Aug 18, 2017

Algae triggered the evolution of first animals on Earth

Associated Press

Scientists in Australia believe they've solved the mystery of when and how animals first appeared on Earth: it was linked to the rise of algae, preceded by 50 million years of huge glaciers pounding entire mountain ranges into powder.

"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," said the lead researcher, Jochan Brocks.

Why it matters: Understanding the conditions that led to complex life here could help to determine whether and how live evolved elsewhere in the universe.

The back story: Scientists have known for awhile when complex forms of life began to show up on Earth, triggering evolutionary processes that culminated in the broad diversity of life we now see across the planet. It generally happened after a time known as "Snowball Earth" (a period when the planet was frozen beginning about 700 million years ago lasting 50 million years). What they didn't know was what triggered the evolution of complex life.

To answer that, a research team crushed ancient sedimentary rocks from central Australia into powder and then extracted molecules from organisms inside them in order to study them more closely.

What they found: Glaciers may have pounded mountain ranges into dust 650 million years ago, releasing nutrients into the oceans and creating perfect conditions for the rapid spread of algae. The researchers think the world's oceans then transitioned from a place dominated by bacteria to one inhabited by algae that served as food for more complex life. Eventually, some of that complex life slithered and crawled onto dry land. The rest is evolutionary history.

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Updates: George Floyd protests continue for 8th day

Police officers wearing riot gear push back demonstrators outside of the White House on Monday. Photo: Jose Luis Magana/AFP via Getty Images

Protests over the death of George Floyd and other police-related killings of black people continued across the U.S. for the eighth consecutive day, prompting a federal response from the National Guard, Immigration and Customs Enforcement and Customs and Border Protection.

The latest: The Minnesota Department of Human Rights announced an investigation on Tuesday into the conduct of the Minneapolis Police Department over the past decade, after filing a civil rights charge related to the death of George Floyd.

Minnesota files civil rights charge against police over George Floyd's killing

Police spray protesters with pepper spray during a demonstration outside the Third Police Precinct on Wednesday in Minneapolis, Minnesota. Photo: Kerem Yucel/AFP via Getty Images

The Minnesota Department of Human Rights (MDHR) announced an investigation on Tuesday into the conduct of the Minneapolis Police Department over the past decade, alongside a civil rights charge into the killing of George Floyd.

The big picture: Complaints of excessive force brought against the city's law enforcement officers "have become commonplace, especially by African-American residents," the New York Times reports.

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Sen. Tim Scott. Photo: Andrew Harnik - Pool/Getty Images

Republican lawmakers are weighing in on President Trump's decision to tear gas and physically clear peaceful protestors from outside the White House on Monday in order to stand in front of the historic St. John's Episcopal Church for a photo op.

The state of play: While some Republicans are backing the president's actions and condemning protestors, others are lamenting the decision and calling for improvement.