Thursday, 22 January 2015

Unintelligently Designed Reproduction

Petunia (P. × atkinsiana)
Credit: Hiroyuki Kakui
Sophisticated system prevents self-fertilization in petunias | EurekAlert! Science News

Why would an intelligent designer design a system which is prone to errors then design a mechanism for avoiding those errors, and then, in different circumstances, have to break that avoidance mechanism because the solution is worse that the problem it was intended to solve?

I don't expect any self-respecting intelligent design creationists to answer that question because the default, "It's all a mystery which humans can't be expected to understand", or the easier, "I'm ignoring that question because it can't be true", response should have cut in by now.

The problem though is that the natural world is full of examples of just those things if you look at it from an ID creationist point of view. Take the example above, where plant biologists have worked out how petunias avoid the problem of self-pollination by having a mechanism that recognises and rejects their own pollen - termed 'self-incompatibility'.

But maybe I need to explain the basics of the problem here:

In order to replicate sexually, which gives an evolutionary advantage in shuffling the genes around so beneficial combinations can come to dominate the genepool, plants and animals need to produce 'male' and 'female' gametes which unite to form a new individual. Most plants and many animals produce both sorts of gametes - Yes! Despite what the Bibles says (Genesis 6:19), creationists, many animals are not male or female but male and female (hermaphrodite)! The problem is that this means there is a good chance that a 'male' and a 'female' gamete from the same individual will fuse, so wasting the entire effort which went into the mechanism for ensuring a shuffling of the genes in the first place.

Leopard slugs (Limax maximus) mating
Source: Wikipedia. Credit: T. Hiddessen
This means that there is normally considerable advantage in having a mechanism of some sort to avoid this happening. Some species avoid it by producing different types of gamete at different times; some by having a recognition system like petunias; some by having a carefully controlled transfer mechanism such as slugs and snails have, and some, like most higher animals and some plants by having male and female individuals who only produce one sort of gamete anyway.

However, some plants have managed to overcome these self-incompatibility avoidance mechanism because being self-fertile at least means you produce seeds which survive into the next season even if it would have been better if you had managed to shuffle the genes. In circumstances where there is a high risk of not being pollinated by a different individual, and a good chance that you won't survive the winter, suddenly, self-fertilisation makes sense again, so the avoidance mechanism has to be broken or abandoned.

I showed an example of this a couple of year or so ago with a common garden and agricultural weed called the red shepherd's purse (Capsella rubella) which probably arose from a single incidence of 'selfing' in a related species (Capsella grandiflora) about 30-50,000 at the dawn of agriculture when human agricultural activity happened to create an environment in which selfing gave an advantage. This happened because the self-incompatibility mechanism broke. In this example, of course, we also have an example of a new species arising by mutation.

So, the obvious question for creationists, to which I don't expect an intelligently designed answer, is, why would any intelligent designer design a reproductive method that carries such a high risk of wasted effort that has to be overcome in so many different ways, and then break that mechanism when the solution to the problem turns out to be worse than the problem it was designed to overcome?

And how is this a better explanation that the one offered by Darwinian Evolution by Natural Selection with no intelligence and no purpose involved and where short-term utilitarianism rules, please?

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