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Evo­lu­tion


A Col­lec­tion of News by Moos


201720Aug07:55

Mys­tery of how first ani­mals appeared on Earth solved, say researchers

Infor­ma­tion
pub­lished 20 August 2017 | mod­i­fied 20 August 2017
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Oil droplet molecules ancient organismsResearch led by the Aus­tralian National Uni­ver­sity (ANU) has solved the mys­tery of how the first ani­mals appeared on Earth, a piv­otal moment for the planet with­out which humans would not exist.

Lead researcher Asso­ciate Pro­fes­sor Jochen Brocks said the team found the answer in ancient sed­i­men­tary rocks from cen­tral Aus­tralia. “We crushed these rocks to pow­der and extracted mol­e­cules of ancient organ­isms from them,” said Dr Brocks from the ANU Research School of Earth Sci­ences. “These mol­e­cules tell us that it really became inter­est­ing 650 mil­lion years ago. It was a rev­o­lu­tion of ecosys­tems, it was the rise of algae.”

Dr Brocks said the rise of algae trig­gered one of the most pro­found eco­log­i­cal rev­o­lu­tions in Earth’s his­tory, with­out which humans and other ani­mals would not exist. The researchers’ dis­cov­ery is pub­lished online on 16 August in Nature.

Snow­ball Earth
“Before all of this hap­pened, there was a dra­matic event 50 mil­lion years ear­lier called Snow­ball Earth,” he said. “The Earth was frozen over for 50 mil­lion years. Huge glac­i­ers ground entire moun­tain ranges to pow­der that released nutri­ents, and when the snow melted dur­ing an extreme global heat­ing event rivers washed tor­rents of nutri­ents into the ocean.”

Dr Brocks said the extremely high lev­els of nutri­ents in the ocean, and cool­ing of global tem­per­a­tures to more hos­pitable lev­els, cre­ated the per­fect con­di­tions for the rapid spread of algae. It was the tran­si­tion from oceans being dom­i­nated by bac­te­ria to a world inhab­ited by more com­plex life, he said.

These large and nutri­tious organ­isms at the base of the food web pro­vided the burst of energy required for the evo­lu­tion of com­plex ecosys­tems, where increas­ingly large and com­plex ani­mals, includ­ing humans, could thrive on Earth,” Dr Brocks said.

Co-​lead researcher Dr Amber Jar­rett dis­cov­ered ancient sed­i­men­tary rocks from cen­tral Aus­tralia that related directly to the period just after the melt­ing of Snow­ball Earth. “In these rocks we dis­cov­ered strik­ing sig­nals of mol­e­c­u­lar fos­sils,” said Jarrett.

We imme­di­ately knew that we had made a ground-​breaking dis­cov­ery that snow­ball Earth was directly involved in the evo­lu­tion of large and com­plex life.

Dr Jar­rett, an ANU Research School of Earth Sci­ences PhD graduate

(Source: ANU news release, 17.08.2017)


Goal: 7000 tigers in the wild

Tiger range countries map

Tiger map” (CC BY 2.5) by Sander­son et al., 2006.

about zoos and their mis­sion regard­ing breed­ing endan­gered species, nature con­ser­va­tion, bio­di­ver­sity and edu­ca­tion, which of course relates to the evo­lu­tion of species.
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