Precambrian Eon- Geologic & Biological Evolution 4 Billion Years Ago | GEO GIRL

[@stevenbaumann8692]

I stumbled upon your channel. Well done! I’ve always called it the Hay-Dee-in. But I’ve heard it called both. You keep doing this! I love it when young people are interested in geology. I like the continental pod analogy. We have no continental crust from 4.4Ga. I don’t know why your textbook says that. The oldest confirmed continental crust is only 3.8Ga. Plate Tectonics likely didn’t start until the late Archean, possibly not even until the very end of the Archean. TTGs, greenstone belts, etc. Some of the he zircons pulled from the Jack hills are over 4Ga. But they are detrital in much younger sediments the rocks the crystallized from are long gone. I think some textbook writers don’t differentiate the two.

[@GEOGIRL]

Wow thanks so much, I am so glad someone as knowledgeable as you appreciates what I am doing. I will keep going and keep trying to improve! Thank you for the info as well, I think my book mentioned that they based that statement off of zircon evidence but I don't have it in front of me right now so not exactly sure how they justified it. In any case, what you said makes total sense, thanks for setting that straight! :)

[@stevenbaumann8692]

@@GEOGIRL anytime. The Precambrian is my thing. There’s not a lot of us. Everyone likes big fossils but so much was going on in the Precambrian! I think some textbook writers don’t know the difference between a primary and detrital zircon. No ones perfect. It may not be their area

[@dmj4489]

Hey! Love this channel ❤️ the precambrian is just so mind blowing 🤯 like 90 percent of time. Doesn't that make you want to cry?? And then 2 billion years of evolution goes extinct😢 insane. I've had a passion for geology forever so finding these videos is so so cool! Your a great teacher, speaker and thinker! And super cute! 😊

[@isejanus2714]

Love your channel! I assumed it was pronounced like Hades, the Greek realm of the dead ruled by Hades the eponymous God of the same. We should ask Plato how to say it, if he isn't preoccupied with starring at the shadows on his his cave wall. I always assumed the oxidation events had to reach a threshold of O2 concentration to provide an energy benefit for evolution to kick in. I am also curious of the alignment of these continents on the globe. I have always assumed that the poles have always been frigid because their climate is dictated by the tilt if the earth's axis relative to the sun, hence pulses in extinction and evolution might be more easily be related to extreme cold rather variations of atmospheric gases.

[@brahmburgers]

Very good presentation and graphics. Thanks!

[@malsawmtluangisailo1055]

I have exam on Precambrian crustal evolution tomorrow and this is very helpful.

[@GEOGIRL]

Yay! So glad you found it helpful :D Good luck on your exam, you're gonna do great, I can feel it!

[@BillySugger1965]

Yeah Rachel, you were pronouncing Hadean correctly at the start. Stress on the first syllable. Named after Hades, (pr hay-dees).

[@robertbradley8309]

Excellent!! I have learned and reviewed stuff from my geology classes.

[@GEOGIRL]

So glad you found this video helpful! ;D

[@pgantioch8362]

Rachel: Starting ~3:42, ammonia is NH3, not NH4.

[@A31415]

Ha, just noticed it too

[@kokolanza7543]

omg, I'll have to watch this again, maybe get some basic literature to help get oriented. This is great. Thanks! I mean it's kind of hard to wrap my head around 4 billion years to 542 million years. The 2 or 3 oxidation events... How the heck does oxygent help give organisms more energy!?!?!

[@GEOGIRL]

I have a newer video answering that exact question! ;D Check it out here: kzbin.info/www/bejne/hYvcXqlmi8mkg9E Hope you enjoy!

[@rsdogra1595]

Thanks ma'am , watching from himalayas😊

[@mikelong9638]

I just looked at my junior year college textbook "History of the Earth" (1970). There are exactly 35 pages devoted to the Precambrian. That would be almost 90 % Earths history in 35 pages. 🙂

[@billkallas1762]

I have to add that my textbook from 1968 (Geological Evolution of North America) had 5 pages on it. I hope that the next 50 years equals the leap in knowledge that we've had in the last 50.

[@NullHand]

Like historical history, the further back you try to read, the fewer books (or rocks) there are.

[@ogrejd]

I know we should be grateful to cyanobacteria for making it possible for us to breathe, but it's really annoying when it shows up in this day and age and poisons lakes for a couple of weeks each summer in my area. :/

[@GEOGIRL]

Totally understandable! They are a blessing and a curse.

[@KerriEverlasting]

What happens to the lake when it gets cyanobacteria? Are there any experiments you can do with it?

[@thesjkexperience]

Blame the phosphates not the life.

[@CarminesRCTipsandTricks]

You've got it right at first... HAY-de-an, as in Hades, a Hellish existence. Don't let someone repronounce that too.... I'm still irked that har-ASS-ment became HARRIS-ment, because a select few in the 1970's decided to change the pronunciation!! 🤬 Off the Soapbox, this was a fascinating Lecture! Like all of your Lectures. The beginning of EVERYTHING is always fascinating!! 💯 The "Great Oxygenation Event" was HUGE! (Unless you were Anoxic life forms, then it sucked!!)

[@surajdaslaskar6873]

Your explanation is very good..and easy to understand...I am from India🙏🙏

[@GEOGIRL]

Yay! So glad to hear that, thank you! :D

[@anticorncob6]

I also had the same issue with how to pronounce "Hadean". I also pronounced Archean with the stress on the first syllable, before I heard anyone say it aloud. Took a while to get used to the correct pronunciation. And I also pronounce "ediacaran" different from you!

[@GEOGIRL]

Haha I know right, I wish I could press a button every time I read a word that would say it aloud lol. I think you are correct when it comes to ediacaran, I say it differently (I think correctly) now in my more recent videos, but in this one and other old ones I said it incorrectly (based on listening to other scientists at conferences say it lol) ;)

[@wafikiri_]

At 4:32, a picture of Earth's plate tectonics is shown that does not correspond to the Hadean eon being talked about but to present time. It is only the general plate tectonics mechanism that should be considered by viewers, not its geographical morphology.

[@GEOGIRL]

Yes, I used that diagram of the modern scenario to show the increasing ages of oceanic plates further away for the mid ocean ridges because I think it gets the point across about how mid ocean ridges form crust, but I realize it is not representative of the scenario that would've been present on Hadean Earth. If I had an equivalenet diagram for early earth, trust me I would've used it! haha ;)

[@wafikiri_]

@@GEOGIRL I know you would, but I'm sure it would probably be a highly speculative scenario depiction. You did well.

[@sparkyfromel]

Walked in Shark bay in western Australia , the stromatolites there are the direct decedents of the pre-cambrian life , un-evolved and still going strong !

[@billkallas1762]

Where I live, I have a few hundred feet of Glacial Till on top of Silurian limestone. I live quite close to the 280 million year old "DesPlaines Disturbance", an 8 km diameter impact crater.

[@GEOGIRL]

Woah!! That is SO COOL!!

[@bradleynorton3365]

Thanks!

[@GEOGIRL]

Thank you! ;D

[@muhammadabbas4838]

Lecture and lecturer both are beautiful

[@RoyCoffee-w5b]

It's very interesting. Chemosynthesizing had a head start on life creation even before the earth had a breathable atmosphere, or so it seems. It was a slow uphill process to get what we have-4.5 billion. Give humans 3 or 4 centuries, and we'll make it into a Mars-like world.

[@MrGuzmanra]

Why were there no more "snowball" earths after 600Ma?

[@GEOGIRL]

Wow, what a great question! If I had to guess I would say that the ice ages after 600 Ma were less intense because the feedbacks (factors controlling how cold it could get before it had to get warmer) were stronger. For example, life became dominant in both the ocean and on land around this time, which made climate trends more 'buffered' if you will. For example, the current warming trend is buffered by trees and phytoplankton in the ocean that take up CO2 (if those weren't around the trend would get out of control much quicker). Same thing happens with cooling trends, if the earth was cooling after 600 Ma, the living organisms that breathed out CO2 would help buffer that trend. Moreover, the sun's radiation was much less intense before 600 Ma, which is one of the reasons we had the major snowball earth events on early earth and I talk about it in the snowball earth video: kzbin.info/www/bejne/g6u8qmyYer-hmNk :)

[@MrGuzmanra]

@@GEOGIRL sorry for all the questions. But I'm so curious. When did the ice ages begin after the kt boundary? And why then?

[@GEOGIRL]

@@MrGuzmanra At or after the KT boundary? At the KT boundary, any cooling trend was likely caused by ash that was sent up into the atmosphere by the volcanic activity that resulted from the asteroid impact. which I talk about in the extinction video: kzbin.info/www/bejne/m5-zgnhmocqigNk. After the KT boundary the next major glaciations were relatively recent (in the late tertiary/quaternary) and I talk about these in the Holocene epoch video if you wanna check it out: kzbin.info/www/bejne/Y4qqdWeMmNN-e7M. And no need to apologize for the questions! I love them because I don't know all the answers so it inspires me to look into it as well :D Keep 'em coming!

[@mortkebab2849]

Perhaps because the Sun has steadily become more luminous.

[@JasonKale]

@@GEOGIRL I have often wondered since as you mention the Suns radiation was less intense 600 MA years ago. Could the types of frequencies, temps, Type of radiation, solar flare activity etc any solar output change have a direct impact on the DNA or just fluctuations in general. We have particles coming from the sun this second passing through us. Ive seen Astronauts are having DNA damaged while in space. Could their be specific settings of the sun that actually trigger the DNA to make changes in a positive way. I wooly Mammoth wasnt an elephant one day and say to itself I need to grow hair to stay warm. For things like that to be an advantage one would think the DNA would need time to make the changes for future conditions. We know the cold cycles on earth are often caused by changes in the Earths orbit around the sun. So where would the DNA get the original instructions if not completely random and just work...I think ive seen when we think life on earth started the Sun was not like today? My thought is more along the lines of the Change in frequency or what wed consider the sound coming form the sun i assume it has changed over time depending on amount of solar output.

[@JasonKale]

@16:00 Why it took for so long for life to explode? I cant help but think What Robert Penrose thinks about the Universe and it being a sort of clock and his theories that the Universe will not be able to keep time once its too large. Is it possible All life functions on some sort of inherent Genetic or universal clock that is built into the the laws of the universe from its inception that we are not aware of as of yet? Obviously since there is life on this Planet, we clearly know the universe has inherent rules of physics and chemistry that life does and will evolve with as we know a Certain size and type of Star and Earth like conditions. I am aware Human like species are often dated From DNA based on what we believe the time it takes for Genetic changes to occur. So, once there was abundant oxygen and life forms to utilized it could the timing of the DNA just move way slower in Humans time scales.? A few Billion years is really nothing in the 13.8 Billion years we think the Universe existed and for the Billions more the universe should continue to exist. We should almost think of the Time frame of life not solely based on the time Scales the Planet Earth provides but in the time scales of the universe as a whole?

[@GEOGIRL]

Ah, it is funny that you mention some sort of 'genetic clock' because there is actually something called the molecular clock that estimates a similar thing to what your describing, the time required for genetic mutations to occur in certain species, aka the time required for certain species to evolve. These times for life on Earth, however, are much shorter than billions of years (they are definitely on the scale of thousands to millions of years, even for the life that eventually did evolve after the boring billion period that I talk about here, the period in between oxidation events), so it's pretty clear and well established that the reason complex life didn't evolve until the Neoproterozoic is the lack of oxygen even after the GOE. But I am very impressed that you thought of the molecular clock idea because it is actually a real thing and you are absolutely right that it is something that we have to take into account when estimating when things should've evolved in Earth's history. :)

[@JasonKale]

@@GEOGIRL We need a diagram of the genetic clock in time scales of the universe it self or time scales of our solar system.

[@GEOGIRL]

@@JasonKale Yea, and it would be really cool to compare molecular clocks across different planets/moons with life! But that will have to wait until we find that life haha It's so frusterating having Earth be the only data point for life in the universe. Can't wait til we have at least ONE more!! :D

[@JasonKale]

@@GEOGIRL HAHA I had the same thought how much easier this all would be if we could observe a protoEarth But then wed have to position some sort of satellite for Billions of years...haha. I also wonder what Quantum Physics has to say about all of this? Because all the Rules that make up the Quantum like Quarks making protons and the amount of protons thus making the elements. If we literally dig deeper into the Quantum are we going to find something that initiated the molecules as we now know them to form life? There are obviously rules in place even at the Quantum level for any biological life to exist at all and all those rules must have been in place when the universe itself began. I hope this makes sense as I am not a scientist..haha

[@GEOGIRL]

@@JasonKale What an interesting thought! My general assumption is that all the elements and molecules that make up life had to come together in a certain way to make life possible, but by that point everything that was coming together to do that was already of molecular size (so larger than quantum), but it is interesting to think about how quantum mechanics could've played a role in both helping and hindering the origin of life. I'm sure that people have looked into the relative roles that molecular and quantum physics played in the origin of life, but I'm not a quantum physicist by any means so I wouldn't know how to interpret it haha. But it's fun to think about for sure! Also, I would say with how much curiousity you have and the questions you are asking that you are a scientist haha, actually that all humans are scientists at some level! ;)

[@DavidFMayerPhD]

Magnesium is NOT a heavy (dense) element, having a density of only 1.738 compared to iron with density of 7.874 NH4 (ammonium) is not a gas, but a positive ion. NH3 is ammonia, a gas.

[@krisvandyck9738]

I wonder what role the moon played in the origin of plate tectonics. It never comes up in any video, but surely the moons gravity at the time must have had an enormous impact on the earth's crust and the liquid mantel. I'm not a scientist and don't have a degree in anything related.

[@acefire4050]

I remember when those things were real tiny before they formed up into great big rocks.

[@thesjkexperience]

Don’t worry too much about pronunciation. Geology is international and with everyone’s different accents it comes out a bit differently.

[@GEOGIRL]

Wow, thank you, you have no idea how nice it is to hear this! ;)

[@thesjkexperience]

@@GEOGIRL you are talking to people who love rocks. We are forgiving and kind. We gotta stick together 😻

[@MarcusHalberstramVP]

She’s very sweet.

[@ILikeMyYT123]

I'm always intrigued by women/girls who are both very smart AND very pretty, like you, just as I'm intrigued by nature and science. 🧐

[@GEOGIRL]

Thanks so much for the sweet comment! I am so grateful to be able to represent women in stem on KZbin :D I hope more and more continue to join and share their knowledge through KZbin and similar platforms :)

[@KerriEverlasting]

@@GEOGIRL I like how you put in so much effort and work hard to share your enthusiasm. No one is smart without work and pretty is never our fault. Lol 💖

[@Jemalahmed-qf7lu]

First I appreciate you lecture thanks But sister, I wanna ask you questions, and it goes like this .... As you know, our knowledge of events is limited, so there must be superpowerful who is controlling this . So we can't say God is not exist My dear sister I am calling you form my heart to the religio of logic and scientific fact. islam You can wach the videos of dr zakir naik on science and quran If you don't follow the last revelation, almighty will put you in hill fire when you die. Please accept islam 😢