SCIENCE: A new row evolves

Evolution is again under fire. Charles Arthur looks at the arguments

This autumn, schoolchildren opening their biology textbooks in the American state of Alabama will find warnings pasted to some pages. Evolution, the stickers say, is "a controversial theory that shouldn't be considered fact". Meanwhile, in New Mexico, Texas and Michigan, the six-yearly review of those states' school course material is in progress - and there are fears that similar challenges will be mounted to what has been called "the unifying theory of life and earth sciences".

Who is challenging evolution? Religious groups and individuals keen to push a "creationist" point of view, based on the Biblical scriptures, who see the theory first put forward by Darwin as a challenge to their beliefs. What is worrying is that in some states, such as Alabama, they are driving tiny wedges into some areas of teaching that could, in future, lead to bigger cracks in the public's understanding of science and its uses.

In some US states, the depth of religious feeling has meant that Darwin's theory has always sparked strong opposition. In 1925, the teacher John Scopes was found guilty in Tennessee of the heinous crime of teaching evolution to schoolchildren. Things have improved - in June a Tennessee teacher was suspended for two days for introducing a creationist guest speaker to secondary-school children who told them "as far as the formation of the Earth goes, there are two theories: one is evolution and one is creationism. There's no third position. Either the Earth formed slowly or very quickly."

Advocates of "creationism" (or the more recent "creation science", which attempts to create a coherent theory that coincides with Biblical thinking) do, though, face one huge obstacle: the US Constitution forbids the government establishment of religion. That meant, first, that Biblical teachings could not be put up in direct opposition to science teaching in classrooms.

The lobbyists then tried another tack, by attempting to have "creation science" put onto an equal footing with evolution as "a theory" which should be examined and tested against evidence. It seemed promising - but the Supreme Court knocked it down in 1987, ruling that "creation science" is religion, and so cannot be taught in publicly funded schools.

(The situation in the UK is a lot clearer: evolution is part of the National Curriculum for GCSE science, and so is compulsory.)

In the face of the court decisions, the only alternative left for US creationists has been to try to chip away at the credibility of the theory of evolution by questioning its validity.

But why does it matter if American teachers do or don't teach evolution, and if textbooks call it a "theory" (which, after all, it is)? "There's a variety of reasons," says Molleen Matsumura, network projects director for the National Center for Science Education, a non-profit group based in Berkeley, California, which acts as a national clearing house for information to "keep evo- lution in the science classroom and 'scientific creationism' out".

"First, it leads to inadequate textbooks and the intimidation of teachers. If they're told their jobs are at risk if they teach evolution as a fact, what else might they be prevented from teaching for political and religious reasons?

"Second, it has an impact on general scientific literacy. Every two years the National Science Foundation carries out a survey of the general public: the latest one [performed in 1995] found that only 2 per cent understood science as the development and testing of theory." More worryingly, only 44 per cent agreed with the statement "Human beings, as we know them today, developed from earlier species of animals."

Ms Matsumura notes, "If children don't understand science as a process, they don't see how knowledge is created. And you have to understand how people use words in everyday language. If somebody says 'That's just a theory', they mean it's like a guess. They don't understand what a scientist means by saying that evolution is a theory."

But in a country so large and which contains such extremes of religious thinking, it's clear that organisations like NCSE have their work cut out keeping tabs on religious groups' attempts to chip away at the tenets of science. Part of the problem is that, especially with school-age children, it is easier to raise the objection ("How could the first self-replicating molecule create itself?) than explain the answer.

Meanwhile, the NCSE is readying itself for the next rounds of the battle. "When school restarts in the autumn, we expect to see more activity - more teachers being intimidated about what they can teach, more pressure on what textbooks can include," says Ms Matsumura. "The funny thing is that many religions - such as Catholicism - are quite happy to accept evolution as a theory which explains how we developed. But sometimes, the people raising the objections don't know it."

COULD YOU DEFEND EVOLUTION?

The 16 questions below are shortened versions of those on the "Creation Science" Web page (http://emporium.turnpike.net/C/cs/quest.htm), which challenges supporters of the theory of evolution to explain various aspects of it. If you can't answer at least 10 of the 16 quite easily (and saying "Because it does" doesn't count), perhaps you should brush up your reading: try Climbing Mount Improbable and The Blind Watchmaker (both by Richard Dawkins). You could also have a look at one response by an American student, Mark Vuletic, at .

1. How could the Big Bang generate something from nothing? And explosions create disorder, not order - how could the Big Bang have led to the formation of stars, planets and people?

2. The Universe depends on fundamental physical laws (gravity, conservation of mass and energy, etc) like a computer program depends on its hardware. How could these great controlling principles develop by accident?

3. The Second Law of Thermodynamics says that systems become more disordered over time. How could evolution have generated order from disorder in a closed system - the Universe?

4. Information theory states that "information" cannot arise from random events. How could humans have arisen from randomness?

5. How could self-replicating life have emerged from dead chemicals?

6. Cells require both DNA (the "plan") and RNA (the "copier"), which are tremendously complex, to survive. What chance is there that both these co-dependent necessities came into existence at exactly the same time?

7. Life is complex: how reasonable is it to believe that purely natural processes, with no designer, no intelligence, and no plan, produced humans?

8. If evolution has been taking place for so long, shouldn't there be many more transitional fossils between species? And why are the few examples shown by archaeologists intermediate in only one feature, rather than many?

9. Could an intermediate between one species and another survive, since it would not be ideally suited to its old environment or its new one?

10. How could reproduction evolve? And why should two sexes evolve so many times - wouldn't asexual reproduction be more efficient?

11. How could the first plants survive without photosynthesis - a very complex process?

12. How do you explain symbiotic relationships, where plants and animals need each other to survive?

13. Why should natural selection start to make an eye or a wing (or anything else), if that would not benefit the animal until it was complete?

14. How can evolution explain the metamorphosis of a caterpillar into a butterfly?

15. Why can't scientists demonstrate evolution? It should be easy, if it is the grand mechanism that produced all natural things. It should be possible to prove its existence in a matter of weeks or days. But even the simplest of experiments has not been able to document it - why not?

16. Complex things require intelligent design - so what designed us?