Dr. Michelle Thaller, "Some day i wonder if people will have myths about, you know, the days when stars rained down free sunlight and free energy" .. loved her video .. now i'm wondering what form and living situation those people could possibly have? .. mostly robotic? .. a bubble about earth? .. sure would be dark and cold outside it ..
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Finding Tiktaalik: Neil Shubin on the Evolutionary Step from Sea to Land
.. someone could write a Tickle taa lick song for Tiktaalik .. lolol .. the first on the last day when Tiktaalik came to play, driven by fear with an instinct to fill...
Skull in Underwater Cave May Be Earliest Trace of First Americans
Posted by David Braun of National Geographic on February 18, 2011
PET/GUE Divers descend into the abyss at Hoyo Negro.
Photo by Daniel Riordan-Araujo
By Fabio Esteban Amador
Explorers have discovered what might be the oldest evidence of humans in the Americas.
Alex Alvarez, Franco Attolini, and Alberto (Beto) Nava are members of PET (Projecto Espeleológico de Tulum), an organization that specializes in the exploration and survey of underwater caves on the Yucatan Peninsula in Mexico.
Alex, Franco and Beto have surveyed tens of thousands of feet of mazelike cave passages in the state of Quintana Roo. The team’s relatively recent explorations of a large pit named Hoyo Negro (Black Hole, in Spanish), deep within a flooded cave, resulted in their breathtaking and once-in-a-lifetime discovery of the remains of an Ice Age mastodon and a human skull at the very bottom of the black abyss.
After trekking through the jungle, carrying multiple scuba cylinders, and traveling thousands of feet inside the Aktun-Hu cave system, PET/GUE Member Alex Alvarez discovered a human skull.
Photo by Daniel Riordan-Araujo
Beto recalls the amazing day of the discovery of Hoyo Negro.
“We started the exploration while following the main tunnel and progressed relatively fast by using scooters to cover more terrain.
“After about 1,500 feet [450 meters] we began to see the light of another entrance, so we headed towards it and surfaced.
“After taking a moment to chat and laugh about what a great dive we were having, we dropped down to continue the work.
“After about 400 feet [120 meters] the tunnel narrowed to form a circular shape, almost like a huge cement pipe. I made one tie-off and, while waiting for Franco to complete his surveying effort, I took a good look at the strangely shaped tunnel.
“All I could see was the whiteness of the cave walls along the sides, and beyond that it was all black. I thought to myself that this is either the largest tunnel I have seen or there is something unusual at the end of it.
“After Franco caught up, we continued for another 200 feet [60 meters] and eventually reached the end of the tube-shaped tunnel. To our surprise the floor disappeared and all we could see was blackness in all directions. It felt like we had reached a big drop-off or the edge of a canyon wall.
“We tried to slow down our heart rates as we were not really sure of what to do next.”
The Aktun-Hu cave system, where Hoyo Negro is located, is completely filled with water and is fully decorated with speleothems, like the Double Column formation shown in this photo.
Photo by Daniel Riordan-Araujo
Where is Hoyo Negro?
Hoyo Negro was reached by the PET team after the divers travelled more than 4,000 feet [1,200 meters] through underwater passages using underwater propulsion vehicles, or scooters, which enabled them to cover long distances in the flooded cave system.
Once they reached the pit, they began to survey and document its dimensions. The pit is approximately 200 feet [60 meters] deep and 120 feet [36 meters] in diameter and is located inside the Aktun-Hu cave system in the state of Quintana Roo, Mexico.
Submerged cave systems in Quintana Roo have been systematically surveyed and mapped by teams of highly specialized divers. The PET team is affiliated with Global Underwater Explorers .. http://www.gue.com/ , as is the Mexico Cave Exploration Project .. http://www.mcep.org.mx/ .
“The immense size of Hoyo Negro is difficult to comprehend. Once you enter the pit you cannot see the floor below, and all that can be seen in front of you is a black void — an inviting entrance to the abyss, ” recalls Franco.
The team of explorers touched bottom at 197 feet [57 meters], where they made their incredible discovery.
How Did the Tunnels Form?
The Yucatan Peninsula’s geology is almost entirely limestone — a karstic shelf that is easily dissolved by rainwater, forming caves and sinkholes.
Approximately 12,000 years ago, at the end of the Pleistocene epoch, Earth experienced great climatic changes. The melting of the ice caps caused a dramatic rise in global sea levels, which flooded low lying coastal landscapes and cave systems. Many of the subterranean spaces that once provided people and animals with water and shelter became inundated and lost until the advent of cave diving.
PET/GUE Diver Alex Alvarez looks at the remains of an extinct mastodon at the base of Hoyo Negro.
Photo by Daniel Riordan-Araujo
Ironically, the Yucatan Peninsula does not have any major rivers or lakes; however, there are many underground rivers and water-filled caves or sinkholes known as cenotes (a Spanish word derived from the Maya dzonot).
What Was Found at the Bottom of the Black Hole?
While the team of explorers conducted various dives for the purpose of mapping and surveying of this newly discovered pit, they noticed some peculiar bones sitting on the bottom. They first came across several megafauna remains and what was clearly a mastodon bone, while subsequent dives proved even more exciting when they spotted a human skull resting upside down with other nearby remains at about 140 feet [43 meters] depth.
“I was searching for more of the mastodon remains, when I saw what looked like a human skull. I had thought we already had a great discovery after finding the remains of several Pleistocene animals…but finding a human skull was totally amazing for us. All of our efforts… walking through the jungle, carrying all the gear, securing the helium required to do such a deep dive, laying thousands of feet of exploration line… paid off at that moment. This is the Holy Grail of underwater cave exploration,” Alex said.
“This is the Holy Grail of underwater cave exploration.”
Soon after the discovery, the team contacted Guillermo de Anda, an archaeologist from the University of Yucatan in Merida .. http://www.uady.mx/ (UADY) who has also been documenting Pleistocene megafauna sites and who helped in the identification of the Hoyo Negro discovery.
“The findings of Hoyo Negro are a once-in-a-lifetime discovery.The skull looks pre-Maya, which could make it one of the oldest set of human remains in the area. Gaining an understanding of how this human and these animals entered the site will reveal an immense amount of knowledge from that time. Therefore, protecting and learning the secrets of Hoyo Negro should be one of the main priorities for the archaeologists in the region,” Guillermo told News Watch in an interview.
PET/GUE Diver Franco Attolini places a scale and directional marker near an ancient human skull as part of the team’s recent exploration efforts in the Yucatan Peninsula underwater caves.
Photo by Daniel Riordan-Araujo
The PET team formally announced the discovery at Hoyo Negro to Pilar Luna Erreguerena, Director of Underwater Archaeology for Mexico’s National Institute for Archaeology and History .. http://www.gobiernodigital.inah.gob.mx/mener/index.php?id=25 (INAH). Pilar is the founder of underwater archaeology in Latin America and has been instrumental in protecting Mexico’s submerged cultural heritage.
“This discovery is extremely important and confirms the cultural diversity and richness that can be found in the Yucatan Peninsula,” said Pilar Luna. “INAH’s division of underwater archaeology is preparing a multidisciplinary project together with discoverers of the site. This team work will allow us to scientifically recover the data and the evidence in its own context, so that experts may really get to know the true value of this discovery and turn it into a deeper knowledge or understanding of the prehistoric era in this part of Mexico.”
At present, the entrance to the site is limited to INAH’s research team since they are responsible for maintaining the integrity of the site.
Studies in the Tulum area, similar to those currently being planned for Hoyo Negro, were accomplished for the very first time by Pilar Luna’s collaborators, namely Arturo González, Carmen Rojas, Octavio Del Río, Eugenio Aceves, and Jerónimo Avilés, with the support of Adriana Velázquez, Director of Centro INAH Quintana Roo.
GUE and INAH divers participate in a Nautical Archaeology Society training course in Tulum.
Photo by Olmo Torres Talamante
What is the Significance of the Discovery of Hoyo Negro?
The human found with the megafauna remains in Hoyo Negro could represent the oldest evidence of humans yet discovered in the Americas.
Archaeological and genetic data have long supported a northeast Asia origin for the populations that first settled North and South America. The so-called “First Americans” or Paleoindian peoples likely entered into these new lands sometime between 15,000 and 20,000 years ago.
Although a number of early archaeological sites have been excavated, only few sets of Paleoindian remains have been found. A detailed analysis of the human skeletal remains from Hoyo Negro can help us to better understand who these First Americans were and when they arrived here, which is one of the greatest mysteries in American archaeology.
Radiometric dating of the human bones from Hoyo Negro will have to wait for now, but its location within the cave, and its position relative to the mastodon remains, are suggestive of its antiquity.
PET/GUE Divers exit from Hoyo Negro after a long documentation dive where they collected photos and videos of prehistoric remains.
Photo by Daniel Riordan-Araujo
Waitt Institute .. http://wid.waittinstitute.org/ .. archaeologist and New World cave expert, Dominique Rissolo, offers a compelling argument for the importance of this site and similar discoveries. “The cenotes of Quintana Roo, Mexico, have emerged as one of the most promising frontiers for Paleoindian studies in the Americas.
“Recent discoveries of human remains deep within the region’s flooded caverns, as well the bones of mastodons and other extinct species of Pleistocene megafauna, offer an extraordinarily rare glimpse into a period that witnessed the peopling of the New World.
“During the Late Pleistocene, these caves were dry. The first people to occupy what is now the Caribbean coast of Mexico wandered into these caves, where some ultimately met their demise.
“As the last glacial maximum came to end, the melting of the polar ice caps and continental ice sheets raised sea levels worldwide. The caves of the Yucatan Peninsula filled with water and the First Americans were hidden for millennia — only to be discovered by underwater cave explorers
“It is within these dark reaches that cave explorers are discovering and documenting the oldest human skeletons yet found in the Western Hemisphere,” Rissolo said.
Future Research at Hoyo Negro
In the summer of 2010, Pilar Luna organized a Nautical Archaeology Society .. http://www.nauticalarchaeologysociety.org/ .. training course for the Hoyo Negro team. The course, which was funded by National Geographic Magazine thanks to Chris Sloan, a magazine editor, covered the essentials of underwater archaeological site recording.
In collaboration with INAH, the team hopes to continue their exploration of Hoyo Negro and to thoroughly document the findings at the site.
Perhaps this is a turning point in scientific exploration in the region, where successful research will depend upon the knowledge and experience of a multidisciplinary team that includes underwater archaeologists, geologists, and paleontologists working side by side with highly skilled divers.
National Geographic has been active in featuring similar discoveries made by cave divers on the Yucatan peninsula. In 2008 National Geographic Daily News published the discovery of the Eve of Naharon, a female skeleton dated to 13,600 years old, which was also found in an underwater cave in Quintana Roo. (Oldest Skeleton in Americas Found in Underwater Cave? .. http://news.nationalgeographic.com/news/2008/09/080903-oldest-skeletons.html )
In addition to the latest extraordinary expedition and amazing discovery, Robbie Schmittner connected the Aktun-Hu cave system (where Hoyo Negro is located) to the Sac Actun cave system .. http://www.caves.org/project/qrss/new.htm . Together they may now represent the longest underwater cave system in the world.
Future investigations in Hoyo Negro will no doubt reveal new clues about the peopling of the New World.
Fabio Esteban Amadoris the program officer for the NGS/Waitt Grants Program .. http://www.nationalgeographic.com/field/grants-programs/waitt-grants.html ..at National Geographic and an associate research professor of anthropology at George Washington University.. http://www.gwu.edu/. He is an archaeologist specializing in Mesoamerican cultures and Pre-Columbian and historic earthen architecture. Amador studied archaeology at Rutgers University and received a Ph.D. from SUNY Buffalo. He has worked in archaeological sites in North, Central and South America and is presently conducting research in Mexico’s Yucatan Peninsula. Before joining National Geographic, he was a professor of archaeology and a researcher for the Council for Scientific Investigation at the National University of El Salvador. Fabio Esteban is also a founding member and coordinator for OLAS .. http://olasubacuatica.org/OLASubacuatica.org/OLAS.html.. (Latin American Organization for Underwater Archaeology), a new community of professionals devoted to the study and conservation of submerged cultural patrimony in the Americas.
A negative image of KKs 3, made using the Advanced Camera for Surveys on the Hubble Space Telescope. The core of the galaxy is the right hand dark object at the top centre of the image, with its stars spreading out over a large section around it. (The left hand of the two dark objects is a much nearer globular star cluster.) Credit: D. Makarov.
The team, led by Prof Igor Karachentsev of the Special Astrophysical Observatory .. https://www.sao.ru/Doc-en/About/ .. in Karachai-Cherkessia, Russia, found the new galaxy, named KKs3, using the Hubble Space Telescope .. http://www.spacetelescope.org/ .. Advanced Camera for Surveys (ACS) in August 2014. Kks3 is located in the southern sky in the direction of the constellation of Hydrus .. http://en.wikipedia.org/wiki/Hydrus .. and its stars have only one ten-thousandth of the mass of the Milky Way.
Kks3 is a ‘dwarf spheroidal .. http://en.wikipedia.org/wiki/Dwarf_spheroidal_galaxy ’ or dSph galaxy, lacking features like the spiral arms found in our own galaxy. These systems also have an absence of the raw materials (gas and dust) needed for new generations of stars to form, leaving behind older and fainter relics. In almost every case, this raw material seems to have been stripped out by nearby massive galaxies like Andromeda, so the vast majority of dSph objects are found near much bigger companions.
Isolated objects must have formed in a different way, with one possibility being that they had an early burst of star formation that used up the available gas resources. Astronomers are particularly interested in finding dSph objects to understand galaxy formation in the universe in general, as even HST struggles to see them beyond the Local Group. The absence of clouds of hydrogen gas in nebulae also makes them harder to pick out in surveys, so scientists instead try to find them by picking out individual stars.
For that reason, only one other isolated dwarf spheroidal, KKR 25, has been found in the Local Group, a discovery made by the same group back in 1999.
Team member Prof Dimitry Makarov, also of the Special Astrophysical Observatory, commented: “Finding objects like Kks3 is painstaking work, even with observatories like the Hubble Space Telescope. But with persistence, we’re slowly building up a map of our local neighbourhood, which turns out to be less empty than we thought. It may be that are a huge number of dwarf spheroidal galaxies out there, something that would have profound consequences for our ideas about the evolution of the cosmos.”
The team will continue to look for more dSph galaxies, a task that will become a little easier in the next few years, once instruments like the James Webb Space Telescope .. http://www.jwst.nasa.gov/ .. and the European Extremely Large Telescope .. http://www.eso.org/public/teles-instr/e-elt/ .. begin service.
Astrophysicist Dr. Neil DeGrasse Tyson was asked by a reader of TIME magazine, "What is the most astounding fact you can share with us about the Universe?" This is his answer.
Neil goes on to say "For me, that is the most profound revelation of 20th century astrophysics and I look forward to what the 21st century will bring us, given the frontiers that are now unfolding."
Copyright Disclaimer Under Section 107 of the Copyright Act 1976, allowance is made for "fair use" for purposes such as criticism, comment, news reporting, teaching, scholarship, and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. Non-profit, educational or personal use tips the balance in favor of fair use. All copyrighted materials contained herein belong to their respective copyright holders, I do not claim ownership over any of these materials. I realize no profit, monetary or otherwise, from the exhibition of this video.
Fish Changed in a Surprising Way Before Invading Land
Tiktaalik peers out of the water
Even before they grew strong legs, their eyes surged in size.
Ed Yong Mar 7, 2017
Around 385 million years ago, fish started hauling themselves onto land. Over time, their flattened fins gradually transformed into sturdy legs, ending in feet and digits. Rather than paddling through water, they started striding over solid ground. Eventually, these pioneers gave rise to the tetrapods—the lineage of four-legged animals that includes reptiles, amphibians, and mammals like us. This transition from water to land is an evocative one, and for obvious reasons, people tend to focus on the legs. They are the organs that changed most obviously, that gave the tetrapods their name, and that carried them into their evolutionary future.
The earliest tetrapods had much bigger eyes than their fishy forebears. MacIver always assumed that this enlargement happened after they marched onto land, allowing them to see further and to plan their paths. “That was an expectation fueled by ignorance,” he says. Actually, after studying the fossils of many fishapods—extinct species that were intermediate between fish and tetrapods—MacIver found [ http://www.pnas.org/content/early/2017/03/06/1615563114 ] that bigger eyes evolved before walking legs.
As the eyes swelled in size, they also moved to the tops of their owners’ heads, allowing them to peer out of the water surface like crocodiles do today. These traits enabled them to see further than their aquatic ancestors and to look over a much greater range of space, allowing them to snatch up prey from the shoreline. And that ability could have given them the impetus to leave the water entirely, driving the evolution of their vaunted legs. Perhaps eyes, not legs, led the invasion of the land. Perhaps, as MacIver puts it, “the gateway drug to terrestriality was being like a crocodile.”
“This study helps explain how fishes built for life in the water could be lured to shore without losing their competitive edge along the way,” says Lauren Sallan [ http://www.laurensallan.com/ ] from the University of Pennsylvania, who was not involved in the work.
Eyes don’t fossilize, but you can estimate how big they would have been by measuring the eye sockets of a fossilized skull. MacIver and his colleagues, including fossil eye expert Lars Schmitz, did this for the skulls of 59 species [ http://www.pnas.org/content/early/2017/03/06/1615563114 ]—from finned fish to intermediate fishapods to legged tetrapods. They showed that over 12 million years, the group’s eyes nearly tripled in size. Why?
Eyes are expensive organs: it takes a lot of energy to maintain them, and even more so if they’re big. If a fish is paying those costs, the eyes must provide some kind of benefit. It seems intuitive that bigger eyes let you see better or further, but MacIver’s team found otherwise. By simulating the kinds of shallow freshwater environments where their fossil species lived—day to night, clear to murky—they showed that bigger eyes make precious little difference underwater. But once those animals started peeking out above the waterline, everything changed. In the air, a bigger eye can see 10 times further than it could underwater, and scan an area that’s 5 million times bigger.
In the air, it’s also easier for a big eye to pay for itself. A predator with short-range vision has to constantly move about to search the zone immediately in front of its face. But bigger-eyes species could spot prey at a distance, and recoup the energy they would otherwise have spent on foraging. “Long-range vision gives you a free lunch,” says MacIver. “You can just look around, instead of moving to inspect somewhere else.”
Those early hunters would have seen plenty of appetizing prey. Centipedes and millipedes had colonized the land millions of years before, and had never encountered fishapod predators. “I imagine guys like Tiktaalik lurking there like a crocodile, waiting for a giant millipede to walk by, and chomping on it,” says MacIver. “No invertebrate on land would have been a match for it.”
So here’s what MacIver thinks may have happened. In shallow, freshwater rivers and lakes, some fish gradually moved their eyes to the top of their skulls, to better exploit the down-welling sunlight. This happened during the Devonian period, when the Earth’s oxygen levels were declining. Struggling to get enough oxygen in the water, creatures like Tiktaalik evolved breathing holes at the tops of their heads, just behind their eyes. They started surfacing more regularly, allowing them to tackle prey that wandered near the water. At first, they would only have seen the blurry outlines of their targets, but even small changes to their eyes would have produced enormous benefits. Over time, their eyes became bigger. And eventually, their limbs changed too, allowing them to make longer forays into this new world—a world of not only solid ground, but also large distances.
Some of this is speculative, but it fits with the patterns that MacIver’s team see in their fossils and their data. Jenny Clack [ http://www.zoo.cam.ac.uk/directory/jenny-clack ] from the University of Cambridge, who is an expert on the evolution of tetrapods, is pleased that the team have measured the increase in socket size—something that others have noted, but never in this much detail. But “socket size doesn’t always correlate with eyeball size,” she says. It’s better to look at the sclerotic ring—a disc of bone that’s found around the eyes of many animals. MacIver counters that in the fossils that he and Schmitz studied, the correlation between eyeball and socket is “very good,” and that “the presence of the ring doesn’t seem change our predictions.”
“They took a very creative and new approach to an old problem,” says Neil Shubin [ http://pondside.uchicago.edu/oba/faculty/shubin_n.html ] from the University of Chicago, who discovered Tiktaalik. Most people who study the evolution of tetrapods have focused on their limbs and jaws. Instead, MacIver’s group focused on sense organs—the eyes. And they suspect that the eyes are linked to the evolution of another critical organ—the brain.
MacIver’s idea is that long-range vision changes the type of mental abilities that an animal benefits from. Underwater, a fish is like a driver zooming along a foggy road. It can only react to what’s directly in front of it—life, as they say, comes at you fast [ http://knowyourmeme.com/memes/life-comes-at-you-fast ]. But a tetrapod, walking on land, can scan a much greater area. In a way, bigger eyes let you see further into time as well as space. Now, there are more benefits to abilities like planning, strategic thinking, and complex decision-making. Animals become less reactive, and more proactive.
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