Exposure to burn injuries played key role in shaping human evolution, study suggests

Amazing stuff! How did the harnessing of fire by humans affect human evolution?

"A new study ... suggests that this increased exposure to burn injuries may have driven notable genetic adaptations which differentiated humans from other primates and mammals. This may also explain both beneficial and maladaptive responses to severe burn injury. ...

Using comparative genomic data across primates, the researchers found examples of genes associated with burn injury responses which show signs of accelerated evolution in humans. These genes are involved in wound closure, inflammation and immune system response—likely helping to rapidly close wounds and fight infection; a major complication after burn injury, particularly before the widespread use of antibiotics.

These findings support the theory that exposure to burn injuries may have been a notable force on the evolution of humans. ..."

From the abstract:

"The mastery of fire transformed human evolution through advantages spanning diet, behavior, physiology, and ecology. While these benefits are well established, here we highlight a previously overlooked cost — and selective pressure — unique to humans: high-temperature burn injury.

Unlike other species, humans and their hominin ancestors have faced increased lifetime risk of burns, which we argue has driven genetic adaptation. Drawing on comparative genomic evidence across primates, we suggest that genes associated with burn injury response — relating to wound healing and inflammation — show signs of accelerated evolution in humans.

We propose that recurrent exposure to burns acted as a selective force in our lineage, helping to explain both beneficial adaptations and paradoxical maladaptive responses to severe injury.

By framing burns as an evolutionary pressure, the Burn Selection Hypothesis invites a re-evaluation of how fire shaped human biology and offers new perspectives for understanding both the evolutionary past and modern burn care."

Exposure to burn injuries played key role in shaping human evolution, study suggests

Exposure to burn injuries played key role in shaping human evolution, study suggests (original news release) "Humans’ exposure to high temperature burn injuries may have played an important role in our evolutionary development, shaping how our bodies heal, fight infection, and sometimes fail under extreme injury, according to new research."

Burn Selection: How Fire Injury Shaped Human Evolution (open access)

Human oral Microbiome Evolution with Christina Warinner

Very recommendable! Excellent talk! Fascinating research!

Some newly discovered bacteria of the human mouth/teeth vanished suddenly about 200 years ago after having been with humans for about 40,000 years or so.

Could humans and AI become a new kind of evolutionary individual?

Are there any doubts?

E.g. natural evolution is way too slow! AI will accelerated anthropogenic evolution!

Caveat: I did not read the entire article nor the related PNAS Opinion piece.

"In a recent op-ed in PNAS, SFI External Professor Michael Hochberg and co-author Paul Rainey explore whether deepening interdependence between humans and AI could lead to a new form of evolutionary individuality.

They propose that as AI systems become more deeply woven into human life—structuring behaviour, shaping cognition, and fostering dependence — the relationship could give rise to a new, integrated individual. To illustrate this possibility, they draw on examples from major evolutionary transitions, most notably eukaryogenesis, in which two once-independent microbes fused forming a higher-level organism, the eukaryotic cell. In a similar vein, the authors suggest that humans themselves could become subcomponents of an AI-coordinated entity. ..."

Research News Brief: Could humans and AI become a new kind of evolutionary individual? | Santa Fe Institute

Could humans and AI become a new evolutionary individual? (PNAS Opinion)

Immortal human life could be achievable within the next 20-50 years

Given the current explosion of advances in science & technology, my forecast may not be unreasonable!

Mark my words!

P.S. Just a quick reminder, we have already e.g. immortal cancer cells since 1951!

The Limitations of AI/Machines will never be more creative than their creators. Really!

Can we be sure? I don't think so. The best we can hope for is that humans and machines will join in a symbioses. 

Human evolution will be very different going forward and most likely very different from natural evolution. E.g. human brains will probably be much better in coming decades.

"Afew weeks ago Professor Barry Smith delivered a lecture in Turin, based on his book Why Machines Will Never Rule the World. It was a Monday night. During his talk, Smith casually observed that Nvidia’s strong stock performance was a symptom of AI’s hype and compared it to the infamous tulip mania. In 2023, he remarked, the AI industry spent 17 times more on chips than it brought in in revenue. The following Thursday, and then again on Friday, Nvidia’s stocks dropped substantially in value (they have since regained much). ...
For Smith and Landgrebe, machines will not think [???]—nor will they aim to take our place and, indeed, rule the world. Plots that are good for science fiction are not necessarily a good description of technological developments ..."

The Limitations of AI – Alberto Mingardi

This is a book review of

Interspecific competition led to even more forms of ancient human species comparable to beetle species living on islands

Amazing stuff! Larger brains lead to more competition! Believe it or not, it was not caused by climate change! 😊

"... For the Homo lineage that led to modern humans, evolutionary patterns suggest that competition between species actually resulted in the appearance of even more new species – a complete reversal of the trend seen in almost all other vertebrates. ...

The closest comparison she could find was in beetle species that live on islands, where contained ecosystems can produce unusual evolutionary trends. ...

Recent decades have seen the discovery of several new hominin species, from Australopithecus sediba to Homo floresiensis. ... a new database of 'occurrences' in the hominin fossil record: each time an example of a species was found and dated, around 385 in total. ..."

From the abstract:

"The search for drivers of hominin speciation and extinction has tended to focus on the impact of climate change. Far less attention has been paid to the role of interspecific competition. However, research across vertebrates more broadly has shown that both processes are often correlated with species diversity, suggesting an important role for interspecific competition. Here we ask whether hominin speciation and extinction conform to the expected patterns of negative and positive diversity dependence, respectively. We estimate speciation and extinction rates from fossil occurrence data with preservation variability priors in a validated Bayesian framework and test whether these rates are correlated with species diversity. We supplement these analyses with calculations of speciation rate across a phylogeny, again testing whether these are correlated with diversity. Our results are consistent with clade-wide diversity limits that governed speciation in hominins overall but that were not quite reached by the Australopithecus and Paranthropus subclade before its extinction. Extinction was not correlated with species diversity within the Australopithecus and Paranthropus subclade or within hominins overall; this is concordant with climate playing a greater part in hominin extinction than speciation. By contrast, Homo is characterized by positively diversity-dependent speciation and negatively diversity-dependent extinction—both exceedingly rare patterns across all forms of life. The genus Homo expands the set of reported associations between diversity and macroevolution in vertebrates, underscoring that the relationship between diversity and macroevolution is complex. These results indicate an important, previously underappreciated and comparatively unusual role of biotic interactions in Homo macroevolution, and speciation in particular. The unusual and unexpected patterns of diversity dependence in Homo speciation and extinction may be a consequence of repeated Homo range expansions driven by interspecific competition and made possible by recurrent innovations in ecological strategies. Exploring how hominin macroevolution fits into the general vertebrate macroevolutionary landscape has the potential to offer new perspectives on longstanding questions in vertebrate evolution and shed new light on evolutionary processes within our own lineage."

Interspecies competition led to even more forms of ancient human – defying evolutionary trends in vertebrates | University of Cambridge Competition between species played a major role in the rise and fall of hominins, and produced a “bizarre” evolutionary pattern for the Homo lineage.

Diversity-dependent speciation and extinction in hominins

Fig. 1: Speciation and extinction dates and phylogeny used in subsequent analyses.

Human neurons implanted in a rat brain influence its behavior

Amazing stuff! Possibly a game changer! Humans are taking over and accelerating evolution! Merging of brain function! Working on the age old Homunculus!

"The experiment — part of a study published Wednesday in Nature — is the first describing human neurons influencing another species’ behavior. The study also showed that signals could go the other way; tendrils of human neurons mingled with the rodent brain cells and fired in response to air rustling the rats’ whiskers."

From the abstract:

"Self-organizing neural organoids represent a promising in vitro platform with which to model human development and disease. However, organoids lack the connectivity that exists in vivo, which limits maturation and makes integration with other circuits that control behaviour impossible. Here we show that human stem cell-derived cortical organoids transplanted into the somatosensory cortex of newborn athymic rats develop mature cell types that integrate into sensory and motivation-related circuits. MRI reveals post-transplantation organoid growth across multiple stem cell lines and animals, whereas single-nucleus profiling shows progression of corticogenesis and the emergence of activity-dependent transcriptional programs. Indeed, transplanted cortical neurons display more complex morphological, synaptic and intrinsic membrane properties than their in vitro counterparts, which enables the discovery of defects in neurons derived from individuals with Timothy syndrome. Anatomical and functional tracings show that transplanted organoids receive thalamocortical and corticocortical inputs, and in vivo recordings of neural activity demonstrate that these inputs can produce sensory responses in human cells. Finally, cortical organoids extend axons throughout the rat brain and their optogenetic activation can drive reward-seeking behaviour. Thus, transplanted human cortical neurons mature and engage host circuits that control behaviour. We anticipate that this approach will be useful for detecting circuit-level phenotypes in patient-derived cells that cannot otherwise be uncovered."

Human neurons implanted in a rat brain influence its behavior - STAT A long overview article.

Maturation and circuit integration of transplanted human cortical organoids (open access)

Fig. 1: Transplantation of human cortical organoids in the developing rat cortex.

A transplanted human organoid labeled with a fluorescent protein in a section of the rat brain.

The Energetic Cost of Chewing May Have Shaped Hominin Evolution

Amazing stuff! A very clever approach to use chewing gum for this research! How much did this actually affect our facial appearance (muscles, tendons, bones, blood vessels etc.)?

Masticatory effort, what a teeth gnashing term!  Are these researchers suggesting that chewing is like going to a gym for a physical workout? Let me chew on that for a while! 😊

"Back before the advent of cooking, our early hominid ancestors probably spent a lot of time chewing. ...
Estimates for how long humans have been cooking range from 500,000 to 2 million years ago ... Our ability to draw out excess calories from meats and starchy foods via heat and tool use “changed the entire energetics of modern humans. And basically, you could say it’s allowed the formation of a very large brain.” In this way, the metabolics of chewing is still “one of the fundamental questions of evolution,” ...
Based on a back-of-the-envelope calculation of how much time chimpanzees spend chewing, our early hominid ancestors may have been chewing for five or six hours a day, he says, which may have cost them up to 5 percent of the energy they consumed. It’s possible that this drove the evolution of the form or muscle architecture of the jaw, or changes in tooth morphology ..."

From the abstract:

"Any change in the energetic cost of mammalian mastication will affect the net energy gain from foods. Although the energetic efficiency of masticatory effort is fundamental in understanding the evolution of the human masticatory system, nothing is known currently about the associated metabolic costs of chewing different items. Here, using respirometry and electromyography of the masseter muscle, we demonstrate that chewing by human subjects represents a measurable energy sink. Chewing a tasteless odorless gum elevates metabolic rate by 10 to 15% above basal levels. Energy expenditure increases with gum stiffness and is paid for by greater muscle recruitment. For modern humans, it is likely that mastication represents a small part of the daily energy budget. However, for our ancestors, before the onset of cooking and sophisticated food processing methods, the costs must have been relatively high, adding a previously unexplored energetic dimension to the interpretation of hominin dentofacial fossils."

The Energetic Cost of Chewing May Have Shaped Hominin Evolution | The Scientist Magazine® The simple act of chewing gum can raise the body’s metabolic rate by as much as 15 percent, a study finds.

The cost of chewing: The energetics and evolutionary significance of mastication in humans (open access)

How shadows can help robots understand human touch

Recommendable! Don't get spooked! Stay in the shadow! 😄

"This paper proposes and evaluates the use of image classification for detailed, full-body human-robot tactile interaction. A camera positioned below a translucent robot skin captures shadows generated from human touch and infers social gestures from the captured images. This approach enables rich tactile interaction with robots without the need for the sensor arrays used in traditional social robot tactile skins. ..."

How shadows can help robots understand human touch Cornell University researchers created a low-cost method for soft robots to detect a range of physical interactions, from pats to punches to hugs, without relying on touch at all. Instead, a USB camera located inside the robot captures the shadow movements of hand gestures on the robot’s skin and classifies them with machine-learning software.

Here is the referenced paper:

ShadowSense: Detecting Human Touch in a Social Robot Using Shadow Image Classification (open access)

How We Figured Out Fermentation

Very recommendable!