I had the good fortune to attend a lecture on Friday by Dr John Paterson about the Cambrian Explosion, and how good inferences about the behaviour of organisms from that distant springtime of life can be made by considering such things as fossilized organisms that have healed after an injury, fossilized gut contents, and the size distribution of ensembles of organisms fossilised in different environments. The earliest dates for things like predation and herd/school behaviour seem to be being pushed further and further back.
Once again I was inspired by the magnificent beauty and complexity of the vision that is deep time, and how the contingent, irreproducible events of history have shaped the world that we know.
Best of all, I now realise there is an excellent way to push our search for the origins of life back beyond the fossil record. Molecular fossils! While most of the actual molecules that comprise ancient organisms are long gone, in some strata some of these molecules are tenacious and remain, and others have been transformed in systematic ways into compounds that still preserve some information about their origin. Perhaps succeeding generations of proto-life have not truly eradicated all traces of their predecessors as effectively as I thought.
These molecular fossils also seem to be a fantastic way to answer a question of great relevance to the 'Dr Jumba' theory of intelligent design. How closely related to the Cambrian Explosion beasties were the Ediacaran beasties? The Ediacaran world was very different, Dr Paterson told us- flat microbial mats with flat beasties: nothing that dug beneath the mats, nothing that ate anything else. Were those beasties based on the same chemistry as us? Or not? Surely the chemicals associated with them would give us a clue. I will explore the literature and return with a report.
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