What Was The First Fungus?

in the early morning hours over gondwana the air is calm and still as the stars gradually fade away in the rapidly lightening sky a few clouds high in the atmosphere catch a glimpse of the sunrise to come [Music] reflecting the same pink that now grows through the sky's lower reaches [Music] suddenly and silently without a warning or fanfare a flaring brightness pierces the horizon and the orb of the sun emerges shimmering appearing improbably large reflected in the ocean's surface [Music] the world turns and as the sun's light washes over the eastern shore of gondwana the landscape of this devonian world is transformed land surfaces that were dimly lit by diffuse and hazy pre-dawn glow mere moments ago are now cast into sharp and eerie contrast as the sun's impossibly low angle projects elongated shadows from every hillside bluff and living thing under this bizarre lighting the reality of a 400 million year old terrestrial world is revealed gone are the days of the baron lifeless supercontinent this immense land surface is now covered from shore to shore with terrestrial life but it is still early days for the organisms who have forsaken the safety of the ocean [Music] insects and worms inch crawl and clamber but none have yet taken to the skies plants alien and strange to our eyes only recognizable as such by their green coloration spread haphazardly over the reddish soil there are few of the leaves stalks seeds and roots that will come to characterize later vascular plants and trees instead these early colonizers creep and extend occasionally projecting a fragile rubbery stem a few tens of centimeters above the earth even under the low morning sun the shadows of these plants are like the primitive plants themselves stunted but occasionally huge slender shadows extend many meters across the rolling landscape [Music] immense organic but otherwise featureless towers the largest of which reaches eight meters in height and one meter across [Music] in an early terrestrial world dominated by primitive plants no more than a metre high these monumental columns are huge and bizarre [Music] but they are not plants neither have they been wrought by the might of the earth or the craft of any sentient life as we know it they are fungi unimaginably huge mushroom skyscrapers that dwarf all other life on the surface of the devonian earth [Music] it is strange enough to consider a fungus reaching such mammoth proportions today but it is even more remarkable in the relatively young terrestrial niche [Music] the first fossils of these mysterious organic structures recovered from gaspe bay in quebec were described more than 160 years ago by canadian geologist john william dawson as was not uncommon at the time john dawson was a creationist believing that all living things bestowed upon the earth were of the great creators making arguing vehemently against charles darwin's new and radical theory of evolution it is perhaps not surprising then when faced with these bizarre devonian fossils dawson's explanation erred on the side of the familiar they were he claimed the remains of partially rotten giant conifers and he named them prototaxities roughly translating as first u [Music] but dawson supposedly rotten specimens weren't even the first prototaxity's fossils to be collected [Music] some 17 years earlier one of darwin's friends and colleagues joseph hooker recovered similar remnants from devonian rocks in scotland unfortunately the samples being mislaid until 2012. [Music] in the intervening years many other examples of prototaxities were found from terrestrial rocks all over the world now they can be found in abundance in deposits from the mid or division 417 million years old to the late devonian aged 360 million years these mysterious living monuments existed for 20 times the length of humanity's own reign given the immense diversity of fungi today from slime molds fungal infections to edible oyster mushrooms the bizarre morphology of prototaxities has attracted many alternative explanations from that of a stringy alga like seaweed to a fortuitously rolled up bundle of non-vascular plants like liverwort but the scientific consensus of the 21st century is that these seemingly impossible structures are in fact members of a long overlooked but nevertheless omnipresent kingdom the fungi prototaxity's large size and widespread habitat throughout the devonian is a clear implication that they were successful and likely owed that success to a long and prosperous evolutionary line the humble fungi which live their lives practically out of sight and without which many of our modern ecosystems would not be able to survive have been lurking in the background for longer than we may imagine so as we rewind the evolutionary clock from this curious age when vast mushrooms towered over all life on earth how far must we go to find their beginnings what were the first fungi on the planet and how did they come to shape our modern world the answer might just be more amazing than we could have possibly imagined the implications stretching far into our future as well as our past [Music] the history of our world spans more than four billion years that's a lot of ground to cover this episode of history of the earth is brought to you by our partners at curiositystream where you can find a vast catalogue of documentaries to help you get to grips with this immense span of time [Music] 300 million years and ancient earth are two that we enjoy recently but there are thousands of others to choose from on practically any topic you can think of so head over to curiositystream.com forward slash history of the earth to sign up use our code history of the earth and save 25 right now that's an entire year for 14.99 just 1.25 a month thanks [Music] [Music] in the blue mountains of eastern oregon bright alpine lakes shine like gemstones amidst the mountain meadows [Music] marching pine forests stretch off into the distance [Music] the mallard national forest is a peaceful natural wilderness popular with hunters herders and hikers alike and yet unlikely as it seems this forest is home to the largest and one of the oldest living beings on earth [Music] like the mythical sasquatch it hides from sight this enigmatic organism can only be spotted at certain times of the year and then only if you know where to look however unlike bigfoot once glimpsed this elusive entity is unable to make good its escape since it is rooted quite literally beneath the ground in 1998 a team of scientists set out to map the distribution of a deadly pathogenic fungus in eastern oregon in the moist autumns of the u.s pacific coast dark honey mushrooms sprout all around the bases of ailing pine trees named for the golden colour of their caps that they are certainly attractive specimens but they're a symptom of a much more sinister phenomenon unfolding beneath the surface for the honey mushrooms are only the fruiting bodies of the armillorea fungus which survives by infecting and attacking the roots and trunks of living trees it is a parasite feared by foresters all over the world and by the time its mushrooms emerge it is typically too late for the luckless tree which has been eaten away from the inside by the insinuating fungal fibers in order to investigate the spread of this fungal parasite throughout the idyllic woodland of malur the scientists combined traditional mycological techniques with the latest in 20th century genetic fingerprinting taking samples of the fungal fibers from separate afflicted trees they combined them in a petri dish to see if they would grow together and fuse implying that they were of compatible genetic stock and by extracting and analyzing their dna the similarities and differences in their genes could be compared side by side the results of this analysis were astounding at every tree they sampled over a 10 square kilometer area the armeloria fungus was genetically identical just as the cells in our own bodies are genetic clones of one another so too with these fungal fibers and just as our genetic makeup defines our individuality from other members of our species so the fibers of armellorea were all part of one immense fungal individual here just beneath the forest floor was the largest individual organism on earth nicknamed the humongous fungus for good reason three meters beneath the surface it extends over an area of some 2384 acres [Music] it dwarfs the largest living animal the 33 meter long blue whale and even trumps the largest plant colony the 107 acre quaking aspen of utah named pando and yet this monstrous fungus could easily be missed if not for its golden mushrooms and the dying trees it leaves in its wake [Music] because the immense body of armor luria is actually made of a network of gossamer fibers which even at their densest look little more than white moldy fur and yet this mycelial network the true vegetative form of many fungi all over the world is much greater than the sum of its diminutive parts not as an individual per se but a collective the armillaria of eastern oregon is not only remarkable in its size but also its age based on its rate of growth scientists estimate this humongous fungus to be at least 2 400 years old and possibly almost twice that it has seen the rise and fall of civilizations and religions the lives and deaths of almost 100 human generations but this ancient organism is far from dormant it like all mycelia is vibrantly alive continually shifting and migrating through the forest soil much faster and stranger than the roots of a plant for as we now know from roots discovered in 2017 mycelium itself seems to have been around for far longer perhaps for more than two billion years roughly half of earth's history [Music] the mycelial network stretching beneath the forest floor is composed of countless fungal fibers known as hyphae each five times thinner than a human hair but with the capacity to branch and fuse to create a woven mesh this three-dimensional net can be so dense for the single teaspoon of mycelium can contain as much as 10 kilometers of ultrafine hyphae each fungal individual defines and expands its borders through the probing growth of hyphal tips similar to the exploratory hairs of plants roots and shoots yet far more numerous a large mycelial network may contain billions of hyphal tips whose exploration through the soil helps to locate food sources grow and renew the fungal body hyphae may be small but they are mighty despite being only one cell thick they can nevertheless knit together to create solid three-dimensional structures [Music] like the golden edible mushroom caps of armillaria [Music] the rigid shells of the polypore bracket fungus and even the towering columns of prototaxities there have been documented cases of newly surfaced roads being ripped open by the growth of mushrooms through the tarmac and experiments have shown that growing hyphy can summon enough force to penetrate kevlar of course the main purpose of these mycelial hyphae is not to pierce armor and ravage our infrastructure when they're not assembling elaborate fruiting bodies haify are primarily occupied with the all-consuming task of feeding the voracious fungal entity oozing digestive enzymes out into the space around them they supervise the breakdown of organic matter [Music] then reabsorb the products but they are capable of much more than just devouring the probing behavior of millions of hyphal tips is like that of an immense swarm acquiring and integrating information simultaneously on a massively parallel basis and on a scale that rivals most home computers [Music] recent experiments having proven that mycelium can navigate its way through mazes to find the quickest route to the end [Music] deciding whether to pursue or abandon a path of exploration relies on communication between distant reaches of the mycelial network although scientists are still unsure precisely how such communication takes place they have observed it to be lightning fast much faster for example than the chemical discourse of plants and perhaps more similar to the electrical signaling along our own nerve cells the hyphy grow sever or reinforce their links dynamically based on the information they receive the mycelial network on the whole may be likened to a brain are my serial fungi therefore capable of decision making problem solving like octopi lacking a conventional nervous system yet seeming to think with their tentacles do they possess a spark of intelligence in that hyphal brain a composition of many life forms coming together to create a larger more formidable whole acquiring new abilities horizontally if so it is unlike any intelligence that we are accustomed to recognizing and yet it was charles darwin who wrote that intelligence is based on how efficient a species becomes at doing the things they need to survive [Music] given the monumental success of the giant armillaria and all other fungi whose bodies are composed of shifting entwining haiful nets it's not hard to appreciate their efficiency even if acknowledging intelligence is a step too far though bizarrely they do seem to exhibit traits of memory on occasion without the need for a brain as we would recognize it in truth we still know very little of fungi and their strange collective lives by themselves mycelial networks are forced to be reckoned with and yet their power to shape and transform a living ecosystem is even more formidable the inexorable growth of hyphae and the enzyme cocktail they excrete is enough to shatter rock over and over creating the first soils in a bare landscape and then through their dense organic net holding the ground in place it is fungi who help pave the way for modern plants and animals to colonize virgin ground [Music] and it was likely fungi who helped plants to make the leap onto land in the first place 417 million years ago [Music] for those first colonizing plants did not yet have the root systems that would allow them to access nutrients from the thin or division soil [Music] and so researchers think that mycelial networks stepped up and fulfilled that role at least for a few tens of millions of years a role they continue to be an integral part of in forests all over the world in this way it was fungi who have enabled shaped and guided the course of terrestrial evolution [Music] fungi make mushrooms but first they have to unmake something else in this great recycling of organic matter that keeps our world moving keeps evolution ever pushing onwards they are the main players and yet still now despite decades of research we still know so little about these creatures with whom we share a common ancestor modern science is still delving deep to find out just how far these inscrutable fungal lives are entwined with our own and with every other living thing on earth [Music] in the year 1487 so says the spanish friar diego duran writing two generations later a particularly significant occasion took place at the mexica aztec capital of tenochtitlan one of the largest cities the world had ever seen the beating heart of the most powerful of all mesoamerican empires an early anthropologist of sorts duran sought to preserve the history of the rapidly disappearing aztecs by his day subject to christianity and harsh spanish colonial rule he did this by doing what many refused to do by talking and engaging with the surviving elders recording for posterity what they told on this particular occasion in 1487 juran records a particularly grisly event [Music] the new emperor ahwed sotol one of the most formidable military leaders in the entire history of the new world did things on a grand scale following his accession and successful conquests into new lands over the course of four days tens of thousands of captive warriors ascended the temple mayor at the heart of the city one by one their beating hearts were cut from their chests sacrificial blood offered to the gods as part of the ceremonial rededication of the empire yet for those not taking part in the orgy of human sacrifice the extended coronation festival is cause for uninhibited celebration chocolate is drunk songs are sung and a very special delicacy is enjoyed known locally as tejna cattle the flesh of the gods is a small spindly mushroom with a white stem and golden cap celebrants eat it raw all with a little honey and are instantly transformed some find themselves laughing and dancing uncontrollably others experience strange and disturbing visions of war demons or even their own deaths some are overcome weeping openly while others take quietly to their houses in a meditative mood and after these journeys and visions they come together to discuss what they saw they believe that the mushrooms were gifted to the aztec people by the serpent god quetzalcoatl and that consuming them gives them the power to commune with their gods they are a frequent component of celebrations healing and religious rituals whether juran or subsequent spanish colonizers also sample the sacred mushrooms we do not know and later conquistadors made great efforts to erase all records of the mind-altering substances as well as the culture of the pre-columbian americas after the fall of the aztec empire it was difficult to learn more about these supposedly psychedelic fungi or even identify the individual mushrooms responsible their very existence became controversial was the flesh of the gods little more than a myth itself invented by a traumatized chronicle at a distance from the horrors of human sacrifice samples sent to harvard arrived to rotten to be properly studied and it was only when 20th century adventurers retraced diego duran's steps to mexico and witnessed a modern-day mushroom ceremony that the psychoactive mushrooms were finally found to be real after all now of course we know these transcendental fungi as magic mushrooms containing a chemical compound called psilocybin that can produce a psychedelic trip and hallucinations like that of the drug lsd [Music] in fact lsd itself was first synthesized from the chemicals produced by different kind of fungus and there are many such mushrooms capable of inducing similar experiences while diego duran might have been one of the first westerners to hear of the ritual consumption of these mushrooms the 15th century aztecs were by no means the first to partake ancient manuscripts that predate the spanish conquest depict feathered deities holding and eating mushrooms and mushroom-shaped statues have been discovered from mesoamerica stretching back to the second millennium bc [Music] elsewhere in the world reverence for the spiritual mushroom extends back even further cave paintings in algeria created between 7000 and 9000 bce depict a godly figure with an animal's head and mushroom-like figures sprouting from its shoulders and arms in classical greece a secretive ceremonial meeting known as the elusinian mysteries frequented by the likes of plato has long been theorized to involve the use of the psychedelic ergot fungi it is the kind of bizarre image that the straight-minded might find hard to interpret but which makes ultimate sense to a psilocybin connoisseur the deep interlinked history of humans and psychedelic fungi has even given rise to a controversial theory that it is the mushrooms themselves that are the architects of our humanity anthropologists have long grappled with the puzzling speed by which human culture social structure commerce and art seem to appear among the human species 50 to 70 000 years ago during the paleolithic era scars on fossilized leaves from 48 million years ago indicative of infection by the cordyceps fungus suggests fungi may have been manipulating mines for as long as there have been minds to manipulate witnessing the transformative effects of psilocybin on the human mind today and the uncanny ability of certain fungi to influence the life forms around them certain fringe scholars have suggested it was the hallucinogenic effects of these mushrooms that allowed our ancestors to expand their minds in the first place [Music] this so-called stoned ape theory of human evolution certainly sits at the fringes of science and with little tangible evidence from that time unfortunately we may simply never know how much of our modern civilization we owe to the psychedelic trips of our forebears [Music] but even if hallucigenic mushrooms have played a marginal role fungi in general have had a potent connection with humans for at least as long as there have been humans certain yeasts in particular that live on our bodies have adapted so much that they can't live without us [Music] neanderthal remains have been found with traces of penicillin producing molds ground into their teeth thought to be a treatment for dental problems in a practice similar to that known from indigenous australians and ancient egyptians more recently otzi the iceman the five thousand year old mummy found frozen in the ice of the austro-italian alps carried with him pieces of the polypore fungus which he likely used as tinder for starting a fire ink caps were used by medieval chroniclers to record words on parchments and untold amounts of edible mushrooms have been invaluable allies throughout history despite being feared and shunned in many cultures [Music] eventually penicillin would be rediscovered accidentally and isolated into a powerful antimicrobial medicine just in time to turn the tide of the second world war we are at least part of our success as a species to the humble fungus and humans are far from the only organisms that benefit from the diverse capabilities of the fungal kingdom as has become better understood for the last decade or so the mycelial networks that spread ubiquitously through forest floors all over the world do more than merely feed themselves they also act as a vital communication network for the plants in the forest it has been likened to a social network for the woodland penetrating the roots of trees and weaving them together and providing vital nutrients that support their growth some scholars have gone so far as to liken this activity to trees talking to one another via underground fungal webs [Music] much more akin to cooperation rather than competition for this wood wide web is capable of so much more it can transmit warnings between individual trees [Music] if one comes under insect attack the fungal network beneath the ground carries the warning to nearby vegetation allowing them to mount a chemical defense before the threat arrives and in a strange altruistic tendency carbon is moved from areas of abundance to those of scarcity this is biological cooperation or symbiosis on the scale of entire ecosystems [Music] but fungi are also capable of collaborating on a much more individual and intimate level lycan are strange plant-like growth that can be found on rocky surfaces man-made monuments and even certain slow-moving animals the crusted scaly or feathered life forms are thought to encrust as much as eight percent of the earth's surface often in places where no other living thing can survive they can even withstand the freezing desiccated and irradiated environment of space [Music] but lichens are not actually a single organism rather they are an intimate symbiosis between photosynthesizing algae and fungus many different species of algae and fungi can come together and lyconise the specific individuals determining their lycon's ultimate appearance and capabilities their relationship was actually one of the first symbioses to be described in the natural world a swiss botanist simon schwendener put forward his dual hypothesis of lichens in 1869. in this he posited that the fungi were enslaving parasites that had forced the photosynthetic algae into service to produce sugar and energy for them albeit with the promise of harbour and nutrients in return [Music] today however we know the relationship between the two lycan partners to be much more equitable although the deeper scientists probe the more complex the picture becomes [Music] in most lichens there are more than two cooperating organisms [Music] as several different fungal species work together in a way that mutually benefits all parties [Music] indeed lycan scholars have yet to find how deep the symbiotic rabbit hole goes [Music] whether with algae and lichens with trees in the wood wide web or with humanity in modern civilizations fungi have made themselves invaluable partners in many of earth's ecosystems their integration and interaction with nearly every living thing on the planet ultimately blurs the line of where funky end and everything else begins [Music] a collection of organisms not just master and slave not just individual singers but a song [Music] and so tracing the origins of these remarkable organisms requires that we first understand exactly what they are [Music] chernobyl 1986 a catastrophic explosion at a nuclear plant in what is now northern ukraine sees radioactive waste spread across much of europe for many kilometers around the leaking plant contamination levels are high enough to cause radiation poisoning and deadly cancers in arguably the worst nuclear disaster the world has ever seen a 10 square kilometer area of the surrounding forest is killed outright by radioactive material amounting to 20 times that of the atomic bombings of hiroshima and nagasaki [Music] the region becomes known as the red forest after the colour of its dead and dying trees every animal that couldn't flee ultimately perishing from the overwhelming corruption after the disaster the chernobyl plant itself was closed down but the radioactive fuel it still contained was left in situ in order to prevent any further reaction and to protect the immediate area from the effects of radiation the fuel is stored in huge vats of water the clear water itself glows with unearthly blue cherenkov radiation generated as the decaying fuel splits water molecules releasing energy in the form of light only the water isn't clear anymore over the years it has become blackened and the agent of this darkening is remarkably a fungus many species of fungi are known to be extremophiles they are able to tolerate conditions well beyond the limits of what we would consider a comfortable existence one such tolerance is the ability to withstand high levels of radioactivity the same levels that were enough to ravage the planets and animals of the red forest and so here in the intensely radioactive waters of the abandoned chernobyl plant the radio-resistant fungi have found a way to survive even more surprisingly these hardy organisms seem to be doing more than merely surviving here scientists have found them growing towards the hot radioactive particles and using the energy from radioactive decay in much the same way as plants use the light energy from the sun against unimaginable dangers these fungal organisms have found a way to feed on radioactivity perhaps digging deep in their primordial genetic makeup to find a new niche in the wake of radioactive devastation the discovery has staggering implications if a mushroom can adapt to eat nuclear waste then surely other waste products can be consumed too perhaps most importantly plastics [Music] the remarkable colonisers of chernobyl comprise just a single variety among a staggering diversity of fungal species with seemingly endless adaptations to a wide range of habitats lifestyles and symbiotic association there are single-celled yeasts vast mycorrhizal networks funky that build mushrooms of every conceivable shape and size funky that are cultured exclusively inside the nests of leafcutter ants fungi that live only on and in the human body and not to mention the countless lycanized forms hiding in plain sight although only 150 000 species have been formally described scientists estimate there may be as many as 3.8 million species here on earth outnumbering plants by roughly 10 to one they have been incredibly successful and are incredibly old 500 million years at the very least if close enough in evolution mycelium from some fungi can blend seamlessly with other species of course given this cross-species breeding and being fungi are almost the very definition of other the polyphonic way they experience the world is immensely different to our monophony with so much diversity it can become difficult to identify the features that unite fungi rather than set them apart from one another one mycological idea is that we should abandon dividing them into species altogether due to the inadequate categorizations given to them for hundreds if not thousands of years thought to be merely parasites until very recently for influential swedish botanist carl inaeus they were chaos incarnate others genuinely thought them caused by lightning strikes by the 19th century they were categorized as plants and only in the mid-1960s where they granted an entire kingdom of their own for in reality fungi are closer to animals they are eukaryotes set apart from their bacterial cousins through the presence of a nucleus and other membrane-bound machinery inside their cells they lack the photosynthetic chloroplasts that plants possess and despite being historically grouped among plants on account of their vegetative lifestyle fungi actually share more in common with animals than with any other kingdom indeed many fungi contain the same light-sensitive pigments as can be found in our own eyes and their compatible biochemistry is what makes them such potent allies in the field of human medicine together with animals and single-celled protists the fungi are part of a larger group known as apisticons but justify their own kingdom through the possession of unique features shared by neither animal or protist [Music] they are defined in part by their unique mode of growth from probing hyphal tips and the ability of these high fee to digest their food outside the fungal body rather than an internal stomach typically high fee can be recognized by their ability to branch often at right angles and to converge and fuse again further down the line [Music] and fungal cells regardless of their habitat are all strengthened by a specific kind of biological polymer known as chitin some animals also make use of chitin for protection it is especially common in the ecosystems of arthropods like insects and crabs but only in fungi is it ubiquitous around each and every cell this toolkit of classifying features allows paleontologists to trace the fungal kingdom back through the mists of time and to begin to search for the origins of fungi on earth it is the uniquely hyphal microstructure found in fossil specimens of prototaxites that best supports its fungal interpretation but an absence of corroborating biochemistry makes the conclusion of giant fungi 470 million years ago a somewhat tentative one instead paleontologists consider the oldest uncontested fungal fossils to be those preserved in intricate cellular detail in the 410 million year old glassy church of riney scotland here a wide diversity of fungal types are preserved as if in crystal clear resin painting a picture of a terrestrial devonian world in which fungi have already found and exploited many of their modern day niches these specimens are by no means the first of their kind appearing as they do already adapted to their chosen lifestyles but they do serve an important purpose in modern paleontological analysis genetic and physiological analysis of fungi alive today allow them to be plotted onto an evolutionary family tree with more recently derived species forming the most distant twigs and more ancestral forms branching closer to the root finding and plotting the fossil specimens onto this family tree helps to orient those relationships in time as well as in evolutionary space and to calibrate estimates on the rate of fungal evolution on the basis of genetic transformation using these statistical tools modern paleontologists have estimated that the origins of the fungal kingdom extend back long before the age of giant prototaxities [Music] indeed they suggest that we should be searching for the first fungi back in the neoproterozoic between 1750 million years ago before even plants or animals have made a definitive appearance long before the green abundance of the devonian when the terrestrial earth was still a wasteland with no soil to speak of all nutrients trapped within rocks it seems at least possible that algae and fungus made it onto the land together like the aftermath of chernobyl and countless mass extinction events before early pioneers leading the way for more life to follow [Music] just outside the thriving city of mujimai in the heart of the democratic republic of congo rolling tropical grasslands are pushed aside by the inexorable advance of industry ever since the discovery of diamonds here in 1909 the gentle hillsides have been torn open exposing wounds of bright red soil and filling the rivers with the same blood red silt today though one of the most troubled regions on the planet the area supplies some 10 of the world's diamonds prospecting geologists continue to search for more in the ancient rocks beneath the surface there is no other material like it in the absence of any great mountains or sharp rocky escarpments in this part of the country prospectors must actively drill down into the rocks beneath their feet and one such drill core not far from the bustle of the drc's second city has revealed hidden treasures although not the kind that will bring economic geologists running the kanshi b-13 core penetrates the limestone and shady rocks that are neoproterozoic in age and which were likely deposited in a warm perennial lake [Music] here as in so many rocks of this age paleontologists have found spherical microfossils that are thought to belong to primitive eukaryotic algae [Music] but at a depth of more than 100 meters the extracted core contains something else something much more remarkable for the time in a layer aged between 810 and 715 million years old an international team of scientists have identified curious filamentous fossils preserved in three dimensions by crystalline limestone each filament is less than 10 microns 100 of a millimeter across and up to a millimeter in length [Music] but together they pack densely into an interconnected mesh of branching and fusing strands in shape and arrangement alone they are surprisingly similar to the hyphy of modern mycelial network but at an age almost double that of the oldest confirmed fungi it will take more than morphology to make a case for these supposed neoproterozoic fungi fortunately these filaments are preserved in such a way that allows scientists to search for other strengthening strands of evidence to support the fungal conclusion using a technique called raman spectroscopy which uses laser light to reveal the nature of chemical bonds in a structure they found the filaments to be composed of organic material that had undergone the same heating and compression as the surrounding rock this implies that they are just as ancient as the limestone that surrounds them and not the result of some secondary infiltration next the researchers employed a kind of chemical straining that's typically used to identify fungi in modern soils the stain clings to the chitin that uniquely makes up fungal cell walls and not to anything else causing the fungal members of a community to glow green under specific microscopic light and sure enough when the fossil filaments were treated with the stain they glowed the characteristic green suggesting that chitin was a significant part of their original organic structure [Music] these multiple lines of evidence from morphology to chemical composition are necessary to substantiate what is ultimately a remarkable claim that recognizable fungal mycelia had already evolved at least 715 million years ago [Music] this mycelium would have lived within the sediment just under the water or at the shore of the neoproterozoic lake feeding on decaying organic matter from algae and bacteria it is a lifestyle almost identical to that of many mycelia today and these fossils suggest it has an origin deeper in the past than we might imagine but even these are not the oldest fungal candidates found to date in the far north of the canadian northwest territories on the desolate frosted shores of the arctic ocean dark-coloured shales have been dated to around 1 billion years old some 2 or 300 million years older than the limestones of the drc here traditional micropaleontological methods which involve dissolving away the solid rock to leave behind the organic material trapped within has yielded microfossils with a unique shape and structure that hints at a fungal affinity large spheres between three and eight hundredths of a millimeter across are attached to narrow filaments which branch at right angles to one another researchers have interpreted these structures as the reproductive spores and connective hyphae of fungi and while the wealth of analytical data is not as great as the younger african specimens chemical analysis of these canadian examples does seem to suggest the presence of fungal chitin within the walls as well although these conclusions are more tentative the possible appearance of already distinct fungal structures at this earlier point in time does seem to be honing in on the earliest origins of the fungal kingdom elsewhere around the world fossils reveal some of the earliest possible hollow zoans the precursors to true animals that the fossil evidence of fungi seems to be consistent with genetic estimates of their appearance too helps to build a picture of microbial diversity at the very beginning of the neoproterozoic perhaps due in part to the stability and worldwide strife of the boring billion this then could be the age where our ancestors and the fungi went their separate ways diverging on very different evolutionary paths [Music] however there is one more fungal fossil candidate which seems to blow this neatly converging picture apart in 2017 paleontologists from sweden and australia found structures inside the bubbles of ancient lava flows that also seemed to show a curiously fungal habit the key difference is that these samples from south africa are 2.4 billion years old inside these basaltic bubbles which form naturally as gases attempt to escape through sticky liquid magma the researchers have found filaments the typical dimensions of fungal hyphae which branch and fuse in a compellingly mycelial way the morphology argument may be strong but the unique preservation and extreme antiquity of these specimens renders any supporting chemical analysis impossible and at more than a billion years older than when the fungal genome is thought to have emerged the fungal interpretation is perhaps too extraordinary a claim yet even if they are not true fungi as we have come to define them there is no denying the mycelial habit perhaps more primitive organisms whether bacteria or some of the first eukaryotes experimented with a mesh mesh-like mycelium long before the fungal kingdom made it their own all of these ancient fungal and mycelial discoveries have been made within the last five years highlighting just how immature the science of fungal paleontology is much like mycology in general which hovers awkwardly somewhere between plant and animal studies indeed it is only in the last few decades that ecologists have come to realize the staggering diversity and vital importance of fungi in modern ecosystems catching glimpses of them within the fossil record whether in their monumental success as devonian prototaxities their understated diversity in the rhine shirt or in their earliest microbial manifestations in the neoproterozoic reveals just how influential fungi have been through much of life's history they have played a crucial role in cycling nutrients and shaping ecosystems for much longer than we may have imagined perhaps creating soil in the first place and certainly keeping it healthy for other forms of life it is very likely that it was fungi that supported and enabled the success of other kingdoms of life throughout the neoproterozoic and beyond just as it was fungi who facilitated the colonisation of land some 450 million years ago as well as the recolonisation of blasted landscapes after mass extinction events [Music] for as much as a billion years or more it seems everywhere life seeks to explore fungi have been one step ahead preparing the way [Music] and with the development of so-called mica texture being investigated for space travel and habitation it is a role that may just continue long into the future you've been watching the entire history of the earth don't forget to like and subscribe let us know what you think in the comments and we'll see you next time you

Channel: History of the Earth

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Length: 62min 9sec (3729 seconds)

Published: Mon May 30 2022

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[u/Eric_EarlOfHalibut]

Thanks for posting. That was really interesting.

[u/Bdi89]

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