New fossils found in Gabon might push back the origin of multicellular life. By about 200 million years.Here we report the discovery of centimetre-sized structures from the 2.1-Gyr-old black shales of the Palaeoproterozoic Francevillian B Formation in Gabon, which we interpret as highly organized and spatially discrete populations of colonial organisms.
Macrofossils in colony form from the FB2 level. Scale bars, 1.0 cm.
The authors deduce that these long structures (up to 12 cm) aren't just colonies of bacteria, but must have had cell-to cell signalling and coordinated-growth behaviour.
Although we cannot determine the precise nature and affinities of the 2.1-Gyr macroorganisms from the Francevillian B Formation of Gabon, we interpret these fossils as ancient representatives of multicellular life, which expanded so rapidly 1.5 Gyr later.I'm not at all educated to have an opinion here... They look convincing enough like fossils, but if experts were to tell me that these structures could have been formed by non-organic processes, I'd have to believe them. On the other hand, while this is definitely a story that is deservedly on the cover of Nature, moving the origin of
Evidence of early life, and the chemical state of the atmosphere and oceans, from News & Views article in Nature by Donoghue ∓ Antcliffe, Early life: Origins of multicellularity. The Gabon fossils would push back the first occurrence of
Four different specimens in four different views. a, Original specimen. b, Volume rendering in semi-transparency. c, Transverse (axial) two-dimensional section. d, Longitudinal section running close to the estimated central part of the specimen. Scale bars, 5 mm.
Reference:
Albani, A., Bengtson, S., Canfield, D., Bekker, A., Macchiarelli, R., Mazurier, A., Hammarlund, E., Boulvais, P., Dupuy, J., Fontaine, C., Fürsich, F., Gauthier-Lafaye, F., Janvier, P., Javaux, E., Ossa, F., Pierson-Wickmann, A., Riboulleau, A., Sardini, P., Vachard, D., Whitehouse, M., & Meunier, A. (2010). Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago Nature, 466 (7302), 100-104 DOI: 10.1038/nature09166
Update 7/8:
I have changed all instances of 'metazoan' with 'multicellular', also in the title. My mistake. Thanks to Psi Wavefunction for pointing that out.
Very interesting. We know that at just about the time, enough uranium accumulated in this very region to trigger fission chain reaction in nature (the Oklo phenomenon) that continued intermittently for millions of years. Would radiation from the reaction have had a hand in this development is something to be pondered over.
ReplyDeleteKrishnan
Apropos of nothing, I thought you might be pleased to know that I used the title of your blog in a recent post. Not being a biologist, there is no way I would have known the word "pleiotropy" otherwise -- so thank you for indirectly helping me to articulate my meaning more clearly!
ReplyDeleteRe: pleiotropy. For the win!
ReplyDeleteMetazoans at 2.1Gya? Veeeery skeptical. Very. Freaking. Skeptical.
ReplyDeleteAlso, I haven't had the chance to look through the paper yet but in the timeline diagram they say 'oldest record of _macroscopic_ multicellularity, not metazoans. There are quite a few non-metazoan eukaryotic multicellular lineages that have evolved multicellularity independently. There are also plenty of modern multicellular bacteria (in the full meaning of the term, IMO, as they have differentiated cells and said cells are stuck together; if Streptomyces, eg, isn't multicellular, then neither are fungi...), and it wouldn't be too surprising if there have been past lineages that formed some intricate large structures, esp given the availability of that niche.
I wouldn't believe Metazoan origins at ~1.9 Gya unless there was some damn good, solid and plentiful evidence for it. 'looks like a clump of cells' doesn't quite cut it...
Disclaimer: I'm with those who believe eukaryotes and archaebacteria evolved 1-1.4Gya out of eubacteria, who are paraphyletic... (eg. Cavalier-Smith 2006 PTRSB; Biol Direct)
Psi, I have updated the main post re: metazoan. Thanks.
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