and reproduce.

Darwin supported his arguments with examples he found during his around-the-world trip in the 1830s.

    The book laid the foundation of modern biology. It changed how other scientists understood the

appearance of life on Earth.

    A hundred and fifty years later, Darwin's theory (理论) of natural selection still has great influence in

the world of science. But some people have a question: since medicine and modern life have made people

healthier, are we still evolving (进化) by natural selection?

    The answer is yes, according to Stephen Sterns and his team of Yale University researchers. They did

a study on 2,238 women in the US. They found that shorter, heavier women have more children then

thinner, taller ones. This trend (趋势) runs among their female children and grandchildren. So if this

continues, women in 400 years will be about 2cm shorter and a kilo heavier.

    Sterns' findings are supported by other scientists. For example, John Hawks at the University of

Wisconsin, US and his team believe they have found nearly 2,000 gene variations (基因变异) in modern

humans. Those variations allow people to drink milk, fight disease and improve brain development.

1. Was The origin of Species a popular book? 

2. When was the book published?

3. What does natural selection mean?

4. Why does the writer introduce Sterns' findings in the passage?

5. Why is Darwin's theory of natural selection important?