Natures Wonders- living fossils (Introduction)

by David Turell @, Wednesday, November 15, 2017, 14:27 (432 days ago) @ dhw

DAVID: What the shark does is raise the question of why certain species survive forever, and does God play a role? That was the issue I raised, without an answer.

dhw: Unless you believe in God, nothing lasts forever, and I don’t suppose Frilly Fred will last much longer if Monster Man gets to work. My guess is that he’s been lucky enough so far to be in an environment that hasn’t killed him off. However, I was curious as to how you would fit him into the one and only plan you allow God to have. But I suppose I’ll just have to add him to the long, long list of things extinct (or lucky enough to be extant) to eat or be eaten until God produced the human brain.

But there is an ancient life form (stromatolite) from the probable beginning of life that is still here:

"A previously unknown type of stromatolite – rare and ancient biological structures that first evolved around 3.7 billion years ago – has been found living in freshwater wetlands in the Australian island state of Tasmania.


"Stromatolites comprise layers of biochemical material that gradually accrete from a combination of trapped sediments and mats of microbes, particularly cyanobacteria.

"Stubborn survivors of the Eoarchean Era, stromatolites are extremely rare today. They are found mainly in shallow marine environments or hyper-saline lakes.

"The best-known examples are located at Shark Bay in Western Australia. Others have been found in Chile and Brazil, Mexico and the Bahamas.

"Despite the association of other examples with salty sea water and lakes, the Tasmanian stromatolites exist in mildly alkaline spring water surrounded by peaty soil. They comprise not only cyanobacteria, but also other microbes including alphaproteobacteria and an unusually high number of photosynthesising chloroflexi – a combination, say the researchers, that makes them unique.

"Also unusual is the fact that some of the stromatolites extend several centimetres above the water level.

“'Cool-temperate freshwater wetlands are not a conventional stromatolite niche,” the researchers write, “suggesting that stromatolites may be more common than previously thought.”

"Whatever abundance stromatolites achieved during their first couple of billion years of existence was sharply curtailed around 600 million years ago when multicellular organisms started to emerge. Immobile and edible, the stromatolites were both easy to out-compete and consume.

"Perhaps significantly, Proemse and her colleagues report that in the area of the UNESCO-listed Tasmanian Wilderness World Heritage Area where they made their finds, complex invertebrates are uncommon. Snails, known stromatolite predators, are extremely scarce, because the peaty soil leads them to accumulate debilitating levels of carbonate in their shells."

Comment: Obviously some life forms survive forever with no need to evolve. I repeat my suggestion that there a drive to complexity that obviously is not present in some organisms, which also raises the issue that external stresses and challenges may not be the only driver for evolution of life.

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