Trilobites Had Five Pairs of Head Appendages, New Fossils Show

Based on multiple analytical techniques applied to well-preserved soft-bodied specimens of two trilobite species, the Late Ordovician species Triarthrus eatoni and the Middle Cambrian species Olenoides serratus, paleontologists argue that an additional pair of cephalic appendages occurred just behind the antennae, indicating that trilobites had five pairs of cephalic appendages and six segments.

Triarthrus eatoni. Image credit: Jin-bo Hou & Melanie J. Hopkins, doi: 10.1111/pala.12723.

Trilobites are extinct arthropods that dominated the faunas of the oceans of the Paleozoic era.

During their time on Earth, which lasted much longer than the dinosaurs, they survived two major episodes of mass extinctions and dominated ocean floor ecosystems.

They appeared in ancient oceans in the Early Cambrian, about 540 million years ago — well before life emerged on land, and disappeared in the mass extinction at the end of the Permian, about 252 million years ago.

They were extremely diverse, with about 20,000 species, and their fossil exoskeletons can be found all around the world.

Like other arthropods, the bodies of trilobites are made up of many segments, with the head region comprised of several fused segments.

As with other parts of the trilobite body (thorax and tail), these segments were associated with appendages, which ranged in function from sensing to feeding to locomotion.

“The number of these segments and how they are associated with other important traits, like eyes and legs, is important for understanding how arthropods are related to one another, and therefore, how they evolved,” said Dr. Melanie Hopkins, curator and chair of the Division of Paleontology at the American Museum of Natural History.

The segments in the trilobite head can be counted in two different ways: by looking at the grooves (called furrows) on the upper side of the trilobite fossil’s hard exoskeleton, or by counting the pairs of preserved antennae and legs on the underside of the fossil.

The soft appendages of trilobites are rarely preserved, though, and when looking at the segments in the trilobite head, researchers regularly find a mismatch between these two methods.

In the new study, Dr. Hopkins and Nanjing University’s Dr. Jin-Bo Hou examined new specimens of Triarthrus eatoni.

These fossils, known for the gold shine of the pyrite replacement preserving them, show an additional, previously undescribed leg underneath the head.

“This fantastic preservation style allows us to observe 3D appendages in hundreds of specimens directly from the ventral side of the animals, just like looking at the appendages of horseshoe crabs on a beach by grabbing them and turning them upside down,” Dr. Hou said.

By making comparisons with another trilobite species, the exceptionally preserved Olenoides serratus from the Burgess Shale in British Columbia, the authors propose a model for how appendages were attached to the head in relation to the grooves in the exoskeleton.

“This model resolves the apparent mismatch and indicates that the trilobite head included six segments: an anterior segment associated with the developmental origin of the eyes and five additional segments, associated with one pair of antennae and four pairs of walking legs, respectively,” they explained.

• Their paper was published today in the journal Palaeontology.
• Jin-bo Hou & Melanie J. Hopkins. 2024. New evidence for five cephalic appendages in trilobites and implications for segmentation of the trilobite head. Palaeontology 67 (5): e12723; doi: 10.1111/pala.12723

{ https://www.sci.news/ }

15-09-2024 om 20:20 geschreven door peter  

In the remote wilderness of the Shoria Mountains in southern Siberia, a long-hidden secret has remained untouched for millennia. Far from the reach of modern civilization, a discovery was made that would challenge our understanding of ancient human history. 

In 2013, a team of 19 researchers, led by Georgy Sidorov, embarked on an expedition to explore this mysterious region. Their destination was Gora Shoria, a mountain towering 3,600 feet above sea level in a remote part of Russia. Intrigued by reports of strange megalithic structures, the team ventured into this secluded terrain. 

What they found was extraordinary: an immense super-megalith dating back roughly 100,000 years that defied conventional history. These massive stone blocks, later known as the Gornaya Shoria Megaliths, appeared to be made of granite, featuring flat surfaces and precise right angles. The most astounding detail was the weight of the stones, exceeding 3,000 tons—making them the largest megaliths ever discovered. 

The arrangement of these granite blocks suggested a deliberate design, far beyond what could be explained by natural formations. The blocks were carefully stacked, reaching a height of approximately 140 feet. This raised profound questions: how were such massive stones carved, transported, and assembled in this remote and rugged landscape? 

Some researchers have speculated about the existence of a pre-flood civilization, a sophisticated society wiped out by a cataclysmic event. 

Also a deep, narrow vertical shaft was uncovered. The shaft, lined with parallel stone slabs, appeared to be human-made. 

The walls of the shaft were straight and polished, descending 40 meters (around 130 feet) before opening into a vast underground hall, 36 meters (around 118 feet) high. These walls were constructed from large megalithic blocks, perfectly fitted with minimal gaps. Some of the stones resembled columns, reinforcing the idea of deliberate design. The full explored length of the shaft spanned over 100 meters (approximately 350 feet). 

The precision and scale of this structure left no doubt that it was an artificial creation of immense proportions. The polished walls and massive blocks bore a striking resemblance to the shafts within the Great Pyramid of Khufu in Egypt, suggesting a level of architectural sophistication that defies conventional explanations.  

Speculation abounds regarding the shaft’s original purpose. Some believe it served an advanced technological function or was part of a larger, undiscovered structure. The exploration team took over an hour to reach the bottom of the shaft, which required significant climbing expertise and endurance. It is believed that additional chambers and channels, still unexplored, may lie even deeper underground. 

How could these gigantic 200-ton stone blocks have been assembled with such accuracy, deep underground? What kind of technology was used to construct the shaft and underground chamber?  

Some researchers have speculated that it may have been part of an ancient factory, a seismological research device, or even an energy generator. Others believe it was the underground portion of a long-lost pyramid that once stood on the surface of the mountain. 

Despite differing theories, we may wonder what ancient forces or lost civilizations left their mark on this remote corner of the world?

  

{ https://ufosightingshotspot.blogspot.com/ }

14-09-2024 om 20:52 geschreven door peter  

Top 10 Underwater Ruins Of Lost Civilizations

11-09-2024 om 17:38 geschreven door peter  

Het “echte” Atlantis bestaat en bevindt zich in Griekenland: een stad die al 2400 jaar onder water staat

door Janine

Pexels

Bijna alle culturen zijn gefascineerd door verhalen over grote overstromingen of compleet verzonken beschavingen. Een van de bekendste mythen is ongetwijfeld die over Atlantis, de legendarische stad die volgens Plato in de golven verdween en waarvan het bestaan nog steeds wordt onderzocht. Misschien is Atlantis alleen maar een fantasie, maar het is mogelijk dat juist een oude stad verhalen over verzonken beschavingen heeft geïnspireerd. Het verschil is dat het een plaats is die echt heeft bestaan en waarvan de overblijfselen ook zijn gevonden.

Het verhaal van Helike, een stad verzonken in de golven

We bevinden ons in de Peloponnesos aan het begin van de vierde eeuw voor Christus: Helike is een bloeiende stad en zetel van de Achaeïsche Liga, een alliantie van verschillende Griekse poleis. In 373 v.Chr. werd echter binnen een paar uur een hele stad onder water gezet door de golven als gevolg van een sterke aardbeving, en verdween met haar tempels, huizen en inwoners. Het lijkt een verhaal dat we al eerder hebben gehoord, en dat miljoenen mensen vanaf dat moment zullen horen, zij het onder een andere naam.

De verdwijning van Helike moet in de eerste plaats gevolgen hebben gehad voor de burgers van de Griekse poleis, waaronder verschillende schrijvers die de gebeurtenissen beschreven of zich herinnerden. Later wekten de literaire getuigenissen echter een ander soort nieuwsgierigheid: eeuwen na het verhaal van Helike vroegen veel geleerden zich af waar deze stad verdwenen zou kunnen zijn en vooral of het mogelijk is om haar terug te vinden.

Archeologische opgravingen: de herontdekking van Helike

Drekis/Wikimedia Commons - CC BY-SA 3.0

Om te begrijpen waar de overblijfselen van de stad Helike konden rusten, analyseerden onderzoekers de geologische veranderingen die de noordelijke Peloponnesos troffen. En na eeuwen van vergetelheid leverden de onderzoeken eindelijk enkele resultaten op: aan het begin van de 21e eeuw werden overblijfselen gevonden die verenigbaar waren met de klassieke stad, niet ver van de positie die in de bronnen wordt vermeld. Daarnaast hebben archeologen in het gebied ook een nederzetting gevonden die dateert uit de late bronstijd.

De Helike Foundation en het Helike Project houden zich al jaren bezig met de ontdekkingen, met doelstellingen variërend van onderzoek naar de oude Griekse stad en de verschijnselen die de verdwijning ervan veroorzaakten, tot de verspreiding en bescherming van de opgravingslocaties. Om deze reden is Helike opgenomen in de lijst van sites die het meeste risico lopen van het World Monuments Fund.

Is Helike Atlantis?

Ja en nee. Naast de voor de hand liggende overeenkomsten die ook door het verhaal van hun verdwijning worden gegeven, zouden Helike en Atlantis meer met elkaar verbonden kunnen zijn dan we denken, althans op narratief niveau. Naast de wetenschappelijke pogingen om het oude Helike te identificeren, mogen we de datum van de gebeurtenis niet vergeten: deze vond plaats in dezelfde periode waarin Plato zijn dialogen schreef, inclusief die waarin hij spreekt over de mythe van Atlantis.

Natuurlijk kunnen mythen uit het verleden, zoals de Minoïsche uitbarsting die leidde tot de ondergang van het eiland Santorini, hebben bijgedragen aan het verhaal van de filosoof. Maar Plato kan ook geïnspireerd zijn geraakt door het fenomeen dat de verdwijning van Helike veroorzaakte. Per slot van rekening is dat van Atlantis ook om deze reden een mythe: het lijkt op veel echte gebeurtenissen, maar kan niet tot één daarvan worden herleid.

{ https://www.curioctopus.nl/ }

30-08-2024 om 22:04 geschreven door peter  

{ https://thedebrief.org/category/science/ }

23-08-2024 om 21:06 geschreven door peter  

4000 jaar oude Babylonische tabletten voor het eerst ontcijferd: het zijn grimmige voortekenen gebaseerd op maansverduisteringen

door Janine

The British Museum - Takori234/Wikimedia commons - CC BY-SA 4.0

Deskundigen zijn er eindelijk in geslaagd enkele zeer oude Babylonische tabletten te ontcijferen, maar wat ze zeggen is helemaal niet geruststellend. Laten we er meer over te weten komen.

De betekenis van oude Babylonische tabletten ontdekt

Meer dan honderd jaar geleden werden Babylonische tabletten met spijkerschrift van 4000 jaar oud ontdekt. Ze worden momenteel bewaard in het British Museum in Londen, Engeland, maar zijn in al die tijd nooit ontcijferd. Tenminste, tot vandaag.

Wetenschappers hebben eindelijk wat licht geworpen op hun betekenis, maar het nieuws is verre van geruststellend. Blijkbaar bevatten de tabletten informatie over maansverduisteringen, waarvan sommige zijn geïnterpreteerd als voortekenen van belangrijke negatieve gebeurtenissen voor de mensheid. Andrew George, Babylonisch docent aan de Universiteit van Londen, en onderzoeker Junko Taniguchi, leggen in hun studie uit dat de vier kleitabletten "de oudste voorbeelden vertegenwoordigen van compendiums van voortekenen van maansverduisteringen die tot nu toe zijn ontdekt.

Babylonische tabletten, voortekenen gebaseerd op maansverduisteringen

The British Museum

Volgens de auteurs van het onderzoek berekenden degenen die de tabletten hebben gemaakt de nachttijd, de beweging van de schaduwen, de datum en de duur van maansverduisteringen om hun voortekenen te formuleren. Op basis van bepaalde kenmerken van eclipsen voorspelden de oude Babyloniërs de gevolgen ervan. Een van de voortekenen verwijst bijvoorbeeld naar het feit dat als de zonsverduistering “in één keer vanuit het midden donker wordt en in één keer licht wordt”, dit ongeluk zou betekenen voor de koning en de stad Elam, een regio in Mesopotamië waar Iran zich vandaag bevindt.

Als de zonsverduistering in het zuiden zou beginnen en vervolgens opklaarde, spreekt de voorspelling over de “val van Subartu en Akkad”, twee andere gebieden in het oude Mesopotamië. Andere negatieve gebeurtenissen werden verwacht in het geval van een zonsverduistering gedurende de avond. Waarschijnlijk baseerden astrologen uit die tijd hun voorspellingen op eerdere gebeurtenissen, die al hadden plaatsgevonden na maansverduisteringen.

Hemelse gebeurtenissen en voorspellingen in het oude Mesopotamië

Volgens Andrew George zouden de voortekenen in feite afkomstig kunnen zijn van gebeurtenissen die daadwerkelijk hebben plaatsgevonden, ook al waren de meeste voorspellingen naar alle waarschijnlijkheid geformuleerd door de eigenaardigheden van de eclipsen op een volledig theoretische manier met de verschillende voortekenen te associëren. In het oude Babylon geloofde men namelijk dat kosmische gebeurtenissen de toekomst konden voorspellen. De studie zegt dat, volgens mensen uit die tijd, “gebeurtenissen in de lucht gecodeerde signalen waren die daar door de goden waren geplaatst als waarschuwingen over de toekomstperspectieven van degenen die op aarde leefden. Zij die de koning raad gaven, hielden de nachtelijke hemel in de gaten en vergeleken hun waarnemingen met het academische corpus van teksten over hemelse voortekenen".

Aangenomen wordt dat de tabletten afkomstig zijn uit Sippar, het huidige Irak. Toen ze 4000 jaar geleden werden gemaakt en geschreven, breidde het Babylonische rijk zich uit naar verschillende gebieden van Mesopotamië. Tussen 1982 en 1914 werden ze onderdeel van de collectie van het British Museum, maar pas nu zijn ze voor het eerst ontcijferd.

{ https://www.curioctopus.nl/ }

22-08-2024 om 16:36 geschreven door peter  

 

By Emma Soteriou

The mystery over Stonehenge's origins has deepened after a "jaw-dropping" discovery.

Most of the monument's bluestones were sourced from the Preseli Hills in Wales - around 150 miles from the site.

But fresh research suggests the largest Altar Stone at the heart of Stonehenge is actually Scottish.

The "remarkable" discovery has left experts "stunned" and busts a century-long held belief about the origins of the bluestone.

It is unclear when the stone arrived at the site on Salisbury Plain in Wiltshire, but the scientists say it may have been placed within the central horseshoe of stones during the second construction phase at about 2620-2480 BC.

The new discovery implies that one of the most famous stones in the world was moved much further than had been believed - at least 435 miles.

For the last century, the six-tonne sandstone was believed to have come from Wales, with the rest of the bluestones.

After work to examine the stone's chemical composition and mineral grains, scientists can say with 95% confidence that the sandstone is very likely to instead have come from north-east Scotland.

The study involved scientists at Aberystwyth University, University College London and, in Australia, Curtin University and the University of Adelaide.

The findings indicate a striking similarity between the Old Red Sandstone of the Orcadian Basin in north-east Scotland and the Stonehenge Altar Stone.

Co-author Professor Richard Bevins, from Aberystwyth University, said: "These findings are truly remarkable - they overturn what had been thought for the past century.

"We have succeeded in working out, if you like, the age and chemical fingerprints of, perhaps, one of the most famous of stones in the world-renowned ancient monument.

"It's thrilling to know that our chemical analysis and dating work has finally unlocked this great mystery.

"We can now say that this iconic rock is Scottish and not Welsh.

"Although we can say that much, and confidently - the hunt will still very much be on to pin down where exactly in the north-east of Scotland the Altar Stone came from."

The scientists used their analysis of the ages of the mineral grains in the stone to create a fingerprint of the source of those grains.

They matched ages found in rocks of the Orcadian Basin found in the north-east of Scotland, and are completely different from Welsh-sourced stones.

Anthony Clarke, from the Timescales of Mineral Systems Group at Curtin University, in Perth, Western Australia, said: "Considering the technological constraints of the Neolithic, our findings raise fascinating questions about how such a massive stone was able to be transported over the vast distance implied.

"Given major overland barriers en route from north-east Scotland to Salisbury Plain, marine transport is one feasible option."

Commenting on the findings, he added: "All four of us were stunned. We couldn't believe it."

Co-author Dr Robert Ixer, of the UCL Institute of Archaeology, said: "This is a genuinely shocking result, but if plate tectonics and atomic physics are correct, then the Altar Stone is Scottish.

"The work prompts two important questions: why and exactly how was the Altar Stone transported from the very north of Scotland, a distance of more than 700 kilometres, to Stonehenge?"

{https://www.lbc.co.uk/ }

18-08-2024 om 01:10 geschreven door peter  

The lost island of Atlantis may have been found 2km under the ocean

(Picture: Getty)

The lost island of Atlantis may have been found 2km under the ocean
Some people believe that in the Atlantic Ocean, lying west of the Strait of Gibraltar, lies the legendary island of Atlantis. The island itself is thought to have been created by the philosopher Plato. His tale of a fabled civilization that the Gods plunged into the ocean as a punishment for its citizens' pride and arrogance has survived thousands of years. And now researchers think they may have found Plato’s inspiration for such a legend. In an area north of the Canary Islands, Spain, scientists have uncovered a vast submerged mountain that likely sank off the coast of the islands millions of years ago 

(Picture: IGME-CSIC)

The lost island of Atlantis may have been found 2km under the ocean
The seamount, which has been dubbed as Mount Los Atlantes, has three inactive volcanoes each around 50km (30 miles) in diameter, with their bases over 2km under the ocean surface, according to researchers from Spain’s Geological and Mining Institute (CSIC). Some of the lost islands even, after all this time, still have their beaches intact. The team said that some of the beaches sit just 60m (200 feet) below the ocean's surface. During the last ice age, when sea levels were far lower than they are today, the inactive volcanoes would have become islands again, which could have been used to inhabit wildlife 

 (Picture: IGME-CSIC)

The lost island of Atlantis may have been found 2km under the ocean
These volcanoes were once part of a system of islands that sat around the east of Lanzarote, off the coast of West Africa, during the Eocene era around 56 million years ago, CSIC said. Geologist and project coordinator Dr Luis Somoza told LiveScience: ‘This could be the origin of the Atlantis legend’ referring to the Ancient Greek philosopher’s tale. In a statement he said: ‘They were islands in the past and they have sunk, they are still sinking, as the legend of Atlantis tells. Some of us have been able to verify that they still maintain their beaches’

(Picture: IGME-CSIC)

The lost island of Atlantis may have been found 2km under the ocean
The team of geologists went aboard the Sarmiento de Gamboa, an oceanographic vessel of the CSIC, and used an advanced remotely operated vehicle (ROV) to survey the waters at depths around 2.5km (1.5 miles) for a better understanding of the region’s volcanic activity. The dive was part of the team’s Atlantis project which aims to understand underwater volcanic and hydrothermal activity in the region 

(Picture: IGME-CSIC)

The lost island of Atlantis may have been found 2km under the ocean
They also assessed the state of the seabed around the archipelago from June 27 to August 6 to look for signs of magma and underwater volcanic activity that may pose risks to Spain’s population in the future. Some of the volcanoes in the underwater region may be more modern than previously thought, and could be the submarine equivalents of Spain’s Timanfaya volcano system, the team suggested 

 (Picture: IGME-CSIC)

The lost island of Atlantis may have been found 2km under the ocean
The researchers also looked at how underwater minerals form in such extreme conditions as well as the water’s levels of microorganisms encouraging the formation of metals like manganese, cobalt, and phosphates, which are important for energy transition. The team will analyse the samples collected from Los Atlantes to date the volcanic rocks and pinpoint when the islands began to sink

(Picture: IGME-CSIC)

The lost island of Atlantis may have been found 2km under the ocean
The study also reflects the vast life that exists on the seabed after the underwater lava flows formed the lava deltas, revealing how underwater life is reborn after the recent eruptions with new gardens of corals and sponges, or areas covered with bacterial next to the hydrothermal sources 

{ Metro’s News Updates newsletter }

16-08-2024 om 18:09 geschreven door peter  

De oorsprong van de beschaving kan zijn ontstaan na de inslag van een komeet: oude gravures onthullen dit

door Janine

Time and Mind/AI generated-Freepik

Waaruit is de beschaving ontstaan? Een studie heeft misschien het antwoord gevonden in Turkije: het lijkt erop dat alles begon na de inslag van een oude komeet.

Gravures op de archeologische vindplaats Göbekli Tepe

Archeologen onderzochten gravures op een Turkse vindplaats die naar schatting 7000 jaar ouder zijn dan de Grote Piramide van Gizeh. In een poging om ze te interpreteren kwamen ze tot de conclusie dat ze de inslag van een oude komeet op aarde zouden kunnen voorstellen. Concreet gaat het om de archeologische vindplaats Göbekli Tepe, waarvan experts denken dat het de oudste zonnekalender op onze planeet zou kunnen zijn. Dit 12.000 jaar oude monument is de meest gedateerde architectonische constructie gewijd aan aanbidding die ooit is ontdekt.

Op de tempelachtige omheiningen van de site zijn complexe symbolen gegraveerd. Het onderzoeksteam verklaarde dat deze naar alle waarschijnlijkheid een weergave zouden kunnen zijn van een kosmische gebeurtenis die een keerpunt vormde voor de menselijke beschaving. Als dat zo is, zou dat betekenen dat de oude mensen astronomische informatie gebruikten om een zonnekalender te maken die vergelijkbaar is met de kalender die duizenden jaren later door de Grieken werd uitgevonden.

De impact van de komeet en de lunisolaire kalender

Time and Mind

Martin Sweatman, scheikundig ingenieur aan de Universiteit van Edinburgh, Schotland, en eerste auteur van het onderzoek, zei: "Het lijkt erop dat de inwoners van Göbekli Tepe scherpe waarnemers van de hemel waren,  wat te verwachten was gezien het feit dat hun wereld was verwoest door de inslag van een komeet."

Na een dergelijke gebeurtenis lijkt het erop dat de Ouden gegraveerde V-vormige symbolen gebruikten om de individuele dagen op hun kalender aan te geven: door het tellen van de gravures identificeerden de onderzoekers 365 dagen op een van de pilaren, verdeeld in twaalf maanmaanden en 11 extra dagen. Sommige vogelachtige figuren hebben een V op hun nek en zouden volgens de auteurs godheden kunnen voorstellen. Als de interpretaties kloppen, zou dit monument de oudste lunisolaire kalender worden die ooit is ontdekt.

Een komeet begon de beschaving 13.000 jaar geleden

Time and Mind

Maar wat weten we over de hemelse gebeurtenis die dit alles heeft veroorzaakt? Onderzoekers geloven dat het prehistorische monument is opgericht ter ere van de dag waarop fragmenten van een komeet 13.000 jaar geleden op de aarde neerstortten. In feite lijkt een van de pijlers van de site de meteorieten van de Tauriden af ​​te beelden, waarvan de stroom de regen van fragmenten zou hebben veroorzaakt die 27 dagen duurde.

Zo'n inslag rond 10.850 voor Christus zou een kleine ijstijd kunnen hebben ingeluid over een periode van meer dan 1.200 jaar, wat zou hebben geleid tot het uitsterven van verschillende diersoorten. Paradoxaal genoeg maakte de komeet “ruimte” voor het ontstaan van een beschaving in de Vruchtbare Halve Maan in het Midden-Oosten, die de overgang markeerde van jagen en verzamelen naar landbouw. Bovendien behield het monument millennia lang een prominente rol in de cultus van de beschaving, wat mogelijk zelfs leidde tot het ontstaan van een nieuwe religie. Zoals Sweatman uitlegde, kan de inslag van de komeet “de beschaving hebben aangewakkerd, een nieuwe religie hebben doen ontstaan ​​en de ontwikkeling van de landbouw hebben gestimuleerd om het koude klimaat het hoofd te kunnen bieden. Het is aannemelijk dat de pogingen van de Ouden om vast te leggen wat ze zagen, de eerste stappen waren in de richting van de ontwikkeling van het schrift duizenden jaren later."

15-08-2024 om 17:33 geschreven door peter  

Scientists Drilled Into An Underwater Mountain In the Atlantic’s ‘Lost City’ To Obtain A Massive Core Sample

The deep ocean is packed with clues about early life.

by Doris Elín Urrutia

 

Johan Lissenberg

Johan Lissenberg, igneous petrologist at Cardiff University, and his colleagues are fascinated with the extreme temperatures of melted rock. Earth churns out molten rock, and seawater cools it down. It is intrinsic to the planet itself, and likely created life. The undersea mountain, called the Atlantis Massif, is home to a hot spring environment known as the Lost City hydrothermal field. Eons ago, a place like this may have been the cradle of unique microbes and the creatures that consumed them.

In a new study published Thursday in the journal Science, Lissenberg and a team of scientists analyzed the mantle rock the JOIDES Resolution research ship drilled out of Atlantis Massif last year. The trip was led by the International Ocean Discovery Program.

Down below the surface

Atlantis Massif is one of the rare places on Earth where geochemists can get their hands on material from the largest part of our planet: the upper mantle.

“Say three to four billion years ago, the continental crust was formed from magma that was sourced in the mantle," Lissenberg tells Inverse.

“But the oceanic crust is always forming. Every day, basically,” he adds. As subaquatic tectonic plates spread apart, the melted rock that makes up Earth's mantle rises up. The material that reaches the surface forms new crust. So, the drill core is a snapshot of processes happening deep below the oceanic floor otherwise inaccessible to researchers.

“The rocks that were present on early Earth bear a closer resemblance to those we retrieved during this expedition than the more common rocks that make up our continents today,” Susan Lang, an associate scientist in Geology and Geophysics at the Woods Hole Oceanographic Institution and co-chief scientist on the expedition, said in a study announcement.

Enigmatic reactions

The ship’s sample is mantle rock, the residue of partial melting underneath Earth’s crust. Embedded within it are minerals that may have been key to understanding early life, like serpentine. This mineral gets its name from a resemblance to snake skin. It’s usually grayish, white or green in color. It occurs when the primary mineral in mantle rock, called olivine, reacts with seawater.

This process releases hydrogen. “Hydrogen can then make compounds such as methane, which can then underpin microbial communities,” Lissenberg says.

Going forward, Lissenberg really wants to understand those reactions. The new study is a start. As the team logged the details of the core centimeter by centimeter, they were surprised. Instead of being rather homogenous, they saw a variability in the mineral composition.

This matters when scientists reconstruct the “chemical kitchen,” Lissenberg says, that led to reactions supporting life. Ultimately, Lissenberg wants to understand all the “flavors” of the upper mantle.

{ https://www.inverse.com/ }

12-08-2024 om 16:35 geschreven door peter  

Fossielen van oude kleine mensen genaamd "hobbits" onderzocht: studie onthult mogelijke oorsprong

door Janine

Cicero Moraes et alii/Wikimedia commons - CC BY 4.0

Er zijn nieuwe fossielen ontdekt van de Floresmens, een uitgestorven soort die net iets meer dan twee decennia bekend is en veel twijfels heeft opgewekt onder wetenschappers.

Floresmens, klein mens uit het verleden

Fossielen van de zogenaamde ‘hobbits’ die op Indonesisch grondgebied zijn gevonden, vertellen over minuscule mensen die 700.000 jaar geleden leefden. De nieuw ontdekte overblijfselen voegen informatie toe over hun twijfelachtige oorsprong: deze oude menselijke soort, die het eiland Flores bewoonde en ongeveer 50.000 jaar geleden uitstierf, heeft in feite voor veel verwarring onder wetenschappers gezorgd.

Homo floresiensis werd eenentwintig jaar geleden voor het eerst ontdekt en dit leidde tot twijfels over het oorspronkelijke idee dat de menselijke evolutie een lineair pad volgde, met een voortdurende ontwikkeling van primitieve wezens tot de moderne mens. De homo "hobbit", zo genoemd vanwege zijn kleine formaat, leefde echter in vrij recente tijden ondanks zijn kleine lichaam.  Bovendien, hoe slaagde hij erin om de oceaan over te steken naar het Indonesische eiland, waar past hij in de stamboom van de mensheid en waarom is hij uitgestorven?

Homo hobbit, miniatuurversie van Homo erectus?

Nature Communications

De auteurs van een nieuwe studie probeerden deze twijfels weg te nemen door fossielen te onderzoeken die toebehoorden aan een van deze kleine mensen en die ontdekt zijn op de eindplek Mata Menge, een van de slechts twee plaatsen op het eiland Flores waar overblijfselen van deze soort zijn gevonden. De resultaten van het onderzoek, zo leggen de auteurs uit, bevestigen de al eerder geformuleerde hypothese, volgens welke hobbits een soort miniatuurversie zouden zijn geweest van Homo erectus, de eerste die Afrika 1,9 miljoen jaar geleden verliet. Fossielen van Homo erectus zijn gevonden in Azië, Afrika en op het eiland Java, in Indonesië. Volgens wetenschappers bereikten ze het eiland ongeveer een miljoen jaar geleden en hier nam de omvang ervan in de loop van 300.000 jaar drastisch af.

Hetzelfde proces komt ook voor bij andere dieren die op afgelegen eilanden leven, vanwege de beperkte beschikbaarheid van hulpbronnen. Yousuke Kaifu, eerste auteur van het onderzoek en professor aan de Universiteit van Tokio, legt uit: "Misschien was het niet nodig om een groot lichaam te hebben, dat meer voedsel nodig heeft en er langer over doet om te groeien en zich voort te planten. Het geïsoleerde eiland Flores had geen roofdieren van zoogdieren en andere hominide soorten, dus de kleine omvang was prima".

Daarom was de hobbit zo klein

De hobbit waartoe de fossielen behoorden was een volwassene van ongeveer 100 meter lang en de tanden leken sterk op die van de Homo erectus die op Java is gevonden. Een andere bekende Homo floresiensis, ontdekt in de grot Liang Bua in 2003, ongeveer 75 km van Mata Menge, was zes centimeter groter en ongeveer 60.000 jaar oud. Dit verschil in grootte zou kunnen worden toegeschreven aan het verschil dat bij de moderne mens is gevonden. Homo floresiensis heeft zijn kleine formaat echter lange tijd consistent behouden.

De vondsten suggereren dat deze kleine mensen op het eiland konden overleven en zich konden vermenigvuldigen, ondanks de aanwezigheid van krokodillen en Komodovaranen, waarvan de lengte 3 meter bedroeg. De auteurs schrijven dat "de eerste dramatische vermindering en de daaropvolgende stabiliteit in omvang erop wijzen dat het hebben van een kleinere lichaamsgrootte op dit eiland een overlevingsvoordeel was voor deze archaïsche mensen."

Naast de hobbit leidt de ontdekking van andere kleine mensen zoals Homo naledi uit Zuid-Afrika en Homo luzonensis uit de Filipijnen, maar ook de grotere Denisovamens uit Tibet, tot de conclusie dat er verschillende soorten mensen bestonden, waarvan vele uit de tijd van de onze, Homo sapiens, en dat geen enkele soort zich in de loop van de tijd heeft ontwikkeld. Hoe dan ook, niet alle experts zijn het eens over de oorsprong van de hobbits en hun geschiedenis moet nog definitief worden opgehelderd.

{ https://www.curioctopus.nl/ }

11-08-2024 om 00:54 geschreven door peter  

Fossielen ontdekt diep in het hart van Groenland: de ijskap was ooit een toendra

door Janine

Calotta glaciale della Groenlandia

Het centrum van de Groenlandse ijskap is in een niet al te ver verleden gesmolten, zo blijkt uit een onderzoek: het onomstotelijke bewijs zijn fossielen die zijn gevonden in wat ooit een groene toendra was.

Ook het centrum van Groenland is in het verleden gesmolten

Tegenwoordig zien we Groenland als een witte ijsvlakte, maar ooit was dat helemaal niet zo. Voortdurende ontdekkingen over het verleden van dit ijzige gebied op aarde onthullen steeds meer ongelooflijke achtergronden, zoals het feit dat het er uitgesproken “groen” uitzag. Nieuw onderzoek heeft bewijs gevonden dat niet alleen de randen, maar ook het midden van de Groenlandse ijskap in een nog niet zo ver geologisch verleden is gesmolten en dat het “oude” landschap eruitzag als een toendra.

In 1993 werd een ijskern van meer dan 3 kilometer lang uit het centrale deel van het grondgebied gewonnen en vervolgens tot op de dag van vandaag bewaard in een afzetting in Colorado, VS. Nu heeft een groep wetenschappers opnieuw de sedimenten op de bodem van dit halfronde stuk ijs onderzocht en iets spannends ontdekt.

Fossielen in het midden van de ijskap

Halley Mastro/University of Vermont

Het team ontdekte dat de sedimenten schimmels, insectenresten, wilgenhout en een maanzaad bevatten, allemaal ongerept. Paul Bierman van de Universiteit van Vermont, co-auteur van het onderzoek samen met Halley Mastro, stelt: "Deze fossielen zijn prachtig."

Onderzoek heeft het feit bevestigd dat de enorme ijskap van Groenland in het verleden is gesmolten als gevolg van een bijzonder warme periode, waardoor een groen eiland is ontstaan. Aangenomen wordt dat dit in de afgelopen miljoen jaar heeft plaatsgevonden, wat betekent dat de ijskap veel kwetsbaarder is dan wetenschappers hadden gedacht. Sinds het ijs in het midden van Groenland smolt, spreekt het voor zich dat de rest van het eiland hetzelfde lot onderging en, volgens Bierman, duizenden jaren lang, genoeg om een ​​terrein te creëren dat klaar was om een ​​ecosysteem te huisvesten.

Richard Alley, klimatoloog aan de Pennsylvania State University, verklaarde na bestudering van de resultaten van het onderzoek: “Het bevestigt en breidt het feit uit dat een groot deel van de zeespiegelstijging plaatsvond in een periode waarin de oorzaken van de opwarming niet bijzonder extreem waren”, en ziet het als een waarschuwing voor wat er zou kunnen gebeuren als het klimaat verder opwarmt door toedoen van de mens.

GISP2 till and macrofossils found in it: (A) Photo of the angular-clast-rich till section of the GISP2 subglacial core, taken 1994, up core to left (Credit: T. Gow, supplied by D. Meese). (B) Overview of sediment, mostly quartz and fossils. (C) Wood fragment. (D) Vertical orientation typical of GISP2 wood. (E) Wood at higher magnification showing simple pits in lateral vessel wall (1) and distinct simple perforation plate (2), along with the helical thickening typical of GISP2 wood. (F) Bud scale of Salix (willow). (G) Sclerotium of the soil fungus C. geophilum* (H) Insect eye, possibly from a fly*. (I) S. rupestris megaspore. (J) Seed of Papaver sect. Scapiflora. The asterisk shows macrofossil types also found in Camp Century sediment by ref. 5. Wood fragment images are same specimen.

De “kwetsbaarheid” van Groenland bevestigd

In feite stijgt de zeespiegel met 2,5 cm per jaar en in een versnellend tempo. Tegen het einde van deze eeuw zullen de oceanen naar verwachting ongeveer zes meter hoger stijgen dan nu.

In 2016 werd dezelfde ijskern, GISP2 genaamd, onderzocht door wetenschappers van Columbia University: de resultaten suggereerden dat de huidige ijskap niet ouder kon zijn dan 1,1 miljoen jaar en dat Groenland tijdens het Pleistoceen lange tijd zonder ijs heeft gezeten, minstens 90% van zijn grondgebied. In 2019 werden in een andere ijskern, die in de jaren ’60 werd gedolven, kleine takken en gefossiliseerde insecten gevonden die 416.000 jaar oud waren. Het huidige onderzoek bevestigde dat dit bevroren eiland niet zo sterk en veerkrachtig is als eerder werd gedacht: meer dan 3 meter ijs smolt gemakkelijk, waardoor er tijd en ruimte overbleef voor de ontwikkeling van een toendra. 

{ https://www.curioctopus.nl/ }

08-08-2024 om 22:45 geschreven door peter  

Artikel door thedailydigest.com

Een achtste continent onder water

Wetenschappers uit Australië en Nieuw-Zeeland hebben onlangs een nieuw onderwatercontinent herontdekt, namelijk Zealandia.

Afbeelding: NEOM/Unsplash

Een groep eilanden

Het is in feite een groep eilanden die vergelijkbaar is met de eilanden waaruit Nieuw-Zeeland bestaat, met een oppervlak dat iets minder groot is dan de helft van Brazilië.

Afbeelding: Marjan Blan/Unsplash

Een oud supercontinent
Er wordt aangenomen dat Zealandia deel uitmaakte van het oude supercontinent Gondwana, dat enkele honderden miljoenen jaren geleden een groot deel van het zuidelijk halfrond van onze planeet bedekte.

Afbeelding: Benjamin L. Jones/Unsplash

Indrukwekkende afmetingen
Volgens een artikel van de BBC zijn de afmetingen van dit ondergedompelde continent indrukwekkend: 4,9 miljoen vierkante kilometer.

Afbeelding: Jean Beller/Unsplash

De grootte van India
Volgens een ander team onderzoekers, dat in 2017 het continent Zealandia voor het eerst claimde te hebben ontdekt, heeft het ongeveer dezelfde grootte als India, zo bericht Ouest France.

Afbeelding: Greg Rosenke/Unsplash

Bijna het gehele oppervlak bevindt zich onder water
Het land van Zealandia maakte waarschijnlijk deel uit van een uitgestrekt gebied boven zeeniveau. Tegenwoordig bevindt 94% van het oppervlak zich echter onder water.

Afbeelding: Yannis Papanastasopoulos / Unsplash

Wat is het precies?
Gaat het om een groot eiland of een continent? Zoals de Times of India opmerkt, is er geen geologische parameter die een precieze grens tussen de ene of de andere term vastlegt, en maakt het daardoor onderwerp voor discussie.

Afbeelding: Jay Wennington / Unsplash

Afgezonderd van het Australische continent
Ondanks de nabijheid van Australië geloven wetenschappers dat de twee groepen afzonderlijk van elkaar bestaan. Al wordt de term 'Australazië' soms gebruikt om het volledige landgebied van het zuidwesten van de Grote Oceaan aan te duiden.

Afbeelding: Alex Rose / Unsplash

Gedetailleerde kartering
Geowetenschappers hebben Zeelandia gedetailleerd in kaart gebracht, waarmee ook de locatie van vulkanische activiteit werd onthuld en belangrijke informatie over de opbouw van het continent werd verkregen.

Afbeelding: NOAA / Unsplash

Monsters genomen van de bodem in de oceaan
Om deze kartering uit te voeren, verzamelden de onderzoekers geologische monsters van de landmassa die zich onder water in de oceaan bevindt.

Afbeelding: Tyler Lastovich / Unsplash

Een schat aan mineralen
Het tijdschrift Slate berichtte dat er een echte schat is aangetroffen: "Een mengsel van verschillende soorten zandsteen, basalt en kalksteen".

Afbeelding: Christian Wiediger / Unsplash

Magnetische afwijkingen
De datering van deze monsters en het onderzoek van hun magnetische afwijkingen stelden wetenschappers in staat om de Zealandia op een waardevolle manier in kaart te brengen.

Afbeelding: Matt Hardy / Unsplash

Waarom ligt Zeelandia onder water?
De meest voor de hand liggende verklaring hiervoor is dat de tektonische platen door het uitrekken van Gondwana braken, waardoor het oceaanwater vrij spel kreeg.

Afbeelding: Dan Stark / Unsplash

Een dunne, ondergedompelde aardkorst
Het loskomen van Antarctica zou de aardkorst van Zeelandia geleidelijk hebben verdund tot het land volledig was ondergedompeld.

Afbeelding: Dan Gold / Unsplash

Meer kennis over de eigenschappen van de aardkorst
De ontdekkingen in Zealandia zouden wetenschappers meer kennis kunnen geven in waarom de aardkorst zo dun werd en zo sterk uitrekte.

Afbeelding: Matteo Paganelli / Unsplash

Zijn er nog andere verborgen continenten?
We weten niet of er meer onderzeese continenten zijn, omdat we eigenlijk maar weinig weten over de diepten van de oceanen. De ruige omgeving bemoeilijkt dit soort plekken. Daarom is deze recente ontdekking zo waardevol!

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08-08-2024 om 21:05 geschreven door peter  

What Are Diffractive Deep Neural Networks?

D2NNs are constructed from individual transmissive layers that are optimized through deep learning, allowing them to perform computation almost entirely through the use of optics.

In their recent research, the UCLA team, led by Professor Aydogan Ozcan, worked with a pyramid-shaped diffractive optical network, a design that allowed the team to achieve unidirectional imaging with fewer diffractive degrees of freedom.

The result is a design that helps to ensure high-fidelity image formation, but only in one direction. By contrast, significant image inhibition occurs in the opposite direction, conditions that are key for use with applications where imaging in one direction (i.e., unidirectional imaging) is required. Such fields include defense and security technologies, telecommunications applications, and systems used for privacy protection.

Artist’s concept of the pyramid diffractive optical network designed by Ozcan and his colleagues at UCLA

(Credit: Ozcan Lab / UCLA).

The team was also able to demonstrate modularity and scalability for their novel pyramid-structured system by cascading several P-D2NN modules. This allowed them to achieve even greater magnification or demagnification factors.

The Pyramid Mystery

The pyramid shape has long captivated human minds, and there is arguably no better example of this than the enigmatic pyramids at Giza.

In simple terms, a pyramid is a three-dimensional shape resulting from the construction of triangular faces arising from a polygonal base. Each of the points of the triangular portions meets at the highest point or apex.

This gives rise to a unique shape where weight is evenly distributed, which allowed ancient architects to rely on this design for the construction of some of the largest structures ever built, with the most famous examples comprising the Giza pyramids, monuments that are still impressive by today’s engineering standards, and which have proven their resilience by persisting for thousands of years. Given their enigmatic appearance, the pyramids have also contributed to a number of fringe ideas over the years, involving the mysterious powers the monuments at Giza may possess themselves or purported technologies (many of them pseudoscientific) based on the pyramid shape and powers it allegedly possesses.

The famous pyramids at Giza

(Credit: Osama Elsayed/Unsplash).

For the UCLA team, the pyramid structure offered real-life advantages in that the ascending structure allowed them to scale the layers of the new D2NN in such a way that aligns with the direction of image magnification or demagnification. In other words, the pyramid shape offers a sort of guide that either enlarges or shrinks the image in question in a controlled manner. The result is that high-fidelity imagery is able to pass progress through the network, but only in the desired direction.

During their research, the team also succeeded in experimentally validating the new P-D2NN system by using terahertz (THz) illumination. 3D-printed diffractive layers were tested under continuous-wave THz illumination, producing results that the team says very closely matched earlier numerical simulations.

Applications and Future Prospects

The system is ideal for various applications, including technologies that provide optical isolation for photonic devices and decoupling of transmitters and receivers in telecommunications. In the coming years, the new pyramid-shaped system could also benefit security and even surveillance technologies.

Overall, the team’s P-D2NN architecture represents a considerable advancement in optical imaging technology, which its developers believe could help pave the way toward a range of future innovations and applications. All of which, of course, relies on one of the most iconic and captivating ancient monumental shapes in human history.

The team’s findings were published in the journal Light: Science & Applications on July 31, 2024.

• Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. He can be reached by email at micah@thedebrief.org. Follow his work at micahhanks.com and on X: @MicahHanks.

{ https://thedebrief.org/category/science/ }

07-08-2024 om 01:26 geschreven door peter  

“The question of how our early ancestors arrived there from Southeast Asia is one of the most captivating in prehistoric migration, mainly because of the vast distances covered and advanced seafaring skills that would have been required,” explained Mr. Hendri Kaharudin, a PhD candidate at the Australian National University (ANU) and the lead author of the study outlining the advanced maritime technologies employed by these early sailors that helped them reach the Tanimbar Island of Elivavan.

“This discovery marks one of the southern route’s earliest known sites, making it a crucial piece of the puzzle,” Mr. Kaharudin added.

42,000 Years Ago, the First Human Migrants Sailed to Tanimbar

While scientists have often theorized about the first arrival of human migrants in Indonesia from Southeast Asia, no concrete theory is universally accepted. According to the team’s research published in Quarternary Science Reviews, recent discoveries made on the Indonesian Tanimbar island of Elivavan revealed that people first arrived there around 42,000 years ago.

“Along with tiny fragments of pottery, we also found evidence of things like bones, shells, and sea urchins that point to the island’s role as a hub for early maritime activities,” Mr. Kaharudin said.

To reach this remote location, ancient mariners would have had to traverse exceedingly long distances over treacherous seas. Mr. Kaharudin said these ancient mariners would have had to traverse bodies of water over 100 kilometers in the distance “regardless of their direction of travel.” According to the press release announcing the new findings, “the risky nature of the sea crossings suggests the colonists had developed advanced maritime technology by around 42,000 years ago.”

The Debrief previously reported on discoveries showing that Stone Age sailors from 7,000 years ago employed some advanced nautical techniques to sail long distances. However, this research is the first to identify similarly advanced techniques from tens of thousands of years earlier.

Mystery of Ancient Routes Potentially Solved

If the discoveries made on Elivavan ultimately confirm the first route to Indonesia taken by ancient mariners over 42,000 years ago was a southern one, it will solve a long-standing debate between scientists about which route these original colonists took to get there.

“There are two main routes that have been explored as possibilities since the mid-20th century, a northern path via islands like Sulawesi, and a southern track passing near Timor and the Tanimbar islands,” Kaharudin explained. This particular location, which lies along the southern route, is significant, the researcher notes, as “Tanimbar is located just off the ‘Sahul shelf’, which encompasses modern-day Australia, as well as New Guinea.”

To make such a dangerous crossing, the researchers believe that these ancient seafaring humans likely hopped along the coasts, moving from island to island as they slowly spread out. This strategy evolved over time, the researchers note, meaning that the colonization was not a single event but “a gradual process involving successive waves of seafaring populations.”

“Coastal communities likely navigated shorelines, exploiting marine resources and establishing resilient settlements along their journey,” Mr. Kaharudin explained. “This island-hopping strategy facilitated cultural exchange and adaptation, shaping diverse societies across the land mass.”

Studying Remote Locations Could Uncover More About Ancient Human Life

Although the discovery of human occupation on Elivavan of the Tanimbar Islands over 42,000 years ago is significant, the researchers behind the discovery note that there is still much more work to be done. This includes taking a closer look at the area where these discoveries were made to paint a more complete picture of these early seafaring humans. In fact, according to Kaharudin, it is the exploration of these remote locations that could answer the mysteries of ancient human migration.

“As more work is done in lesser-explored regions like the Tanimbar Islands, I expect we’ll uncover more about early human life and migration patterns,” he explained.

• Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.

{ https://thedebrief.org/category/science/ }

05-08-2024 om 22:02 geschreven door peter  

Now, if this story were true, then even in the modern day we should have found that our cranial capacities are gradually increasing over time. Instead, dozens of elaborate studies have revealed the exact opposite! The human brain has been consistently shrinking in volume over the past 12,000-odd years, since the end of the last Ice Age. We are dumber today than any time before in the Holocene era!

In one of the early studies titled, “Decrease of Human Skull Size in the Holocene”, published in the Human Biology journal in 1988, scientists computed cranial capacity (CC) for nearly 9500 male crania and 3300 female crania, originating from Europe and North Africa. The study found,

“Among male samples the peak CC (cranial capacity) occurred in the Mesolithic (1593 cc), the lowest value falls in modern times (1436 cc); in females sample timing is the same: Mesolithic maximum of 1502 cc and modern minimum of 1241 cc. For both males and females the decrease through time is smooth, statistically significant and inversely exponential. A decrease of 157 cc (9.9 % of the larger value) in males and of 261 cc (17.4 %) in females is a considerable one, of the order of magnitude comparable to the difference between averages for H. Erectus and H. Sapiens.”[1]

Separate studies conducted on large samples from Europe, the Near East, Africa, Japan and Australia have confirmed this general trend. Human cranial capacity has decreased by approx. 10% of its average value (i.e. 100-150 cc) since the Late Pleistocene until the early 20th century.[2]

If evolution by natural selection is consistently making us smarter then why did we lose such a large chunk of brain volume at a time when, supposedly, for the first time, humans transitioned from a hunter-gatherer lifestyle to settled, agricultural communities that allowed the first great civilizations of the world to flourish?

One of the first recognizable members of the genus Homo is called Homo erectus (meaning “upright man”), whose earliest appearance in the fossil records occurred around 2 million years ago. Homo erectus is thought to have been the earliest human ancestor capable of using fires, hunting and gathering in coordinated groups, caring for injured or sick group members, seafaring, and possibly art-making. The difference between the average cranial volume of Homo erectus and Homo sapiens is roughly the same as the amount of cranial volume that has been lost in the past 12,000 years in the Holocene period. 

Allow that to sink in. In just 12,000 years, we have lost the same amount of intelligence that, purportedly, took nearly 2 million years to develop! How does that happen? And why has the cranial volume been declining at a time when the most significant advancements in human civilization supposedly took place?

Clearly, something is amiss here. The data does not lie. Certain unfounded assumptions appears to have been made about human evolution and the origins of civilization that does not accord with the precipitous decline in human cranial capacity during the Holocene period. One of the thoughts that struck my mind when I came across this stunning data is, how do evolutionists and anthropologists explain it? 

I had a hard time finding a well-written paper or article on this topic until I came across this piece in the Discover Magazine titled, “If Modern Humans Are So Smart, Why Are Our Brains Shrinking?”[3], in which, science writer Kathleen McAuliffe, tells us that she was utterly dismayed when anthropologist John Hawks of the University of Wisconsin told her that, over the past 20,000 years, the average volume of the human male brain has decreased from 1,500 cc to 1350 cc, losing a chunk the size of a tennis ball. “This happened in China, Europe, Africa - everywhere we look,” Hawks informed her. 

When Kathleen contacted other experts to find out if they knew about the shrinking human brain, she came to a startling realization. It was a closely guarded secret. “Only a tight-knit circle of paleontologists seem to be in on the secret, and even they seem a bit muddled about the matter,” she wrote to her utter surprise. 

One of the experts she consulted was Christopher Stringer, a paleoanthropologist at the Natural History Museum in London. Stringer told her something quite stunning: “Scientists haven’t given the matter the attention it deserves. Many ignore it or consider it an insignificant detail”. I could hardly believe this. This absolutely jaw-dropping piece of scientific data, which turns the Darwinian theory of gradual evolution by natural selection on its head, is treated by some scientists as an “insignificant detail”. What really is significant then? How the Homo erectus learned to pick his nose?

Besides, why is there so much secrecy around this information? Why is it that only a “tight-knit circle of paleontologists” knows about this, and everyone else seems to be in the dark? Isn’t it the duty of scientists, academia and the media to widely disseminate this kind of shocking information and invite debates and discussions over it? 

The truth is that, and many have written about it, scientists and academics do not earn any brownie points by ruffling the calm surface of “Lake Consensus”, as John Anthony West put it. There is a strong tendency to adhere to the status quo, and very often, errant academics who do not toe the official line, are put in their place by being denied grants, positions and other academic privileges. As a result, even if grave anomalies are observed in a theory that has achieved consensus, they are ignored or quietly filed away from the public eye. This kind of knowledge filtering goes on continuously, and what we know as the truth is simply a “consensus”, and nothing more.

Kathleen went on to write that, some scientists have tried to explain why our brains are shrinking, but their explanations are vague, muddled and inconsistent. According to Christopher Stringer, the reduction in cranial volume may be due to the decline in human stature since the Holocene period, since a larger brain is required to control a bigger body mass. However, John Hawks has contested this, claiming that the brain has shrunk much faster than the body. “For a brain as small as that found in the average European male today, the body would have to shrink to the size of a pygmy”, Hawks said. Besides, the scientific data indicates that human height declined till the end of the Bronze Age, after which it has been steadily increasing. But, brain volume has continued to decline till the modern period. This means there cannot be any cause-effect relationship between body size and brain size. 

Cognitive scientist David Geary of the University of Missouri believes that people actually became dumber in the Holocene period. According to him, as population density increased and complex societies emerged, people did not have to be as smart to survive; they could get by with the help of others. This created the selection pressure for the brain to become smaller. However, historical facts do not support his contention. It is only around c. 5000 BCE in the Eastern Mediterranean that we see a jump in population densities, followed by the emergence of complex Bronze Age societies. In many other parts of the world, complex societies arose even later than that. By that time, there had already been a substantial reduction in cranial volume. What this implies is that, only after humans became substantially stupid they began to form large, complex societies, and, as a result, some people were able to get by without possessing any specific skill or sufficient gray matter.

John Hawks put a different twist on the situation. He believes that humans may be getting smarter due to a re-wiring of the brain. The brain is an energy guzzler; it consumes nearly 20 percent of our calorie intake. A bigger brain uses up more energy. So, optimally, we need a brain that packs the most intelligence for the least energy. Hawks believes that, over the past 10,000 years, due to a series of advantageous brain-related mutations, the neural connections of the brain may have become streamlined and the molecular activity at the synapses improved, thereby making us more intelligent than our Paleolithic ancestors, even though we have smaller brains.

So, what Hawks is essentially saying is that, after moving in the wrong direction for nearly 2 million years, turning itself into an energy-guzzling SUV, the brain went through a sudden awakening at the end of the last Ice Age and decided to change course and transform itself into a Tesla. Hawks himself admits that such a course correction would require a large number of very rare, beneficial mutations, the chances of which are extremely slim. The fact is that random new mutations are more likely to reduce than to raise intelligence. A course correction for the human brain after 2 million years of evolution in the wrong direction, due to the sudden appearance of extremely rare beneficial mutations, is wishful thinking at best. 

Besides, there is no tangible evidence that the neural connections in the brain suddenly became more efficient after the onset of the Holocene Period. Nor is it likely that any such evidence will ever be found since brain tissue is not preserved for such long periods of time. If they were, we might have found that even the neural connections have degraded! 

The truth is very simple. Our declining cranial capacity indicates that we have been getting dumber over the course of the past 12,000 years. Our memories have declined substantially compared to our ancestors who could remember massive volumes of data, and transmit them orally to the next generation. Our powers of judgment and discrimination have declined because of which we cannot distinguish between the truth and lies, or discern what truly serves our welfare as opposed to what takes us down the path of misery. Our ethics and morality have nosedived, along with all the subtle abilities of the brain that we possessed in the bygone ages such as intuition, telepathy, clairvoyance, etc. 

Unfortunately, most people have been brought up to believe otherwise. They think that we are the smartest generation of people that ever lived since that is the idea that is pushed down their throats from an early age. The problem is, once people have been indoctrinated with a specific belief or ideology, no amount of evidence is enough to overturn that. The hardest things to get rid of are deeply held biases, and scientists are no exceptions to this.

Although the decline in cranial capacity during the Holocene period is at odds with Darwinian evolution, it is perfectly aligned with the doctrine of the Yuga Cycle or Great Year. The last 12,000 years comprise the descending arc of the Yuga Cycle, when human consciousness, memory and intelligence are supposed be in a state of continuous degradation. In the Mahabharata, the sage Markandeya told Yudhisthira, “Know, O Yudhisthira, that the period of life, the energy, intellect and the physical strength of men decrease in every Yuga!”[4] These statements, which have been generally brushed away as fanciful notions, are amply borne out by the scientific data collected over the past few decades. 

Since we are now approaching the end of the Kali Yuga, the shrinking of the human brain has already started tapering off in some populations. We can expect that, once we come out of the Kali Yuga, our cranial capacity will again start increasing gradually and attain their peak value in the next Golden Age or Satya Yuga, after another 12,000 years evolution along the ascending arc of the Yuga Cycle. 

So, what does all of this mean for human evolution? It means that the sinusoidal fluctuation in cranial volume, height and lifespan has been going on for millions of years, ever since man first appeared on the earth. Over a period of roughly 25,800 years, the cranial volume goes up and down with a 10% - 15% fluctuation in its value. 

Contrary to oft-repeated claims, there has not been a gradual increase in cranial volume over the past 2 million years. That is an assumption and not a fact. We have found less than 200 pre-Holocene hominin skulls. 200 skulls in a span of 2 million years! How can such a scanty collection of pre-Holocene crania reveal the pattern of human evolution? A regression line was fitted through these data points assuming that cranial volume must have increased linearly. That is an unacceptable assumption. Any kind of curve can be drawn through a scatter of 200 data points over a 2 million-year time period. There are hundreds of thousands of years in the graph without a single data point! 

On the other hand, tens of thousands of Holocene crania have been found, and that data indicates that cranial volume has been decreasing over the past 12,000 years and gradually flattening out. Surely, the true nature of the cranial capacity curve will be revealed where the data density is the highest. 

The only sensible conclusion to be drawn from this is that human cranial capacity fluctuates in a sinusoidal manner over a 25,800-year cycle. I propose that all the available Homo sapiens cranial specimens can be plotted on this sinusoidal curve. Since I do not have access to a well-dated set of human skulls I cannot test it out myself. But, there is a well-known set of cranial specimens belonging to the Cro-Magnon, which supports this argument.

The Cro-Magnons were one of the earliest examples of modern Homo sapiens in Western Europe. Cro-Magnons were taller than modern humans, had more robust bones, with a cranial capacity of around 1600 cc, which is comparable to the peak cranial capacity of the Mesolithic period.[5] Their fossils have been found between 30,000 to 40,000 years ago, which straddles the peak of an earlier Golden Age at around 38,676 BP (Before Present) or 36,676 BCE. 

This can be easily calculated from the Yuga Cycle timeline. The peak of the last Golden Age was reached around 10,876 BCE, and we need to add 25,800 years to get the previous peak i.e. 36,676 BCE. This means that the Cro-Magnons lived in an earlier Golden Age and some part of the descending Yuga Cycle. This is why, their morphology and cranial capacities are larger than that of modern humans and comparable to the peak cranial capacities of the Mesolithic period i.e. the most recent Golden Age.

What this means is that, over the past 2 million years, since the first hominin fossils began to appear, our cranial volume has been oscillating over a 25,800-year cycle, without a net increase or decrease in any direction. This is true not only for Homo sapiens crania but is likely to be equally applicable to all the extinct members of the human family, including the Neanderthals and Homo erectus. 

For instance, the Neanderthals had a bigger skull than modern humans with an average cranial capacity of around 1500 cc, which is comparable to the cranial volume of humans who lived at the end of the last Ice Age. However, even Neanderthal skull capacities vary between 1300 to 1600 cc, and it is quite possible that this variation occurs in tandem with the 25,800-year precession cycle. No one has tested for this till now, but if we plot out the available Neanderthal skulls on this curve, we may be taken by surprise.

However, cranial specimens need to be accurately dated before plotting on the 25,800-year sinusoidal curve, because even a small percentage error in dating can make things go haywire. The difference between the peaks and troughs of the curve is only 12,900 years, which is very small in geological terms. Ideally, the hominin cranial specimens which have been discovered in the past 100,000 to 200,000 years should be used for plotting this curve, so that the error in dating is not very significant.

In case you are wondering what could be responsible for the decline in our cranial capacity during the Holocene period, certain studies indicate that genetics is the main driving factor. Over the past 12,000 years, we have been acquiring harmful gene mutations, and passing them on to our children, leading to the gradual degeneration of the human race. In a couple of papers published in the journal Trends in Genetics (2012), Professor Gerald Crabtree of Stanford University showed that, as a species, we are gradually declining in average intellect because we are accumulating mutations that deleteriously affect brain development or function.[6]

Professor John Sanford of Cornell University firmly believes that the human race is devolving and that there is no evidence of human evolution being directed by the forces of natural selection. In the book Genetic Entropy & the Mystery of the Genome (2008), he argued that the minimal rate of human mutation is estimated to be 100 new mutations per generation. While most mutations do not have any effect, some of them are deleterious. This causes a genetic degradation that leads to the gradual extinction of a species through time. In an interview with Jim Cantelon, he explained the new findings in the field of genetics:

“It’s kind of a trade secret amongst population geneticists - any really well-informed population geneticist understands that man is degenerating…what’s happening is that, every gene in every chromosome of every cell in my body is mutating, and so that guarantees my aging and my death. But the problem is that - these mutations that are accumulating in my body - some of them are transmitted to my children. I take all the mutations that I inherited from my ancestors – tens of thousands of deleterious mutations in my body – and I add my own contribution to that – about 100 new mutations at least – and pass it on to the next generation…It means we are a perishing people living in a dying world…there is no circle of life where things just continue staying the same, and it’s not an upward spiral of evolution where things keep getting better and better, it is a downward spiral. ”[7]

A downward spiral indeed! In other words, the descending arc of the Yuga Cycle or Great Year in which human intellect gradually declines. The wisdom of the ancients is now being validated by different scientific disciplines. But why is there so much secrecy? 

John Sanford said that the degeneration of man is a “trade secret amongst population geneticists”, while Kathleen McAuliffe had noted that the phenomenon of the shrinking human brain is a secret known to “only a tight-knit circle of paleontologists.” Why is this knowledge being concealed from the people at large? Why not just come out and say, “It's confirmed guys. We are idiots, and we are getting dumber, and that’s why we are messing up the world.” Is that too much to ask? 

I believe that John Sanford’s statement that we are “a perishing people in a dying world” is a bit too pessimistic, for it seems to imply that there is no hope for the world. That is not exactly true. Had the deterioration of the human brain been going on ceaselessly for the past 2 million years, then we would have transformed into chimps by now. Or become extinct. But we didn’t, right? This means that the process of degeneration is not unidirectional, but reverses itself at periodic intervals. Humanity is not headed towards extinction but towards transformation. 

At some point after the completion of the Kali Yuga, the harmful genetic mutations will get replaced by beneficial genetic mutations, which will then keep on accumulating and drive the upward spiral of evolution till the next Golden Age. This is how the Cycle of the Ages operate, and it is a shame that this essential wisdom has been discarded by the modern civilization. But, then, this is exactly what happens in the Kali Yuga, the age of ignorance and darkness, when, in spite of having so many advanced technologies, humanity remains completely oblivious of its origins and purpose.

One might naturally wonder what could be causing the harmful and beneficial genetic mutations to fluctuate over a 25,800-year cycle. Could the radiation from some powerful cosmic source be driving this phenomenon? The answer is yes, and I have explored this idea in my book Yuga Shift, and I shall write about it in future articles.

References

[1] Maciej Henneberg, “Decrease of Human Skull Size in the Holocene”, Human Biology, June 1988, Vol.60, No.3, pp. 395-405, https://digitalcommons.wayne.edu/humbiol/vol60/iss3/5/
[2] Christopher B. Ruff et al, “Body mass and encephalization in Pleistocene Homo”, Nature, 1997, Vol.387, pp. 173 - 176.
[3] Kathleen McAuliffe, “If Modern Humans Are So Smart, Why Are Our Brains Shrinking?” Discover Magazine, 20 January 2011, https://www.discovermagazine.com/the-sciences/if-modern-humans-are-so-smart-why-are-our-brains-shrinking
[4] Mahabharata 3.189, https://www.sacred-texts.com/hin/m03/m03189.htm
[5] “Cro-Magnon”, Britannica, https://www.britannica.com/topic/Cro-Magnon
[6] Gerald R. Crabtree, “Our fragile intellect. Part I” and “Our fragile intellect. Part II”, published in Trends in Genetics. Taken from Kevin J. Mitchell, “Genetic entropy and the human intellect”, Trends in Genetics, 2013, Vol.29, No.2, pp. 59-60.
[7] Dr. John Sanford, author of “Genetic Entropy and the Mystery of the Genome”, in an interview with Jim Cantelon, on the YouTube channel 100huntley, https://www.youtube.com/watch?v=K8KbM-xkfVk

{ https://mysteriousuniverse.org/ }

31-07-2024 om 22:40 geschreven door peter  

The entrance to Leang Karampuang cave, where some of the oldest cave art has been found.

Google Arts & Culture

Recent studies involving advanced laser ablation techniques examined the images on the cave’s walls, which include ancient depictions of animals like pigs and bovines along with stick renderings of anthropomorphic shapes. The new analysis reveals that the art is likely several thousands of years older than previously thought.

However, the extreme age of the art within the cave may point to another intriguing possibility: that its creators were not modern humans, and instead may have been one of our ancient hominin cousins. Such a discovery, if proven, would have profound implications for the origins of figurative art and the cognitive capabilities of our now-extinct hominin relatives.

THE ENIGMA OF SULAWESI

Renowned for its ancient cave paintings, Sulawesi has long fascinated archaeologists. Among the island’s most notable works of cave art include a 14-foot-wide panel that depicts crude imagery of early humans hunting what are commonly believed to be warty pigs and dwarf bovines with spears.

Past work had already revealed the presence of what archaeologists recognized as some of the world’s oldest rock art on the island. A process known as solution uranium-series (or U-series) was used to analyze calcite deposits that had formed over the art on the walls of Maros-Pangkep, a rock art location on the southern portion of the island. This technique, which scans rock walls without taking physical samples, provides a more accurate estimate by distinguishing between layers of sediment.

Cave art found at Maros-Pangkep on southern Sulawesi

(Credit: Cahyo/Wikimedia Commons/CC BY-SA 3.0).

However, in their recent study, researchers led by Indonesian archaeologist Adhi Augus Oktaviana used what they describe as “a novel application of this approach,” called laser-ablation U-series imaging, which allowed them to more accurately date some of the earliest cave art in the area.

In a recent study detailing their work, the researchers write, “This method provides enhanced spatial accuracy,” resulting in older minimum ages for previously dated art.

The scene, covered with calcium carbonate deposits, shows three human figures and a pig.

Dominic Julian/BRIN Google Arts

Three human-like figures and a large pig are drawn on a limestone cave wall. Griffith University

REDATING THE WORLD’S OLDEST CAVE ART

The new analysis revealed remarkable results. A hunting scene found at the Leang Bulu’ Sipong 4 location, previously dated to at least 43,900 years ago during previous analysis, has now been revealed to have a minimum age closer to 51,200 years ago, making the art at the location at least 4,040 years older than initial estimates had placed it.

{ https://thedebrief.org/category/science/ }

30-07-2024 om 23:20 geschreven door peter  

Het iconische zeedier dat een schaal in de vorm van een taco had: een nieuwe studie onthult zijn “geheimen”

Door Janine

The Burgess Shale - Royal Ontario Museum

Vijfhonderd miljoen jaar geleden leefde er een zeedier in de vorm van een “taco” in de wateren van de aarde. Een ongekende fossiele analyse heeft iets nieuws ontdekt over dit merkwaardige uitgestorven dier.

Odaraia alata, het vreemde zeewezen uit het Cambrium

In het Cambrium, toen het leven op aarde dramatisch explodeerde, leefde een vreemd wezen dat op een garnaal leek in de eerste oceanen die zich op onze planeet vormden. Landdieren die worden gedefinieerd als geleedpotigen met onderkaken of tangkaken bestaan voor ongeveer 70% uit krabben, bijen, duizendpoten en garnalen. 

Daartoe behoorde de Odaraia, waarvan de specifieke schaal hem beschermde tegen mariene gevaren, in de prehistorie, ongeveer 508 miljoen jaar geleden. De Odaraia bewoog zich in ondiep water, was bijna twintig centimeter lang en door zijn taco-vormige schaal, de beroemde Mexicaanse tortilla, kon hij zowel in normale houding als ondersteboven voortbewegen in zee.

De Odaraia had kaken: het is bevestigd

Ghedoghedo/Wikimedia commons - CC BY-SA 3.0

Onderzoekers van het Royal Ontario Museum in Toronto, Canada, hebben het eerste concrete bewijs geleverd dat dit schepsel was uitgerust met onderkaken, waarmee het zich voedde in open zee en niet alleen op de zeebodem. Door het analyseren van fossielen is het mogelijk geweest om enkele gaten in de evolutie van geleedpotigen op te vullen, en de Odaraia heeft in dit geval meer dan honderd jaar lang twijfels opgeroepen onder paleontologen.

In 1912 en 1981 werd de hypothese geopperd dat dit grote waterinsect in staat was om voedsel door zijn kaken te filteren, net als moderne garnalen. De beschikbare fossielen waren echter niet voldoende om deze theorie te bevestigen. De nieuwe studie, onder leiding van paleontoloog Alejandro Izquierdo López, heeft eindelijk wat duidelijkheid gebracht: na onderzoek van 150 exemplaren uit het Royal Ontario Museum die tot nu toe nog niet bestudeerd waren, koos het team 24 van de best bewaarde exemplaren uit om in detail te analyseren. De fossielen in kwestie waren gevonden in de rotsformatie Burgess Shale, waar de conservering van vondsten doorgaans buitengewoon goed is.

Ontdekt hoe de Odaraia zich voedde

Qohelet12/Wikimedia commons - CC BY-SA 4.0

De ongelooflijke staat van bewaring, zelfs van de zachte delen van het lichaam, maakte het mogelijk om te ontdekken dat de Odaraia doorzichtige kaken had, uitgerust met kleine tandjes. Tussen de kaken stond een enkele tand, die waarschijnlijk diende om voedsel beter te kunnen kauwen. Izquierdo López verklaarde dat “het lijkt op een drietand. Het is iets dat nog nooit bij een ander dier uit het Cambrium is gezien."

Verder bleek uit het onderzoek dat de 30 paar kleine poten van de Odaraia bedekt waren met talloze stekels en honderden kleine puntjes, die er samen uitzagen als een soort visnet voor de jacht op plankton. Een dier dat “deels filtervoeder, deels roofdier” was, met voor die tijd bijzonder grote ogen. Na meer dan een eeuw is het geheim van de bizarre Odaraia dus eindelijk onthuld en het helpt om de evolutie van de kaak bij de oude geleedpotigen van onze planeet te begrijpen.

Odaraia alata is portrayed swimming upside down. You can see its large eyes and mandibles, or pincers, at the front near its mouth.  

Artist's reconstruction of Odaraia alata. It has now been classified as a mandibulate, and rsearchers believe it could have swum upside down to gather food with the help of the many spines along its legs. Less 

ILLUSTRATED BY DANIELLE DUFAULT. COURTESY ROYAL ONTARIO MUSEUM

{ https://www.curioctopus.nl/ }

27-07-2024 om 22:35 geschreven door peter  

99-Million-Year-Old Burmese Amber Reveals Oldest Known Skink

 by Natali Anderson

Paleontologists have found the remains of a previously unknown species of lizard in a piece of mid-Cretaceous amber excavated in northern Myanmar.

Life reconstruction of Electroscincus zedi; areas of the lizard not represented in the material available are depicted as blurred.

Image credit: Stephanie Abramowicz.

The newly-discovered species was a small lizard with an estimated snout-vent length of 3 cm (1.2 inches).

Named Electroscincus zedi, it lived during the mid-Cretaceous period, approximately 99 million years ago.

It differs from all other known squamates (lizards and snakes) from the Mesozoic by the presence of imbricate, compound osteoderms arranged in a staggered pattern around the body, supporting its placement in the skink family Scincidae.

“Scincidae is a megadiverse clade of squamates, which today has attained a near cosmopolitan distribution in temperate and tropical regions worldwide,” said Dr. Juan Daza of Sam Houston State University and his colleagues.

“It is represented by more than 1,745 described living species, comprising nearly 15% of all living lizards.”

“Typical skinks have cylindrical bodies and relatively short limbs and, in over 50 skink lineages, evolutionary transitions towards limb reduction or loss have occurred.”

“Among living scincoids (Xantusiidae, Gerrhosauridae, Cordylidae, Scincidae), members of Scincidae exhibit the greatest range in body length, including some miniaturized forms having a body length of only a few centimeters to the extinct Tiliqua frangens, which may have reached half a meter or more.”

“Skinks also show great variation in the number of presacral vertebrae, ranging from 26 to 108, which, in combination with cycloid scales and compound osteoderms, may have facilitated the repeated evolution of fossorial and limbless morphotypes.”

“Most skinks are characterized by possession of smooth, cycloid scales underlain by compound osteoderms — bony plates in the dermis that are made up of several articulated osteodermites per scale.”

Electroscincus zedi, fossil in ventral (a) and dorsal (b) views; detail of the right foot (c, e) and osteoderms (d); X-ray of the whole specimen showing the skeletal remains, and several articulated and scattered osteoderms (f).

Image credit: Daza et al., doi: 10.1038/s41598-024-66451-w.

A piece of Burmese amber (Burmite) that preserves Electroscincus zedi was found in the mid-Cretaceous outcrops in the Myitkyina district, Kachin province, northern Myanmar, approximately 100 km west of the town of Myitkyina.

The specimen includes two disconnected parts of the skink, containing the scales and mostly appendicular bones, but is clearly part of a single individual

“Currently over 100 specimens of squamates are known from Burmite,” the paleontologists said.

“In this large sample, this new fossil is the only one that preserves this osteodermal morphology which makes it diagnosable to the Scincidae, and differentiates it from all known fossil squamates from the Cretaceous.”

“The specimen is incomplete, but it does retain both postcranial skeletal elements and integumentary structures and, though less than ideal, it provides a basis for comparison with any putative scincid material that might be found in the future.”

“The specimen has a combination of compound osteoderms and overlapping cycloid scales that is limited to skinks.”

“We propose that this type of osteoderm evolved as a response to an increased overlap of scales, and to reduced stiffness of the dermal armor,” the researchers concluded.

• Their paper was published in the journal Scientific Reports.
• J.D. Daza et al. 2024. Compound osteoderms preserved in amber reveal the oldest known skink. Sci Rep 14, 15662; doi: 10.1038/s41598-024-66451-w

{ https://www.sci.news/ }

24-07-2024 om 18:47 geschreven door peter  

Story by May Man

 

©Freepik

Research Suggests all Humans Share One Single Ancestor—and it's not Adam
Diversity is often hailed as the essence of beauty—an observation that is readily apparent when we consider the vibrant array of flowers, animals, landscapes, and humans that populate our world.

Yet, this remarkable diversity wasn’t always the norm. In fact, all life on Earth traces its lineage back to a singular origin.

©New Scientist

The True Ancestor Humans: LUCA
Contrary to popular beliefs—like those found in biblical texts—the progenitor of all living organisms wasn’t named God or Adam but is known as LUCA.

LUCA stands for "Last Universal Common Ancestor," a term used by scientists to describe a fundamental, primitive organism from which all life has descended.

©Wikimedia

The Ancient Root of All Life

This tiny, rudimentary life form is considered the root of the entire tree of life, encompassing everything from the tiniest bacteria to the most massive creatures that have ever existed.

Recent research, however, has revealed that LUCA’s existence may date back even further than previously thought

©Wikimedia

New Findings Suggest LUCA Predates Earlier Estimates
For a long time, scientists estimated that LUCA emerged approximately 4 billion years ago—around 600 million years after the Earth was formed.

But new findings, detailed in a recent study published in Nature Ecology & Evolution, suggest that LUCA might have appeared even earlier.

©Alexander Gerst/ESA via Getty Images

Detailed Insights into LUCA and Early Earth
The research not only pushes back the timeline of LUCA’s existence but also provides fascinating insights into its characteristics and the conditions of early Earth.

An international team of researchers from the UK, Netherlands, Hungary, and Japan undertook the challenge of pinpointing LUCA’s exact appearance on Earth.

©Sangharsh Lohakare/Unsplash

Genetic Analysis
To achieve this, they employed a technique that involved analyzing genetic data from modern species and tracking the mutations that have accumulated since these species diverged from their common ancestor—LUCA.

By applying a genetic equation to estimate the separation time between species, the team concluded that LUCA may have been around as early as 400 million years after Earth’s formation.

©Hellbus/Wikimedia

Life Amidst Earth’s Fiery Beginnings
This new timeframe places LUCA squarely within the Hadean Eon, a tumultuous period named after Hades, the Greek god of the underworld.

The Hadean Eon, which also draws from the Hebrew word for "hell," was characterized by extreme conditions, including a molten surface, relentless volcanic eruptions, and frequent asteroid impacts.

©flydime/Wikimedia

Surviving the Extreme
The fact that LUCA managed to survive in such a harsh environment is remarkable.

The researchers were keen to understand how this early ancestor endured these brutal conditions.

©iStock

LUCA's Primitive Immunity
Their investigation revealed that, despite LUCA’s simplicity as a prokaryote—a single-celled organism lacking a nucleus and membrane-bound organelles—it likely possessed a primitive immune system.

This early immune system would have enabled LUCA to fend off the primordial viruses that were pervasive at the time.

©Wikimedia

Early Microbial Ecosystems and Recycling
Tim Lenton, a co-author of the study from the University of Exeter, noted, “It’s clear that LUCA was exploiting and changing its environment, but it is unlikely to have lived alone.”

“Its waste would have been food for other microbes, like methanogens, that would have helped to create a recycling ecosystem.”

©Wikimedia

Ongoing Research
Although LUCA remains the oldest known common ancestor, the path from this primordial life form to the complex organisms we see today is still a subject of ongoing research.

Scientists continue to delve into our primordial past to uncover the intricate processes that led to the evolution of complex life and the remarkable diversity that defines our world today.

©Jakub Hałun/Wikimedia Commons

Unraveling the Evolution from LUCA to Modern Diversity
Further exploration is needed to fully understand how life evolved from its earliest beginnings.

Additionally, this research will help clarify how these early forms of life gave rise to the extraordinary variety of organisms we see today.

{ https://www.msn.com/en-us/channel/topic/Science/ }

23-07-2024 om 21:09 geschreven door peter