Theoretical origin of life; new earliest? (Introduction)

by David Turell , Thursday, December 21, 2017, 00:09 (2529 days ago) @ David Turell

A review article of the latest findings. If life started as early as proposed it seems that it was mandated to start:

https://www.livescience.com/61232-oldest-known-fossils.html?utm_source=ls-newsletter&am...

"Although the fossils were estimated to be about 3.5 billion years old, the diversity of microbes in the group suggested that life probably emerged on Earth even earlier than that, the study authors reported.

"But not everyone may agree that these fossils represent the oldest life on Earth. Some experts have indicated that there are other samples that could be even older than the Australian microfossils, while other researchers have cast doubt on whether these sediments house traces of life at all, suggesting that chemical markers thought to represent biological evidence were the result of geothermal activity.

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"But microbe fossils, though neither structurally complex nor large, are unrivaled when it comes to age. The first life on Earth was microbial, and fossils from this time offer a tantalizing glimpse of the forms from which all creatures — living and extinct — evolved over billions of years.

"In recent years, other studies have reported microfossils holding evidence of ancient microbial life, such as tiny hematite tubes embedded in iron-rich volcanic rock in Quebec, which may have housed microbes that lived between 3.77 billion and 4.29 billion years ago. Another study described cone-like structures detected in rocks in southwestern Greenland, which could represent sediments surrounding fossilized microbial colonies that lived 3.7 billion years ago.

"Both of those discoveries indicate possible evidence of life that would be older than the microbes evaluated in the new study. However, the new investigation is the first to examine and describe individual, fossilized microbes, finding "both the morphology and geochemical signature of life" in samples that are this old, study co-author John W. Valley, a professor of geoscience at the University of Wisconsin-Madison, told Live Science in an email.

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"After they scanned the fossils, they isolated and compared carbon isotopes — forms of carbon with the same number of protons but different numbers of neutrons. They found that the ratios of two particular isotopes "are characteristic of biology and metabolic function," Valley said in the statement.

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"The study authors further identified the microbes as a diverse group, which included some microbes that were methane producers, some that would have consumed methane and others that would have relied on the sun to produce energy.

"The differentiation between these microbes was especially noteworthy, because it suggests that life had already been on Earth long enough for it to begin to diversify and specialize, the study authors reported. While it's impossible to say when life made its first appearance on the planet, these microbes hint that very primitive microbial life could have emerged even in Earth's infancy.

"'We have no direct evidence that life existed 4.3 billion years ago but there is no reason why it couldn't have," Valley said in the statement."

Comment: the Earth formed about 4.5-6 bilion years ago. It was hot and bombarded by space rocks (planetismals), and then life popped up right away! Only if guided by God.