Why would an animal lose its brain?
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Cephalopods are very distantly related to us. Our last common ancestor with cephalopods is also our last common ancestor with slugs and hookworms. Yet many species are obviously highly intelligent. Their intelligence seems to work very differently from vertebrate intelligence.
So, it's interesting thing that some descendant species of whoever invented brains opted out. But either way some sort of convergence did happen. Maybe brains evolved twice. Maybe they evolved many times from a common primitive nerve bundle that performed a very different function. Maybe this happened in a tangle of back and forth.
The aye-aye lemur and the striped possum both evolved a long bug catching finger. We know that it's convergent rather than common ancestry because (among lots of reasons, but this is a neat example) it's a different finger. But, they both had fingers to elongate in the first place. So, given the same machinery to evolve and the availability of similar ecological niches (no woodpeckers, lots of bugs) they came up with a smiler solution.
We know that brains, and their components are very flexible even in a mature organism. So it makes sense that evolution is wild and creative, repurposing the tool constantly. I mean the diversity in sense perception in different animals seems like evidence of radically evolving brains over relatively short periods of time. Even entirely new senses (eg echolocation) seem to evolve fairly easily and quickly.
TLDR: depending on what your precise definition of "brain" is, this seems very likely. Aye-ayes & striped possums both have elongated fingers that evolved separately from regular fingers. The fact the they both evolved from regular fingers is interesting, but neither here nor there for most interesting conclusions. Brains are probably like this, but way more interesting any mysterious.
^I feel like I have to credit Douglas Adams who wrote beautifully about these animals.
I think we already knew that once you acquire a CNS, it can evolve rather rapidly to quite complex brains, and that doesn't seem intuitively surprising. It's that first leap to a basic nervous system which seems like the high activation energy barrier, and if it may have happened twice rather than just the once, then I find that interesting.
Maybe another way to put it is 'The definition of brain used in this article might apply to organs other than the brain in modern species." It's basically a nervous system, centralized or not. Who knows what it did or what it was for. It may have a predecessor outside the animal kingdom. Plants have sensory perception, or some version of it.
I'm not disputing the claims in this article or anything else. I'm basically agreeing with you.
Whether or not some nervous system, nerve cells or complexes of nerves evolved 520+mya and were 'lost' in some phyla or was evolved through convergent evolution a little later, it's partially a semantic issue: do we call something a brain. Most of what makes a brain a brain probably came later and evolved separately in different phyla. This means radically different ways of doing things.
BTW, Richard Dawkins really turned me on to evolutionary biology (a side gig, when he's not arguing with dummies) in some of his books. "Ancestors Tale" is awesome for really getting the "phylogenetics" way of thinking discussed here.
Similarly old low bit-width CPUs are "as" potent as nowadays CPUs according to the work/dataflow they have to handle. Or even OSes, win95 could do a lot that a recent Linux/WM can do at a tiny fraction of the structural cost/complexity. Also text encodings.
It's expensive (money or calories) and the extra functionality doesn't help in getting more out there (selling or reproduction).
1. http://www.ted.com/talks/daniel_wolpert_the_real_reason_for_...
The intro to Idiocracy makes the point well: https://www.youtube.com/watch?v=hL1-340ODCM
It's kind of a joke, but also really not. It's frightening.
It is a joke.
Idiocracy relies on the assumption that the "more intelligent" people are snobs and too busy and too perfectionist with their life to have children, while the "less intelligent" people are mostly having sex and are too lazy to apply contraception properly.
Essentially, the first half of the movie is a justification for elitism.
I'm less afraid of Idiocracy to become true, but more afraid of politicians acting as if they believed in this movie.
The second half of this movie is more interesting, though. It may be interpreted as an analogy of how the most gifted people (in the sense of "intellectual giftedness") may feel living in today's world. (by putting today's "normal" people into a dumb world) But even that is, of course, a funny hyperbole, and nothing to take too seriously.
The joke is in the exaggerations and charicatures. The truth is what is real that would cause this joke to be made in the first place.
Obviously smart does not equate to "snobbery" or "perfectionism". And less smart does not equate to "more horny". It is a comedic layer added by the directors to make you laugh, because it is a comedy.
But the truth beneath the funny is that less smart people generally make poorer life decisions. For many people in many contexts, less children for a longer time is a smart life choice, and more children more quickly is not. Because more children more quickly is, in most contexts, in the category of poor decision, it tends to happen more with less smart or educated people.
I don't see how it is an argument for elitism at all. It's an argument for promoting education.
I see it the same way, as an argument for promoting education, throughout the whole population, not just some "elite".
However, I've also seen people arguing for the opposite direction: That the "elite" must be protected from the "mob", must be socially more separated than it already is, or it will die out. And that it must become more attractive especially for the "elite" to become children, while the "mob" will take care of themselves. (The argument wasn't phrased with exactly those words, but the sentiment was essentially that.)
The culprit, however, doesn't seem to be raw intelligence as such, but modern western education, which seems to have a dose dependent sterilizing effect on females. In that light, high IQ isn't fertility-reducing in itself, rather low IQ is protective against modern western education.
Also generally, more clever people focus more on quality rather than quantity, and babies are no exception. Norm are 1-3 kids, not because women are not fertile anymore (unless climacterium is reached), rather time & resources are considered.
Even this is very simplistic & dumbed down view on these matters.
I admire the way you phrased this.
The difference in size between educated and uneducated families might be very large in societies that are in transition on the development scale, but I wonder if the same is true in a society that is stable on that scale. Do uneducated families in the West have more kids than educated families, or do they just have their 2.1 children earlier in life?
Besides which, it's fictional. While there is some truth to the fact that "less educated" people tend to reproduce at a comparatively higher rate than the more educated, it's a fallacy that somehow this is resulting in a "dumbing down" of the human race. For example, raw IQ test scores have been increasing over time quite dramatically (IQ is always normalized to the mean so 100 IQ is by definition the average).
Idiocracy is an entertaining story, and it holds some lessons worth taking to heart, but it is not the truth.
So, I'm agreeing with you in a strict selection sense.
First, you have to avoid conflating culture with genetics. No one 'evolved' to be a good engineer: there has been an insufficient amount of time and probably selective pressure for an engineering gene to arise, spread, and flourish. Instead, we've developed an engineering culture, which can readily spread independent of the genes of the individuals currently carrying the engineering culture. Indeed, even today after a century or two since the dawn of modern engineering there are many fantastic first-generation engineers.
Second, I don't really believe that modern civilization is deficient as an environment for breeding intelligence. Fundamentally, intelligence isn't excellence at a particular culture or being supremely well suited to a particular niche, intelligence is adaptability. Intelligence lets us survive in a great variety of niches, that our ancestors never had the chance to evolve for, to learn new skills and develop new cultures.
Unlike the static worlds of yesteryear where generations could go by without a change and you could expect to live a life identical to your parents with (maybe) different names for the principals involved, everything changes now constantly. Culture, technology, jobs, food, language, social mediums. Everyone has to deal with it. People may not need to demonstrate their intelligence in a way that pleases a certain subset of the intellectual elite, but they're being required to adapt -- by their peers, their mates, their potential mates -- on a scale that has rarely if ever existed in human history.