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Post Info TOPIC: Ancient life


L

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Anomalocaris
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The meters-long, carnivorous "shrimp" from hell that once ruled the seas of Earth a half billion years ago may have been a real softy, it turns out. A new 3-D modelling of the mouth parts of the Anomalocaris, along with evidence that these parts were not hard like teeth, but flexible, shows that the famed predator could not have been munching on the hard shells of trilobites and other such creatures of the early seas.
What's more, there is no evidence from fossilised stomach contents or faeces that Anomalocaris' ate anything hard enough to leave a fossilised trace. In fact it was this lack of fossil evidence backing any dietary preference ? right alongside other animals that do show fragments of what they ate in their gullets ? which inspired the investigation, said palaeontologist James "Whitey" Hagadorn of the Denver Museum of Nature & Science.

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RE: Ancient life
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The Blob Creature

Often just the timescales that scientists are working with make us think. Dr Mark Sutton and a team of researchers from the Department of Earth Science and Engineering at Imperial College London have created a three dimensional model from a fossil. The creature is called a Drakozoon and it lived in the ocean during the Silurian Period around 416 to 444 million years ago.
The Drakozoon, approximately 3mm long, was discovered about six years ago in whats called the Herefordshire Lagerstätte, a site rich in soft-bodied fossils. Though such creatures would normally decompose, this area was covered in volcanic ash which preserved it.

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Energy revolution key to complex life

The evolution of complex life is strictly dependent on mitochondria, the tiny power stations found in all complex cells, according to a new study by Dr Nick Lane, from UCL (University College London), and Dr William Martin, from the University of Dusseldorf.
For 70 years scientists have reasoned that evolution of nucleus was the key to complex life. Now, in work published today in Nature, Lane and Martin reveal that in fact mitochondria were fundamental to the development of complex innovations like the nucleus because of their function as power stations in the cell.

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Tiny tubes thought to have been etched into South African rocks by microbes are at least 3.3 billion years old, scientists can confirm.
A new analysis of the material filling the structures shows they were created not long after the volcanic rock itself was spewed on to the seafloor.
The tubules could therefore represent the earliest "trace" evidence of activity by life on Earth.

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L'énigme des Treptichnus de la limite Précambrien-Cambrien résolue

La transition Précambrien-Cambrien (540 millions d'années) est marquée par d'innombrables traces fossiles, présentes sur l'ensemble du globe dont certaines connues sous le nom de Treptichnus. Leur origine était jusqu'alors inconnue. Des chercheurs de Lyon, Hambourg et Varsovie viennent d'élucider le mystère : ces traces fossiles typiques proviennent de vers priapuliens. C'est grâce à des expériences réalisées avec des priapuliens actuels, vivants dans des milieux boueux très pauvres en oxygène, que le décryptage de ces traces énigmatiques a pu être fait. Ces travaux viennent de paraître dans la revue Gelology.

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Did life on earth evolve twice?

Life on earth may have begun around 90 million years earlier than scientists had previously thought, a new fossil find suggests.
Dr Adam Maloof of Princeton University explains the importance of his discovery.

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Discovery of Possible Earliest Animal Life Pushes Back Fossil Record

Scientists may have discovered in Australia the oldest fossils of animal bodies. These findings push back the clock on the scientific world's thinking regarding when animal life appeared on Earth. The results suggest that primitive sponge-like creatures lived in ocean reefs about 650 million years ago.
The shelly fossils, found beneath a 635 million-year-old glacial deposit in South Australia, represent the earliest evidence of animal body forms in the current fossil record, predating other evidence by at least 70 million years.

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Drakozoon
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Ancient blob-like creature of the deep revealed by scientists

A unique blob-like creature that lived in the ocean approximately 425 million years ago is revealed in a 3D computer model in research published today in the journal Biology Letters. The model is helping researchers to understand what primitive species on early Earth looked like and how they might have evolved into the types of creatures that are on Earth today.
The scientists, from Imperial College London, have developed a detailed 3D model of the only known fossilised specimen in the world of a creature called Drakozoon. The specimen was found by one of the team approximately 6 years ago in the Herefordshire Lagerstätte, one of England's richest deposits of soft-bodied fossils.
Drakozoon lived in the ocean during the Silurian Period, 444 to 416 million years ago, and today's model hints at how it lived.

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Grypania
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Relics of some of the first stirrings of modern life may have been uncovered.
Scientists report in the journal Nature the discovery of centimetre-sized fossils they suggest are the earliest known examples of multicellular life.
The specimens, from Gabon, are 2.1 billion years old - 200 million years older than for any previous claim.

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RE: Ancient life
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Atmospheric oxygen concentration on earth first started increasing about 2.45-2.32 billion years ago. So when did the first multicellular organisms that lived in aerobic (oxygen present condition) environment appear?
The earliest known eukaryote is a coil-shaped fossil Grypania spiralis which existed about 2 billion years ago (2 Gyr). Now the record has been pushed further back by 0.10 billion years.
The discovery of centimetre-sized structures of "highly organised and spatially discrete populations of colonial organisms" in black shales from southeastern Gabon (west central African country) has been reported today (July 01) in Nature.

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