The world is just so incredibly awesome, I have no words for how awesome it is.

[summer_jackel]

http://richarddawkins.net/article,3361,n,n

Thanks starchy for pointing me in the direction of this absolutely exquisite discovery which may shed light on the cambrian speciation event. Science is just so awesome, in the literal sense, and our magnificent world moreso than I am able to put into words.

Also, as long as I'm here, I should mention the pointy muzzle sticking into my armpit and the curious, soulful, piercing blue eyes looking up at me. He's an odd, quiet, quirky little dogchild. Evidence of the individual that this young being is becoming include the couch pillow that I found carefully arranged in the dog bed yesterday and the way that all of the dog and cat toys magically gravitate to the foot of my bed every morning. Coba's come home. He is going to be an amazing little companion, and I am grateful for his unique presence.

Comments

[hakeber.livejournal.com]

I love living fossils.

And dogs. I also love dogs.

[summer-jackel.livejournal.com]

Two of my favorite things too. :)

[chipuni.livejournal.com]

Coba sounds like a wonderful being, and a generous soul. (He wants you to have the toys!)

[summer-jackel.livejournal.com]

Coba is a neat little guy! very unique pup. And he does share. It's precious.

[nesting.livejournal.com]

coba is a great name. i like it!! he's going to be lovely.

great article too. just WOWWWWW.

[summer-jackel.livejournal.com]

I adore the little guy. :) And his name is short for Outlaws Cobalt Gambit. I'm pleased you like it.

Cellular differentiation as Cambrian Explosion trigger

[cphoenix.livejournal.com]

What caused/enabled/triggered the Cambrian Explosion? I theorize that it was cellular differentiation. A jellyfish can regenerate from a single polyp: the cells are specialized but not differentiated. This implies that they need constant chemical signaling to tell them what to be - an energy cost, and a barrier to complex finely-featured organ systems that will break if they accidentally reconfigure. (The animal ancestors of jellyfish, unlike most animals, predate the Cambrian Explosion.)

Methylation is a candidate mechanism for differentiation. Organisms all the way back to bacteria use methylation as an evolutionary "tuning knob" allowing adaptation in just a few generations. But methylation _on command_ would require a distinct mechanism. The methylation patterns of stem cells and differentiated cells are known to be different...

From the point of view of single-celled organisms, or even Cnidarians, the ability of a cell to lock itself and its descendents irreversibly into a non-totipotent state would appear to be suicidal. It could easily have taken tens of millions of years for such an innovation to develop and be found fit by evolution. But once it developed, it would allow much more complex and ramified organ systems at much lower cost - a brief burst of intense sharp-edged chemical signaling during embryogenesis, and you've got your organs in shape for your whole lifespan.

One of these days, I'll finish revising the paper I'm writing on this hypothesis... copies on request.

Re: Cellular differentiation as Cambrian Explosion trigger

[summer-jackel.livejournal.com]

Oh, awesome! Thanks for this. I am quite interested. Science makes me happy.