Complex life a billion years earlier than thought? May 17, 2016 Please Register or Log in to view the hidden image! Organic fragments extracted from the host rock of the Gaoyuzhuang macroscopic fossils showing well-preserved cellular structure. Credit: Maoyan Zhu. Researchers said Tuesday they had uncovered fossils showing that complex life on Earth began more than 1.5 billion years ago, nearly a billion years earlier than previously thought. But the evidence, published in Nature Communications, immediately provoked debate, with some scientists hailing it as rock solid, and others saying they were wholly unconvinced. After first emerging from the primordial soup, life remained primitive and unicellular for billions of years, but some of those cells eventually congregated like clones in a colony. Scientists even took to calling the later part of this period the "boring billion", because evolution seemed to have stalled. Read more at: http://phys.org/news/2016-05-complex-life-billion-years-earlier.html#jCp
http://www.nature.com/ncomms/2016/160506/ncomms11500/full/ncomms11500.html Decimetre-scale multicellular eukaryotes from the 1.56-billion-year-old Gaoyuzhuang Formation in North China Abstract: Fossils of macroscopic eukaryotes are rarely older than the Ediacaran Period (635–541 million years (Myr)), and their interpretation remains controversial. Here, we report the discovery of macroscopic fossils from the 1,560-Myr-old Gaoyuzhuang Formation, Yanshan area, North China, that exhibit both large size and regular morphology. Preserved as carbonaceous compressions, the Gaoyuzhuang fossils have statistically regular linear to lanceolate shapes up to 30cm long and nearly 8cm wide, suggesting that the Gaoyuzhuang fossils record benthic multicellular eukaryotes of unprecedentedly large size. Syngenetic fragments showing closely packed ~10μm cells arranged in a thick sheet further reinforce the interpretation. Comparisons with living thalloid organisms suggest that these organisms were photosynthetic, although their phylogenetic placement within the Eukarya remains uncertain. The new fossils provide the strongest evidence yet that multicellular eukaryotes with decimetric dimensions and a regular developmental program populated the marine biosphere at least a billion years before the Cambrian Explosion.
I don't think that it's so unexpected to find eucaryotes from 1.56 bya. Apparently they are believed to have been numerous even 500 million years before that. These so-called 'acritarchs' resembled algae and were perhaps the most common form of life during this very extended period. Interestingly, they started developing spines on their cell walls later in their history, and this is sometimes taken to be evidence of defence against the first hypothetical predation. (Very small algae-eaters presumably, single celled protozoa like things or maybe the first ediacaran multicellular animal-like organisms) Acritarch numbers rose and fell according to conditions, falling to low levels in the hypothesized snow-ball earth periods and rising to great abundance when conditions were more favorable. http://paleobiology.si.edu/geotime/main/htmlversion/proterozoic3.html https://en.wikipedia.org/wiki/Acritarch
