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Scientists reveal origin of mammal evolution milestone: warm-bloodedness



  • 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.”


Elon Musk lands in Tel Aviv to meet Israeli president, families of hostages




Tech entrepreneur Elon Musk has begun his wartime visit to Israel as he landed in Tel Aviv on Monday to discuss “rising antisemitism” on social media with Israeli President Isaac Herzog.

During his visit to Tel Aviv, the tech billionaire will also meet the relatives of the hostages held by Hamas following their October 7 attack. 

“In their meeting, the president will emphasise the need to act to combat rising antisemitism online,” said President Herzog’s office on Sunday after announcing the meeting with Musk.

His meeting comes after the tech guru was accused by civil rights groups of amplifying anti-Jewish hatred on the microblogging website X, formerly known as Twitter.

The tweet accused Jews of promoting hatred against whites, and Musk’s reply, acknowledging the statement as the “actual truth,” triggered a fierce online backlash.

Musk, later defending himself against accusations of anti-semitism, asserted that such claims were “nothing could be further from the truth.” He clarified his intentions, expressing goodwill towards humanity and a desire for a prosperous future for all.

In an effort to counterbalance the controversy, Musk announced his commitment to donating advertising revenue from his company, X, to hospitals in Israel and Gaza.

Last week, Israeli media reported that Musk would visit Israel this week, with plans to tour Gaza border towns.

According to N12, the Tesla magnate was expected to engage in discussions with Prime Minister Benjamin Netanyahu and President Herzog during his visit.

Additionally, Musk had previously pledged to provide internet satellite connectivity to Gaza’s remaining civilians and humanitarian workers.

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Here’s how WhatsApp plans to enhance display of profile info




To further enhance user experience, WhatsApp is working on a new update to further enhance the display of profile information by acting on the user feedback and incorporating desired updates into the platform.

The development was discovered via the latest WhatsApp beta for Android update available on the Google Play Store, reported WaBetaInfo.

The meta-owned platform is working to allow the displaying of profile information within conversations beneath the contact name.

Once introduced, the feature will provide users with an easier and faster way to interact with profile information when it is made visible in our conversations.

— WaBetaInfo
— WaBetaInfo

Users would be able to easily view the profile information within the chat rather than having to navigate to the chat info screen. 

Furthermore, this enhances visibility in the event that users have recently updated their profile information, guaranteeing that those involved in the conversation are promptly informed of any modifications.

It is significant to remember that the user’s privacy settings will only permit the display of this information.

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OpenAI’s ChatGPT offers human-like voice feature for all regular iOS, Android users




OpenAI has rolled out a significant update for ChatGPT, enabling regular users on both iOS and Android devices to engage with the chatbot using a human-like voice. 

Initially introduced in September, the voice feature was exclusively available to Plus and Enterprise users until yesterday. This expansion signifies a milestone in ChatGPT’s accessibility, allowing a broader audience to experience conversational capabilities in voice mode.

To activate the voice feature, users will find a headphone icon at the bottom right of the screen upon opening ChatGPT. Clicking on it prompts users to choose from five distinct voice options: Juniper, Ember, Breeze, Cove, and Sky, representing a spectrum from feminine to masculine. Users can easily switch between these options later.

The interaction with the voice assistant is visually engaging, with a grey circle appearing in the centre, transforming into a white cloud-like image while the chatbot processes information. 

The voice assistant, exemplified by options like Sky with a raspy voice, introduces a more human-like element, including pauses during responses, fostering a conversational experience.

Despite the innovative leap, some users noted that the voice function occasionally prompted assistance queries even when the user remained silent, and there was a lack of a clear mechanism to turn off the application. 

However, the flexibility to exit the app while keeping it active in the background enhances multitasking possibilities, catering to scenarios where users may want information while engaged in other activities.

This move towards a voice-centric interaction marks a departure from traditional text-based chatting, offering a more natural and engaging conversational AI experience. 

OpenAI’s decision to make this feature available to a wider user base underscores the evolution of ChatGPT, positioning it as a versatile and accessible tool for diverse interactions.

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