Mass Extinction Events from the Precambrian to Mid-Paleozoic that Nobody Talks About! GEO GIRL

[@drex6347]

Here's a rundown of some extra minor extinctions not mentioned here: - Anoxic extinction: When oxygen levels rose during the GOE (Lomagundi-Jatuli event) they eventually went down to much lower lovels (Shunga-Francevillian event). There is some, controversial, evidence of multicellular organisms appearing at the end of the high oxygen epoch (ie. Francevillian biota or "Diskagma"). If these organisms existed, well, the fossil record doesn't show any other complex organisms until much later, so presumably they all died out. - Snowball extinctions: Pretty self-explanatory, when the Earth went through a snowball/slushball phase many organisms had to have perished. However the scaricity of the fossil record, combined with seemingly no disappearances in major groups may contradict the view of them being extinctions at all. - Ediacaran extinction: Most ediacarans vanish from the fossil record at the end of the period, before the Cambrian explosion took place (there's a 20-ish million year gap inbetween). May be more of a lack of adaptation rather than an extinction thou, again the scarce fossil record isn't helping. - Carbonifeorus Rainforest Collapse: Can't be really called a mass extinction, more like a mass contraction, as species didn't really disappear but saw their numbers and habitats diminished. However this is also linked with the (slighly posterior) carbon dioxide low and the eruptions of the Tarim and Skagerrak LIPs. - Olson's Extinction: Initially considered a gap in the fossil record much like Romer's gap. Seems, again, to be more of a faunal turnover as the world switched from a wet icehouse to an arid hothouse. - Aptian Extinction: This one was mostly a marine extinction and was caused by anoxia. At the time the Earth was at its warmest since the Earliest Triassic, and as oxygen dissolves poorer in hot water, sea creatures struggled to breathe. There were no major changes in land, and in the long run the sea level rise due to the heating caused an increase in biodiversity (ie North America was split in two separate landmasses). - Oligocene-Miocene Extinction: Another climate-related extinction as the Earth switched from a hothouse to an icehouse phase. This one is associated with lowering sea levels which led to easier crossings by species, decimating the faunas of smaller places such as Europe. More of a turnover, as no major extinctions affected large landmasses. - Holocene extinction: Could already qualify as a major disturbance in the biosphere, and the fact that continent-specific species are found worldwide will for sure puzzle future paleontologists.

[@GEOGIRL]

Woow! This is awesome! Thanks for the list AND descriptions, this will really help round out the video! ;D

[@IljaMuromec114]

Also there was an extinction between the white sea and nama assemblage of the ediacaran likely caused by anoxia where a lot of the famous ediacaran species such as dickinsonia, spriggina and tribrachidium went extinct

[@MrPhillip2]

As a retired geologist, I enjoy catching up on topics that have been revised and better understood since I graduated in ‘78. Thanks! In the Devonian slide, you show the ocean saline conveyor as operating presently, however, according to Scotse’s paleo-plate rotations, the land masses were south of the equator and mostly joined together. Could you create or explain how the thermal-haline conveyer possibly worked in that continental configuration?

[@ianhorsham7751]

I had a similar thought but wondered if it was just an example of showing ocean currents. I wonder if we can actually be sure of what those currents would look like. It also made me wonder if continental configuration would effect the carbon sequestration.

[@GEOGIRL]

Both great questions! Unfortunately I couldnt find a picture of the ocean currents as how they would've been then, so I just used a modern example to get the point across because technically it's applicable to most any continental arrangment as long as cool waters are at the poles. But I actually have an entire video about how we can reconstruct & model past ocean circulation conditions on Earth and how they may have contributed to ocean anoxic events and extinctions! :) Here's the link: kzbin.info/www/bejne/fZC3aKuPqpuGo8U

[@jeremychristopher6330]

​@@GEOGIRL your very pretty

[@felderup]

@@jeremychristopher6330 you're very pretty too.

[@Zebred2001]

I realize that if we has a time machine there would be a lot of adjustment to all of these models but it is astonishing that we have the level of "resolution" we do to understand events from so long ago.

[@MaureenLycaon]

No kidding! Fifty years ago, the closest that scientists could pin down dates in the Mesozoic or Paleozic was, "Maybe five to ten million years." Now, in many cases, we can pin it down to a few hundred thousand years, and sometimes even less.

[@amberkat8147]

@@MaureenLycaon Yeah, I LOVE that. I was raised to reject evolution and all that, I changed my mind in college but my parents are still unconvinced. I love to see how much detail they can get because I keep hoping that some day it'll be enough to convince my parents.

[@noitalfed]

Thanks! Great topic. Important aspect of Earth History.

[@GEOGIRL]

Thanks so much! Glad you enjoyed it, it is certainly one of my favorite topics to research and discuss! ;D

[@junebegorra]

Yes! We are so phanerozoic-biased with everything. The world needs this.

[@GEOGIRL]

Agreed! :D

[@Svensk7119]

Huh?

[@mspicer3262]

I have an Emotional Support Trilobite, her name is Trillian. She may seem stone-cold, but she's got a heart of gold...

[@sarahrosen4985]

❤❤❤❤❤❤

[@GEOGIRL]

Yes! Gotta love trilobites :)

[@hdufort]

There should be a video about the end Ediacaran. Almost all complex lifeforms disappeared in a short amount of time. Then it took very long time (more than 20 million years) for new animal communities to form (basically the whole Terreneuvian).

[@georgefspicka5483]

Hi Geo Girl :) Awesome. Learning about all the extinction events Earth has experienced, is one of the things I like to work on. You've given me a bunch more to check out. I can hardly wait 'till you get to the Cenozoic Era. The first I want to learn more about is the Eocene-Oligocene Extinction Event, especially in relation to the several large meteorite impacts around this time, especially the Chesapeake Bay Bolide. Some think the Popigai impact structure in Siberia was a large, fragmented part of this bolide. It's the 4th largest crater on the planet. Another fragment is thought to have formed "Tom's Canyon", about a hundred miles east of Atlantic City, NJ. The Chesapeake Bay Crater is the largest impact crater in the U.S., covering an area twice the size of Rhode Island, and nearly as deep as the Grand Canyon. I still come across statements that claim Arizona's "Barringer Meteorite Crater" is the largest, like in Encyclopedia Britannica. However, the crater in Arizona is only about a mile across and 750 feet deep. Part of the issue may be that the Barringer Crater hit on land, while the Chesapeake Bay Bolide hit in the Atlantic Ocean, in an area that's now at the mouth of the Chesapeake Bay. Since it's underwater, a lot of people don't seem to know that it exists. Another interesting thing, Earth gradually got cooler after the impacts, until the beginning of the modern ice-age began about 2.5 mya. gfs p.s. Another event is the Mega Fauna Extinction, which in geologic time happened only yesterday :)

[@GEOGIRL]

I actually have videos about these events! Here's one on the PETM and following Eocene-Oligocene cooling: kzbin.info/www/bejne/e6KXdatjf7V1q6c, and here's one discussing geology of this time, including the Chesapeake Bay impact: kzbin.info/www/bejne/sJC0e2yho56he6M. I don't yet have a video on the extionctions that occurred during the PETM or Eocene-Oligocene cooling, though, so I will look into that for a future video! Thanks for the idea :D Edit: Oh I also have one about the megafauna extinction haha, it's in my pleistocene-holocene video: kzbin.info/www/bejne/Y4qqdWeMmNN-e7M

[@nw5524]

It's always nice to learn about the Tommotian fauna!

[@herbertkeithmiller]

When you're so well documented you run out of cards to link. 😊 When I was in the upper peninsula of Michigan I picked up an interesting looking rock because well who wouldn't. It had a black section with rust colored bands running through it below that was a layer of churt. When I got home I googled up red and black banded rock with layer of churt. Turns out my little find was a piece of the great oxidation event and it is called an iron banded rock. I find that imminently fascinating that the greatest environmental change the Earth is ever seen is represented by rust colored bands in black rock.

[@sydhenderson6753]

There was some sort of Ediacaran extinction and likely a couple associate with the Cryogenian glaciations. I'm not sure how much we know about the latter. I'm really glad you talked about the Cambrian extinctions. They stand out when you graph the events that killed off a large percentage of species but people treat them like Bruno. (We don't talk about Bruno.) By the way, I discovered last year that I had been mispronouncing Ediacaran for more than 20 years.

[@GEOGIRL]

Good! I feel less alone knowing I am not the only one who had been mispronouncing it lol ;)

[@barbaradurfee645]

Excellent video. The smart and thoughtful comments add so much!!

[@maozilla9149]

Fascinating video

[@francoislacombe9071]

Interesting fact. Oxygen is actually more intrinsically toxic to life than chlorine. If you expose anaerobes to oxygen and to chlorine, the ones in oxygen will die faster. At least, I seem to recall reading that somewhere, so I'm not 100% sure about it, so feel free to correct me if I'm wrong.

[@GEOGIRL]

So cool! It makes sense given how harmful oxygen radicals (intermediate compounds) can be to life! Aerobic life has enzymes that help break down the harmful forms of oxygen so we can use it safely. If life never evolved those enzymes we wouldn't be here! :)

[@robbabcock_]

Fascinating! It's interesting how life on Earth is at once fragile yet also resilient. There have been so many vast extinction events but life, uh, finds a way!😁

[@GEOGIRL]

Yes it does! ;D

[@Ozymandius_corn_maze]

Great video. I'm glad we aren't having to wait ten million years for the next one! lol

[@Svensk7119]

Well done, GEO G.! I expected the G.O.E. to have been left out completely! Well-Done! Usually when it is covered, folks say it took 99%plus of life, but since not only did multicells not yet exist, neither did eukaryotics. And you are correct. The fossil record from then.... stinks. I think your pronunciations are perfectly fine.

[@amirshay]

Fascinating, can’t wait for part 2🙌🏻

[@MrSiwat]

Wow! Your videos are fantastic. Thanks so much for the content.

[@GEOGIRL]

Thank you so much! ;D

[@Alberad08]

Thank you very much for providing this interesting video - and for reintroducing me to graptolites and tentaculitids which I have to research more about regarding more recent ideas & findings (which, at least at first glance, seem to be rather meager)! Already looking forward to the 2nd part. 🙂

[@jackthetford7558]

Enlightened concepts like this will bring interest to a largely misunderstood field. Wonderful!

[@wolframreactor74]

@GeoGirl you need to use the instrumental versions of The Ocean Collective discs Phanerozoic I and II. The songs are named after geologic eras/epochs in the timelines. The music and lyrics kind of match what life was doing in their time periods. Quiet interludes after crescendos represent extinctions… kind of Uber geo-geeky 😊 enjoy

[@michaeleisenberg7867]

Hi Rachel, at 6:37 you have an artist's rendition of early Cambrian. There appears to be green grass. You sent me to the internet. The internet says no on seagrasses & underwater plants in the early Cambrian?

[@philochristos]

Thank you for another interesting and informative video! I sometimes wonder what the world would be like if there were never any mass extinctions. I assume things would've continued to evolve, but maybe not as quickly. Maybe there wouldn't be quite as much diversity in life. I don't know, though. It would be interesting if you made some speculative alternate history type videos where you going into what might've happened if this or that major geological event hadn't happened or had happened another way. On the other hand, I guess that might change what your channel is really about. I'm going to go ask that What If guy.

[@GEOGIRL]

I think you are absolutely right, it would've gone slower and thus, would not be nearly as diverse or advanced today! I think we would have much more primitive life on Earth today if that were the case (so we wouldn't be here). But who knows for sure! :D

[@chrishofland2135]

Great cliff-hanger of an ending -- and that cliff has interesting strata!

[@GEOGIRL]

Hahaha! Exactly!

[@peterdore2572]

So much insight!

[@Beastclub679]

Vary nice video geo girl 💖👏👏

[@GEOGIRL]

Thank you! :)

[@Beastclub679]

@@GEOGIRL most welcome 😁✨

[@petersmythe6462]

There were certainly MANY, MANY precambrian mass extinctions that are just not well preserved. All the "and then Earth became a giant ball of ice" type events and giant impactors must have killed a lot of stuff.

[@Adam_First]

Great video. Wish you didn't split the content in two I'm outside my comfort zone having to go looking for it lol

[@williamhastie2772]

Great vid again Rachel.

[@GEOGIRL]

Thank you!

[@chrisk1944]

Very well presented, thank you. If we're doing pronunciations, note that "familiar" has no 'r' in it ;-) 06:45

[@tedetienne7639]

One of these days, you'll have such a library of excellent videos, half of any new video is going to consist of you referencing and linking to earlier videos!

[@GEOGIRL]

Yes! Haha especially with my earth history content, there is just so much! lol

[@acedes8689]

love to see paleontology channels, subscribed!

[@takashitamagawa5881]

A complicated story of extinction and re-emergence for fauna such as the trilobites and conodonts through the Paleozoic. Amazing what can be gleaned from paleo-chemistry and isotope analysis. Reconstructing ecosystems from hundreds of millions of years ago clearly doesn't just depend on the fossil record.

[@KAZVorpal]

Do you happen to know which of the secondary extinction events are still based on a narrow contemporary geographic region? In other words, at one time many of them were known from one region, where they were first identified, for example the eponymous era...Mississippi, Alberta, et cetera. Eventually they are often found elsewhere, but sometimes it was actually the same geographic region, separated by continental drift. The problem is that under those circumstances, it is a leap to assume a global extinction, instead of a local change.

[@stevenbaumann8692]

I'm glad you addresses the Paleoproterozoic extinction. There was at least one more. 1850 Ma the Sudbury impact. BIFs we're almost wiped out. There's one I may have found at about 1088 Ma. But it could be regional. I don't want to let the cat out of the bag on that one yet.

[@scottparker6664]

I’m literally studying life on earth and the big big mass extinctions this video will help come my exam lol

[@GEOGIRL]

So glad to hear that! Best of luck on your exam! :D Sounds like a fun class!

[@scottparker6664]

@@GEOGIRL yes I have it after Easter so will be watching this video along with your other videos on rocks as I got another exam on sedimentary and metamorphic rocks after Easter as well. I watched some of igneous rocks videos after Christmas to revise for my exam I had in January as well thanks

[@GEOGIRL]

@@scottparker6664 You are very welcome! So glad the videos have been helpful for you! ;D

[@oker59]

I think the mass extinctions are interesting from a Gaia theory perspective. Some mass extinctions are due to impacts; but appears that was only one mass extinction(during the multicellular life era - the last five hundred million years). So the rest could be considered almost like when Gaia is ill? Gaia has a fever?

[@1969kodiakbear]

Mass extinction. By the way, I have difficulty communicating because I had a stroke in Broca’s area, the part of the brain that controls speech. 2/8/2021 but I lived again. (My wife helped me compose this.)

[@stephenelberfeld8175]

What I tend to struggle with is what was living in the deep oceans, and what was living in the inland Seas. Also when considering sediments, would the deposition of volcanic ash cause extinctions or a fast flora and fauna recovery?

[@williamhastie2772]

Would or have you ever given a thought to doing remotes? One on one discussion with experts in a particular field at a museum or at interesting geological areas?

[@GEOGIRL]

Yes! Absolutely, I think once I graduate I'd love to incorporate more videos like that! :D

[@BenjaminT.Minkler]

so this makes me wonder if it is possible to have life without it always developing into a 'run away' mass extinction sooner than later(or is that just part of life, is the definition that "life" must always have a beginning and also an end)...and if there actually could really be a way to ever get it perfect? to like theoretically do the Noah's Arc thing with just the right balance of lifeforms that could stay in check to survive - or maybe I should ask: *what was the most successful life on Earth has ever been? going the longest without screwing it up themselves* the other thing I always think about is a "Goldie Locks" window of time; how you could come to Earth or any other planet, and the chances of it being 'just right' in that tiny moment of your visit is next to impossible ....and that we should feel really really lucky that we just oddly happen to BE HERE NOW, cause if time were to slip just a little forward or back, then not so much of a good thing for anyone or living thing at all

[@GEOGIRL]

Wow great questions! To the first one, I would say a couple things. One, life is not the thing that typically causes the extinction event (and if it is a trigger, it is typically a group that is not too heavily affected), so it isn't really about what kind of life was 'successful' enough to make it through a bunch of extinction events, it is more so what kind of life was 'lucky' enough to haha ;) And two, I would say the mots long-living group that still looks the same as it did in the Cambrian, that is it hasn't evolved much, but it's been through almost all the mass extinction events, is lingula brachiopods. This is a genus of brachiopods that looks like a finger nail. There are very few examples of animals that have evolved so little through so much time. However, I should mention that many bacteria and archea (microbial organisms) do have very primitive forms still living today. Many cyanobacteria themselves are very similar to those that first spread 3.5 billion years ago, so I mean sometimes something is so good it doesn't need changing ;) To the second question, I would'nt be so quick to say that given that we are in the beginning stages of a mass extinction and we've only been around for hundreds of thousands of yrs rather than millions haha. Yes, the past looks like it has been peppered with extinction events over and over again, but the interim periods, even though they don't look long when looking at this condensed timescale, lasted millions, typically tens of millions of years, even hundreds of millions of yrs in some cases! So I think we have actually been relatively unlucky to only get a few hundred thousand years before an extinction event begins... although it's not just luck this time because we are causing it, I guess it's karma lol ;) But I don't want to sound all doom and gloom, there's still a chance we can turn it around! ;D

[@nicholasmaude6906]

I'm surprised and disappointed that the trilobites didn't survive the Great Dying.

[@GEOGIRL]

Everyone is ;(

[@mikeandcammy]

Love your content! Engineering Geologist, FWB FL.

[@GEOGIRL]

Thanks so much! :D

[@shadeen3604]

Thanks geo girl

[@NewMexico1912]

Imagine the mass extinctions of microorganisms during the early Phanerozoic that we know nothing about. Undoubtedly there were mass die offs with the early microorganisms that aren’t documented in the fossil record. While the earths atmosphere and oceans were completely unstable. Similar to establishing a home aquarium. The reason you have to cycle a tank, before adding more complex life forms, is because the ecosystem within the tank goes through natural bacterial build ups and collapses before the system equalizes for more complex life to be able to thrive. For sure the earths oceans went through similar cycles, especially given much more complex variables like the constant evolution of the atmosphere, and weathering and chemical changes caused by continental crust, and life moving to land, etc…

[@davidrogers8030]

Don't know how much control you have over merch layout, but : couldn't find hat on site. Might need prompt to help identify t-shirt colours. Is $8 US shipping?

[@GEOGIRL]

Here's the more direct link to the hat: www.geogirlscience.com/merch/p/team-trilobite-baseball-hat You just have to pick the color you want, the one I am wearing here is the dark gray :) I do need to clean up the layout a bit, sorry about that! I will work on it! Also, standard shipping in the US is $3.99 for hats and another $2.00 if your order two. I do not control shipping prices, those are automatically set by printful (the storefront service I use) and they depend on the item, how many you are buying, and where it's being shipped to. Let me know if you are outside of the US and I can try and give you an estimate :)

[@davidrogers8030]

@@GEOGIRL Thank you. You shouldn't be attending to individual orders.

[@JohnMitchellCalif]

super interesting! Subscribed

[@GEOGIRL]

Thanks!

[@KarlBunker]

I love the hat! ... On you, that is; not sure if it would be right for me.

[@sent4dc]

What is isotope excursion?

[@stax6092]

Oh Good, I was like "Who the Hell is Miss. Penn and how'd she get a Mass extinction named after her?", glad that it was explained and not just left to my imagination.

[@GEOGIRL]

Hahaha Miss Penn, I love it lol!

[@heymikeyh9577]

My freshman college biology prof told us that it doesn’t matter how you pronounce technical terms as long as you do it loudly, confidently, and with no hint of self-doubt ;-)

[@GEOGIRL]

I love that! That's a good prof right there! haha ;)

[@TheaSvendsen]

What do you mean when you said that rocks hadn’t evolved yet? Have I gone all my life believing that rocks were always there (at least since the earth cooled down enough for the crust to solidify)…?? :-O

[@GEOGIRL]

Oh no, did I say that? If so, I didn't mean that haha. Rocks have been around since earth accreted ;) The only thing I can think of that I probably meant to say is that certain fossils or skeletonized animals or organisms hadn't evolved yet... Do you remember where in the video I say it? haha thanks!

[@chrisgriffiths2533]

Good Stuff. But this Highlights the Ocean Fossils Verses Land Life Fossils Problem.

[@AnnoyingNewsletters]

🎶We don't need no oxidation We don't need no oxygen Anaerobic in the darkness O2, leave those microbes alone 🎶

[@meesalikeu]

for cambrian changes in the ocean, upwelling and volcanos it makes me think maybe the earth was still getting hit by stray meteriods.

[@billkallas1762]

Good idea to cut the lecture in half. Most people have trouble turning their brain power up to 11, for 45 minutes.

[@petersmythe6462]

One wonders about mass extinctions that have taken place on other solar system objects. Venus in particular was probably far more comfortable before carbonate rocks released all their CO2, possibly in the best resurfacing event. If that is the case, Pre-Fortunian Venus could also have had life and therefore mass extinctions. Perhaps even complex multicellular life, as it would have been incapable of preventing the warming sun from dooming its planet.

[@petersmythe6462]

Unfortunately, my proposal to drill a gigantic column of rock out of the surface of the oldest Venusian rock we can find under lead-melting heat is unlikely to get anywhere.

[@kerriemckinstry-jett8625]

Awesome video! Now if we could just make sure that scientists who discover things have easy-to-pronounce names... 🤣

[@GEOGIRL]

YES!!! We need them at least to be less syllables! hahaha

[@kerriemckinstry-jett8625]

@@GEOGIRL *cough* *cough* Mohorovicic discontinuity...

[@rapauli]

Oh let's just call ours the "AnthropoCarbinacious"

[@JKTCGMV13]

💯

[@johnvl6358]

😎

[@nebulan]

"Spice event" sounds like something that would have happened in "Dune". Lip eruption sounds gross. (I'm sure geology classes have lots of puns.)

[@PraiseDog]

What happened to "Future Rachel". Oh, on the Earth spin one I suggested that Future Rachel wear a hat. So maybe that has something to do with the name change.

[@GEOGIRL]

Oh haha I forgot I called her future rachel before, I thought it was editing rachel, my bad haha! I did wear the hat due to your suggestion ;)

[@donkrapf]

Oxygenation, not oxidation.

[@GEOGIRL]

Both are correct :) The Great Oxidation Event is also sometimes called the Great Oxygenation Event. The meaning of the two words are different (oxygenation being the increase in oxygen and oxidation being the chemical reactions that resulted), but both occurred due to the increase in oxygen production by photosynthesis, so both can be used ;)

[@donkrapf]

​@@GEOGIRL Yes. Cyanobacteria oxygenated the sea water and the atmosphere. The oxygen then killed most of the anaerobic organisms by oxidizing parts of them.

[@peterkavanagh64]

If yhus period . Epoch ending is aiur current mqss extinction lif3 experiencing then lets log what is the windiows and most lijly bipedaks to ooenit walk its nit thet ledge its a eindow to the ground so you wek rmfugure it . Snd walk thorugh.. . Who is remindung thsy walking is evoovukiob and hmm.maybe the dig

[@DavidFMayerPhD]

Why do SMALLER animals survive mass extinctions far better than LARGER animals: Smaller animals exist in larger numbers than larger animals. Smaller animals reproduce faster than larger animals, that is, generation time is shorter. Smaller animals usually produce more offspring per generation. All of the above give smaller animals MORE VARIATION than larger animals, which gives them GREATER chance for survival in a changed environment.

[@GEOGIRL]

Absolutely, the more variation the better! I also think in some mass extinction events, smaller animals faired better because they could get away from the bad conditions by burrowing or climbing or in some cases flying. They also need less food and water to sustain their body mass compared to larger animals. :)

[@enckidoofalling2883]

Big 5 next!

[@ronpetticrew2936]

Ediacaran extinction not on the list

[@GEOGIRL]

A lot of them are hard to distinguish the magnitude of due to patchy fossil record and it's hard to say for sure if they were extinction events for this reason. The Ediacaran is an example of this, we are certain that many types of species were 'tested' in a sense and then went extinct, but there is a lot of mis-matched timing depending on the type of organism, which makes it hard to discern whether it was truly a global catastrophic event that caused global extinctions, or a biological catastrophe that took place in steps of local and regional extinctions throughout the Ediacaran. (Or at least that's how I was taught about that extinction, but I haven't read about it in a while, so there may be more recent findings that give a completely different story and make me completely wrong haha) Let me know if you know of any recent work on this one! I'd love to research it for a future video :D Thanks!

[@anthonymichaelwilson8401]

Our planet is very unstable, so we definitely don’t need wars

[@michaelbrodsky]

What about the extinction of low-rise jeans and return to 1970s hi-rise hippie pants? Huh? Huh? Nobody ever talks about that. There’s treachery afoot!

[@aaronfranklin324]

They don't talk about the Americas and Europe- North African ones 12900, 26000, and 39000 years ago much either. Or the 100kA one previously thought to be Toba that caused human, ostrich, elephant, Chimp, orangutans population bottlenecks to a few thousand individuals globally and many extinctions too. At this point in the last interglacial. To close to home and predictive of the current one huh?

[@TheDanEdwards]

"To close to home and predictive of the current one huh?" - she mentioned the ongoing extinction event near the beginning of the video.

[@GEOGIRL]

I think they were referring to the last interglacial period and the extinction of the large megafauna? As well as some other small Cenozoic and relatively recent extinctions? I am not familiar with all of them but I am assuming from the context they are not connected with the current one. I will have to look into them and see what I can find. Maybe I can find enough info for a future video :) Thanks for the inspo!

[@jeremychristopher6330]

Girl your very beautiful

[@vincentnieto7792]

This is the one of main reasons I watch her videos 😅

[@PhilEbel]

I am a retired geologist. I like your information, but I disagree with some of your chemical analysis. Analysis of the chemical content of rocks on the surface and their results are only open to suggestion.

[@rjlchristie]

Hi, your videos would benefit from adopting a more relaxed editing style. allow some air between the delivery of your sentences and ideas. There is no need to strip every millisecond of silence from the commentary when editing. Listen to and learn from the masters such as Attenborough. A non stop barrage of information can actually be very fatiguing for the viewers.

[@adamc1966]

...but Noah and his ark were supposed to save all living things...? 🤣🤣🤣🤣

[@Ken_Peartree]

All of these discussions of change here, increase there; but never why any of the changes occurred. This is just very poor attempts at guess-work. Absent a reason why conditions on earth changed, you are just making it up. Project Terrella

[@7inrain]

Oh, the irony. A deluded crackpot accusing science of making stuff up.

[@michaellimoges7655]

Pretty girl use big words, big words hurt brain, brain sleep now 😴

[@theaquarian5849]

Book of the Damned, look it up 👍