If you haven’t already, I recommend watching PBS Eons videos here on UA-cam! They’re produced by the same group that does scishow and put out long form videos usually focusing on evolution and natural history!
Couldn't the older ones just have been very localized for a long time, and then suddenly spread due to some new advantage? Maybe we're just not looking in the right place.
Thought the exact same thing. Maybe the basal angiosperms were extremely niche organisms and as rare as current surviving species, before diversifying and taking over the world
@@BlackSakura33 True, but look at the range of the venus fly trap. It's TINY. If they somehow became the dominant plant group after staying localized for millions of years, future paleontologists would be hunting for a needle in a haystack to find the first ones. Granted, I know sundews and such are related, which widens the area, but you get my point.
Perhaps angiosperms split off into their own lineage during the Triassic, but didn't evolve having flowers until the late Jurassic. Flowering would then give the angiosperms a major advantage over other plants, and that's why they only become common enough to fossilize in the Cretaceous.
this is my field! yes i would say Rob is probably the closest ^ a flower is really an amalgamation of traits. a lot of this comes from the fact that for decades floral evo ppl thought that flowers had evolved from within the gymnosperms (cone bearing plants) but we now know the split btw flowers and gymnos happened much earlier before either lineage diverged. so the angiosperm ancestors were probably gymnosperm-like. molecularly this is still a separate lineage but morphologically we would bin stem group flowers as gymnos. angiosperms have many traits that are very advantageous, and even the the evolution of the flower itself requires many steps that all confer some advantage, but once you have finally created a true flower, it triggers diversification. in this case the whole is not the sum of the parts and the flower opens up a whole new door.
See, this is why I like science. You ask a question, and you eventually get an answer. Then, you get more evidence, and that answer can change a bit. Makes it REALLY hard for people to be a smug know-it-all for very long if they don't actually keep up with current research.
Oh god ffs, I swear know how teachers teach in books about certain people in history who were so wrong? This will be evolution, it's so stupid that it makes me so sad that countless people don't even want to argue it. How the f does a flower imitates a bee to ward off other things. What in a freaking plant gives it that ability?
I wonder if it could be possible that the answer lies somewhere in between, as in, angiosperms evolved earlier, but they didn't take the forms that we'd recognize as angiosperms until later, so we don't find pollen until later in the fossil records.
"Molecular clock"-based dates tend to be substantially earlier than dates derived for paleontological (or archaeological) finds. This seems to be a pretty consistent methodological bias and is highly debated, especially when it involves the "recent" history of our species (i.e. within the last 100,000 years). One reason may be that crown groups undergo faster-than-usual evolution in their early diversification, once they spread over large regions and have to suddenly adapt to a bunch of new ecological/environmental pressures, for instance. Hence, the rate of mutation assumed by the molecular clock model is slower than what it was in reality. (But take this explanation with a grain of salt; as I said, it's an ongoing debate.) Besides the possibility that it is just a methodological error, it's possible that the genetics-based date is earlier simply because old enough fossil finds have yet to be found. In other words, it would be an absence-of-evidence fallacy with regard to the fossil record (which is of course never "complete", but often very patchy, and should be acknowledged as such). These two explanations should be kept in mind whenever, as frequently happens, geneticists and paleontologists disagree on the age of a biological event such as the diversification or common ancestor of a clade.
As far as I know, the notion that angiosperms have become dominant in the mid to late Cretaceus is generally accepted. Or is it not? If so, the odds of us having no fossil _at all_ in the Jurassic, not even a single grain of pollen, seem quite slim. On the other hand, it is easy to speculate that the evolution of mutualism with specialised pollinators might have made flowering plants evolve very rapidly in the beginning, coupled with the "trick" of frequent polyploidy. Do we know when bees and butterflies appear? Does any of this hold any water? PS: I admit I have a bias against geneticists, as it seems to me they are very often a bit too much in love with their shiny toys :D
What would be nice is a timeline along the bottom of the video showing the geological ages whenever "jurrasic", "triassic" etc are mentioned with a little red arrow to help us know how far back you are talking. Excellent video!
"The ancestors of flowering plants diverged from gymnosperms in the Triassic Period, 245 to 202 million years ago (mya), and the first flowering plants are known from ~140 mya. They diversified extensively during the Early Cretaceous, became widespread by 120 mya, and replaced conifers as the dominant trees from 100 to 60 mya." en.wikipedia.org/wiki/Flowering_plant
One reason to put a lot of credibility in the liklihood that angiosperms did not exist until we start finding their pollen in the fossil record is that pollen is extremely hardy and easily fossilized, plus it tends to get distributed widely in air, water, and soil. So unless pre-Cretaceous angiosperms were confined to a tiny area and few species, it's likely they simply did not exist before the Cretaceous, or much before at least.
It always bugs me when people date a species by fossil evidence. All that fossils can tell you is that it is AT LEAST that old, and pretty much incontrovertibly much older. How many thousands or even millions of years does it take for a species to leave behind enough fossils for us to find one? There is not really any way to tell.
so you think you’re just smarter than every floral evolutionary biologist. gosh all this time we should have been looking in youtube comments for the answer
nobody is just dating the fossils and walking away saying well i guess that’s when they evolved. no. the radiation of angiosperms was unprecedented and required the evolution of TENS of separate traits. the fact that we do not see the legacy of any, is unique, and surprising, given the widespread abundance of unequivocal fossilized flowers of crown group angiosperms. darwin called this “an abominable mystery” and people work on this from every angle every single day. i was so excited when this vid was posted bc it is my field but it’s pissing me off that everyone in the comments thinks they’re smarter than an entire field of researchers and dismissing this debate, chalking it up to people misunderstanding what a fossil is and what inferences can be drawn from it. if you actually were familiar with the fossil record you could have a better grasp on the mystery of angio evolution
@@KuK137 Nice reading comprehension there where you just skipped over their statement that they are in fact one of the researchers in the field. But go off "KuK137" clearly you're the expert here.
Another thing to remember with DNA clocks, is that just because the genes we think should make it a flowering/fruit bearing plant are present. Doesn't mean it actually looked like one in fossil record. Meaning the genes were there but they were not expressed like we think they should.
Almost certainly not and the reason is explained in the video: genetics does not only provide a "molecular clock" estimate (which is clearly off by a lot in this case) but also a much more reliable phylogeny. And the phylogeny fits perfectly with the paleonthological pollen record, so it's 2 pieces of very solid evidence vs one piece of very muddy modeling.
Convergent evolution might be the answer to why the molecular clock gives us a crazy estimate. If angiosperms evoloved twice, the DNA would just show us crazy values that has nothing to do with when angiosperms evolved. Probably it would answer the question of when plants that later evolved to become angiosperns seperated from one another, which could be the very reason for this gap
I assume the gap is related to pollination species available. When more pollinator species evolved, so the number and diversity on Angiospermae grew. Pollinators are specialists and occupy a very narrow niche, as such they are susceptible to variations in plant populations, adverse weather affect both in a harder way, harder then if they weren't in symbiosis/mutualism/protocooperation.
this is one theory ! yes. it does seem angios diversified right around the time when pollinators diversified. in order to achieve successful pollinator-driven radiation you need a fully fledged flower, rather than a “partial” flower, and when all traits of the flower had finally evolved and pollinator interactions established, it was like an explosion, the diversification and specialization of flowers
There is an issue with DNA chronology, mutation rates are not necessarily stagnate or consistent. Under periods of extreme but survivable stress genetic mutation can occur more rapidly.
Mutations certainly occur at a regular rate on average. If the genetic pool is large enough (and it is unless we're talking mitochondria or similar) that's not the problem, the problem is that we just don't know which is that regular rate and "molecular clockmakers" make assumptions (typically wrong calibration points) that they inject into their model, resulting in trash in: trash out. They need to revise, not the overall molecular clock model, but the calibration points.
It does just sound like we don't have enough data yet. We need to do more research and data collection really. My approach would be to enter some hypothetical values into the mathematical model, and see what it would take in order for the genome to match the fossil history and go from there.
You just give too much credibility to the molecular clock: it only works (somewhat) if properly calibrated and in this case it's clearly wrongly calibrated. Nothing to see here, move along, the paleonthologists are right, the geneticists wrong (on the molecular clock thing only, the phylogeny is fine, just stop trying to assign dates until you have fossils that give an actual date).
Or maybe the earliest angiosperm weren't flowering plants? Just like the time when mammals and reptiles seperated, the "mammal" part wouldn't be mammal for millions of years.
I mean, I'm not a science pro or anything, I love science and learning and probably have at least a slightly above average understanding as compared to the average person (I'm actually strongly considering being a science/math teacher since IT definitely did not work out) - but when I think about fossils, it just seems intuitive to me that there are (obviously) things that we haven't discovered, gaps like this in our understanding, missing key information that might remain that way for a long time to come, etc. The explanation about just not having found the older fossils yet seems right to me.
Simple answer: fossils are very rare (less than 1/10th of all living species become fossilized and even less than that are actually discovered). It is the height of hubris to think we have found all the missing links, let alone explained/dated them properly. A 70 million year difference between DNA diversity and fossilized discoveries? DNA discrepancy projections appears to make sense and could wind up being accurate. Finding and dating real fossils? Not so much. I'll take the stance that we need to collect a whole lot more (very rare) fossils and start to date them properly over a "mystery" biological disrpecany any day.
hey i’m a floral biologist, i think they maybe just did not do a great job articulating the magnitude of the gap, and how suddenly (and widespread! and diverse!) the angio fossils are when they do appear, along with fossils of every other land plant group. even darwin called the diversification of flowers “an abominable mystery.” while nobody will argue that the fossil record is patchy at best (i do molecular work) it is a shocking switch between a fossilized world of ferns and seed bearing plants, to the widespread presence and diversity of flowers. it is not as if they appear in one location and then spread about. it is truly unparalleled, when comparing it with the evolution of gymnosperms, ferns, vascular plants, and animals.
@@gracepisano I remember reading something about a fossil plant from the Early Jurassic which displayed angiosperm like characteristics back in 2017. Did that result not hold up or was it too distantly related to shed any light on the issue?
@@Dragrath1 Nanjinganthus, yes, there are many others too. however it is difficult to establish beyond doubt that early jurassic fossils aren't gymnosperms. i could say a lot more but i will just say- they are not widely accepted as angiosperms because we can't rule out that they are preserved cones of an extinct gymnosperm
I have another theory... Maybe the speed of those molecular clocks were somewhat faster in the past because of some environmental issue. Maybe less ozone and so more UV.
But the ozone content is directly proportional to the atmospheric oxygen level and we mapped those pretty closely during the last few hundreds of millions of years, so they could be accounted for. And against the UV hypothesis stands the fact that we would see the same happening today because of how much we destroyed the ozone layer. Compared to today, the ozone layer back in the Jurassic was like a 70+ factor sun lotion.
@@midnight8341 - Maybe more surface radioisotopes? I know there's been enough surface U-235 to power natural nuclear reactors in Africa. Also, I don't know that the ozone has been depleted for long enough for us to get a good measurement. I mean, I literally don't know. 🙂
you would expect to see the same phenomenon in non flowering plants and animals then, which we don’t really see. plants do a lot to cope with high UV, especially the first land plants, since UV is (especially, WAS, 500mya) much higher than in water. when UV is higher and begins to do genetic damage, living things will find biological ways to negate that and early plants did have to evolve mechanisms to cope
@@Omnifarious0 but then you would have found unusually high rates of radioisotopes or decay products in stone from that era, so that also would have been accounted for. And it wouldn't have taken that much time, actually. Since it is a physical effect, not a chemical or biological, it's immediate. The ozone layer is depleted? Immediate higher irradiation with UV light. Higher UV levels directly correspond to more DNA damage and higher mutation rates. These kinda go hand in hand.
@@midnight8341 - I guess for molecular clocks it doesn't matter if the mutations are successful or not. I was thinking there would be a delayed effect because most damage would be fatal.
If I recall there are evidences in many different areas of life when evolution mugh fast forward in certain times, and thus muddle the molecular clock for estimation.
It can go faster and can go slower but on average, when many many loci are used, they should have a consistent rate, the problem is not there, the problem is that their molecular clock model is wrongly calibrated.
One should search for the signs of coevolution with pollinating insects and continue to evolve the model, as we know al models are wrong but some models are useful
What I'd really like to know is how you find fossilized pollen in the first place, or any other microscopic bits and bobs for that matter. Are they ubiquitous and all you have to do is identify and classify them, or is it just good old magic?
Neither of the two most-basal extant plants, waterlilies and Amborella trichopoda, are wind-pollinated. Pollen microfossils are nearly all from wind pollinated plants, because wind-dispersed is produced in abundance and dispersed widely in the general environment. Pollen that is adapted for insect pollination is more sticky and mostly not produced in such great quantities. I do find the fact that pollen of the major taxa appears in the microfossil record in the order suggested by molecular phylogeny very persuasive. This would be extremely unlikely if the lack of angiosperm fossils through the Jurassic were due to narrow ecological niches or geographically restricted ranges.
Pure speculation follows: I think focusing on the perceived "gap" might be the wrong focus. A more compelling (and observable) phenomenon is the angiosperm explosion of the early Cretaceous. Lots of species that existed in small, scattered populations, living on the margins of an environment have poor (or even non-existent, known only by their inferred existence) footprints in the fossil record. Since the best evidence for the existence of the "gap" comes from hardy pollen grains, maybe the evolution of hardier pollen (and the environmental changes that selected it) also led to the this explosion. richard -- "After all, it is as respectable to be modified ape as to be modified dirt" -- T.H.Huxley, Written in a letter to Dr Frederick Dyster 30th Jan 1859, i.e. before the publication of the Origin.
What if the Genes that later became useful for later angiosperms first started to appear in plants 70mil years ago. So basically 70 mill is the the estimated time the angiosperm lineage split and we had Pseudoangiosperms that later diversified into the flowering plants we see today.
Kinda like the way insect eating plants appeared in different parts of the world different plants developed ways to release pseudo-pollen until one or some conversely evolved to create different types of what we now call pollen
That would explain the sudden appearance in the fossil record but not the common ancestor they shared with other plants 100 millions earlier according to the genetic clock.
Haven't they found fossil plants which appear to share angiosperm characteristics dated to the Early Jurassic? I remember that getting published back in 2017.... Also from what I have read at least by the late cretaceous Angiosperms were the dominant understory plants adapted to low light levels which helped them survive the K-Pg extinction. Plus as others have suggested they may have not really diversified until later but having eked out an existence earlier with limited geographical range and or niche only rapidly diversifying once true flowers evolved allowing them to rely on insect vectors. Or maybe we have already found them just they looked quite different from what we would have expected? For example maybe the pollen shape didn't arise until later selected convergently by insect based pollination?
I wonder about all of the different fruits, vegetables, and animals that went extinct that we just barely missed that would have changed everything if they weren’t gone. Hopefully with quantum computers we can emulate DNA and see what kind of things were lost and see what kind of new species we can build. It would be such a crazy beautiful world if people would just help each other grow instead of tearing each other apart.
i think the problem is with Estimate rates at which those plants genomes change it can change depending on many factors including climate and catastrophic events
there are adjustments for site rate specific heterogeneity, rate changes between taxa and the like. the mathematical models are complicated and include a lot to account for the uncertainty in sequence evolution. these dates are reliably predicted, whether nuclear or chloroplast dna are used, including high numbers of taxa, and this probably does reflect the evolutionary history of the lineage, not necessarily that of the flower itself
Not really, the molecular clock does provide a pacing (on average and thus appliable to large enough genomic sets), the problem is how large is each step, each averaged mutation time. That's solved by proper calibration but the proper calibration in this case is what paleonthologists say, so clearly they are producing the wrong date if they crash with solid paleonthological evidence that, additionally, also fits the other part of the genetic data: the phylogeny, much more reliable than the molecular clock. So they need to review the measurement of their ticks: they are happening much faster than they assumed.
How is the potential for various rates of DNA mutation figured in? Does the model assume steady evolution? Would an event like a gamma-ray burst account for a burst of DNA mutation? Perhaps also accounting for the time gap?
love to see people in youtube comments thinking they’re smarter than an entire field of scientists. just because YOU don’t understand it, doesn’t mean it’s arbitrary or random
@@gracepisano - But The Moon is right: there are major problems in taking molecular clock at face value, without considering the underlying assumptions, which is "what is that MC model calibrated with?" MC as such gives no dates, just a pacing for the phylogeny, it needs to be calibrated with actual data, in this case paleonthology. If the MC model and the actual facts on the ground crash, the MC model needs to be recalibrated 99.99% of the time.
@@LuisAldamiz MC estimates from nuclear and organelles genomes agree though, increases in taxon sampling and better analyses only converge further on the same window. no one saying MC is perfect but its not a random estimate. there is good evidence the lineage is older than the flower and it probably reflects the evolutionary path rather than just some clock error. we now know that angiosperms and gymnosperms diverged from an early seed bearing relative and so its not surprising that the lineage traces much further back than the actual origin of fossils with extant angiosperm morphology. the comment "they are using estimates to estimate" and the conclusion that that is unreliable dismisses so much good science
@@gracepisano - I know quite a bit about the molecular clock methodology and how genetists are worryingly determined to sell it as if it was C-14... without the required testing and without updating their calibration points according to the best available material evidence from more traditional (and consolidated) fields. I am most famliar with the human genetic aspect and I know for a fact that genetists have not updated their calibrations in 20 years, even if a lot of new archaeology and hominid paleonthology should have forced such recalibrations long ago. The problem is systemic and is very serious and has two main causes (which are ultimately the same one): 1. Scholastic inertia, a paper cites a paper that cites a paper that cites a paper.... all the way to the late 20th century, when archaeology was suggesting very different dates for the human expansion out of Africa than it is today. 2. Lack of interdisciplinarity: the field of genetics feels a bit too arrogant and willing to tell other fields how to do their job just because genetics is so new and cool and offers so many new bits of info. In some aspects they are right, genetics has provided a lot of new very interesting data, often solving conundrums that had lasted for decades unsolved, but in the issue of the molecular clock they are utterly wrong, because there's no molecular clock without external calibrations that provide the appropriate time bracket in which to count the mutations. MC says that the human migration out of Africa happened some 60,000 years ago. Why? Because that's the calibration point they picked 20 years ago, when it used to be the archaeological/prehistorical consensus. By now we know that it's rather 125-100 Ka ago but the MC has not been updated and to this new, rather uncontrovertible, data. How do we solve it? Each time we see an academic MC estimate for humans, we double it (I actually use a 150-200% correction because there are other considerations and I'd rather have my CI interval large than err). This, I know, is the opposite of what is happening with the floral gap, in which the MC estimate is much older than what the fossil record seems to allow. As such it could go either way (the fossil record can have gaps, although pollen is like everywhere, so hard to leave gaps provided sufficient research) but if the palinological record is coincident with the genetic phylogenetic order of appearance, then it's very clear to me: what is wrong is (again) the molecular clock, in the opposite direction to the one I'm used to but wrong nevertheless. You need to recalibrate, for science's sake!
Also it could happen that angiosperms developed first in a region of the world the science of paleontology knows not much about, like Africa. Another what-if: The first flower was so gymnosperm-like that it would be hard to tell the difference. Yet more: The first angiosperm fossil has been found long ago only not its flower, paleobotanists almost never have complete plants to study.
What if it evolved in a remote valley or on an island that wasn't connected to the rest of the world for millions of years? Followed by a connection event that spread it everywhere. The only thing we now about the fossil record is that we haven't found it everywhere in that time period. Maybe we just haven't found the right place.
yes there are 2 hypotheses: “wet and wild” and “dark and disturbed.” these posit that angios were aquatic plants, or understory shrubs, respectively, in a gymnosperm dominated world, and that they only diversified later on. but this begs the question of what triggered diversification, if the flower had already evolved 50 million years prior, and it also contradicts some of the morphological data from extant flowers. it’s more likely that flowering plants probably did not actually evolve flowers until later in their evolution and when the complete flower finally appeared, diversification happened
As I expect someone is already researching it but I'll ask. Couldn't it be it took a while for insects and the like to get used to pollination cycle until enough it they could really take off ?
DNA would surely be able to tell us what the most basal angiosperm would have been like? And what habitat it would have lived in? Perhaps we can narrow down the fossil hunt with that information - if we know it was a rainforest type plant, then we can search for fossils in sediments known to contain fossils belonging to that environment at all points along the gap?
Yes and no... It takes about 60times the raw input sequences to generate an okay-ish genome assembly for a unknown plant. Depending on the plant, that can be done in a day or two, like with a few algae, but for my master thesis, I would have had to sequence about 1.5 Terabases of sequences for that kind of coverage (which would be equivalent to about 500times the size of the completed human genome). Now think about how much data you would need to get to reliably calculate a basal genome of an ancestor of about 90% of all land plants. And then we would need to account for the extraordinary changes plants go through, like consecutive whole genome duplications, rapid transposon expansion, cross-polination and hybridization with different species... But not just in the last few millenia or a million years or so. No, you would have to account for about 200 million years of those plants conquering the entirety of the planet and adapting to every níche there is... Some plants are nothing more than parasitic twigs, some need special acid treatments for their seeds to germinate, others keep ants as pets to ward off pests, while others grow nothing but two leaves in 50 years. And there you wanna find something as simple as a tropical, or subtropical adaptation? We can breed that into plants in a century or two and those are still 99% identical with the wild type plant we bred them from. I feel very much flattered by how much you think with can do, but that's just not possible.
@@midnight8341 It would be very difficult to calculate a whole genome for a hypothetical last common angiosperm ancestor (let alone determine the environment that it likely lived in) but some general details about the morphology of the plant may be able to be ascertained with less work. The problem is that this doesn't really help narrow down the search (i.e. What good is knowing that the ancestral angiosperm was woody with vaguely such-and-such flower pattern when you don't know when or where it could have lived?). I would however caution against immediately disregarding the suggestion that the commenter above is making. I am of course ignorant of the subject of plant genetics, but none of the problems you brought up seem to make what he is proposing explicitly impossible. Sometimes when other methods fail the best option is just to bite the bullet and take the most direct path forwards.
the meteor crashed and caused plants to evolve into angiosperms. what dinosaurs were left after the meteor, struggled for survival as angiosperms quickly took over their usual food sources. finishing off almost all the rest of dinosaurs. that's my cool new hypothesis :)
doesn't fit the data as while some dinosaur groups declined (non titanosaur sauropods) others thrived and the angiosperm take over happened too early and suddenly in the Cretaceous when dinosaurs were at their prime. By the late cretaceous Angiosperms were everywhere predominately as understory plants
Could you compare insects like butterflies and other nectar consuming bugs, against the clock? if our earliest fossils of flowers can be found with evolved pollinators, logic would suggest it happened earlier then the fossils we have. If there is a lack of nectar consuming specialists in that part of the fossil record, then flowers were a new niche yet to be used by nature and the clock is off a bit... just a thought
nectar probably evolved after pollinator interactions were established. but your idea is on track. it could be associated with pollinator diversification, and that did occur around the same time. the question is really, if flowers were established at radiation, where are all the pre-flowers, as there are several evolutionary steps in the making of an angiosperm
What I really want to know is what is the last common ancestor between angiosperms and gymnosperms? And if it's not a tree, how did hardwoods end up having such similarities with softwoods?
for many years we thought that the angiosperms had evolved from within the gymnosperms, and it was , basically like two decades of trying to fit a square peg into a round hole. we now know that the divergence happened at the base of both clades and the ancestor was probably an early seed bearing plant. then angiosperms and gymnosperms diversified separately. this is the mystery. if angiosperms and gymnosperms, aka flowers and cones, split at the same time, what prevented the flowers from diversifying earlier.
but anyway yes, the earliest seed plants did have the ability to produce wood and angiosperms and gymnosperms inherited that ability. they also evolved leaves somewhat separately from ferns so they share the same type of leaf. they had a specialized style of primary growth and branching they had ovules a.k.a. seeds. and of course, pollen
Interestingly though, wood has evolved several times, in fact, extinct ferns and lycophytes show various types of wood production and actually much of the coal we harvest is from dead tree-like lycophytes that evolved arborescent habit independently. however, the seed plants share a secondary cambium, a special type of stem cell niche that allows them to produce xylem and phloem (vascular tissue) throughout their life , aka WOOD!
@@gracepisano Thank you ! I've been wondering this for so long ! Never been able to find an answer. I can't believe something like a tulip or a tomato plant comes from a tree like plant ! How is this possible ?!
1:31 Wasn't the Jurassic period a movie or something? I'm pretty sure I've seen it, there's this scientist and the hero was played by Leonardo DiVinci or whatever...
i'd rather think that the people analyzing DNA didn't properly take into account the metabolism rate of plants in extreme environments of which there's no clear data on.
@@LuisAldamiz No, evidence is not the same as proof. Example majority of evidence can show that mr X is murderer, but in reality he could be framed (also there can be contradicting evidence, but never contradicting proof). Proof is something that gives certainty. In the most strict sense proofs exist only in math, but in practice very solid evidence is considered as proof.
@@user255 - Mathematical proof is not science, let alone legally useful in any way before a jury, it's just logic (as in methodical philosophy and not as in "reasoning"). In fact in such specific context, which usually ends with the acronym "Q.E.D.", the word proof is used as "proving" as logical process and not as item of evidence, there's no evidence in mathematical proof, it'd be too complicated to proof that "x" is not just in the mind of the mathematician. And whoever says "x", says "y" or even "+/-", all things that do not clearly exist in reality, unlike pollen grains and smoking guns.
@@LuisAldamiz I completely agree on your points about math and I never claimed anything contradicting what you said. I merely stated the definitions of the word "proof".
Maybe they were just rare and that's there are no fossils found yet. The most primitive flowering plants I know of are some species still existing in New Caledonia and they are not very vigorous or very invasive they very slow-growing and sluggish probably the earliest ancestors were not that different
Your fixed time to upload video like 2:21 AM EVERYDAY ( TIME According to India ) . Btw thanks for every bit of knowledge I receive from you every very early morning 😊
ya, angiosperms and gymnosperms both inherited pollen from a common ancestor, but all living angiosperms have pollen that is a certain shape, and the switch to this type of pollen in the fossil record is abrupt
Molecule structure like eggshell the cocktail ingredients 2 place in a cocoon similar to the Pharaoh coffins coffins are like cocoons maybe you should look at the Egyptian hieroglyphs warning
Im so happy theres been so much evolution content lately, it's the type of stuff that makes you daydream in awe
@@AxxLAfriku you won't just stop spamming. At least this reply isn't talking about your "two hot girlfriends"
If you haven’t already, I recommend watching PBS Eons videos here on UA-cam! They’re produced by the same group that does scishow and put out long form videos usually focusing on evolution and natural history!
@@FireFog44 i will make good use of that intel lol thank you
+
Apart from PBS Eons I’d also recommend trey the explainer and ben g thomas
Couldn't the older ones just have been very localized for a long time, and then suddenly spread due to some new advantage? Maybe we're just not looking in the right place.
It could be. But it’s a huge time gap.
Thought the exact same thing. Maybe the basal angiosperms were extremely niche organisms and as rare as current surviving species, before diversifying and taking over the world
@@BlackSakura33 True, but look at the range of the venus fly trap. It's TINY. If they somehow became the dominant plant group after staying localized for millions of years, future paleontologists would be hunting for a needle in a haystack to find the first ones. Granted, I know sundews and such are related, which widens the area, but you get my point.
Perhaps angiosperms split off into their own lineage during the Triassic, but didn't evolve having flowers until the late Jurassic. Flowering would then give the angiosperms a major advantage over other plants, and that's why they only become common enough to fossilize in the Cretaceous.
this is my field! yes i would say Rob is probably the closest ^ a flower is really an amalgamation of traits. a lot of this comes from the fact that for decades floral evo ppl thought that flowers had evolved from within the gymnosperms (cone bearing plants) but we now know the split btw flowers and gymnos happened much earlier before either lineage diverged. so the angiosperm ancestors were probably gymnosperm-like. molecularly this is still a separate lineage but morphologically we would bin stem group flowers as gymnos. angiosperms have many traits that are very advantageous, and even the the evolution of the flower itself requires many steps that all confer some advantage, but once you have finally created a true flower, it triggers diversification. in this case the whole is not the sum of the parts and the flower opens up a whole new door.
The Fault in Our Fossils, John Green's new young adult novel
😂😂😂
Would you buy that book ?
This one is also massively overrated!
I don’t think I’ve ever snorted so loudly 🤣
See, this is why I like science. You ask a question, and you eventually get an answer. Then, you get more evidence, and that answer can change a bit. Makes it REALLY hard for people to be a smug know-it-all for very long if they don't actually keep up with current research.
Lol unless its about covid,masks, or vaccines not allowed to question that science
Oh god ffs, I swear know how teachers teach in books about certain people in history who were so wrong?
This will be evolution, it's so stupid that it makes me so sad that countless people don't even want to argue it.
How the f does a flower imitates a bee to ward off other things. What in a freaking plant gives it that ability?
More wholesome, deep time content please. Jurassic angiosperms don't have to think about my problems
Could one day you do a syconium video? They're plants like figs where the flowers grow inside the stem
+1
Woah
Syconium isn't a plant, it's a form of inflorescence present only in the ficus genus. Easy enough to study
2:33 it's coarse, rough, irritating and gets everywhere like Sand
Indeed
I scrolled down to the comments right when he said that.
And it makes new plants too! which then flowers and make more pollens!
a surprise to be sure, but a welcome one
I wonder if it could be possible that the answer lies somewhere in between, as in, angiosperms evolved earlier, but they didn't take the forms that we'd recognize as angiosperms until later, so we don't find pollen until later in the fossil records.
Binarokaro Yeah, my guess too.
"Molecular clock"-based dates tend to be substantially earlier than dates derived for paleontological (or archaeological) finds. This seems to be a pretty consistent methodological bias and is highly debated, especially when it involves the "recent" history of our species (i.e. within the last 100,000 years). One reason may be that crown groups undergo faster-than-usual evolution in their early diversification, once they spread over large regions and have to suddenly adapt to a bunch of new ecological/environmental pressures, for instance. Hence, the rate of mutation assumed by the molecular clock model is slower than what it was in reality. (But take this explanation with a grain of salt; as I said, it's an ongoing debate.)
Besides the possibility that it is just a methodological error, it's possible that the genetics-based date is earlier simply because old enough fossil finds have yet to be found. In other words, it would be an absence-of-evidence fallacy with regard to the fossil record (which is of course never "complete", but often very patchy, and should be acknowledged as such).
These two explanations should be kept in mind whenever, as frequently happens, geneticists and paleontologists disagree on the age of a biological event such as the diversification or common ancestor of a clade.
You should have made this video
As far as I know, the notion that angiosperms have become dominant in the mid to late Cretaceus is generally accepted. Or is it not? If so, the odds of us having no fossil _at all_ in the Jurassic, not even a single grain of pollen, seem quite slim. On the other hand, it is easy to speculate that the evolution of mutualism with specialised pollinators might have made flowering plants evolve very rapidly in the beginning, coupled with the "trick" of frequent polyploidy. Do we know when bees and butterflies appear? Does any of this hold any water?
PS: I admit I have a bias against geneticists, as it seems to me they are very often a bit too much in love with their shiny toys :D
Really interesting, thank you!
Also, does this mean they were likely correct that the real date falls somewhere in between the two estimated ranges? For angiosperms at least?
Adaptive mutations would change more quickly than random mutations in junk dna. They could look for that, specifically, to make sure it's not biased.
What would be nice is a timeline along the bottom of the video showing the geological ages whenever "jurrasic", "triassic" etc are mentioned with a little red arrow to help us know how far back you are talking.
Excellent video!
"The ancestors of flowering plants diverged from gymnosperms in the Triassic Period, 245 to 202 million years ago (mya), and the first flowering plants are known from ~140 mya. They diversified extensively during the Early Cretaceous, became widespread by 120 mya, and replaced conifers as the dominant trees from 100 to 60 mya."
en.wikipedia.org/wiki/Flowering_plant
@@eljanrimsa5843 Thanks!
‘Atten-bow-row’ *giggles in UK English*
One reason to put a lot of credibility in the liklihood that angiosperms did not exist until we start finding their pollen in the fossil record is that pollen is extremely hardy and easily fossilized, plus it tends to get distributed widely in air, water, and soil. So unless pre-Cretaceous angiosperms were confined to a tiny area and few species, it's likely they simply did not exist before the Cretaceous, or much before at least.
Of course, the Jurassic flowers may be completely unrecognisable in the fossil record
Of course, and what do you mean by this?
Eljan Rimsa unrecognisable as flowers.
Maybe bcs pollinator isn't existed yet
It always bugs me when people date a species by fossil evidence. All that fossils can tell you is that it is AT LEAST that old, and pretty much incontrovertibly much older. How many thousands or even millions of years does it take for a species to leave behind enough fossils for us to find one? There is not really any way to tell.
so you think you’re just smarter than every floral evolutionary biologist. gosh all this time we should have been looking in youtube comments for the answer
nobody is just dating the fossils and walking away saying well i guess that’s when they evolved. no. the radiation of angiosperms was unprecedented and required the evolution of TENS of separate traits. the fact that we do not see the legacy of any, is unique, and surprising, given the widespread abundance of unequivocal fossilized flowers of crown group angiosperms. darwin called this “an abominable mystery” and people work on this from every angle every single day. i was so excited when this vid was posted bc it is my field but it’s pissing me off that everyone in the comments thinks they’re smarter than an entire field of researchers and dismissing this debate, chalking it up to people misunderstanding what a fossil is and what inferences can be drawn from it. if you actually were familiar with the fossil record you could have a better grasp on the mystery of angio evolution
@@gracepisano Says armchair kid who thinks he is smarter than genome scientists.
KuK137 what??
@@KuK137 Nice reading comprehension there where you just skipped over their statement that they are in fact one of the researchers in the field. But go off "KuK137" clearly you're the expert here.
Maybe flowers first evolved in an isolated location like a large island.
AA - RON
COINCIDENCE ?
I THINK NOT !
Large islands are continental fragments (they don't appear and disappear) and all are quite well studied by paleonthologists. So almost certainly not.
@@LuisAldamiz I wonder what percentage of what was land has been even surveyed for fossils by professionals.
Another thing to remember with DNA clocks, is that just because the genes we think should make it a flowering/fruit bearing plant are present. Doesn't mean it actually looked like one in fossil record. Meaning the genes were there but they were not expressed like we think they should.
Almost certainly not and the reason is explained in the video: genetics does not only provide a "molecular clock" estimate (which is clearly off by a lot in this case) but also a much more reliable phylogeny. And the phylogeny fits perfectly with the paleonthological pollen record, so it's 2 pieces of very solid evidence vs one piece of very muddy modeling.
Convergent evolution might be the answer to why the molecular clock gives us a crazy estimate. If angiosperms evoloved twice, the DNA would just show us crazy values that has nothing to do with when angiosperms evolved. Probably it would answer the question of when plants that later evolved to become angiosperns seperated from one another, which could be the very reason for this gap
Whatever the reason for the gap may be, let me just say so happy we have flowering plants! Idk what my high ass would do without them.
I assume the gap is related to pollination species available. When more pollinator species evolved, so the number and diversity on Angiospermae grew. Pollinators are specialists and occupy a very narrow niche, as such they are susceptible to variations in plant populations, adverse weather affect both in a harder way, harder then if they weren't in symbiosis/mutualism/protocooperation.
this is one theory ! yes. it does seem angios diversified right around the time when pollinators diversified. in order to achieve successful pollinator-driven radiation you need a fully fledged flower, rather than a “partial” flower, and when all traits of the flower had finally evolved and pollinator interactions established, it was like an explosion, the diversification and specialization of flowers
Interesting
There is an issue with DNA chronology, mutation rates are not necessarily stagnate or consistent. Under periods of extreme but survivable stress genetic mutation can occur more rapidly.
Mutations certainly occur at a regular rate on average. If the genetic pool is large enough (and it is unless we're talking mitochondria or similar) that's not the problem, the problem is that we just don't know which is that regular rate and "molecular clockmakers" make assumptions (typically wrong calibration points) that they inject into their model, resulting in trash in: trash out. They need to revise, not the overall molecular clock model, but the calibration points.
"Mr. President, we cannot allow... an Angiosperm Gap!"
Yo shout out to Ant Mountain. That is an awesome presentation by DA. Also if you like that check out Life in the Undergrowth!
It does just sound like we don't have enough data yet. We need to do more research and data collection really.
My approach would be to enter some hypothetical values into the mathematical model, and see what it would take in order for the genome to match the fossil history and go from there.
You just give too much credibility to the molecular clock: it only works (somewhat) if properly calibrated and in this case it's clearly wrongly calibrated. Nothing to see here, move along, the paleonthologists are right, the geneticists wrong (on the molecular clock thing only, the phylogeny is fine, just stop trying to assign dates until you have fossils that give an actual date).
Next time I'm late I'll just blame the data input for why my Internal Molecular Clock was wrong.
Or maybe the earliest angiosperm weren't flowering plants? Just like the time when mammals and reptiles seperated, the "mammal" part wouldn't be mammal for millions of years.
Plants are so cool!!
Ahh, Rocks vs. Clocks, Round 2.
When flowering plants produced pollen, the dinosaurs sneezed and they went extinct ;-)
Coincidentally I’m studying plants in my IB bio HL unit rn lmao
I mean, I'm not a science pro or anything, I love science and learning and probably have at least a slightly above average understanding as compared to the average person (I'm actually strongly considering being a science/math teacher since IT definitely did not work out) - but when I think about fossils, it just seems intuitive to me that there are (obviously) things that we haven't discovered, gaps like this in our understanding, missing key information that might remain that way for a long time to come, etc. The explanation about just not having found the older fossils yet seems right to me.
Simple answer: fossils are very rare (less than 1/10th of all living species become fossilized and even less than that are actually discovered). It is the height of hubris to think we have found all the missing links, let alone explained/dated them properly. A 70 million year difference between DNA diversity and fossilized discoveries? DNA discrepancy projections appears to make sense and could wind up being accurate. Finding and dating real fossils? Not so much. I'll take the stance that we need to collect a whole lot more (very rare) fossils and start to date them properly over a "mystery" biological disrpecany any day.
hey i’m a floral biologist, i think they maybe just did not do a great job articulating the magnitude of the gap, and how suddenly (and widespread! and diverse!) the angio fossils are when they do appear, along with fossils of every other land plant group. even darwin called the diversification of flowers “an abominable mystery.” while nobody will argue that the fossil record is patchy at best (i do molecular work) it is a shocking switch between a fossilized world of ferns and seed bearing plants, to the widespread presence and diversity of flowers. it is not as if they appear in one location and then spread about. it is truly unparalleled, when comparing it with the evolution of gymnosperms, ferns, vascular plants, and animals.
@@gracepisano Thank you for your insights, Grace.
@@gracepisano I remember reading something about a fossil plant from the Early Jurassic which displayed angiosperm like characteristics back in 2017. Did that result not hold up or was it too distantly related to shed any light on the issue?
@@Dragrath1 Nanjinganthus, yes, there are many others too. however it is difficult to establish beyond doubt that early jurassic fossils aren't gymnosperms. i could say a lot more but i will just say- they are not widely accepted as angiosperms because we can't rule out that they are preserved cones of an extinct gymnosperm
Plant evolution
Yep this one's for me🌺🌹
Without actual time travel, we'll never solve the fossil record
I have another theory... Maybe the speed of those molecular clocks were somewhat faster in the past because of some environmental issue. Maybe less ozone and so more UV.
But the ozone content is directly proportional to the atmospheric oxygen level and we mapped those pretty closely during the last few hundreds of millions of years, so they could be accounted for.
And against the UV hypothesis stands the fact that we would see the same happening today because of how much we destroyed the ozone layer. Compared to today, the ozone layer back in the Jurassic was like a 70+ factor sun lotion.
@@midnight8341 - Maybe more surface radioisotopes? I know there's been enough surface U-235 to power natural nuclear reactors in Africa.
Also, I don't know that the ozone has been depleted for long enough for us to get a good measurement. I mean, I literally don't know. 🙂
you would expect to see the same phenomenon in non flowering plants and animals then, which we don’t really see. plants do a lot to cope with high UV, especially the first land plants, since UV is (especially, WAS, 500mya) much higher than in water. when UV is higher and begins to do genetic damage, living things will find biological ways to negate that and early plants did have to evolve mechanisms to cope
@@Omnifarious0 but then you would have found unusually high rates of radioisotopes or decay products in stone from that era, so that also would have been accounted for.
And it wouldn't have taken that much time, actually. Since it is a physical effect, not a chemical or biological, it's immediate. The ozone layer is depleted? Immediate higher irradiation with UV light. Higher UV levels directly correspond to more DNA damage and higher mutation rates. These kinda go hand in hand.
@@midnight8341 - I guess for molecular clocks it doesn't matter if the mutations are successful or not. I was thinking there would be a delayed effect because most damage would be fatal.
If I recall there are evidences in many different areas of life when evolution mugh fast forward in certain times, and thus muddle the molecular clock for estimation.
It can go faster and can go slower but on average, when many many loci are used, they should have a consistent rate, the problem is not there, the problem is that their molecular clock model is wrongly calibrated.
I wish I'd evolved a bigger brain to understand how evolution works.
One should search for the signs of coevolution with pollinating insects and continue to evolve the model, as we know al models are wrong but some models are useful
What I'd really like to know is how you find fossilized pollen in the first place, or any other microscopic bits and bobs for that matter. Are they ubiquitous and all you have to do is identify and classify them, or is it just good old magic?
Good old magic, or in the words of the immortal bard: "sufficiently advanced science".
Pollen are remarkably robust - they are significant part of all sediments globally.
But how will we know what to plant in our Jurassic parks?
Neither of the two most-basal extant plants, waterlilies and Amborella trichopoda, are wind-pollinated. Pollen microfossils are nearly all from wind pollinated plants, because wind-dispersed is produced in abundance and dispersed widely in the general environment. Pollen that is adapted for insect pollination is more sticky and mostly not produced in such great quantities. I do find the fact that pollen of the major taxa appears in the microfossil record in the order suggested by molecular phylogeny very persuasive. This would be extremely unlikely if the lack of angiosperm fossils through the Jurassic were due to narrow ecological niches or geographically restricted ranges.
Seems like something that could be resolved by using coprolites
Pure speculation follows:
I think focusing on the perceived "gap" might be the wrong focus. A more compelling (and observable) phenomenon is the angiosperm explosion of the early Cretaceous. Lots of species that existed in small, scattered populations, living on the margins of an environment have poor (or even non-existent, known only by their inferred existence) footprints in the fossil record. Since the best evidence for the existence of the "gap" comes from hardy pollen grains, maybe the evolution of hardier pollen (and the environmental changes that selected it) also led to the this explosion.
richard
--
"After all, it is as respectable to be modified ape as to be modified dirt"
-- T.H.Huxley, Written in a letter to Dr Frederick Dyster 30th Jan 1859, i.e. before the publication of the Origin.
CuriosityStream: Oh is that what you want? Because that's how you get ants.
What if the Genes that later became useful for later angiosperms first started to appear in plants 70mil years ago. So basically 70 mill is the the estimated time the angiosperm lineage split and we had Pseudoangiosperms that later diversified into the flowering plants we see today.
Kinda like the way insect eating plants appeared in different parts of the world different plants developed ways to release pseudo-pollen until one or some conversely evolved to create different types of what we now call pollen
Have they considered studying Jurassic coprolites for evidence of eaten angiosperms? They need to know their sh*t!
when did bees appear then?
David Attenburrow
so what you are REALLY saying is that aliens brought flowers to earth?
I mean, it's the least they can do before all that back door probing...
Midnight “buy me dinner first”
@@midnight8341: "Stop! We have reached the limits of what anal probing can teach us!"
According to our ancient alien astronaut theorists, 'Yes'.
That would explain the sudden appearance in the fossil record but not the common ancestor they shared with other plants 100 millions earlier according to the genetic clock.
Haven't they found fossil plants which appear to share angiosperm characteristics dated to the Early Jurassic? I remember that getting published back in 2017.... Also from what I have read at least by the late cretaceous Angiosperms were the dominant understory plants adapted to low light levels which helped them survive the K-Pg extinction. Plus as others have suggested they may have not really diversified until later but having eked out an existence earlier with limited geographical range and or niche only rapidly diversifying once true flowers evolved allowing them to rely on insect vectors. Or maybe we have already found them just they looked quite different from what we would have expected? For example maybe the pollen shape didn't arise until later selected convergently by insect based pollination?
I wonder about all of the different fruits, vegetables, and animals that went extinct that we just barely missed that would have changed everything if they weren’t gone. Hopefully with quantum computers we can emulate DNA and see what kind of things were lost and see what kind of new species we can build. It would be such a crazy beautiful world if people would just help each other grow instead of tearing each other apart.
Is it possible that there was a diverging line that both developed angiosperm pollen and one died off WELL before the second bloom of angiosperms?
Ah, I remember Angie. Lovely Irish lass. Pity about her last name.
Lol, most unfortunate
That was her married name, her maiden name is lost to us.
@@christelheadington1136 , maybe O'Plasty
How are Angie and Jim related?
i think the problem is with Estimate rates at which those plants genomes change it can change depending on many factors including climate and catastrophic events
there are adjustments for site rate specific heterogeneity, rate changes between taxa and the like. the mathematical models are complicated and include a lot to account for the uncertainty in sequence evolution. these dates are reliably predicted, whether nuclear or chloroplast dna are used, including high numbers of taxa, and this probably does reflect the evolutionary history of the lineage, not necessarily that of the flower itself
Not really, the molecular clock does provide a pacing (on average and thus appliable to large enough genomic sets), the problem is how large is each step, each averaged mutation time. That's solved by proper calibration but the proper calibration in this case is what paleonthologists say, so clearly they are producing the wrong date if they crash with solid paleonthological evidence that, additionally, also fits the other part of the genetic data: the phylogeny, much more reliable than the molecular clock. So they need to review the measurement of their ticks: they are happening much faster than they assumed.
How is the potential for various rates of DNA mutation figured in? Does the model assume steady evolution? Would an event like a gamma-ray burst account for a burst of DNA mutation? Perhaps also accounting for the time gap?
Where's Olivia? I think... I'm falling in love. With Science!
David Attenburrow. 🤣
2:49 .....Rummy
Loved the video. I'm glad you love David Attenborough. His name is pronounced Atten-bruh.
OK bruh
What a attenbruh moment
what a-tten bruh moment
Nah...in America we pronounce the whole word
0:21 How? Aliens.
How do molecular clock analysis account for periods of evolution being sped up (like right after mass extinction)?
the problem here is they are using estimates to estimate. no wonder it doesnt make sense.
love to see people in youtube comments thinking they’re smarter than an entire field of scientists. just because YOU don’t understand it, doesn’t mean it’s arbitrary or random
@@gracepisano - But The Moon is right: there are major problems in taking molecular clock at face value, without considering the underlying assumptions, which is "what is that MC model calibrated with?" MC as such gives no dates, just a pacing for the phylogeny, it needs to be calibrated with actual data, in this case paleonthology. If the MC model and the actual facts on the ground crash, the MC model needs to be recalibrated 99.99% of the time.
@@LuisAldamiz MC estimates from nuclear and organelles genomes agree though, increases in taxon sampling and better analyses only converge further on the same window. no one saying MC is perfect but its not a random estimate. there is good evidence the lineage is older than the flower and it probably reflects the evolutionary path rather than just some clock error. we now know that angiosperms and gymnosperms diverged from an early seed bearing relative and so its not surprising that the lineage traces much further back than the actual origin of fossils with extant angiosperm morphology. the comment "they are using estimates to estimate" and the conclusion that that is unreliable dismisses so much good science
@@gracepisano - I know quite a bit about the molecular clock methodology and how genetists are worryingly determined to sell it as if it was C-14... without the required testing and without updating their calibration points according to the best available material evidence from more traditional (and consolidated) fields. I am most famliar with the human genetic aspect and I know for a fact that genetists have not updated their calibrations in 20 years, even if a lot of new archaeology and hominid paleonthology should have forced such recalibrations long ago.
The problem is systemic and is very serious and has two main causes (which are ultimately the same one):
1. Scholastic inertia, a paper cites a paper that cites a paper that cites a paper.... all the way to the late 20th century, when archaeology was suggesting very different dates for the human expansion out of Africa than it is today.
2. Lack of interdisciplinarity: the field of genetics feels a bit too arrogant and willing to tell other fields how to do their job just because genetics is so new and cool and offers so many new bits of info. In some aspects they are right, genetics has provided a lot of new very interesting data, often solving conundrums that had lasted for decades unsolved, but in the issue of the molecular clock they are utterly wrong, because there's no molecular clock without external calibrations that provide the appropriate time bracket in which to count the mutations.
MC says that the human migration out of Africa happened some 60,000 years ago. Why? Because that's the calibration point they picked 20 years ago, when it used to be the archaeological/prehistorical consensus. By now we know that it's rather 125-100 Ka ago but the MC has not been updated and to this new, rather uncontrovertible, data. How do we solve it? Each time we see an academic MC estimate for humans, we double it (I actually use a 150-200% correction because there are other considerations and I'd rather have my CI interval large than err).
This, I know, is the opposite of what is happening with the floral gap, in which the MC estimate is much older than what the fossil record seems to allow. As such it could go either way (the fossil record can have gaps, although pollen is like everywhere, so hard to leave gaps provided sufficient research) but if the palinological record is coincident with the genetic phylogenetic order of appearance, then it's very clear to me: what is wrong is (again) the molecular clock, in the opposite direction to the one I'm used to but wrong nevertheless. You need to recalibrate, for science's sake!
BUT WHAT ABOUT THE MOUNTAIN!?!?
Also it could happen that angiosperms developed first in a region of the world the science of paleontology knows not much about, like Africa. Another what-if: The first flower was so gymnosperm-like that it would be hard to tell the difference. Yet more: The first angiosperm fossil has been found long ago only not its flower, paleobotanists almost never have complete plants to study.
You said Attenborough wrong at the end
Who cares?
Not you obviously
when did stefan get so swole...
What was the first edible fruit? Like how far do I have to go in time to find the first edible fruit or fruit ancestor...
but... there are many times that dna has something that should be expressed but isn't... so couldn't that be a plausible explanation?
What if it evolved in a remote valley or on an island that wasn't connected to the rest of the world for millions of years? Followed by a connection event that spread it everywhere.
The only thing we now about the fossil record is that we haven't found it everywhere in that time period. Maybe we just haven't found the right place.
yes there are 2 hypotheses: “wet and wild” and “dark and disturbed.” these posit that angios were aquatic plants, or understory shrubs, respectively, in a gymnosperm dominated world, and that they only diversified later on. but this begs the question of what triggered diversification, if the flower had already evolved 50 million years prior, and it also contradicts some of the morphological data from extant flowers. it’s more likely that flowering plants probably did not actually evolve flowers until later in their evolution and when the complete flower finally appeared, diversification happened
Wow
As I expect someone is already researching it but I'll ask. Couldn't it be it took a while for insects and the like to get used to pollination cycle until enough it they could really take off ?
I'm going to go out on a limb here and say, they've existed for a very, very long time... :P
DNA would surely be able to tell us what the most basal angiosperm would have been like? And what habitat it would have lived in?
Perhaps we can narrow down the fossil hunt with that information - if we know it was a rainforest type plant, then we can search for fossils in sediments known to contain fossils belonging to that environment at all points along the gap?
Yes and no... It takes about 60times the raw input sequences to generate an okay-ish genome assembly for a unknown plant. Depending on the plant, that can be done in a day or two, like with a few algae, but for my master thesis, I would have had to sequence about 1.5 Terabases of sequences for that kind of coverage (which would be equivalent to about 500times the size of the completed human genome).
Now think about how much data you would need to get to reliably calculate a basal genome of an ancestor of about 90% of all land plants. And then we would need to account for the extraordinary changes plants go through, like consecutive whole genome duplications, rapid transposon expansion, cross-polination and hybridization with different species... But not just in the last few millenia or a million years or so. No, you would have to account for about 200 million years of those plants conquering the entirety of the planet and adapting to every níche there is... Some plants are nothing more than parasitic twigs, some need special acid treatments for their seeds to germinate, others keep ants as pets to ward off pests, while others grow nothing but two leaves in 50 years.
And there you wanna find something as simple as a tropical, or subtropical adaptation? We can breed that into plants in a century or two and those are still 99% identical with the wild type plant we bred them from.
I feel very much flattered by how much you think with can do, but that's just not possible.
@@midnight8341 It would be very difficult to calculate a whole genome for a hypothetical last common angiosperm ancestor (let alone determine the environment that it likely lived in) but some general details about the morphology of the plant may be able to be ascertained with less work. The problem is that this doesn't really help narrow down the search (i.e. What good is knowing that the ancestral angiosperm was woody with vaguely such-and-such flower pattern when you don't know when or where it could have lived?).
I would however caution against immediately disregarding the suggestion that the commenter above is making. I am of course ignorant of the subject of plant genetics, but none of the problems you brought up seem to make what he is proposing explicitly impossible. Sometimes when other methods fail the best option is just to bite the bullet and take the most direct path forwards.
Or ,Maybe they evolved 2 separate times?
the meteor crashed and caused plants to evolve into angiosperms. what dinosaurs were left after the meteor, struggled for survival as angiosperms quickly took over their usual food sources. finishing off almost all the rest of dinosaurs.
that's my cool new hypothesis :)
doesn't fit the data as while some dinosaur groups declined (non titanosaur sauropods) others thrived and the angiosperm take over happened too early and suddenly in the Cretaceous when dinosaurs were at their prime. By the late cretaceous Angiosperms were everywhere predominately as understory plants
the fault in our fossils. lol😂😂😂
lol David Attenburrow
Interesting
Whats 70 million between fossils?
well, it’s ..... a lot
it is like a fifth of the seed plant evolutionary history
if the seed plant lineage was america, this would be a whole 50 years of our history. that’s a chunk
The gap in the biological history is what we put into our gas tanks on a regular basis.
Could you compare insects like butterflies and other nectar consuming bugs, against the clock? if our earliest fossils of flowers can be found with evolved pollinators, logic would suggest it happened earlier then the fossils we have. If there is a lack of nectar consuming specialists in that part of the fossil record, then flowers were a new niche yet to be used by nature and the clock is off a bit... just a thought
nectar probably evolved after pollinator interactions were established. but your idea is on track. it could be associated with pollinator diversification, and that did occur around the same time. the question is really, if flowers were established at radiation, where are all the pre-flowers, as there are several evolutionary steps in the making of an angiosperm
True
What I really want to know is what is the last common ancestor between angiosperms and gymnosperms? And if it's not a tree, how did hardwoods end up having such similarities with softwoods?
yes wood evolved first!
for many years we thought that the angiosperms had evolved from within the gymnosperms, and it was , basically like two decades of trying to fit a square peg into a round hole. we now know that the divergence happened at the base of both clades and the ancestor was probably an early seed bearing plant. then angiosperms and gymnosperms diversified separately. this is the mystery. if angiosperms and gymnosperms, aka flowers and cones, split at the same time, what prevented the flowers from diversifying earlier.
but anyway yes, the earliest seed plants did have the ability to produce wood and angiosperms and gymnosperms inherited that ability. they also evolved leaves somewhat separately from ferns so they share the same type of leaf. they had a specialized style of primary growth and branching they had ovules a.k.a. seeds. and of course, pollen
Interestingly though, wood has evolved several times, in fact, extinct ferns and lycophytes show various types of wood production and actually much of the coal we harvest is from dead tree-like lycophytes that evolved arborescent habit independently. however, the seed plants share a secondary cambium, a special type of stem cell niche that allows them to produce xylem and phloem (vascular tissue) throughout their life , aka WOOD!
@@gracepisano Thank you ! I've been wondering this for so long ! Never been able to find an answer. I can't believe something like a tulip or a tomato plant comes from a tree like plant ! How is this possible ?!
1:31 Wasn't the Jurassic period a movie or something? I'm pretty sure I've seen it, there's this scientist and the hero was played by Leonardo DiVinci or whatever...
i'd rather think that the people analyzing DNA didn't properly take into account the metabolism rate of plants in extreme environments of which there's no clear data on.
this does not make sense
@@gracepisano as if cold temperature doesn't reduce your metabolism therefor reduce your cell division rate.
@@gracepisano also listen carefully to what he says 4:40 "learn past environments"
you’re saying metabolic rate- do you mean generation time?
@@gracepisano well if the plant growth rate is hindered there's clearly a lower fertility rate
It could be a case of convergent evolution, no?
convergence of what
No.
American pronouncing Attenborough is entertaining to me but cool vid (it's at-ten-bur-ra)
Great
4:44 are those ticks or beetles?
IMO beetles.
Absence of evidence *IS* evidence for absence. It is just not proof of absence.
Evidence = proof. What you mean is "indication".
@@LuisAldamiz No, evidence is not the same as proof. Example majority of evidence can show that mr X is murderer, but in reality he could be framed (also there can be contradicting evidence, but never contradicting proof). Proof is something that gives certainty. In the most strict sense proofs exist only in math, but in practice very solid evidence is considered as proof.
@bic boi The fact that you didn't understand what I said, doesn't tell anything about my "brightness".
@@user255 - Mathematical proof is not science, let alone legally useful in any way before a jury, it's just logic (as in methodical philosophy and not as in "reasoning"). In fact in such specific context, which usually ends with the acronym "Q.E.D.", the word proof is used as "proving" as logical process and not as item of evidence, there's no evidence in mathematical proof, it'd be too complicated to proof that "x" is not just in the mind of the mathematician. And whoever says "x", says "y" or even "+/-", all things that do not clearly exist in reality, unlike pollen grains and smoking guns.
@@LuisAldamiz I completely agree on your points about math and I never claimed anything contradicting what you said. I merely stated the definitions of the word "proof".
Maybe they were just rare and that's there are no fossils found yet. The most primitive flowering plants I know of are some species still existing in New Caledonia and they are not very vigorous or very invasive they very slow-growing and sluggish probably the earliest ancestors were not that different
David atom bro
Your fixed time to upload video like 2:21 AM EVERYDAY ( TIME According to India ) . Btw thanks for every bit of knowledge I receive from you every very early morning 😊
May stegodaurs ate all angiosperm in the jurassic period so no fossil found😉
Doesn't pollen predate angiosperms? 🤔
Yes, gymnosperms have been using pollen long before angiosperms existed, but their pollen is distinct from eachother
ya, angiosperms and gymnosperms both inherited pollen from a common ancestor, but all living angiosperms have pollen that is a certain shape, and the switch to this type of pollen in the fossil record is abrupt
Faster ! Otherwise I begin to understand what you say.
👍
Molecule structure like eggshell the cocktail ingredients 2 place in a cocoon similar to the Pharaoh coffins coffins are like cocoons maybe you should look at the Egyptian hieroglyphs warning
Damn you scientists, leave some gaps for our gods to hide in
What the effect of epigenetics in plants did you the paternal gene dominance was first seen in peas
Flowers are sexy , they know it , we prolly should know it by now ...it's my party and I glow like a star..
...try a whiff -o- dis !
PBS Eons has a great related video, "When Did the First Flower Bloom?": ua-cam.com/video/13aUo5fEjNY/v-deo.html