ฝัง
- เผยแพร่เมื่อ 2 มิ.ย. 2024
- This video covers major events that occurred in the Holocene (the current epoch). Major glacial and interglacial cycles occurred in the Pleistocene and after the LGM, climate shifted back into a cooling regime called the Younger Dryas. The possible causes of the Younger Dryas include obstruction of ocean circulation and comet impacts. The impact hypothesis has also been proposed as a possible cause of the megafauna extinctions that occurred around this time. Large mammals, such as mammoths, mastodons, saber tooth cats, American elephants, giant armadillos, giant ground sloths, and short faced bears went extinct during this extinction event. Why? 2 hypotheses: the human-hunting hypothesis (humans hunted these animals to extinction) and the climate hypothesis (the rapid switch to cooling and possible comet impacts & wildfires caused the extinctions). After the Younger Dryas, things warmed back up and temperature remained relatively constant until ~1950 when the Anthropocene began. The Anthropocene and current climate change is discussed in the video: The Anthropocene Epoch.
References:
Chapter 20 in Earth System History: amzn.to/3v1Iy0G
Investigations in Historical Geology: Lab Manual by Deborah Caskey and Vicki Harder (2014)
redshelf.com/book/51724/inves...
GEO GIRL Website: www.geogirlscience.com/ (visit my website to see all my courses, shop merch, learn more about me, and donate to support the channel if you'd like!)
0:00 What is the Holocene & outline
1:45 Pleistocene Glaciation
2:57 Last Glacial Maximum (LGM)
5:50 Younger Dryas
8:19 Comet impact hypothesis
11:00 Pleistocene Megafauna Extinctions
12:41 Causes for Extinctions
13:22 Human Evolution
16:20 Evidence for human hunting hypothesis
19:36 Evidence for climate change hypothesis
21:54 Climate from Pleistocene-Holocene
30:55 Sea level change from Pleistocene-Holocene
33:10 Bloopers
Image sources:
images.theconversation.com/fi...
1.bp.blogspot.com/-9SzICrYpX_...
1.bp.blogspot.com/-AXtAZgfRRaM...
opentextbc.ca/geology/wp-cont...
upload.wikimedia.org/wikipedi...
www.researchmagazine.lu.se/wp-...
www.researchgate.net/profile/...
3c1703fe8d.site.internapcdn.n...
www.universetoday.com/wp-cont...
www.nycentral.com/View/wp-con...
i.pinimg.com/736x/53/f6/73/53...
vignette.wikia.nocookie.net/j...
media.web.britannica.com/eb-me...
i.pinimg.com/originals/60/0c/...
cdn0.wideopenspaces.com/wp-co...
i.pinimg.com/736x/c4/fe/b6/c4...
upload.wikimedia.org/wikipedi...
www.museum.zoo.cam.ac.uk/high...
i.pinimg.com/736x/1b/98/5e/1b...
images.fineartamerica.com/ima...
newsimg.bbc.co.uk/media/images...
1.bp.blogspot.com/-2E3OUg9Nh2...
www.sciencemag.org/content/306...
ocp.ldeo.columbia.edu/res/div/...
upload.wikimedia.org/wikipedia...
media.virbcdn.com/cdn_images/r...
co2coalition.org/wp-content/up...
www.ice-age-ahead-iaa.ca/smal...
www.e-education.psu.edu/earth...
Disclaimer: Links in this description may be affiliate links. If you purchase a product with the links I provide I may receive a small commission, but there is no additional charge to you! - วิทยาศาสตร์และเทคโนโลยี
The way Geo Girl tends to laugh about arcane topics such as the Holocene versus the Pleistocene is kind of endearing.
Kind of?! It most totally is--takes the hard edge off the scoops of information--
More amazing content from my favorite TH-cam creator. I’m a hour drive from Lake Michigan, mind boggling that 14,000 years ago where I live was under 300 feet of ice. Now if you’ll excuse me I’m going to watch and enjoy the rest of the video
I ❤️ GEO GIRL
Always glad to see you back ;) you make my day!
Hi
My new favorite series of videos to enjoy. Thank you for the work involved to create all of the informative content.
I’m an elder that sees huge value in knowing that young voices, particularly female voices are explaining science to Americans.
Existential value.
Thank you so much for this comment, it means so much that you see and appreciate what I am trying to do :)
Your explanations are so clear! Keep up great work!
Thanks so much, that is my goal, so it is always nice to hear it is coming across that way! :D
Huh. I never knew why it's called the younger dryas. Learn something new every day. How bout that. Thanks chickadee, super interesting as per usual 💖
As a child, this has been my most loved subject. This is the best paleontology lecture I have watched. Very detailed and well explained. 👍🏻
Thanks so much for the kind words, I am so happy to hear that you enjoyed the lecture! :)
I certainly appreciate and learned more on the Cenozoic era more than anyone previously. Mesozoic era is also my fave.
Added you to my Fave. Have a good evening ☺️
@@easyrhino30 Aw, thanks! You have a good evening too ;)
This video taught me more than an entire semester of Archaeology did. Thanks!
Great video. I especially liked the graphs showing the Treering and Greenland Icecore correlations. Overall, I thought you presented a lot of information in a format that is easy to grasp. I never thought about a favorite megafauna. But now I think the giant camel is my new favorite. Maybe because it is so mind-boggling big!
Thank you! And yes, the camel was insanely big hahaha!
Glyptodonts are also my favourite megafauna from that time. They had that certain ankylosaur vibe. I also find it charming that the little pink fairy armadillo is the closest surviving relative of the extinct glyptodont subfamily.
The Thagomizer on its tail is a delightful example of convergent evolution. 😃
Awesome vid! So interesting and informative, love it!
Thank you! :D
Interesting and informative video, it’s teaching me a lot. I finally got visit a museum for the first time after over a year and a half. Great video, keep it up with the great work.
Oh my gosh, that is so great to hear, I miss museums so much! How was it??
Also, thank you for the kind words and support, I will try my best ;)
@@GEOGIRL You’re very welcome. 😉👍 It was really cool, a lot of interesting exhibits. I was most interested in the exhibits like the saber tooth cat skull and the exhibits about prehistoric animals. I made a video of it if you’re interested. It’s really interesting.
Living in Wisconsin I've been fascinated by the plistocence
My favorite dinosaur is from the Holocene. It's the ivory-billed woodpecker. It's big, it's charismatic, and it's extinct: prime favorite-dinosaur attributes.
Loved the video! Am looking to learn the intracacies of pliestocene and stone-age ecology and this certainly helps explain some of the more global events that were happening around that time. As for a favourite animal, definitely the Wooly Mammoth. Overdone yes, but you cannot deny the sheer awe and impact it inspires and inspired in Humanity.
Really liked your charts and how you put it all together. Favorite animal would say all of them, and so sad to not have known them.
Great content! I really enjoyed how you pointed out the difference between forrest communities moving along latitudes or altitudes because of ice retreat. And at the same time that the speed of adaptation is different for many tree species. Thus changing the composition of the plant / tree communities.
Thanks so much! Yea, that was actually something I was thinking of cutting out to make the video shorter, so you just made me very glad I stuck to my guns and left it in! It is a very interesting tid bit about tree/forest migration that I actually didn't know until researching for this video.
Great video, didn't know about the asteroid hypothesis for the younger dryas
Mine is probably the saber tooth or the dire wolf!! Your video was interesting and well done, thank you for taking the time to make it! I am homeschooled so videos like these really help us out. Also you are really pretty! I will be interested to watch more from you in the future.
Oh wow, I didn't even think about homeschooled students watching these, that is so great to hear that my videos help you! Thanks for leaving the comment, I am glad you will continue to watch what I put out. :) Let me know if you ever have any topic requests ;)
@@GEOGIRL Yeah!! This is the first one I watched so far but I will be watching more soon for a different subject, it really is helpful to find videos like these. Of course! And if I think of any or my mom thinks of any I will possibly drop a comment!
Paraceratherium, the largest land mammal to ever live. That's my favorite Tertiary mammal.
Your video pops up on the right side of the page on google search when searching Holocene Epoch. Thank you for the explanation! 😊
Oh wow, so glad to hear that! Cool, thanks for the comment! I am so glad you found it helpful :)
@@GEOGIRL Off topic, but having studied in detail about how the earth and we humans have evolved, do you agree or disagree to the existence of a God?
@@Mahalakshmi-Khan Actually, neither. I am a very analytical person, and I believe we do not have enough data to prove either argument (that God exists, or that God does not exist), and because I don't study that I feel I cannot speak on that. Hope that answers your question :)
@@GEOGIRL so how do you shape your personal beliefs? Are you religious, agnostic, atheist?
@@Mahalakshmi-Khan As described above, I am agnostic, I do not believe we have an answer. :)
Such an awesome video 🤌
Thank you so much! I am so happy you liked it, this is still one of my favorite videos I've made ;D
Wonderful video!
The major problem is that the Holocene period was thought to have lower water levels, yet the climate was much warmer than ours is now; so it makes sense that the water level would've been higher.
If you take account of the younger drias flood theories, which show evidence of a flood 12k yrs ago, you would have to have had something raise the water levels higher; not to exclude Egyptian temples (most likely created before 12k yrs ago), which have waterway ramps that would've had to have a higher water level then.
Also, humans over hunting is ridiculous, since most of the animal clusters appear to be more "flood-impact" related, where the animals aren't even moved from these clusters; if animals were hunted, the meat or fur would at least be extracted. If a huge flood impacted N. America tho, it make more sense why the bones are found in clusters.
If a huge meteor impact hit the Atlantic (as is suggested by science), fires wouldn't necessarily exist, a flood would put them out.
Also, we have huge oil reserves today, not from dinos, but from all of the downed trees of that period. Mt St Helen's is a great example of dead trees decaying into slate and oil.
The grand canyon could've been created due to this huge flood.
Pretty much every culture has a flood myth.
All mammals that exist today are genetically similar to the larger animals of this era.
Megalithic sites show human ingenuity before/during this era, that trumps today's capacity and capability; huge multi-tonne rocks could maybe be lifted by our machinery, but could never exact the accuracy used at sansayhuaman or other megalithic sites.
Overall, everything points to technology advanced humans and a huge event that created a flood that wiped out most everything.
From after a huge flood, the amount of water dissipating would've pushed our climate lower and forced this excess water to travel to the poles, making the polar ice caps.
I enjoy your videos. I took a geology course eons ago, and could never remember the names of the epochs. Could you do video on how and why they were named, and how you remember them?
Yea, I actually have a video with a song that should help remember the names: th-cam.com/video/3d_y1yK-p7w/w-d-xo.html, but I don't have a video discussing how and why they were named, that is a great idea for a future video, thanks! ;D
Wow you go all the way from the Hadean to the Holocene Rachel!
Great 👍👍👍 you are very consistent in videos 👏👏👏👏
Consistency is key! :) Thanks for the comment, so glad you liked it!
It is pretty wild to see that man was living with these animals around. There are chapters missing. It is fascinating.
You are very good at explaining. You say the big technical words but then you explain what that means. A lot of these channels that deal with prehistory Do not explain the big words or they do not do it very often. I am a fan. I'm about to watch the majority of your other videos. My favorite megafauna is now the giant camel. I knew there was a giant camel but I never seen it side by side with a regular camel which is very large itself. I could not imagine seeing a camel as big or bigger than an elephant!
So glad you enjoy my channel and the way I explain things, thank you! Also, I would love to see that big a camel too, I can't believe how big they got!! ;D
The wooly rhino would be so cool to see. The Aurochs have to be a close second.
Keep up the good work and may you always be younger than Dryas. You should consider a subscriber poll to learn which species your fans are most glad is currently extinct. I vote for giant sea scorpions but Dire Wolf is neck and neck since I live near the tar pits. Also large dangerous chickens seem like a good candidate for human caused extinction since they are so tasty.
very interesting video i heard about the epochs when watching a video on the argentavis bird it would be good to see you do some videos on the animals that existed in those times. (idk if you’ve done some videos on that btw)
What a great idea, I have been going back through periods in Earth's history and talking about the life that was around in each of those periods, so I will try and do that for the pleistocene-holocene as well :D
@@GEOGIRL good to hear
Pleistocene to Holocene transition is because of the the younger dryas impact. That ice sheet can’t just gradually disappear or Lake Agassiz break. There must have been a trigger event. That cause the world temperature to increase drastically because the ice sheet disappeared rapidly
Thank you for saying epoch like epic.
2.6mya to 0mya! I loved that!
GEO Girl, you should write a book! Your command of English is masterful! Or would it be mistressful?....
Anyway. The way you speak is beautiful.
Is there an Older Dryas?
Can I assume that there was different rise in the sea levels depending of the location? Or it was uniformly? Sorry if u have talk about it in another vid or in this one.
120 m is crazy but iirc it takes some thousand years to get to that isn’t it? Even so it feels reasonable that there were flooding of fresh water onto the sea that cause climatic dissorder “wich will hit harder in some places than in others, I wonder if the same effects could produce the “slow” global sea level rise but in others parts be faster.
I don't mean to imply any complacency about, nor deny at all the urgency of, global climate change, but it is comforting to see evidence that human civilization has demonstrated an ability to survive (read: can grow crops), at higher temperatures than today.
My biggest fear about climate change is crop failure and food famines. So I experienced a rare feeling of hope concerning this topic.
Oh.... then I watched the rest of the video. And you totally stole my favorite megafauna w/ the Giant Armadillo, so I'll go with the runner-up Colossus Camel.
Awesome ♥️ 👏👏💯
Thanks so much! ;)
Nice and interesting Video. It is a good addition to my two study lessons in Quaternary Geology and development of the system earth.
All the best from Germany. You rock😉👍🏻🪨💎
That's great, so glad it was informative for you! :D Also, thanks so much for the encouragement, you're the sweetest😊
Good job!
Thank you! :D
We're currently in the Anthropocene, Rachel, on another note have you thought of getting someone to set up a wikipedia page for you?
Can I find your videos in an audio format on SoundCloud or spotify?
My favorite Holocene species is the North American opossum, aka the Virginia opossum. They are actually a species that still exists today and I just love them so much, they are super cute.
Your thought on coral adaptation or extinction with 120m see level rise? (...do we similarly see extinctions in other marine plant life, like kelp)?
Great thought! I am sure we do. I just did a quick search and couldn't find anything specifically about kelp extinctions during that time, but my guess as to why is that coral preservation potential is much higher than that of kelp. Therefore, we can reconstruct the history of corals much more easily than we can kelp or other 'soft' organisms. But in general, I would guess that the entire group of organisms that characteristically inhabit coastal environments would have been heavily impacted by this rise in sea level.
Fascinating as always... So many amazing animals, but that weird ape from Africa that took over the planet is the mot complex an terrifying beast in the Phanerozoic.
Man, if I had a time machine, I would NEVER leave the Pleistocene. I wanna see ALL the megafauna!!
Awesome video, with so much informative content! Personally, i gotta love the giant camel, almost reminds me of a dinosaur...just imagine riding one of those giant camels out in the desert.
10:36 Antonio Zamora has a fascinating TH-cam channel where he presents his hypothesis that there was indeed a meteorite or comet impact on the Laurentide Ice Sheet in Michigan at around 12.8 KYA, and the ejecta produced the long mysterious Carolina Bays. He also does some calculations of the energy released from the ejecta impacts, and they are in the multi-megaton range each. That would explain a lot of the impact and burning evidence we see. Fascinating stuff.
I'm skeptical (as usual) of the hunting/extinction hypothesis because that's not generally what we find today or recently. The Native Americans - also a neolithic culture - did not hunt the bison or other large game animals to extinction. In Africa, the neolithic natives did not hunt the large game animals to extinction. So I don't find the idea persuasive.
Very interesting, and I understood all of this one. lol thx. Nice use of scales around 10 min. where u show the extinct animals.
Thanks! Glad you understood and enjoyed this one haha! This was one of my all time fav videos to make!
Nice video
I have two questions but I'll ask them one at a time. At the end you mentioned 120 m ocean level rise, given that sea levels are higher at the equator than at the poles how do they judge where that sea level rises accounted for? Something many people don't understand is that water is actually deeper at the equator than it is at the northern latitudes because of the spin of the Earth. Therefore Florida will face much more devastation due to rising sea level then New York or areas north of it.
Great question! I think the sea level at the poles versus the equator is not as significant a difference to matter in terms of measuring a 120 m rise in sea level at any point in Earth's history. However, in terms of measuring smaller changes in sea level through the past, I think scientists can do so in a way that they are comparing analogous locations. For example, geologists can reconstruct ancient environment as well as where that environment was (roughly) located on the globe at that time. Therefore, we can make an accurate comparison of sea level from then versus today, but I am sure in many cases it is not that simple, I think that is for ideal cases in which you have a lot of geology to go off of. However, the good news is we have so many wonderful scientists reconstructing these parameters these days, that we have sea level reconstructions from all over the world from all throughout the recent periods in Earth history. Therefore, we can kind of 'check' our estimates to see if they match the bulk of data from that time and if they don't we would have to come up with a good reason why and figure out what it means. Anyway, I really enjoyed both your questions, thanks for asking! I hope my explanations make at least a little sense haha ;D
@@GEOGIRL I figured the effect was far more substantial from the Earth's spin....
Over several billion years, this force, which effectively pushes outwards, has made the planet a bit fatter around the middle. So the diameter of the Earth measured through the equator is today about 21.4 kilometres more than the diameter of the Earth measured through the poles.
But this bulge in the solid Earth took billions of years to slowly develop. This is because the solid matter moved only very slowly in response to the outward force caused by the spin of the planet.
But the liquid water in the oceans is far more mobile and responsive to forces. So the Earth's spin has pushed up this liquid water to an 'abnormal' elevation of about eight kilometres.
In other words, at the equator, thanks to the spinning Earth, the water has been pushed up some eight kilometres higher than in the case of the Earth having no spin
Obumer bought a multimillion dollar home 4 inches above sea level in Martha's Vineyard, so I think we are safe
Do u have source available for the nanodiamonds .. ?
So many big animals that I didn't get to pet.
Another thing most people have no idea about is that the Holocene is temporary, like every interglacial before it. In other words, since the Holocene is a warming between glaciations, there is yet another glaciation ahead. How far ahead, we really don't know. But, there at least two things to take away from this: first, the Holocene is the ONLY global warming currently occurring and, second, NO ONE has ever witnessed climate change, as it occurs over at least centuries (as in the Medieval Warm Period and the Little Ice Age), i.e, longer than the human life span. As for the so-called Anthropocene, like I said, the only climate change is the current Holocene. The term Anthropocene is an attempt by "global warming" alarmists to blame climate change on human activity. But, the Holocene began during the Paleolithic Era, when the extent of human technology consisted of stone tool-making. The thing is, as I just said, no one can witness climate change and, thus, weather is being conflated with climate, for one thing, and the alarmists believe that the changes are happening much more rapidly than any climate change ever has before. But, given the time scale of known glaciations and the interglacials that separated them, it is possible the next glaciation will occur about 3,300 years from, give or take. In other words, sometime around the year 5321. So, this is nothing that anyone now living is ever going to witness directly, but assuming our species continues to exist until then, our far future descendants may witness the beginnings of the next glaciation, and certainly the cooling leading up to it. Given that I'm 69 years old and have seen both cooler and warmer decades within my lifetime, courtesy of the 11-year solar cycle, I am quite amused with all the unfounded hysteria about "runaway warming" and even more amused about some of the predictions made for it. For example, that there will be a desertifcation of the Earth due to a build-up of CO2. This absurdly wrong, as there has been far more CO2 in the past (especially the Mesozoic Era, when the dinosaurs flourished and the planet's landmasses were covered in prehistoric jungle, including the poles. At that time, there was not yet any ice caps, nor any glaciers. CO2 is an essential nutrient for the planet's plant life, so an increase in CO2 would lead to more plants, not fewer.
Haha, no one is saying that climate change happens quickly (over human time scales), but we have the tools to measure/predict is now and it is speeding up thanks to our help.
Also, no one is saying that there will be a desertification of Earth due to CO2 build up, you are 100% correct that that is absurdly wrong. You are even right that many species of plants will thrive. However, there will be consequences that are not human-friendly. And I do not mean that humans will only be directly affected, I think the indirect affects will be even worse.
Especially since much of the land that we rely on will either be drowned, unfarmable, unlivable, too dry to find fresh water + more forest fires, or too wet and cause flooding, extreme weather, etc., and the list goes on. Lastly, no one is denying that there will eventually be another glacial cycle on Earth, that is 100% the norm throughout Earth's history. The question is whether humans will come out on the other side. And no, I do not think we will go extinct. But I know for a fact we will not go unaffected. The harmful affects are already affected humans that live in coastal areas/islands where sea level is rising, dry regions where forest fires are common, regions prone to hurricanes/extreme weather, dry regions where fresh water is scarce (where I live we have this problem), farmland regions that require specific & consistent climate, regions that flood, regions where glaciers (as source for fresh water) are melting, and so much more. This is real, and whether or not you believe we have anything to do with it, we must fight it because it will (and already does) affect us.
Anthony Zamora has videos about an impact on the ice sheet around the Great Lakes, resulting in secondary ice impacts forming the Carolina Bays and Is Nebraska Rainwater Basin. The would have pulverized the North America megafauna. Makes a lot of sense.
Loved that you used Diego from Ice Age!
If I had to pick a favorite, other than mammoths, I would have to choose giant deer (Irish elk, giant moose), extinct pronghorn of some kind, or..... the California condor.
Humans had been hunting these animals the whole time (the ice age). I doubt our efforts at the time were the final blow.
Climate change, if it so impactful now, would be impactful then. Perhaps in some cases we tipped the scales, but blaming us exclusively seems like flagellation-seeking.
Great video! My daughter who is 10 will likely binge watch your channel as she LOVES Earth and planetary science. Our favorite extinct animal are the large flightless terror birds. We are especially interested in their interactions with humans and why they ultimately went extinct. Cave sloths and cave bears and their interactions with humans come in second and third respectively.
Wow! That is so cool that your daughter is into this stuff at such a young age, I hope she enjoys the videos ;)
Also, yes, the terror birds were incredible! Maybe I'll make a future video about them ;D
@@GEOGIRL Yes, she is pretty amazing. She also enjoys anthropology and history. She is currently reading a book about cephalopod s and how they are as close as anything to an alien intelligence. We are currently writing a science fiction novel about a group of kids living on Mars and how they get caught up in the battle for independence from a future tyrannical Earth. It started as one of my bedtime stories that I told her as a kid but those who have heard snippets of the story have convinced me to write it down. So we will hopefully publish that one and possibly my earlier bedtime stories together. Please continue with what you are doing. Your videos are both informative and quite interesting. ☺️
@@resilientfarmsanddesignstu1702 Wow that book sounds amazing! What a great project ;D Please let me know when it's published so I can check it out!!
@@GEOGIRL Thanks for your encouragement. It will take me a bit if time as I have other obligations. The story is really a mystery/action adventure story set in a sci-fi future. Fortunately, I have the basic story but to make it a sci-fi novel, I need to do a bit of research so that the technology and the settings seem realistic and plausible and that the logic of the plot is sound. I also have to write the back history so that I can provide a context and a rationale for the actions and decisions of the characters. I have to describe the characters and the main scenes, etc in detail so that I can add details to the story. As I'm sure that you are well aware, all projects start with optimism and excitement and then quickly turn into work but it is fun to work with my daughter. Her enthusiasm for the project keeps me going. I run everything by her and I ask for her input. It's OUR story not my story. 😊
Good ups.
As far as I understand, the 'robust' evidence for human predation on mega fauna is almost exclusively in tool marks on mammoth and deer bones.
Do we have evidence of human predation of beavers, armadillo, and the dozens of other NA mega fauna?
One hypothesis I heard involved refugia as a way climate and human hunting could have interacted. If I understand it correctly, the idea is that megafauna could have withstood previous pleistocene climate fluctuations by retreating into refugia, or refuges, like maybe mountains, where the warming or whatever was less severe. Then, when conditions imprived for them, they would spread out and flourish again. However, human hunters could have thrown a wrench into this strategy by following their diminishing prey stocks to the refugia and hunting them to extinction there. I don't know if it is true, but it would be a way for human hunters to effect a change not seen earlier in the pleistocene without having the numbers to wipe out a species across an entire continent. Interesting idea, at least. Not sure what kind of evidence you would look for, though.
Favourite? Crows, all the Crows
Think I'd pick the saber-toothed cats as my favorite holocene megafauna. I'm kind of a cat guy. Thanks for the video!
Love saber toothed cats good choice! And of course, glad you liked it ;)
The wierd thing with the milankovitch cycles is that the excentricity seems to be decisive, but then it all goes super fast, the temperature explodes in geological terms. Wierd because earth is already close to the sun for many thousands of years and yet the temperature seems to wait, it does not rise incremently with less excentricity. I guess once the ice starts melting to a certain degree, the albedo decline kick starts the interglacial. edit: Animals probably got that big because it alows better cold resistance (volume to surface ratio). edit: 24:05 there is no evidence whatsoever that our warming happens at an upresedented rate. In fact even in our instrumental data we have a warming from 1910 to 1950 without the vast majority of our emissions. Can you elaborate?
Would be interesting with a CO2 overlay to that eon-long temperature graph.
Speaking of the anthropocene, have you read the 6th extinction? Is it worth reading?
Gray Parrot. That once was my answer to a FB question about what is your favorite dinosaur, and they forgot to specify "non-avian".
I agree. Definately Giant Armadillos are amazing.
Question number two when you were mentioning asteroid impacts When the kt impact occurred I don't think I have ever heard anybody discuss changes in the earth's rotation, tilt or wobble due to such a large impact. Have you ever heard any scientific data discussing how the meteorite may have affected those aspects of Earth making the epoch after very different from those that came in the Jurassic?
Interesting thought! The only impact I know of that was large enough to affect Earth's spin, wobble, etc. was the moon-forming impact, when a mars-sized object impacted Earth just after Earth's formation. But other impacts that I know of throughout Earth's history were not nearly as large and therefore did not affect Earth's astronomical aspects.
@@GEOGIRL yes I know Thea altered dearest tilt wobble and spin however I've also heard that things as simple as earthquakes have sped the earth rotation up or slowed it down only by seconds but if an earthquake can change our rotation by a second or two per year by decreasing the circumference I'm thinking that a meteorite the size of a mountain might have had some significant effect. 😊
@@cluke1620 Wow I never realized that, how cool!? Well, now I need to do some reading, you clearly know more on this topic than I do haha. I am also curious now if anybody has looked into how the KT or other impacts have affected those aspects of Earth, I'll let you know if I find anything ;D
@@GEOGIRL I actually learned about a lot of this by studying astronomy and astrophysics. There are many things that the faster spin of the Earth 3 billion years ago would have caused that I never hear discussed by geologists. For example a faster spinning Earth should have had a much stronger electromagnetic field. Granted there is only bacterial life at that point but I still never here how those changes might have affected the ability for plate tectonics to occur or even the effects of bulging from both the Moon being closer and US spinning faster.
A bit of trivia but they spin of the Earth is why we try to launch spacecraft from as far as South towards the equator as possible. The rotation of the Earth actually gives the spacecraft a spin boost as the ship's launch towards the east in the direction of the Earth spin.
My favorite extinct animal living in the Holocene is definitely the Western Camel! It’s hard to image that camels evolved in the Americas, migrated to the Old World, and went extinct here. :-( Can you imagine what exploring the desert Southwest would have been like, if folks had had camels instead of horses?
Horses also arose in North America and migrated to the Old World, but thru selective breeding, larger breeds of horses were produced than the small, "steppe horses" of central Asia (and North America). Camels WERE brought to the desert SW in the mid-1800s, but it was right around the time of the Civil War and the completion of the Transcontinental Railroad. The camels were deemed unnecessary and were released into the wild.
I didn't know petrified trees still showed their tree rings from 13,765-4500bc?
Is that still possible?
So the sequence the way I got it so far on how an ice age ends: little biomass sequestration so co2 keeps increasing from volcanoes and a nudge from the mylankovich cycle leads to ice melt which starts a positive feedback loop of warming from increased land albedo and co2 methane emissions from decomposing biomass laid bare. This feedback eventually tops out with most of the ice and biomass decomposition over. In the meantime, ocean carbon sequestration has been gearing up because the melting glaciers expose glacial flour full of iron, which is increasingly washed into the oceans from the faster evaporation and rain with increasing temperatures, so that eventually it becomes dominant that that's when co2 falls again and next ice age begins
12:28 I don't see how a meteorite would have led to rapid temp changes only affecting large mammals, and skip the largest one, the elephant.
21:54 the clovis humans would go extinct if they were depleting their food supply by growing while overhunting which they apparently did
Love it. And love you too
Just in time, studying quarternary geology right now:)
Perfect, so glad I can help you out! ;D
Mainly i think climate change played a vital role in the extinction of the megafauna.
The Homosapiens finished them off lol.
I'm a big cat guy so definitely the sabertooth cat 😅
I’ve read that mammoths lived until about 3,000 years ago on Wrangell Island (north of Siberia in the arctic). This if true is hard to explain.
My favorite topic nowadays…
Milankovitch cycles have always existed. Yet the glacial cycles only started 2.6Myrs ago. Presumably, the warm current from the south Atlantic would have flowed pass Panama into the Pacific before then. When the Isthmus of Panama closed, the current turns around, flows out the Florida straits into the north Atlantic. Presumably this increases snow fall, and there's lots of land mass at high northern latitudes. Milankovitch cycles may impact how much melts?
When South American was still connected to Antarctica, ocean currents would have brought warm water to Antarctica? Now, there is cold current wall keeping warm water away
@5:10 looking at the map, forestries are just giant mosses moving at a geological timescale, slowly eating at rock at a rate incomparable to a human lifespan.
the megafona still frozen fresh to this day in Alaska, across Canada and into Siberia. humans didn't have anything to do with that . can you discuss how that happened? wonder if there are any Clovis people still frozen fresh ?
Favorite animal of that time is Gastornus.
@12:54 Not sure why nobody likes to check, but the fossil record is pretty clear. The predators went extinct prior to the prey.
A giant armadillo I imagine would be something akin to a modern-day tank or HUM-V. Lol!
Hi do you know any fun facts about holocene?
Well, other than the facts I shared in this video, I can't think of anything haha ;) Do you?
"My favourite form of rock is Metal" AronRa :)
All I know is that Pleistocene is a fun word to say.
It is a good video though.
Thanks, and yes it certainly is! ;D
One problem with that human hunting hypothesis, as regards the large herbivores: you're certainly not talking about the brontosaurs, right? They went extinct at the same time as all other dinosaurs. Actually, Homo Sapiens have existed since 200,000 years ago and, while the earliest hominids did exist as long ago as 150 million years ago, the "large herbivores" were long gone by then.
Haha, No no one is talking about dinosaurs like brontosaurs, we are talking about large herbivores like mammoths, certain species of elephants, giant sloths, and other types I mention in the video, sorry for the confusion ;)
This is interesting the Mammoth Era?
The giant beaver were high on my list
a little bit too much Pleistocene for a video called "The Holocene Epoch"
Yea, I know, it is technically both, maybe I'll change it to include both in the title haha
The Younger Dryas is of course younger than the Older Dryas that is older than the Younger Dryas.
My Favorite Animal from that time period are Paraceratherium
Oh that's a great one! ;D
We do have Neanderthal DNA mixed in with ours. (it's about 2% unless all of your ancestors never left Africa) It wouldn't surprise me if Neanderthals had some Homo Erectus DNA, leading to it being in us too.
Brilliant thank you. Just please correct the Homo sapiens 150kya part. It’s 300kya (in Africa). Search up Jebel Irhoud sapiens
No problem, I am glad it was helpful to you. Also, thanks for the info! I am only as good (or up to date) as my references, so I will try to be more on top of the latest refs from now on :)
Giant beaver! Tails down the best.
When was the last Yellowstone eruption?
If you discount the shared origin of Sapiens and Neanderthal, Sapiens contain zero interbreeding with the Neanderthal. The Neanderthal was destroyed by Homo Sapiens. Homo Sapiens was the first hominid to build armies ( hunting parties dedicated to eradicating other tribes and especially people that looked different ) and the first hominid to mass produce spears and bows. Yes, the Neanderthal was stronger 1 on 1 but Sapiens used armies, superior weapons, had larger areas in the brain for thinking and planning and were better suited for running and attacking en mass. Aka. The first hominid to create wars.
Ah, couldn't the simultaneous extinction of the Clovis people and the large mammals be explained by the same model of a predator species over-hunting their prey? As they kept killing off their food source, they also declined?
Holocene Fav Fauna for me has to be the North American camel. It's so wacky. Giant camels in the Americas? Wut?
Is it concerning if for most of earths history according to that graph we had an average of +10. We are approaching like 3. We may be raising it quickly but the planet has revealed more and more coping mechanisms. We can take our time and put the work into technology and be just fine.
I should've clarified though, that it is the rate of CO2 increase and temperture increase that is harmful (not the overall amount of CO2 or global temperature). The overall concentration of CO2 being high or low in earth's history does not represent 'worse' or 'better' conditions than today becase the harmful thing is the rate of change in CO2 not the total concentration. So in earth's history it's often been much higher in concentration, which is fine. But whenever it sharpy and rapidly increased or decreased, that is when rapid climate change and mass extinctions occurred. I hope that makes more sense, I like to remind people of this by say 'Warmth is different than Warming' ;)
The only way to ever reduce the impact of humans is to reduce the number of humans.
There isn't an option 2 folks.
My fav was the Giant Armadillo, but that one is on hold because its eating habits were a little too gregarious.... right now I am really into the farmers-favorite, big and not-too-lazy Megatherium americanum, sometimes known as the giant ground sloth, or the megathere, native to the Pampas through southern Bolivia during the Pleistocene. I appreciate its symbiosis with the Avocado...
We Have the Extinct Giant Land Sloth to Thank for Avocados th-cam.com/video/ahc9hb_qJ1k/w-d-xo.html