I’ve just returned from watching Rise of the Planet of the Apes at my local cinema, and I’m happy to report that there were no scientific shortcomings or flaws whatsoever in this movie.

ONLY KIDDING! While it is certainly an enjoyable flick, and boasts terrific visual effects (especially once all the argy-bargy kicks off in the third act), its scientific aspects are indeed a little confused. Now, I’m not naïve: I realise that a movie that portrays the rise of a domineering superspecies of genetically modified ape is unlikely to be wholly realistic. And as well as the overarching fantasy, I am more than happy to accept some of the more trivial scientific anomalies, such as the idea that a few hundred nonhuman primates — species that breed very slowly (maybe one offspring per couple every four or five years) — can threaten to outpopulate humanity itself any time soon.

But what does irritate me a little about the movie is its strapline: ‘Evolution Becomes Revolution‘. Because it is pretty obvious that, while revolution might be apparent, what preceded it was not evolution. At least not in this movie. In fact, the central plot device here runs so counter to the principles of evolution that it appears to belie even Victorian-era biological science. In other words, it pre-dates Darwin.

I’ll try to avoid spoiling the story for readers who haven’t seen the movie yet (although, apparently, scientists have now shown that spoilers actually enhance our enjoyment of movies), and so I will focus on the events portrayed in the official trailer (see above).

It will be clear that the high intelligence of the leading chimp, Caesar, is being attributed to a newly developed gene therapy originally intended to enable the human brain “to repair itself“. It will also be apparent that, eventually, a whole bunch of other apes also become “contaminated” with the therapy, which you see Caesar himself retrieving from a refrigerator. As you might imagine, the stuff also transforms their brains (overnight, as it happens), so that they too become super-intelligent. And then they go on to wreak havoc, etc., etc.

But the original ape, Caesar, was not himself administered with the therapy. Rather, his mother was, which is why we see him as a baby. And what’s more, she received the therapy after having conceived: the scientists in the lab had no idea that she was pregnant (suggesting that they didn’t even take any x-rays, which is surprisingly shoddy). So, apart from being a little messianic, what’s the big problem here? Well, given that the treatment is a gene therapy, it is unlikely that its effects would be transmitted from mother to child in this case. Rather, Caesar’s genes should be derived from those of his mother (and father) at the point he was conceived, which was before the gene therapy was part of the picture. Therapeutically altering the a pregnant mother’s genes should not retroactively alter the genes of her foetus. So Caesar should really just be an ordinary run-of-the-mill chimp, not the revolutionary simian demagogue seen in the movie.

The idea that traits acquired during a parent’s lifetime are then passed on to offspring is sometimes referred to as soft inheritence or Lamarckism (after the biologist Jean-Baptiste Lamarck) and was the prevailing view of trait heritability prior to Darwin. For example, back then it was theorized that giraffes evolved long necks because parents who regularly stretched upwards to reach food on high branches ended up giving birth to stretched-necked baby giraffes. However, what really happens is that genes are transmitted, rather than traits. Stretching to reach high branches will not change your genes, and so will not affect the necks of your offspring (whether or not you are a giraffe). Darwin’s contribution was to point out that genetically long-necked giraffes will be more likely to survive into adulthood and reproduce, and so will transmit the long-neck gene to offspring in greater numbers than their short-necked counterparts.

Actual interference with genes using miracle drugs will certainly complicate matters, and some gene therapy viruses might be able to penetrate the placenta (although the choice of viral vectors usually aims to avoid this). But, overall, the complications should only really emerge if mutagenesis happens before the parents conceive. And this certainly generates something of a plot-hole in the present case (although, admittedly, it is not as bad as the creation myth written into the original 1968-1973 pentalogy, which involved super-apes from the future travelling back in time in order to spawn their own species. Aaargh!).

This is the actual ending of the 1971 movie. Don't have nightmares!

There are a few other smaller problems with the portrayal of evolution in the movie. For example, right at the end, Caesar displays a startling ability that would require far more than just an increase in intelligence, it would also require a plethora of anatomical and physiological attributes (a larger larynx, for one thing) which in human evolution took several thousand generations to emerge. The idea that intelligence-boosting genes or cellular alterations in brain anatomy would achieve this on their own is, well, a bit silly.

And of course, the notion that hundreds of contaminated apes can become super-intelligent instantaneously upon exposure to the gene therapy is completely ludicrous in the context of the role of genetic transmission in influencing biological evolution, and thus in the context of genes themselves.

Don’t get me wrong. This movie is very watchable and good fun and if this were a review, I’d be happy to give it a thumbs-up. It is, after all, fiction. It’s just that ‘Evolution Becomes Revolution‘ is a silly tagline. It’s as though the word ‘Evolution’ is thrown in merely to refer to the presence of apes in the storyline, as if the descent of man from apes is the main thing that evolution involves.

In fact, ‘Something-that-isn’t-evolution-and-has-little-or-nothing-to-do-with-it Becomes Spectacular-CGI-emblazoned-morality-and-action-based-mass-entertainment‘ would have been more accurate.