What Caused The Cambrian Explosion, and What Came Before?

[GEOGIRL]

Awesome video! Love the explanation and your rhetoric ;D Keep it up!

[Andy_Babb]

Thanks for the steady content! Super informative and conveyed simply for us mouth breathers lol

[kimiOfDieLinke]

Ah I didn't knew about this one before :)

[ianchenofficial]

I had a great pun of the Cambrian off the top of my head. Until I realised I didn’t have a head until the Ordovician……

[pitchlumin]

So before the ediacaran, there was a snowball earth. Were the organisms that lived through this period single cell, or was there already an array of multicellular organisms?

Curious how many areas have this ediacaran era layer too? We have a thick enough layer to see a cluster of fossils lower down the layer, and less on top, as you said they were dying off going into the cambrian?

[addish]

So you eyeballed some pictures of Spriggina, notes that it (superficially) resembles a trilobite, and that makes it a trilobite ancestor? That is just poor science. I doubt any Ediacaran researcher thinks this. According to Daley et al,

“No definitive characters have yet been identified that allow us to confidently place these fossils (proarticulatans) within Euarthropoda (or even within Metazoa). Spriggina, for example, does not possess bilateral symmetry, but instead has a marked offset along the midline (103), and this alone is sufficient to reject a euarthropod affinity.”


Now, you did argue that bilateral symmetry could be easily stumbled upon through a simple mutation but what about the many other disparities? I don’t currently think there’s enough time to bridge these as you have missed the crucial issue. There is some ambiguity as to how long lasted because of a lack of precise dates of Ediacaran rocks, but the Cambrian Radiation only lasted at most, 25 million years. There is only at most, 25 million years to go from a Spriggina-like animal to a trilobite and this seems implausible.



When I am arguing such fossils “appeared out of nowhere” it is reference to this interval in the early Cambrian. Taphonomic bias doesn’t explain the lack of ancestral forms because the Ediacaran has multiple lagerstatte with soft tissue preservation. Why do none of these organisms share unequivocal traits of these Cambrian phyletic groups? (and no, eyeballing them doesn’t count. I need phylogenetic analyses.)

[logmonkeyrvr]

Na. Life came from nothing is a religion.