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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.”


WhatsApp to let users ‘pin messages’ within chats, groups




Meta-owned WhatsApp always brings out the best updates for its users, making it easier for them to enjoy the experience while connecting with their loved ones. 

The messaging app is rolling out another feature that would allow its users to pin messages within chats and groups in the future update, WabetaInfo reported Friday. 

The app is launching the new update through the Google Play Beta Program, bringing the version up to 

The feature, however, is inaccessible to the beta testers as of yet because it is not ready and is still under development.

Through this feature, it will become easier for users to find important messages in a conversation. 

— WaBetaInfo
— WaBetaInfo

However, if a message is pinned but the recipient is using an old version of WhatsApp, the messaging app will “add a message in the conversation in order to ask to upgrade to the latest version available on the store”. 

This feature would also help “improve organisation” in the groups as it can become difficult to keep a track of messages, whether it is a group for your friends, family, or workplace. 

These pinned messages will be easily accessible to everyone in the group chat so that people know what is important. 

The feature will be released in a future update of the app. 

Recent iOs update 

Users will be able to react to messages within the announcement group in a new feature that is under development, according to a report from WABetaInfo.

Reportedly, several users discovered that they are unable to react to messages posted within the WhatsApp community announcement group.

Responding to messages in the community announcement group is not possible because doing so would make your phone number public. WhatsApp is working to make it so that the user’s phone number is hidden when responding to messages in this particular group. 

WABetaInfo learned that WhatsApp is working on the same feature for a future update of the iOS app. 

WhatsApp is developing “an in-app banner to announce when an update that brings message reactions within the announcement group is available.”

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ChatGPT owner launches ‘imperfect’ tool to detect AI-generated text




OpenAI, the creator of the popular chatbot ChatGPT, has released a software tool to identify text generated by artificial intelligence, the company said in a blog post on Wednesday.

ChatGPT is a free program that generates text in response to a prompt, including articles, essays, jokes and even poetry, which has gained wide popularity since its debut in November, while raising concerns about copyright and plagiarism.

The AI classifier, a language model trained on the dataset of pairs of human-written and AI-written text on the same topic, aims to distinguish text that is written by AI. It uses a variety of providers to address issues such as automated misinformation campaigns and academic dishonesty, the company said.

In its public beta mode, OpenAI acknowledges the detection tool is very unreliable on texts under 1,000 characters, and AI-written text can be edited to trick the classifier.

“We’re making this classifier publicly available to get feedback on whether imperfect tools like this one are useful,” OpenAI said.

“We recognise that identifying AI-written text has been an important point of discussion among educators, and equally important is recognizing the limits and impacts of AI-generated text classifiers in the classroom.”

Since ChatGPT debuted in November and gained wide popularity among millions of users, some of the largest US school districts, including New York City, have banned the AI chatbot over concerns that students will use the text generator to cheat or plagiarise.

Others have created third-party detection tools including GPTZeroX to help educators detect AI-generated text.

OpenAI said it is engaging with educators to discuss ChatGPT’s capabilities and limitations, and will continue to work on the detection of AI-generated text.

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YouTube launches ‘Study Hall’ which will allow earning college credits online




YouTube, Arizona State University, and Crash Course, the well-known YouTube channel of writers and brothers Hank and John Green, have announced an astonishing expansion of their accessible education programme Study Hall. 

According to YouTube’s announcement, the partnership is “a new approach that demystifies the college process while creating an affordable and accessible onramp to earning college credit,” outlining the chance for online learners to pursue transferable course credits with fewer restrictions than traditional college programmes.

In addition to being able to watch all Study Hall videos for free on YouTube, users can register for related courses developed by Crash Course and academics at Arizona State University in order to receive credits and compile a transcript. 

Beginning on March 7, 2023, the current lineup of four “College Foundations” courses will address postsecondary fundamentals including English composition, college math, American history, and interpersonal communication. Each course costs $25 to enrol in, plus an additional $400 registration fee to acquire credits. Prior to March 7, 2023, each course will cost $350 to enrol in.

When Study Hall is fully operational, the number of credits available will equal the whole first year of study at most institutions and the cost is “less than one-third of the typical course cost at a public four-year university,” according to YouTube.

Enrollment does not require a minimum GPA or even an application, and students are allowed to retake classes as many times as they need to. Any eligible student who wants to use their Study Hall experience toward a degree can apply for admission to Arizona State University through the Earned Admissions program or transfer to any school in the US that accepts ASU credits.

According to Katie Kurtz, head of learning at YouTube, the company wants to serve as a middleman between the general public and higher education.

“At YouTube, we want to empower learners to go further by breaking down barriers to high-impact learning experiences. Postsecondary education is still one of the best drivers of economic and social mobility, yet the path to higher education has too many barriers,” she explained.

“We want to help address this urgent challenge by tapping into our endlessly creative and passionate learning creator community. With 10 years of experience delivering compelling and engaging educational content, we knew Crash Course, paired with ASU’s world class faculty would be a dynamic partnership to address this challenge.”

The Green brothers, well-known for being early, influential creators on both YouTube and Tumblr, launched the Crash Course channel in 2012. The channel has produced a decade’s worth of educational material on a variety of topics linked to early college and Advanced Placement high school courses, including psychology, world history, and even intellectual property law. The Green brothers’ quick and easy educational videos have an even wider audience now that they are both regulars on the TikTok For You Page.

Hank Green discussed his most recent educational endeavour, writing, in a tweet: “Around 43 million Americans are saddled with 1.75 trillion dollars in student debt. This may sound bad, but it’s worse than it seems: 40% of those 43 million people do not have degrees and will not pursue them.”

The biggest obstacles to getting degrees in the hands of students, according to Green and his production firm, Complexly, included fees, the complexity of college admissions systems, and the difficulty of many college courses for people who didn’t acquire a thorough high school education. “With some funding and a lot of hard work, we started to build ‘Study Hall’ with the goal that it helps lower these barriers.”

Along with the new course options, Study Hall also offers educational material on comprehending and navigating the higher education landscape, including a Crash Course series on “How To College” and quick primers to popular ideas and subject areas, hosted by Green and other academics.

By January 2025, the programme is expected to have 12 courses accessible. On the Study Hall website, prospective students can sign up.

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