Shrews eating peppers
NOT evolution in action
A lot of us may like hot spicy foods, but we also know that they produce a burning sensation. So most animals avoid them—probably why plants have them in the first place (as well as to repel insect-borne fungal infections1). The burning sensation is due to a chemical called capsaicin, named after the Capsicum genus in which it was discovered. This stimulates a type of ion-channel receptor called TRPV1, producing similar sensations to burning or abrasion, and also causes the same types of inflammatory response. (The venom of some tarantulas causes the same painful reaction by stimulating the same receptor.2)
However, some Chinese researchers were intrigued to notice captive tree shrews (Tupaia belangeri chinensis) gladly guzzling chili peppers.3 They discovered that a single ‘letter’ mutation in their gene for TRPV1 reduces its sensitivity to capsaicin.4 So they are not so bothered by the chemical.
So how did they end up with such a mutation when there are no chili peppers in their natural habitat? The answer is that these habitats contain another type of pepper, Piper boehmeriaefolium, which contains Cap2, a chemical similar to capsaicin. So the mutation that lowers receptor sensitivity is beneficial to the shrews, because it makes a wider range of food available.
Decoding evolutionary agitprop
Such a change would be no surprise to those informed by a proper biblical Creation-Fall model. It is one of many examples of an information-losing mutation that happens to be advantageous to the animal. However, this sort of change is in the opposite direction required by prokaryote-to-professor evolution, which requires information-gaining changes.5 Furthermore, if it was advantageous enough to leave more surviving offspring, then by definition it would be favoured by natural selection. Note, natural selection was discovered by creationists before Darwin, and does not create the fit; rather, it eliminates the unfit.
This reality is often hidden by the evolutionary code language, which needs a biblical decoder ring to decipher the reality. For example (emphasis added):
- Animals avoid chilis “which is precisely why such plants evolved to be hot and spicy in the first place.”3
Since chilis make capsaicin in a complex synthetic pathway involving many enzymes, it makes sense that they were designed to make them, especially for the foreknown post-Fall world. 6
- “We propose that the mutation in tsV1 is a part of evolutionary adaptation that enables the tree shrew to tolerate pungency, thus widening the range of its diet for better survival.”4
It is certainly an adaptation that widens its diet range, but is not an evolutionary one, because it’s going in the wrong direction.
- “It’s therefore believed that shrews with the mutation in question gained an evolutionary advantage over those without, thanks to their expanded diet.”3
Well, they gained an advantage, certainly. And this advantage enabled it to survive and leave more offspring, so it is a selective advantage.
Such research should be welcomed by biblical creationists. The main points we need to remember are:
- Mutations, even beneficial ones, usually destroy information, while evolution needs huge numbers of information-gaining mutations.7
- Natural selection is not evolution—it’s a culling force, not a creative force.
References and notes
- Tewsbury, J.J. and seven others, Evolutionary ecology of pungency in wild chilies, PNAS 105(33): 11808–11811, 19 August 2008 | doi:10.1073/pnas.0802691105. Return to text.
- Siemens, J., Spider toxins activate the capsaicin receptor to produce inflammatory pain, Nature 444:208–212, 9 November 2006 | doi:10.1038/nature05285. Return to text.
- Tree shrews’ taste for spicy foods explained, BBC focus, September 2018, p. 20. Return to text.
- Han, Y. and 13 others, Molecular mechanism of the tree shrew’s insensitivity to spiciness, PLOS Biology, 12 July 2018 | doi:10.1371/journal.pbio.2004921 Return to text.
- Wieland, C., The evolution train’s a-comin (Sorry, a-goin in the wrong direction), Creation 24(2):16–19, 2002; creation.com/train. Return to text.
- Batten D. (Ed.), How Did Bad Things Come About? Ch.6, Creation Answers Book, 8th Edn, CBP, 2018;creation.com/cab6. Return to text.
- Note: CMI advises against making categorical claims such as “Mutations can never add information.” As information is foundationally an argument from probability, we might expect a few cases of trivial information increase. But evolution from goo to you requires new genes encoding encyclopedic amounts of new information. But case after case of ‘evolution in action’ has turned out to be an information loss, and the pepper-guzzling shrews are no exception. See also Carter, R.W., Can mutations create new information? J. Creation 25(2):92–98, 2011. Return to text.