- Researchers study reduced size of inner ear in fossils of mammal forerunners.
- Endothermy is defining feature of mammals including humans.
- Mammalian lineage evolved from cold-blooded creatures.
WASHINGTON: Scientists have answered a longstanding question about mammalian evolution, examining ear anatomy of living and extinct mammals and their close relatives to determine when warm-bloodedness — a trait integral to the lineage’s success — first emerged.
Researchers said on Wednesday that the reduced size of inner ear structures called semicircular canals — small, fluid-filled tubes that help in keeping balance — in fossils of mammal forerunners showed that warm-bloodedness, called endothermy, arose roughly 233 million years ago during the Triassic Period.
These first creatures that attained this milestone, called mammaliamorph synapsids, are not formally classified as mammals, as the first true mammals appeared roughly 30 million years later. But they had begun to acquire traits associated with mammals.
Endothermy evolved at a time when important features of the mammal body plan were falling into place, including whiskers and fur, changes to the backbone related to gait, the presence of a diaphragm, and a more mammal-like jaw joint and hearing system.
“Endothermy is a defining feature of mammals, including us humans. Having a quasi-constant high body temperature regulates all our actions and behaviours, from food intake to cognition, from locomotion to the places where we live,” said palaeontologist Ricardo Araújo of the University of Lisbon’s Institute of Plasmas and Nuclear Fusion, co-lead author of the study published in the journal Nature.
The high metabolisms of mammal bodies maintain internal temperature independent of their surroundings. Cold-blooded animals like lizards adopt strategies like basking in the sun to warm up.
Mammalian endothermy arrived at an eventful evolutionary moment, with dinosaurs and flying reptiles called pterosaurs — creatures that long would dominate ecosystems — first appearing at about that time. Endothermy offered advantages.
“Run faster, run longer, be more active, be active through longer periods of the circadian cycle, be active through longer periods of the year, increase foraging area. The possibilities are endless. All this at a great cost, though. More energy requires more food, more foraging, and so on. It is a fine balance between the energy you spend and the energy you intake,” Araújo said.
The mammalian lineage evolved from cold-blooded creatures, some boasting exotic body plans like the sail-backed Dimetrodon, mixing reptile-like traits like splayed legs and mammal-like traits like the arrangement of certain jaw muscles.
Endothermy emerged relatively quickly, in perhaps less than a million years, rather than a longer, gradual process, said paleontologist and study co-lead author Romain David of the Natural History Museum in London.
An early example was a vaguely weasel-like species, Pseudotherium argentinus, in Argentina about 231 million years ago. The later true mammals were the ancestors of today’s three mammalian groups: placentals, marsupials and monotremes.
“Given how central endothermy is to so many aspects of the body plan, physiology and lifestyle of modern mammals, when it evolved in our ancient ancestors has been a really important unsolved question in paleontology,” said paleontologist and study co-author Ken Angielczyk of the Field Museum in Chicago.
Determining when endothermy originated through fossils has been tough. As Araújo noted: “We cannot stick thermometers in the armpit of your pet Dimetrodon, right?”
The inner ear provided a solution. The viscosity, or runniness, of inner ear fluid — and all fluid — changes with temperature. This fluid in cold-blooded animals is cooler and thicker, necessitating wider canals. Warm-blooded animals have less viscous ear fluid and smaller semicircular canals.
The researchers compared semicircular canals in 341 animals, 243 extant and 64 extinct. This showed endothermy arriving millions of years later than some prior estimates.
Mammals played secondary roles in ecosystems dominated by dinosaurs before taking over after the mass extinction event 66 million years ago. Among today’s animals, mammals and birds are warm-blooded.
“It is maybe too far-fetched, but interesting, to think that the onset of endothermy in our ancestors may have ultimately led to the construction of the Giza pyramids or the development of the smartphone,” Araújo said. “If our ancestors would have not become independent of environmental temperatures, these human achievements would probably not be possible.”
Facebook and Instagram full of predators for children, alleges lawsuit
Meta’s social media platforms of Facebook and Instagram have become fertile grounds for child predators and paedophiles, revealed New Mexico’s Attorney General, Raul Torrez in a lawsuit.
Torrez’s office used fake accounts to conduct investigations and discovered that these fake accounts of minors were dispatched ‘solicitations’ and explicit content.
The lawsuit seeks court-ordered changes to protect minors, asserting that Meta has neglected voluntary actions to address these issues effectively.
In its response, Meta defended its initiatives in eradicating predators. However, New Mexico’s investigation disclosed a higher prevalence of exploitative material on Facebook and Instagram compared to adult content platforms.
Attorney General Torrez underscored the platforms’ unsafe nature for children, describing them as hotspots for predators to engage in illicit activities.
While US law shields platforms from content liability, the lawsuit argues that Meta’s algorithms actively promote sexually exploitative material, transforming the platforms into a marketplace for child predators.
The lawsuit accuses Meta of misleading users about platform safety, violating laws prohibiting deceptive practices, and creating an unsafe product.
Moreover, the lawsuit targets Facebook founder Mark Zuckerberg personally, alleging contradictory actions in enhancing child safety while steering the company in the opposite direction.
In response, Meta reiterated its commitment to combating child exploitation, emphasizing its use of technology and collaborations with law enforcement to address these concerns.
Meta finally launches end-to-end encryption on Messenger
Meta announced Thursday that it is finally implementing end-to-end encryption for one-on-one conversations and calls on Messenger, delivering on a long-standing commitment.
The company states that when end-to-end encryption is enabled, the only people who can view the contents of a message sent through Messenger are the sender and the recipient.
Messenger’s encrypted chat function was initially made available as an opt-in feature in 2016. However, following a protracted legal dispute, end-to-end encrypted messages and calls for two-person discussions will now be considered the norm.
“This has taken years to deliver because we’ve taken our time to get this right,” Loredana Crisan, vice president of Messenger, said in a statement shared with The Verge.
“Our engineers, cryptographers, designers, policy experts and product managers have worked tirelessly to rebuild Messenger features from the ground up.”
Crisan states that encrypted chats will not compromise Messenger features like themes and custom reactions. However, it may “take some time” for all chats to switch to default encryption.
The end-to-end encryption for group chats is still opt-in. Additionally, Instagram messages are still not encrypted by default, but Meta expects this to happen “shortly after” the rollout of default private Messenger chats.
Meta CEO Mark Zuckerberg announced in 2019 that the company planned to move toward encrypted ephemeral messages across its messaging apps, according to The Verge.
“I believe the future of communication will increasingly shift to private, encrypted services where people can be confident what they say to each other stays secure and their messages and content won’t stick around forever,” he wrote in a Facebook post. “This is the future I hope we will help bring about.”
By enabling encryption by default, most Messenger chats should remain unseen by Meta, and it will also prevent the company from providing the data to law enforcement.
Last year, a 17-year-old from Nebraska and her mother faced criminal charges for illegal abortion after police obtained their Messenger chat history.
Anti-encryption advocates argue that encryption makes it harder to identify bad actors on encrypted messaging apps like WhatsApp.
Elon Musk poised to challenge OpenAI, targets $1bn for his AI startup
Tesla chief Elon Musk’s artificial intelligence venture, xAI, is making waves in the AI world, aiming to raise a substantial $1 billion to compete head-on with OpenAI’s widely-used ChatGPT technology.
According to recent filings with the US Securities and Exchange Commission, xAI has already amassed $134.7 million and is striving to amass the billion-dollar mark.
The filing indicates Musk’s strong commitment to gathering the entire sum, hinting that he might have secured deals to achieve this ambitious target.
Musk recently showcased “Grok,” a chatbot similar to ChatGPT, trained on data from X (previously Twitter), which he acquired for $44 billion last year.
Musk initiated xAI in July, recruiting top researchers from OpenAI, Google DeepMind, Tesla, and the University of Toronto. He expressed that the company’s goal is to “understand the true nature of the universe.”
Since the rise of OpenAI’s ChatGPT a year ago, there has been intense competition among tech giants like Microsoft, Google, Meta, and startups such as Anthropic and Stability AI. Earlier this year, OpenAI reportedly secured commitments of an astounding $13 billion from Microsoft.
Musk’s fundraising efforts coincide with a tumultuous period at OpenAI, as CEO Sam Altman’s return after a brief dismissal has led to delays in the company’s anticipated share sale. Reports suggest the sale, valuing OpenAI between $80 and $90 billion, faced hindrances due to internal disruptions.
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