WASHINGTON (Reuters) - The National Academy of Sciences on Thursday issued a spirited defense of evolution as the bedrock principle of modern biology, arguing that it, not creationism, must be taught in public school science classes.

Giant tortoises are seen on the Galapagos islands, April 29, 2007, where British naturalist Charles Darwin conceived his theory of evolution. The National Academy of Sciences on Thursday issued a spirited defense of evolution as the bedrock principle of modern biology, arguing that it, not creationism, must be taught in public school science classes. REUTERS/Guillermo Granja

The academy, which operates under a mandate from Congress to advise the government on science and technology matters, issued the report at a time when the theory of evolution, first offered in the 19th century, faces renewed attack by some religious conservatives.

Creationism, based on the explanation offered in the Bible, and the related idea of “intelligent design” are not science and, as such, should not be taught in public school science classrooms, according to the report.

“We seem to have continuing challenges to the teaching of evolution in schools. That’s something that doesn’t seem to go away,” Barbara Schaal, an evolutionary biologist at Washington University in St. Louis and vice president of National Academy of Sciences, said in a telephone interview.

“We need a citizenry that’s trained in real science.”

Evolution is a theory explaining change in living organisms over the eons due to genetic mutations. For example, it holds that humans evolved from earlier forms of apes.

The report stated that the idea of evolution can be fully compatible with religious faith. “Science and religion are different ways of understanding the world. Needlessly placing them in opposition reduces the potential of each to contribute to a better future,” said the report.

But teaching creationist ideas in science classes confuses students about what constitutes science and what does not, according to the report’s authors.

The report was released by the academy and the Institute of Medicine, which advises policymakers on medical issues. It updates academy publications issued in 1984 and 1999. It was written by a committee headed by University of California-Irvine biology professor Francisco Ayala.

“Biological evolution is one of the most important ideas of modern science. Evolution is supported by abundant evidence from many different fields of scientific investigation. It underlies the modern biological sciences, including the biomedical sciences, and has applications in many other scientific and engineering disciplines,” the report stated.

The authors highlighted developments in evolutionary biology, citing its importance in understanding emerging infectious diseases. They noted the discovery, published in 2006, of the remains of a Tiktaalik, a creature described as an evolutionary link between fish and the first vertebrate animals that walked out of water onto land 375 million years ago.

President George W. Bush said in 2005 American students should be instructed about “intelligent design” alongside evolution as competing theories. “Part of education is to expose people to different schools of thought,” Bush said.

Advocates of “intelligent design” contend that some biological structures are so complex they could not have appeared merely through natural processes.

A judge in Dover, Pennsylvania ruled in 2005 that the teaching of intelligent design violated the U.S. Constitution, which requires a separation of church and state, because it is based on religious conviction, not science.

A 2006 Gallup poll showed that almost half of Americans believe that humans did not evolve but were created by God in their present form within the last 10,000 years.