A new Tree of Life; are there alien life here? (Evolution)

by David Turell , Wednesday, April 13, 2016, 14:16 (2935 days ago) @ David Turell

An interesting article which says we need to look differently than for standard DNA:-https://aeon.co/essays/does-earth-have-a-shadow-biosphere?utm_source=Aeon+Newsletter&utm_campaign=60912bfe67-Daily_Newsletter_13_April_20164_13_2016&utm_medium=email&utm_term=0_411a82e59d-60912bfe67-68942561-"If multiple lines of life bubbled up on Earth and evolved separately from our ancient ancestors, we could discover alien biology without leaving this planet.-"The modern-day descendants of these ‘aliens' might still be here, squirming around with van Leeuwenhoek's microbes. Scientists call these hypothetical hangers-on the ‘shadow biosphere'. If a shadow biosphere were ever found, it would provide evidence that life isn't a once-in-a-universe statistical accident. If biology can happen twice on one planet, it must have happened countless times on countless other planets. But most of our scientific methods are ill-equipped to discover a shadow biosphere. And that's a problem, says Carol Cleland, the originator of the term and its biggest proponent.-***-"If you have a sample of soil,' she asked them, ‘how will you recognise what's in it?' The scientists rattled off the usual answers: slide it under a microscope, put it in a Petri dish, make millions of DNA copies, catalogue the genes. But that party line disturbed Cleland. ‘You couldn't detect anything that wasn't almost identical to familiar Earth life,' she said. Their methods assumed that all microbes have genetic material that works like ours. Isn't it possible, Cleland wondered, that life arose more than once here? If so, organisms from a second (or third) genesis would never turn up in our tests, because our tests are only meant to turn up familiar life. ‘But these organisms, if they exist, would leave traces in the environment,' Cleland says.-***-"Telling scientists to find a shadow biosphere is like asking a chimpanzee to add oil to a car: they don't know what they're looking for or what tools to use. Nevertheless, Cleland has some suggestions. First, look at life in places where life ‘shouldn't' be. Even the most sauna-happy microbes, called hyperthermophiles, wilt above 122° C. If we find anything living at 150° C, then there's a good chance they're not of our ilk. Send balloons into the upper atmosphere; scramble up to high plateaus; snowmobile to the South Pole; drive Land Rovers into the Atacama Desert; don end-of-world suits and venture into uranium mines. Remain alert for phenomena that make us say not ‘Eureka!' but ‘Huh, that's weird.' And then consider that their explanation might, in fact, be very, very weird.-***-"The discovery of life as we don't know it would hint that biology is a universal law, like physics and chemistry. .....A shadow biosphere - evidence that biology emerged more than once on Earth - suggests that biology emerges as a normal consequence of Goldilocks or just?right conditions, rather than being a mysterious lottery-ticket phenomenon.-***-"Today, if asked whether life concocts itself given the right conditions, many people would respond affirmatively. It's not a new idea. But concrete, complex proof that we are the predictable result of a predictable law would tip over our throne, once and for all."-Comment: On the other hand it might just support God's throne, as the final step in fine-tuning.