Hi all! Around 5:30 we said "Average temperatures for the entire planet hovered around 30 degrees C in the early Devonian, which is twice as high as the current average," when we should've said, "Average temperatures for the entire planet hovered around 30 degrees C in the early Devonian, while today, they're around 15 C." Thanks to those who have pointed this out!
@UCWWV3b8YSDXQweAeI5DMzbQ people were comparing it to absolute 0, so 30C isn't twice 15C when you compare to that. However it is twice as far from the freezing temperature of water at 1 Atmosphere, so they were still correct considering what they used as a measurement (C versus K).
What really gets me is that there was a short period where forests existed but trees with megaphylls didn't yet. So you would just have giant, leafless plants. The middle Devonian is super weird and super underrated.
@@sophiejones3554 No, the Cladoxylopsids genuinely had no leaves. And then eventually evolved megaphylls to become the Progymnosperms and then eventually Gymnosperms. The Lycopsids however were trees with microphylls.
Lycopsid diversity had a huge headstart over that of the euphyllophytes. With the topic here being the rise of the megaphyll, it really can't emphasize the point that for tens of millions of years, lycopsids dominated the forest skylines from the upper Famennian stage to the mid Carboniferous. It could have very well been in excess of 40 million years. Around the time the first forests appear in the fossil record, lycopsids had a beyond significant majority of the vascular biodiversity over the combined monilophytes and progymnosperms. It is hard for most people to conceive, because we have an aborescent view that is modern angiosperm and modern gymnosperm centric. To many people, those forests might as well be artists' conceptions of exoplanet life.
It's also worth noting that RuBisCo, a core enzyme of photosynthesis, has one of the worst enzymatic reaction rates of any enzyme known, and somewhere around 30°c starts running in reverse (binds O2 and cause a reaction chain that releases CO2). Standard 'C3' photosynthesising plants rely solely on it, whilst many desert and tropical plants use 'C4' photosynthesis or CAM photosynthesis to avoid RuBisCo's crapiness.
It's also worth noting that while C4 and CAM have evolved multiple times, all known examples are recent evolution. Not hundreds of millions of years back.
@@IainG10 From my understanding they evolved alongside/as an arms race, with large grazers, so same period as they were evolving, but I"m not sure if that was really the connection, or if the drier environment of that time was what was spurring on both herbivores & grasses/c4's to evolve
So, plants with big leaves are better at cooling off in hot environments. Is that part of the reason why conifers, which tend to grow in colder places, tend towards small needles instead?
@@selenaichtis6762 Their isn't they or them. It's a possessive pronoun and is neutral in gender and isn't referring to Michelle, but to both Michelle and Eons.
I know it's slightly out of topic for this video, but fungi deserve a huge shout-out here! When it was mentioned that early plants didn't have roots that's because fungi were already on land providing that role. It was fungal networks of mycelium that broke down rocks, releasing those minerals for plants and producing the first soils together. It was only when encountering areas where fungi weren't supplying the usual sustainence that it became evolutionarily advantageous for plants to develop their own root systems, mirroring those that the fungi provided. Even today it's more accurate to say that mycelium networks in forest floors are the farmers of the plants and trees above than it is to think of the plants as using the networks for transit. Both are true, but if the network decides to limit a particular tree's uptake there's not too many options it has to get around it. The network benefits from as many healthy partners as it can farm though, so will often do so only for the overall health of the forest, and only until there is once again enough to go around.
Let’s learn about grass next! I’ve always been interested in the fact that there was no grass on the ground until much later in time. And now it’s overtaking everywhere
@@griff4d7 there were ground cover plants. Part of what makes grass weird is that it is high silica (i believe) which makes it 'gritty' which makes it harder to digest and so has an advantage.
@@sarahgargani5836 Yes, it is difficult for herbivores to eat and digest it, so when early grasses began, they had an advantage in NOT being eaten as much. Then as they "gained ground" (Ah ha ha ha!) the herbivores had to evolve to EAT or go extinct. But by that time, grasses had a large head start. Now the herbivores that DO eat grasses can not sustain themselves on the NON grasses as well.
Yeah I just planted 2 of them, hope I will see them big before I die, they were there before the dinosaurs and after my death. It somehow makes me happy
It's so interesting how every single thing is what it is for an specific reason, not because we wonder why things are different like leaves being different colors or why something grows somewhere only, it's amazing
It always gets me how long live took to move onto land. Life on Earth = 4 Billion years. Life on Land = 470 Million years. That gap is just so enormous.
Before avocado trees grow bark they have photosynthetic stems. Theyll also drop all their leaves if they get even a little stressed. I wonder if avocado revert to being more like an early plant when stressed
No, they drop their leaves because they go into a "save resources" phase, maintaining the leaves could take too much energy. If they have a well established root system they can store energy for a fast recovery when the situation improves. Don't quote me though, I'm just applying common sense and have not done research on Avocado plants specifically.
I'd love to see more vivid representations of how these eras changed things. Early plants making rocks into soil, how the first forests must have looked, to how plants and fruits may have looked way in the past.
One question I've had about plant evolution for a long time is how often different forms of photosynthesis convergently evolved in different plant taxa. There are three different methods of photosynthesis known today: C3, C4, and CAM, and all evolved in many unrelated groups of angiosperms at different points in history. So if multiple forms of photosynthesis have appeared so often in just the 66 million years of the Cenozoic, then did these forms also convergently evolve in gymnosperms during the Mesozoic? After all, gymnosperms filled many of the niches that angiosperms fill nowadays in environments where C4 or CAM photosynthesis are prevalent so it's hard to believe that they simply struggled with C3 in unfavorable environments for it at all times. The idea of C4 and CAM gymnosperms before angiosperms seems evolutionarly plausible and has always fascinated me, though I'm not certain how that can be proven through the fossil record.
@@stefanostokatlidis4861 I think you are misinterpreting something by linking two seemingly similar facts together. C4 and CAM photosynthesis are adaptations for arid environments to prevent massive water loss and photorespiration. Neither of these photosynthesis methods occur in habitats with a reliable water supply, where the negative side effects of C3 photosynthesis are negated by the speed and low ATP cost to convert as much CO2 to glucose as fast and cheap as possible. Isoetes as a whole classification are restricted to watery habitats and are so primitive that they lack basic leaf anatomy that is fundamental to either C4 or CAM, so your claim is biologically impossible. I think you are mixing up the fact that isoetes have no stomata with the fact that CAM plants actively open and close their stomata based on the time of day and are concluding that the lack of air holes in a quillwort leaf must therefore make it a CAM photosynthesizer, which is simply not the case.
When showing massive drops/increases in CO2 it would be wise to state exactly how long that took. I'm a teacher and if I put two graphs with wildly different scales on them a fairly high percentage of students will still make direct comparisons between them even if they are magnitudes of order off. Showing CO2 levels rapidly changing over millions of years without stating it is an invitation for less informed to think that it's comparable to the changes that we are currently making.
In the past change of 0.01 ppm CO2 per year was "fast". It accumulated over 10 of millions of years to create a huge drop or rise. Nowadays the change is 2-2.5 ppm per year
Less informed person reporting: Could you explain to me why said changes are not comparable? I'd like to educate myself on the subject. I'm also wondering about the causality between rising global average temperatures and increasing CO2 levels. As a laymen i can't seem to find well documented research on the subject.
@@marcmorel7246 CO2 levels change 10 - 1,000 times slower in geologic time than they are currently changing, this is why it's not comparable and there would be no way to mistake an artificial process for a natural one. CO2 can absorb outgoing long wave infrared radiation, thus effectively "trapping" its energy in the atmosphere instead of allowing it to escape to space. Since most CO2 is near the surface, increasing CO2 levels heat up the troposphere near the surface but cool the stratosphere (because there's less outgoing infrared to heat it). Some might tell you that the absorption bands of CO2 (where its vibrations match infrared wave length) are saturated and thus increasing it wouldn't heat the atmosphere, but absorption bands become broader when there's more of a given molecule. So each doubling of CO2 is less effective as the previous doubling but it still leads to more heat until the point whre Rayleigh scattering overwhelms the effect of any remaining band broadening and more CO2 would cool instead of warm the surface. (That also means Venus's atmosphere is actually overdense and the planet would be hotter if it were thinner, interestingly enough).
I would like it if you somehow chronologicalise all the ages & how they ended & their special features in a series. But that would be a huge undertaking i feel
I love that you make episodes about stuff I never would have thought about. I knew plants had stomata but how and why they came about and how they affected the Earth was a question I never thought to ask. I had paid so much attention to the changes they created by emitting oxygen as a by-product that other ways they modified the Earth kind of slipped by my consciousness. Thanks for this new window of exploration for me, I'm going to be busy finding more vids about this.
I'd love to see a whole series just about ancient plants. Also I really enjoy your presentation style. Very laid back and pleasant. Still the best channel on UA-cam.
Hey, really excellent. I had a plant phys professor in the 70s tell us he thought that the carboniferous was an era of high carbon dioxide. I couldn’t agree with him because I (the entomology major) knew about the giant insects of this period and how they worked. This video finally puts it all together for me, thanks.
I'm sorry for the following nitpick 2:30 light isn't converted into sugar; the energy captured from light is quintessential in stimulating the chemical process through which sugar is formed. It's just words of course, but there might be people that just don't know better and assume much more silly conclusions without an appropriate context (and I'm not even completely aware of the chemical elements involved in at least a few plants to be this much of an ass about this; right now I'm assuming there might be more than one variation of possible molecule recipes involved in the formation of, essentially, plant food).
The Carboniferous Period really made big impact on everything. All that carbon being stored in those trees has had such a drastic effect on the whole world.
Stating that a temperature was 'twice as high' only makes sense if you're working in Kelvins, twice the value in any other scale doesn't mean twice as much energy
This is true from an absolute zero perspective, but 0C and 0F are also a measure of something. Twice as far from 0C would mean twice as much energy from freezing which is still a useful measure. Same with 0F although that is more abstract.
@@wadeinn463 If you are measuring from 0C the answer is 0C. If you are measuring from 0K, then it would be 273C. I was just saying that comparing percentages of temperature in measures other than a base in absolute 0 still mean something, they just have a relationship with something else (in C it is the freezing temperature of water at 1 Atmosphere)
This presenter is absolutely phenomenal! I feel like she is telling me a story that I really want to pay attention to because of the enthusiasm she brings to the script. Just perfect! Thanks for your excellence!
Microphylls are not limited in length by any means, but width. Many modern pine needles are effectively microphylls and lycophyte tree microphylls were very long
There really needs to be an episode discussing the late emergence of primary endosymbiosis that had led to eukaryotes. I'm personally a supporter of the oxtox model and would love to hear their thoughts.
" So it was basically impossible for plants to produce large leafs until CO2 levels fell. " If I understood correctly, they COULD have IF the temperature had been lower. Of course lower CO2 helps cooler temps (but earth could also have been cooler for other reasons). E.g. from my undertsanding, it's more the temperature, ultimately, that held back the larger leafs, even though those would have been useful for breathing.
In desert climates there's a Palo Verde tree. It has a green trunk and tiny leaves. I showed it to someone in Toronto where tree leaves are big. They asked if it was a dead tree. Mesquite has the same type of leaves.
could yall do a series on moss please :) i think that would be an interesting topic and people on youtube never really get into the deeper information on it
I think it takes a lot of practice to turn your brain off to that extent. They usually let slip very quickly that they don't know what evolution is; which probably helps.
The incredible complexity of the topic matter wowed me. So cacbon dioxide is coupled to global temperature, and number of stomata is both coupled to CO2 concentration and temperature. But stomata amount is also related to water loss, which in turn must be controlled with respect to water gain, and THAT is then related to the evolution of powerful vascular systems. So in the Devonian there was barely any megaphylls, and if there were they were tiny. It was almost all Lycolytes with their microphylls. Decrease in the CO2 concentration came with corresponding drops in temperature, causing the Devonian-Cacboniferous ice ages, and so allowed megaphylls to not overheat, ALONG WITH vascular innovation allowing more stomata to be opened without the plant drying up. So, the Carboniferous is the age of megaphylls, with the spotlight shining on ferns. And, oh the CO2 decrease is caused by the land plants themselves, BUT not in the way you'd think. Instead it was a convoluted cause-and-effect chain involving roots breaking down barren mineral rocks starting from the Ordovician, and oceanic algea eating them, AND THEN it was the algea which actually absorbed the CO2. Props to Eons for somehow being able to express all this in about 10 minutes. Wow.
It's always depressing seeing you make a perfect well organised essay on a topic every week when I can't write anything in more than 10 pages even if you give me 6 months. Interesting topic as always !
86C is not twice as high as 43C. It's more like 14% higher because 86 and 43C are actually 359 and 316K. Stop using proportions to describe temperature relationships unless you take into account the full temperature scale down to zero K.
@@at1the1beginning wrong, at least according to this channel, they have a video about how fungi were the first to colonise the land, growing huge, tree like structures & breaking down rocks, well before plants had evolved the ability to leave the water
Tfw as a plant you not only provided the oceans with nutrients but also accidentally caused algal blooms and reduced oxygen levels that could've pressured some groups of lobe finned fish to adapt to their low-oxygen environments by starting to adapt to partially relying on atmospheric oxygen intake at the surface (Via gulping air).
This channel takes me back million years back every time I see their video. I always wanted to feel how the world would have been back then. Thank you so much for these videos and i get know more about evolution too ❤
Please don’t say the temperatures “were twice as high as the current average”! That only works for the Celsius scale. In Kelvin, a real doubling would be 300C! Love the videos… they’re so well pitched.
@@antoniousai1989 OP is right though? 30°C isn't "twice as high as" 15°C. You can only make a statement like this if on the scale you use zero actually means zero, which is the case for Kelvin but nor for °C and °F.
@@antoniousai1989 Sure, but that is completly besides the point. "Half as hot" as 30°C is not 15°C, it's -111°C. The average temperature on earth today is not -111°C.
8:00 I think is supposed to read: "until the temperature decreased" not: "CO2 levels fell". As large leaves are still very possible and likely, in high C02 environments
Also during the carboniferous age there weren't any organisms that could decompose or eat wood. Keeping the carbon in the soil. Nowadays we have lots of fungi and animals that can eat it.
After watching this videos, it leaves me more questions than answers. But surely it sheds a lot more light about natural history of plants. I hope this channel will grow even more informative in the future.
Can I just say that I LOVE YOUR SEPTUM PIERCING! Thank you, PBS, for letting your staff express their individuality in ways most workplaces are arbitrarily against, it makes the content they appear in feel more authentic and shows how awesome of a place PBS probably is, to work at/for.
I would like a video on the evolution of plastids. I know that most organisms, including all plants and algae, ultimately acquired their plastids from the same endosymbiotic event. But evolution has made these diverge considerably over time, including the chlorophyll pigments used (and thus the color). More interestingly, the genus _Paulinella _ and the species _ Pseudoblepharisma tenue_ both had unrelated endosymbiotic events in their histories, acquiring an unrelated cyanobacterium and a purple bacterium, respectively. Finally, the diatom family _Rhopalodiaceae_ has acquired non-photosynthetic cyanobacteria, though it's not clear what advantage they provide.
"around 30 degrees Celsius in the early Devonian, which is twice as high as the current average." -- No, that's not how temperatures work. The scale doesn't start at zero (unless you're working in Kelvin).
30C temperature is NOT twice as high as 15C. Numerically yes, but real temperature/energy is measured from Absolute Zero: -273C. Therefore, the energy involved only increased by about 5%.
30 Celsius is emphatically _not_ twice as hot as 15 Celsius, just twice as far from the melting point of water. Earth's present average temperature of 288 Kelvins doubled would be 576 K, hot enough to melt Tin and Bismuth and almost hot enough to melt lead
m Are plants sentient? We know they sense their environments to a significant degree; like animals, they can “see” light, as a New Scientist feature explains. They “live in a very tactile world,” have a sense of smell, respond to sound, and use taste to “sense danger and drought and even to recognize relatives
Me looking at the leaves of the coccoloba tree pictured: idk they don't look that big Conversion the corner: 2 meters is about 8 and a half feet long Me: OH. OK. THEYRE BIGGER THAN PEOPLE. COOL. COOL COOL COOL COOL COOL
Hi all! Around 5:30 we said "Average temperatures for the entire planet hovered around 30 degrees C in the early Devonian, which is twice as high as the current average," when we should've said, "Average temperatures for the entire planet hovered around 30 degrees C in the early Devonian, while today, they're around 15 C." Thanks to those who have pointed this out!
So... Why was the former a mistake?
You can put in the degree symbol using Alt+0176 as in 30° C.
@UCWWV3b8YSDXQweAeI5DMzbQ people were comparing it to absolute 0, so 30C isn't twice 15C when you compare to that. However it is twice as far from the freezing temperature of water at 1 Atmosphere, so they were still correct considering what they used as a measurement (C versus K).
@@AryadiSubagio Yes, isn't 30° C is twice as high as 15° C?
Understood
Yes, make a series about plant evolution!!!
Yeah
Yeah
Plsss
Botany!
And mashrum evolution
What really gets me is that there was a short period where forests existed but trees with megaphylls didn't yet. So you would just have giant, leafless plants. The middle Devonian is super weird and super underrated.
well the trees would have had microphyll leaves: so think of a modern conifer forest.
@@sophiejones3554 No, the Cladoxylopsids genuinely had no leaves. And then eventually evolved megaphylls to become the Progymnosperms and then eventually Gymnosperms. The Lycopsids however were trees with microphylls.
I would love to be able to visit a Devonian forest.
“The middle Devonian is super weird and super underrated.” Is just 👌 yes.
Lycopsid diversity had a huge headstart over that of the euphyllophytes. With the topic here being the rise of the megaphyll, it really can't emphasize the point that for tens of millions of years, lycopsids dominated the forest skylines from the upper Famennian stage to the mid Carboniferous. It could have very well been in excess of 40 million years. Around the time the first forests appear in the fossil record, lycopsids had a beyond significant majority of the vascular biodiversity over the combined monilophytes and progymnosperms.
It is hard for most people to conceive, because we have an aborescent view that is modern angiosperm and modern gymnosperm centric. To many people, those forests might as well be artists' conceptions of exoplanet life.
It's also worth noting that RuBisCo, a core enzyme of photosynthesis, has one of the worst enzymatic reaction rates of any enzyme known, and somewhere around 30°c starts running in reverse (binds O2 and cause a reaction chain that releases CO2). Standard 'C3' photosynthesising plants rely solely on it, whilst many desert and tropical plants use 'C4' photosynthesis or CAM photosynthesis to avoid RuBisCo's crapiness.
yes, very interesting point :)
It's also worth noting that while C4 and CAM have evolved multiple times, all known examples are recent evolution. Not hundreds of millions of years back.
@@petersmythe6462 I was wondering about that; my biochemistry course covered their existence but not their history.
@@IainG10 From my understanding they evolved alongside/as an arms race, with large grazers, so same period as they were evolving, but I"m not sure if that was really the connection, or if the drier environment of that time was what was spurring on both herbivores & grasses/c4's to evolve
If anybody has any book recommendations on this I would be really thankful
So, plants with big leaves are better at cooling off in hot environments. Is that part of the reason why conifers, which tend to grow in colder places, tend towards small needles instead?
More than likely
I think a study on why conifers tend to grow in colder regions would be interesting to read, or watch.
Conifers in tropical climates even have bigger leaves. The agathis genus has round angiosperm looking leaves....
Plants evolved leaves so that heat could leave.
It partly is to reduce surface area to prevent frezeing of water in the plant
Props to the paleobotanists for working this all out. And to eons for sharing it. And! Michelle for their awesome presentation (:
wait, Michelle uses they/them pronouns or you just don't want to assume?
It's a pleasure to listen to
@@selenaichtis6762 better safe than sorry
@@selenaichtis6762 Their isn't they or them. It's a possessive pronoun and is neutral in gender and isn't referring to Michelle, but to both Michelle and Eons.
@@selenaichtis6762 the first option.
I know it's slightly out of topic for this video, but fungi deserve a huge shout-out here! When it was mentioned that early plants didn't have roots that's because fungi were already on land providing that role. It was fungal networks of mycelium that broke down rocks, releasing those minerals for plants and producing the first soils together.
It was only when encountering areas where fungi weren't supplying the usual sustainence that it became evolutionarily advantageous for plants to develop their own root systems, mirroring those that the fungi provided. Even today it's more accurate to say that mycelium networks in forest floors are the farmers of the plants and trees above than it is to think of the plants as using the networks for transit. Both are true, but if the network decides to limit a particular tree's uptake there's not too many options it has to get around it. The network benefits from as many healthy partners as it can farm though, so will often do so only for the overall health of the forest, and only until there is once again enough to go around.
How the heck did we figure out that they do this?! Wow.
@@slwrabbits Science!
They did a video on this once. Really cool!
I found it strange they said algae broke down the rocks, i knew it mustve been fungi, or atleast lichen
Let’s learn about grass next! I’ve always been interested in the fact that there was no grass on the ground until much later in time. And now it’s overtaking everywhere
Huh, I’ve never even thought about that, but it’s an excellent point and now I wanna hear about it as well. Was the ground just sand and mud?
@@griff4d7 there were ground cover plants. Part of what makes grass weird is that it is high silica (i believe) which makes it 'gritty' which makes it harder to digest and so has an advantage.
@@sarahgargani5836 Yes, it is difficult for herbivores to eat and digest it, so when early grasses began, they had an advantage in NOT being eaten as much. Then as they "gained ground" (Ah ha ha ha!) the herbivores had to evolve to EAT or go extinct. But by that time, grasses had a large head start. Now the herbivores that DO eat grasses can not sustain themselves on the NON grasses as well.
Poe’s law
@@isidoreaerys8745 don’t know what that is but cool
Please make another plant episode centered around ginkgo biloba trees and their unique "retro" leaf design!
it’s kinda wild to me that it’s the only species left of its entire order
Yeah I just planted 2 of them, hope I will see them big before I die, they were there before the dinosaurs and after my death. It somehow makes me happy
@@shadycactus6146 k
Oh great! Now whenever someone says "Leaf me alone!" I'm gonna have to ask them, "What's stomata with you?"
I wish I could give this at least 11 thumbs up.
"I'm bushed!"
How did you come up with this? Lol
It's so interesting how every single thing is what it is for an specific reason, not because we wonder why things are different like leaves being different colors or why something grows somewhere only, it's amazing
It always gets me how long live took to move onto land. Life on Earth = 4 Billion years. Life on Land = 470 Million years. That gap is just so enormous.
So interesting. I’d love to see more content on prehistoric plants!
PBS Eons is the best part of today's PBS neatly packed in a wonderful little channel. thank you!
Before avocado trees grow bark they have photosynthetic stems. Theyll also drop all their leaves if they get even a little stressed. I wonder if avocado revert to being more like an early plant when stressed
Uhh, what? o.O
I know that I do that when I'm stressed XD
No, they drop their leaves because they go into a "save resources" phase, maintaining the leaves could take too much energy. If they have a well established root system they can store energy for a fast recovery when the situation improves. Don't quote me though, I'm just applying common sense and have not done research on Avocado plants specifically.
I'd love to see more vivid representations of how these eras changed things. Early plants making rocks into soil, how the first forests must have looked, to how plants and fruits may have looked way in the past.
leave them alone they're just trying to catch their breath
*Leaf
One question I've had about plant evolution for a long time is how often different forms of photosynthesis convergently evolved in different plant taxa. There are three different methods of photosynthesis known today: C3, C4, and CAM, and all evolved in many unrelated groups of angiosperms at different points in history. So if multiple forms of photosynthesis have appeared so often in just the 66 million years of the Cenozoic, then did these forms also convergently evolve in gymnosperms during the Mesozoic? After all, gymnosperms filled many of the niches that angiosperms fill nowadays in environments where C4 or CAM photosynthesis are prevalent so it's hard to believe that they simply struggled with C3 in unfavorable environments for it at all times. The idea of C4 and CAM gymnosperms before angiosperms seems evolutionarly plausible and has always fascinated me, though I'm not certain how that can be proven through the fossil record.
Isoetes of today has CAM.
@@stefanostokatlidis4861 I think you are misinterpreting something by linking two seemingly similar facts together. C4 and CAM photosynthesis are adaptations for arid environments to prevent massive water loss and photorespiration. Neither of these photosynthesis methods occur in habitats with a reliable water supply, where the negative side effects of C3 photosynthesis are negated by the speed and low ATP cost to convert as much CO2 to glucose as fast and cheap as possible. Isoetes as a whole classification are restricted to watery habitats and are so primitive that they lack basic leaf anatomy that is fundamental to either C4 or CAM, so your claim is biologically impossible. I think you are mixing up the fact that isoetes have no stomata with the fact that CAM plants actively open and close their stomata based on the time of day and are concluding that the lack of air holes in a quillwort leaf must therefore make it a CAM photosynthesizer, which is simply not the case.
This is such an interesting question 😅 ADHD brain wants to desperately search for answers (it’s 1am heLp mEe!)
Super interesting topic. It's possible it might be one of em' ole unkowables though. Things we just... cannot know, idk tho
Or parasitic plants that lose photosynthesis altogether
When showing massive drops/increases in CO2 it would be wise to state exactly how long that took. I'm a teacher and if I put two graphs with wildly different scales on them a fairly high percentage of students will still make direct comparisons between them even if they are magnitudes of order off. Showing CO2 levels rapidly changing over millions of years without stating it is an invitation for less informed to think that it's comparable to the changes that we are currently making.
+
In the past change of 0.01 ppm CO2 per year was "fast". It accumulated over 10 of millions of years to create a huge drop or rise. Nowadays the change is 2-2.5 ppm per year
Less informed person reporting: Could you explain to me why said changes are not comparable?
I'd like to educate myself on the subject.
I'm also wondering about the causality between rising global average temperatures and increasing CO2 levels.
As a laymen i can't seem to find well documented research on the subject.
You're right, it's not comparable. The rate of CO2 change today is multiple orders of magnitude faster.
@@marcmorel7246 CO2 levels change 10 - 1,000 times slower in geologic time than they are currently changing, this is why it's not comparable and there would be no way to mistake an artificial process for a natural one.
CO2 can absorb outgoing long wave infrared radiation, thus effectively "trapping" its energy in the atmosphere instead of allowing it to escape to space. Since most CO2 is near the surface, increasing CO2 levels heat up the troposphere near the surface but cool the stratosphere (because there's less outgoing infrared to heat it).
Some might tell you that the absorption bands of CO2 (where its vibrations match infrared wave length) are saturated and thus increasing it wouldn't heat the atmosphere, but absorption bands become broader when there's more of a given molecule.
So each doubling of CO2 is less effective as the previous doubling but it still leads to more heat until the point whre Rayleigh scattering overwhelms the effect of any remaining band broadening and more CO2 would cool instead of warm the surface.
(That also means Venus's atmosphere is actually overdense and the planet would be hotter if it were thinner, interestingly enough).
Absolutely astounding, i love this series so much
I would like it if you somehow chronologicalise all the ages & how they ended & their special features in a series. But that would be a huge undertaking i feel
Definitely something people study in school 😅 but would be v helpful
Pretty sure they did it. Or scieshow, one of those
@@emg508 link?
There are overview episodes on this in the back catalogue.
An episode on plant evolution and how they "trained" animals to work for them would be awesome!
I love that you make episodes about stuff I never would have thought about. I knew plants had stomata but how and why they came about and how they affected the Earth was a question I never thought to ask. I had paid so much attention to the changes they created by emitting oxygen as a by-product that other ways they modified the Earth kind of slipped by my consciousness. Thanks for this new window of exploration for me, I'm going to be busy finding more vids about this.
I'd love to see a whole series just about ancient plants. Also I really enjoy your presentation style. Very laid back and pleasant. Still the best channel on UA-cam.
Hey, really excellent. I had a plant phys professor in the 70s tell us he thought that the carboniferous was an era of high carbon dioxide. I couldn’t agree with him because I (the entomology major) knew about the giant insects of this period and how they worked. This video finally puts it all together for me, thanks.
Imagine if plants evolved to become mobile and sentient
They did. Their time scale is just so slow compared to our time scale that you do not notice their mobility or intelligence. 😁😁😁
now that is something cool
@@John77Doe not mobile but surprisingly Intelligent
just wait...
Thats us bro
I'm sorry for the following nitpick
2:30 light isn't converted into sugar; the energy captured from light is quintessential in stimulating the chemical process through which sugar is formed. It's just words of course, but there might be people that just don't know better and assume much more silly conclusions without an appropriate context (and I'm not even completely aware of the chemical elements involved in at least a few plants to be this much of an ass about this; right now I'm assuming there might be more than one variation of possible molecule recipes involved in the formation of, essentially, plant food).
The Carboniferous Period really made big impact on everything. All that carbon being stored in those trees has had such a drastic effect on the whole world.
Stating that a temperature was 'twice as high' only makes sense if you're working in Kelvins, twice the value in any other scale doesn't mean twice as much energy
Works in Rankine too
This is true from an absolute zero perspective, but 0C and 0F are also a measure of something. Twice as far from 0C would mean twice as much energy from freezing which is still a useful measure. Same with 0F although that is more abstract.
@@martinhogan9745 gotta ask.. what is twice as high as 0 C? Been pondering this for awhile
@@wadeinn463 If you are measuring from 0C the answer is 0C. If you are measuring from 0K, then it would be 273C. I was just saying that comparing percentages of temperature in measures other than a base in absolute 0 still mean something, they just have a relationship with something else (in C it is the freezing temperature of water at 1 Atmosphere)
This presenter is absolutely phenomenal! I feel like she is telling me a story that I really want to pay attention to because of the enthusiasm she brings to the script. Just perfect! Thanks for your excellence!
Microphylls are not limited in length by any means, but width. Many modern pine needles are effectively microphylls and lycophyte tree microphylls were very long
I'd watch a series on plant evolution. Vote here if you want to as well.
And fungi!
In his agony, the Colonel Kurtz whispered: "The humor... The humor..."
Ok but the real question is what happened to Steve?
He fell
He got a job besides reading scripts on UA-cam
We need more plant episodes!
I miss steve
He'll be back when it's cooled off and he can unfurl his leaves again.
I would love to see a series on paleo botany. I'm very interested in what plants grew in each period, but there is not a lot of information available.
Thank you for this excellent episode!
There really needs to be an episode discussing the late emergence of primary endosymbiosis that had led to eukaryotes. I'm personally a supporter of the oxtox model and would love to hear their thoughts.
Unbe-LEAF-able. Then you told that dive bar joke. Please guys. Only one corny joke per enlightening and informative EONS episode. I just ate.
last time i was this early, land was covered in giant fungi
😂😂😂
This was really cool, and well-explained, too! Thanks for what you do, Eons!
" So it was basically impossible for plants to produce large leafs until CO2 levels fell. "
If I understood correctly, they COULD have IF the temperature had been lower. Of course lower CO2 helps cooler temps (but earth could also have been cooler for other reasons). E.g. from my undertsanding, it's more the temperature, ultimately, that held back the larger leafs, even though those would have been useful for breathing.
In desert climates there's a Palo Verde tree. It has a green trunk and tiny leaves. I showed it to someone in Toronto where tree leaves are big. They asked if it was a dead tree. Mesquite has the same type of leaves.
You guys should have Joey Santore from Crime Pays But Botany Doesn't do a guest appearance on plant evolution videos!
thank god i have been waiting for a pbs eons upload
stomatas be looking sus
What that stomata do?
Thank you very much for providing this great explanatory presentation - I always wondered about these early plant forms!
Babe wake up a new pbs eons video just dropped
The world of the late Silurian and early Devonian was crazy hot. Imagine how it would feel to experience that.
Gladly take the survey. Makes me feel considered and respected as a consumer
What’s stomata? Nothin’ stomata with me: what’s stomata with you?
could yall do a series on moss please :) i think that would be an interesting topic and people on youtube never really get into the deeper information on it
Bro I love his show so much, watch every single episode lol
I was hoping this video would include how some plants, like cacti, lost or reduced eaves due to hot environments.
I never knew that all these "nerdy" subjects as referred by some, are actually so interesting. Wow!
The picture used to described the cocoloba tree is actually an image of the sea grape tree
Seagrape is a species of Coccoloba, not sure if they showed the right species with the 8ft leaves though.
Her contributions to research are fascinating. I also love her as a host, and her personal style! Great addition to the team.
I am so puzzled by folks that deny evolution. There is so much evidence.
I think it takes a lot of practice to turn your brain off to that extent. They usually let slip very quickly that they don't know what evolution is; which probably helps.
The incredible complexity of the topic matter wowed me.
So cacbon dioxide is coupled to global temperature, and number of stomata is both coupled to CO2 concentration and temperature. But stomata amount is also related to water loss, which in turn must be controlled with respect to water gain, and THAT is then related to the evolution of powerful vascular systems. So in the Devonian there was barely any megaphylls, and if there were they were tiny. It was almost all Lycolytes with their microphylls. Decrease in the CO2 concentration came with corresponding drops in temperature, causing the Devonian-Cacboniferous ice ages, and so allowed megaphylls to not overheat, ALONG WITH vascular innovation allowing more stomata to be opened without the plant drying up. So, the Carboniferous is the age of megaphylls, with the spotlight shining on ferns. And, oh the CO2 decrease is caused by the land plants themselves, BUT not in the way you'd think. Instead it was a convoluted cause-and-effect chain involving roots breaking down barren mineral rocks starting from the Ordovician, and oceanic algea eating them, AND THEN it was the algea which actually absorbed the CO2.
Props to Eons for somehow being able to express all this in about 10 minutes. Wow.
Wow this narrator has improved so much since the first time they were on
I almost feel bad for noticing that too :| I feel like they are a bit more comfortable or confident or something
@@ZedaZ80 lol, you're allowed to dislike someone's presentation skills
@@ZedaZ80 always remember if your criticizing someone to help their performance then your doing them a favor. that way they can work on improving
The narrator is nameless?
Her nose bling distracted from the verbiage.
As someone who loves plants, this suits me the best
this is so interesting thank you guys so much for making these videos!!
"the first plants" is such a wild string of words.
It's always depressing seeing you make a perfect well organised essay on a topic every week when I can't write anything in more than 10 pages even if you give me 6 months.
Interesting topic as always !
Of course, it’s a whole team of people!
I echo what others have said...so much of our world revolves around plants and we seek understanding of how they evolved.
86C is not twice as high as 43C. It's more like 14% higher because 86 and 43C are actually 359 and 316K. Stop using proportions to describe temperature relationships unless you take into account the full temperature scale down to zero K.
God I wish there was a Paleobotany program at my university. I have to settle for plant science for now :/
Hold up a second. I thought that fungi made the first soils?
@@at1the1beginning wrong, at least according to this channel, they have a video about how fungi were the first to colonise the land, growing huge, tree like structures & breaking down rocks, well before plants had evolved the ability to leave the water
Tfw as a plant you not only provided the oceans with nutrients but also accidentally caused algal blooms and reduced oxygen levels that could've pressured some groups of lobe finned fish to adapt to their low-oxygen environments by starting to adapt to partially relying on atmospheric oxygen intake at the surface (Via gulping air).
This was neat to learn. I'd like to know more about horticulture and botany from an evolutionary perspective.
This channel takes me back million years back every time I see their video. I always wanted to feel how the world would have been back then. Thank you so much for these videos and i get know more about evolution too ❤
Michele is a great host. I want more episodes with them!
I can't help but imagine traveling back in time to see our planet with very few plants and/or very different plants compared to today.
took the earth hundreds of millions of years to find a balance. took humans hundreds of years to off balance it all.
This video is a great example of how intricate and connected things are on our planet.. and other planets
Please don’t say the temperatures “were twice as high as the current average”! That only works for the Celsius scale. In Kelvin, a real doubling would be 300C!
Love the videos… they’re so well pitched.
It's biology and ecology, why would you use the Kelvin scale? Unless you're advocating in defense of Fahrenheit, which would be funny.
@@antoniousai1989 OP is right though? 30°C isn't "twice as high as" 15°C. You can only make a statement like this if on the scale you use zero actually means zero, which is the case for Kelvin but nor for °C and °F.
@@noradrenalin8062 in common life scenarios you use Celsius, not Kelvin.
@@antoniousai1989 Sure, but that is completly besides the point. "Half as hot" as 30°C is not 15°C, it's -111°C. The average temperature on earth today is not -111°C.
8:00 I think is supposed to read: "until the temperature decreased" not: "CO2 levels fell". As large leaves are still very possible and likely, in high C02 environments
Also during the carboniferous age there weren't any organisms that could decompose or eat wood. Keeping the carbon in the soil.
Nowadays we have lots of fungi and animals that can eat it.
fungi evolved & took over land before wood did! This channel has another video on that
@@mehere8038 true before plants ruled the world there were fungi. The giant Prototaxus was one of them, I think.
@@mehere8038 I know.Fungi just didn't know how to digest wood. That's what I meant. Else the carboniferous age would not exist.
After watching this videos, it leaves me more questions than answers. But surely it sheds a lot more light about natural history of plants. I hope this channel will grow even more informative in the future.
science does tend to do that.
the more you learn about something, the more you realize what you dont know
Can I just say that I LOVE YOUR SEPTUM PIERCING! Thank you, PBS, for letting your staff express their individuality in ways most workplaces are arbitrarily against, it makes the content they appear in feel more authentic and shows how awesome of a place PBS probably is, to work at/for.
i love this narrator!
I would like a video on the evolution of plastids. I know that most organisms, including all plants and algae, ultimately acquired their plastids from the same endosymbiotic event. But evolution has made these diverge considerably over time, including the chlorophyll pigments used (and thus the color). More interestingly, the genus _Paulinella
_ and the species _ Pseudoblepharisma tenue_ both had unrelated endosymbiotic events in their histories, acquiring an unrelated cyanobacterium and a purple bacterium, respectively. Finally, the diatom family _Rhopalodiaceae_ has acquired non-photosynthetic cyanobacteria, though it's not clear what advantage they provide.
Amazing to imagine all this happening.
Their outfit is so cool!
yess please do more episodes on ancient plants and fungi every time you do it's amazing
"around 30 degrees Celsius in the early Devonian, which is twice as high as the current average." -- No, that's not how temperatures work. The scale doesn't start at zero (unless you're working in Kelvin).
I was about to make the same comment. You could fix it by saying that it was twice as high above the freezing point of water as the current average.
Wonderful infographics, video presentation and the style of presentation. Thank you!
30C temperature is NOT twice as high as 15C. Numerically yes, but real temperature/energy is measured from Absolute Zero: -273C. Therefore, the energy involved only increased by about 5%.
I will recomend this video to my class.
Ordovician plants be like:
OMG LMAOOO I CANT BREATHE 😂😂😂😂😂😂😂
3:35 "Yeah right, there's no way that there are leaves longer than I am tall"
*does some googling*
Woah I take it all back plants are amazing!
30 Celsius is emphatically _not_ twice as hot as 15 Celsius, just twice as far from the melting point of water. Earth's present average temperature of 288 Kelvins doubled would be 576 K, hot enough to melt Tin and Bismuth and almost hot enough to melt lead
Interesting that microphyls developed into some of largest trees! (Cedars).
New girl coming in clutch this episode
This is becoming my favorite UA-cam channel
m Are plants sentient? We know they sense their environments to a significant degree; like animals, they can “see” light, as a New Scientist feature explains. They “live in a very tactile world,” have a sense of smell, respond to sound, and use taste to “sense danger and drought and even to recognize relatives
so probably yes, but we're too dumb to be able to confirm it
I have always enjoyed most everything PBS puts out. Even when we had to watch it on TV
Me looking at the leaves of the coccoloba tree pictured: idk they don't look that big
Conversion the corner: 2 meters is about 8 and a half feet long
Me: OH. OK. THEYRE BIGGER THAN PEOPLE. COOL. COOL COOL COOL COOL COOL
5:32 No! 30 C is not "twice as high" at 15 C. Comparing temperature ratios only makes sense if using absolute temperature.