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I ricercatori del Museo svedese di storia naturale, guidati da Stefan Bengtson, hanno scoperto un fossile di un'alga rossa che risale a 1,6 miliardi di anni fa. Il ritrovamento, descritto sulla rivista Plos Biology, è avvenuto in India.
Le tracce più antiche di vita sulla Terra risalgono ad almeno 3,5 miliardi di anni fa. Si tratta di organismi unicellulari, privi di nucleo e altri organelli, diversi dai cosiddetti eucarioti, dotati di nucleo e membrane cellulari. Gli organismi multicellulari eucarioti (che formano il corpo di piante, animali e uomini) si diffusero molto più tardi, circa 600 milioni di anni fa, all'epoca della "vita visibile".
Prima di questa, l'alga rossa più antica mai scoperta risaliva a 1,2 miliardi di anni fa. Il fossile trovato in India è 400 milioni di anni più vecchio, quindi di gran lunga la pianta più antica mai rinvenuta, e indica che i primi rami dell'albero della vita vanno rivisti. "L'epoca della vita visibile sembra essere iniziata molto prima di quanto finora pensato", conclude Bengtson.
ATS/M. Ang.
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