Shark and bony fish evolution, new research


This 9 September 2020 video from England says about itself:

410-Million-Year-Old Fish Fossil Virtual 3D CT Scan

Virtual three-dimensional model of the braincase of Minjinia turgenensis generated from CT scan.

Credit: Imperial College London/Natural History Museum

From Imperial College London in England:

Ancient bony fish forces rethink of how sharks evolved

September 7, 2020

Sharks’ non-bony skeletons were thought to be the template before bony internal skeletons evolved, but a new fossil discovery suggests otherwise.

The discovery of a 410-million-year-old fish fossil with a bony skull suggests the lighter skeletons of sharks may have evolved from bony ancestors, rather than the other way around.

Sharks have skeletons made of cartilage, which is around half the density of bone. Cartilaginous skeletons are known to evolve before bony ones, but it was thought that sharks split from other animals on the evolutionary tree before this happened; keeping their cartilaginous skeletons while other fish, and eventually us, went on to evolve bone.

Now, an international team led by Imperial College London, the Natural History Museum and researchers in Mongolia have discovered a fish fossil with a bony skull that is an ancient cousin of both sharks and animals with bony skeletons. This could suggest the ancestors of sharks first evolved bone and then lost it again, rather than keeping their initial cartilaginous state for more than 400 million years.

The team published their findings today in Nature Ecology & Evolution.

Lead researcher Dr Martin Brazeau, from the Department of Life Sciences at Imperial, said: “It was a very unexpected discovery. Conventional wisdom says that a bony inner skeleton was a unique innovation of the lineage that split from the ancestor of sharks more than 400 million years ago, but here is clear evidence of bony inner skeleton in a cousin of both sharks and, ultimately, us.”

Most of the early fossils of fish have been uncovered in Europe, Australia and the USA, but in recent years new finds have been made in China and South America. The team decided to dig in Mongolia, where there are rocks of the right age that have not been searched before.

They uncovered the partial skull, including the braincase, of a 410-million-year-old fish. It is a new species, which they named Minjinia turgenensis, and belongs to a broad group of fish called ‘placoderms‘, out of which sharks and all other ‘jawed vertebrates’ — animals with backbones and mobile jaws — evolved.

When we are developing as foetuses, humans and bony vertebrates have skeletons made of cartilage, like sharks, but a key stage in our development is when this is replaced by ‘endochondral’ bone — the hard bone that makes up our skeleton after birth.

Previously, no placoderm had been found with endochondral bone, but the skull fragments of M. turgenensis were “wall-to-wall endochondral.” While the team are cautious not to over-interpret from a single sample, they do have plenty of other material collected from Mongolia to sort through and perhaps find similar early bony fish.

And if further evidence supports an early evolution of endochondral bone, it could point to a more interesting history for the evolution of sharks.

Dr Brazeau said: “If sharks had bony skeletons and lost it, it could be an evolutionary adaptation. Sharks don’t have swim bladders, which evolved later in bony fish, but a lighter skeleton would have helped them be more mobile in the water and swim at different depths.

“This may be what helped sharks to be one of the first global fish species, spreading out into oceans around the world 400 million years ago.”

Amazon Bezos COVID-19 price gouging


This June 2020 video from the USA says about itself:

Checking the Power of the Corona-Profiteers: Amazon

While much of the US economy is in trouble, the Amazon corporation is not. Orders are surging and workers are coping with increased demands and dangerous conditions in the workplace. As the Covid-19 pandemic continues, Amazon’s stepped up its use of third-party suppliers to ship non-essential products and has fired employees calling out public health threats while Jeff Bezos has earned $24 billion in wealth since the start of this pandemic.

Dania Rajendra, Executive Director of Athena Coalition, describes how an alliance of grassroots organizations, workers and consumers are collaborating with workers to call the billionaire corporation to account. Amazon’s supply chains may be helping consumers and their communities under lockdown right now, but their business model is a direct threat. Could Amazon be brought under public check — even be seized as a utility? Rajendra joins Laura to explain why now is a time to think bigger and bolder about the institutions that shape our economy.

“It’s going to take all of us to figure out how to restore public oversight over private power.”

For more information about the Athena Coalition, please visit here.

Translated from Dutch NOS radio today:

Amazon raised disinfectant prices after outbreak

Amazon is charging a considerably higher price for hand sanitizers, gloves and other protective products since the outbreak of the coronavirus in the USA. That is the conclusion of the American consumer watchdog Public Citizen. The organization accuses Amazon of acting unethically.

Public Citizen researched nearly 25 products on Amazon‘s site and found that Amazon prices rose by as much as 1000 percent in some cases over the pre-corona pandemic period, as well as compared to prices on other websites. For example, hand soap from the Dial brand at Amazon now costs 6.41 dollars. That same bottle costs $ 1.49 to $ 2.29 elsewhere.

According to the consumer organization, Amazon has broken rules because unlimited price hikes are sometimes prohibited in some US states. Enforcement of those rules is difficult because the legislation is not the same in all states.

… Public Citizen received many more complaints about price increases of products that became scarce due to the coronavirus crisis, such as baking powder and cleaning products.