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TOPIC: Primitive life


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Scientists from Aberdeen have uncovered more than 10 new species of deep-sea life on the Atlantic Ocean floor - and may be closer to finding the missing evolutionary link between backboned and invertebrate animals.
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'Nature's batteries' may have helped power early lifeforms

Researchers at the University of Leeds have uncovered new clues to the origins of life on Earth.
The team found that a compound known as pyrophosphite may have been an important energy source for primitive lifeforms.
There are several conflicting theories of how life on Earth emerged from inanimate matter billions of years ago - a process known as abiogenesis.

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Archaea
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Weird, ultra-small microbes turn up in acidic mine drainage

In the depths of a former copper mine in Northern California dwell what may be the smallest, most stripped-down forms of life ever discovered.
The microbes - members of the domain of one-celled creatures called Archaea - are smaller than other known microorganisms, rivalled in size only by a microbe that can survive solely as a parasite attached to the outside of other cells. Their genomes, reconstructed by a group at the University of California, Berkeley, are among the smallest ever reported.
The researchers also discovered another mine-dwelling microbe that occasionally produces weird protuberances unlike any structures seen before in Archaea and uses them to penetrate the ultra-small microbes.

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Title: Enigmatic, ultrasmall, uncultivated Archaea
Authors: Brett J. Bakera, Luis R. Comollib, Gregory J. Dicka, Loren J. Hauserc, Doug Hyattc, Brian D. Dilld, Miriam L. Landc, Nathan C. VerBerkmoesd, Robert L. Hettichd, and Jillian F. Banfielda,

Metagenomics has provided access to genomes of as yet uncultivated microorganisms in natural environments, yet there are gaps in our knowledge - particularly for Archaea - that occur at relatively low abundance and in extreme environments. Ultrasmall cells (<500 nm in diameter) from lineages without cultivated representatives that branch near the crenarchaeal/euryarchaeal divide have been detected in a variety of acidic ecosystems.

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Monash University biochemists have found a critical piece in the evolutionary puzzle that explains how life on Earth evolved millions of centuries ago.
The team, from the School of Biomedical Sciences, has described the process by which bacteria developed into more complex cells and found this crucial step happened much earlier in the evolutionary timeline than previously thought.
Team leader and ARC Federation Fellow Trevor Lithgow said the research explained how mitochondria -- the power house of human and other cells, which provide complex eukaryotic cells with energy and ability to produce, divide and move -- were thought to have evolved about 2000 million years ago from primitive bacteria.

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Earliest Animals Lived in a Lake Environment, Research Shows
Evidence for life on Earth stretches back billions of years, with simple single-celled organisms like bacteria dominating the record. When multi-celled animal life appeared on the planet after 3 billion years of single cell organisms, animals diversified rapidly.
Conventional wisdom has it that animal evolution began in the ocean, with animal life adapting much later in Earth history to terrestrial environments.
Now a UC Riverside-led team of researchers studying ancient rock samples in South China has found that the first animal fossils in the palaeontological record are preserved in ancient lake deposits, not marine sediments as commonly assumed.

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Lightning Strikes Create Minerals Crucial for Early Organisms
The high energy of a lightning strike creates an unusual form of phosphorus once common on primordial Earth and still used by many microbes today.
Phosphorus forms the DNA molecule's spine, enrobes every living cell as a constituent of their membranes, and is a key component of bones and teeth. Author Issac Asimov once called phosphorus "life's bottleneck," because it makes up 1 percent of an organism but is only present in 0.1 percent of minerals on Earth.

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Early life
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Deciphering the very early history of life on Earth is difficult. In the darkest recesses of the first billion years there are no 'body' fossils - no physical remains. Instead, scientists use chemical signals left behind in the rock record.
Methanogens are single cell microorganisms that make their energy by converting either simple organic compounds or carbon dioxide and hydrogen to methane. Nickel, an important nutrient for these organisms, may be a useful chemical signal to pinpoint the early origins of life on Earth, according to researchers at the University of Bristol, UK, and Penn State University, US.

"Life has had a profound chemical impact on our planet - the most spectacular effect being the high oxygen content of our atmosphere, which is a result of photosynthesising algae, plants and some bacteria producing oxygen as a waste product. But photosynthesis as a means of producing energy for life is a relatively new kid on the block in terms of evolution, probably originating no more than about 2-2.5 billion years ago. Before that, other life modes such as methanogens dominated" - Dr Vyllinniskii Cameron, lead author on the paper published today in PNAS.

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