>>For most of the time Earth has been inhabited, life took the form of single-celled organisms that just sat there in lumps, or floated around on water currents. But now fossils found in the African country of Gabon have turned up the earliest evidence of life showing some initiative and moving around of its own accord. It now seems that life was mobile some 1.5 billion years earlier than previously thought.<<

>>The newly-discovered fossils also fall into this category, but are much older – using geometrical and chemical dating the team says they’re about 2.1 billion years old. That makes them the oldest known examples of locomotion in multicellular organisms, by quite a wide margin.<<

https://newatlas.com/earliest-evidence-life-mobility/58435/

PermeateFree said:

>>For most of the time Earth has been inhabited, life took the form of single-celled organisms that just sat there in lumps, or floated around on water currents. But now fossils found in the African country of Gabon have turned up the earliest evidence of life showing some initiative and moving around of its own accord. It now seems that life was mobile some 1.5 billion years earlier than previously thought.<<

>>The newly-discovered fossils also fall into this category, but are much older – using geometrical and chemical dating the team says they’re about 2.1 billion years old. That makes them the oldest known examples of locomotion in multicellular organisms, by quite a wide margin.<<

https://newatlas.com/earliest-evidence-life-mobility/58435/

They really are quite convincing trace fossils. Well done that team.

“using geometrical and chemical dating”. I’m not sure what that means. I suspect the journalist had a word mashup of “radiometric” + “geochemical”. So I laughed. The original paper is behind a pay-wall.

https://www.pnas.org/content/early/2019/02/05/1815721116

PermeateFree said:

>>For most of the time Earth has been inhabited, life took the form of single-celled organisms that just sat there in lumps, or floated around on water currents. But now fossils found in the African country of Gabon have turned up the earliest evidence of life showing some initiative and moving around of its own accord. It now seems that life was mobile some 1.5 billion years earlier than previously thought.<<

>>The newly-discovered fossils also fall into this category, but are much older – using geometrical and chemical dating the team says they’re about 2.1 billion years old. That makes them the oldest known examples of locomotion in multicellular organisms, by quite a wide margin.<<

https://newatlas.com/earliest-evidence-life-mobility/58435/

“The string-shaped structures are up to 6 mm across and extend up to 170 mm through the strata. Morphological and 3D tomographic reconstructions suggest that the producer may have been a multicellular or syncytial organism able to migrate laterally and vertically to reach food resources. A possible modern analog is the aggregation of amoeboid cells into a migratory slug phase in cellular slime molds at times of starvation.”

Nice. I’m not so sure about “amoeboid” because true amoebas evolved fairly late. So this may be something else, but similar in behaviour.

Interestingly, the infilled tubes seem to have a concentric pattern in cross-section – much like modern worms make. This pattern in icthnofossils indicates that the organism had a tubular structure.

> “using geometrical and chemical dating”. I’m not sure what that means. I suspect the journalist had a word mashup of “radiometric” + “geochemical”. So I laughed. The original paper is behind a pay-wall.

Using sci-hub, I don’t understand the dating method. But here it is.

The pyrite structures display highly negative δ34S values
(−31‰ to −21‰; SI Appendix, Figs. S9 and S10 and Table S1),
which are in the range of the lightest values for sedimentary
pyrite deposited before the late Neoproterozoic Era.
Considering a δ34S value of ∼15‰ for seawater sulfate at 2.1 Ga, the low δ34S values of the string-shaped structures
indicate early diagenetic pyrite formation from sulfide generated
by sulfate-reducing microorganisms close to the sediment–water
interface from a relatively large seawater sulfate pool.