Ancient underwater canyons reveal clues to the world's oldest animal life

nature & planetPhys.orgc. 550 million years ago · Flinders Ranges, South Australia

Ancient underwater canyons reveal clues to the world's oldest animal life

from Phys.org

Geologists have uncovered new evidence that dramatic sea-level changes carved giant underwater canyons in South Australia's Flinders Ranges hundreds of millions of years ago, helping to create conditions that preserved some of the earliest complex life on Earth. The findings, led by Adelaide University, shed new light on the environmental changes that accompanied the rise of the mysterious Ediacaran biota.

explained

The Ediacaran biota ( EE-dee-ACK-ər-ən; formerly Vendian) is a group of large, biologically complex, mostly soft-bodied organisms, which lived during the Ediacaran Period (c. 635–538.8 Mya). These were unusual tube and frond-shaped, mostly sessile, organisms. Three distinct assemblages of these organisms have been discovered, preserved as trace fossils in Ediacaran sandstone. They represent the earliest known complex multicellular organisms.

The Ediacaran biota may have undergone evolutionary radiation in a proposed event called the Avalon explosion, 575 million years ago. This was after the Earth had thawed from the Cryogenian period's extensive glaciation. This biota largely disappeared with the rapid increase in biodiversity known as the Cambrian explosion. Most of the currently existing body plans of animals first appeared in the fossil record of the Cambrian rather than the Ediacaran. For macroorganisms, the Cambrian biota appears to have almost completely replaced the organisms that dominated the Ediacaran fossil record, although relationships are still a matter of debate.

From Wikipedia: Ediacaran biota (CC BY-SA 4.0) ↗

so what

The Ediacaran creatures are our first look at complex animals, and understanding how they were preserved helps us read the fossil record's earliest chapter.

fun fact

Many Ediacaran organisms looked like fronds, discs or quilted mats, unlike any living animal.

D. W. Griffith’s A Corner in Wheat (1909)

the gist

In 1909 D. W. Griffith made a 14-minute film about a speculator who corners the wheat market and doubles the price of bread. A farmer sows his field while a 'Wheat King' gambles in the Chicago wheat pit; bakers raise the loaf from five cents to ten and the poor line up for bread. Griffith cut back and forth between the farm, the feast and the breadline, a technique called parallel editing, so audiences saw both ends of the economy at once. The film drew on Frank Norris's stories and on a real scheme: months earlier Chicago financier James Patten had cornered wheat, sent bread prices up and made about $5 million, roughly $185 million today.

how it works

To corner a market, a trader buys up most of the available supply and the futures contracts that promise more. Anyone who has to deliver the commodity must then buy from the cornerer at whatever price is demanded. The trader profits until the stock is released or the scheme collapses.

so what

A century on, it still shows how markets can be rigged by someone who controls supply, and how the people at either end, farmers and eaters, pay for it. It also helped establish editing as a way to argue a point, not just tell a story.

the bigger pattern

Corners have recurred whenever supply could be locked up, from the Hunt brothers' attempt on silver in 1979 to 1980 to the 'Black Friday' gold panic of 1869. Many such schemes end by collapsing, and the response is often new rules on speculation.

fun fact

In the film the Wheat King dies by falling into a grain elevator and being buried in the wheat he hoarded, an ending borrowed from Norris's novel The Octopus.

Usman Khawaja refuses to answer Sandpapergate question about Pat Cummins | 7.30

from ABC News In-depth

One of the darkest days in Australia's sporting history has been dragged back into the spotlight.

A new autobiography by former Test cricketer Usman Khawaja has made explosive revelations about the Australian Test team's 2018 ball-tampering saga in South Africa.

7.30 host Sarah Ferguson speaks to Usman Khawaja.

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