Recursion in Evolution

Disclaimer: my biology knowledge ends at 9th grade bio - so everything in this blog post is pretty much fake.

Why are so many things in nature very recursive looking? Fingers are limbs on limbs on a base-case body. Trees are branches on branches on branches on a base-case trunk. Many plants are symmetric in a way that seems like it could be specified in a very simple recursive way.

Here’s my (probably unoriginal) current theory why this is: recursive specifications, in some cases, take up significantly less space than their non-recursive counter-parts. In the case of plants and animals, this means that the DNA that can be used to express a tree in recursive form is X pairs, while a similar tree in non-recursive form is 1000X pairs (or something).

I bet that this has a major practical benefit - from the perspective of a tree. Namely, the odds a tree gets some fatal mutation is much smaller; the mission critical set of genes is much smaller - and so with a total amount of space the genes can take up in either case, there can be more backups when there is a smaller specification.

The next obvious question is: why does a tree have to be a tree at all? The answer, I think, is that there is an evolutionary advantage to growing how a tree did: namely, tall and big. So, if a tree wants to be tall and big, it has two options. Use a small set of genes to do it and have less risk of dying due to some mutation. Or don’t, and lose to the trees that did.