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Whatever the origin of the brain organ in evolution, There has certainly been a lot of novel inventions after that time. A lot of interesting "design" has happe

by netcan 12y ago

Whatever the origin of the brain organ in evolution, There has certainly been a lot of novel inventions after that time. A lot of interesting "design" has happened for a long time after that invention, separated by divergence. 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.

caf 12y ago
So I was using "brain" in the same sense as the article, as a shorthand for "central nervous system". 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.
- netcan 12y ago
  The 'earliest known example' (520mya) discussed dates to around the cambrian explosion, the geological period where the fossil record is rich with "earliest examples" and type specimens for phylums. 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.
a_bonobo 12y ago
Interesting that you chose cephalopods - their eyes work similarly in the "basic layout" to vertebrate eyes but cephalopod eyes have a few key differences, which may again be convergent evolution, since the most recent common ancestor didn't have eyes, only a photosensitive spot (which is still present in jellyfish).
agumonkey 12y ago
> 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. 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.

by netcan 12y ago

caf 12y ago

So I was using "brain" in the same sense as the article, as a shorthand for "central nervous system". 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.

netcan 12y ago
The 'earliest known example' (520mya) discussed dates to around the cambrian explosion, the geological period where the fossil record is rich with "earliest examples" and type specimens for phylums. 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.

a_bonobo 12y ago

Interesting that you chose cephalopods - their eyes work similarly in the "basic layout" to vertebrate eyes but cephalopod eyes have a few key differences, which may again be convergent evolution, since the most recent common ancestor didn't have eyes, only a photosensitive spot (which is still present in jellyfish).

agumonkey 12y ago

> 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. 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.