What Darwin won't tell you about evolution - with Jonathan Pettitt
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- เผยแพร่เมื่อ 28 เม.ย. 2024
- How did the complexity of life evolve? Was it via finely-tuned natural selection, or a more messy process altogether?
Watch the Q&A for this video here: • Q&A: What Darwin won't...
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In this talk, Jonathan Pettitt explains how living systems tend to make simple mechanisms more complicated than they need to be. He will show how such ‘unnecessary complexity’ can both restrict and expand an organism’s evolutionary potential.
Jonathan is the 2020 Genetics Society JBS Haldane Lecturer.
The JBS Haldane Lecture recognises an individual for outstanding ability to communicate topical subjects in genetics research, widely interpreted, to an interested lay audience. This speaker will have a flair for conveying the relevance and excitement of recent advances in genetics in an informative and engaging way.
This lecture was filmed at the Ri on 14 June 2022.
0:00 Intro and complexity in the visual system
4:43 Population genetics
5:59 What is genetic drift?
14:46 Where non-coding DNA came from
19:57 Self-splicing introns
22:50 How mechanism that saved eukaryotes
28:00 What C. elegans can teach us about genetics
30:14 How C. elegans translate DNA differently
39:01 Why trans-splicing is important
42:35 Using trans-splicing as a drug target
43:39 Constructive neutral evolution
Jonathan Pettitt is a Professor in Genetics at the University of Aberdeen. He has a long-standing interest in applying the manifold advantages of C. elegans to study the genetics of basic animal biology. His current research investigates the molecular basis of post-transcriptional RNA processing, including nematode-specific mechanisms; the understanding of which may facilitate the development of new drugs to treat parasitic nematode infections.
Jonathan is strongly committed to public engagement with genetics. He believes that the explosion in the availability and application of human genome sequence information, coupled with the development of genome engineering technology, means that there has never been a more urgent need to ensure genetic literacy beyond the traditional areas of research and healthcare.
As a passionate and enthusiastic communicator of genetics, Jonathan has written and presented a broad range of events, including The ‘Cabaret of Dangerous Ideas’ at the Edinburgh Fringe, the Royal Greenwich Observatory, the Royal Institution, and science festivals in Aberdeen, Edinburgh and Sofia, Bulgaria. He was the genetics consultant for Helen Keen’s book, ‘The Science of Game of Thrones’.
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Good lecture, but it needs more beavers
Frank Drebin agrees
You can never have enough beavers
Eww. This isn't the '60s
My wife has one, and i kinda wish she had more.
Ehh I'm a weasel man myself
Please rethink and change titles! "What won't tell you about " is a depreciation of science and teaching / lecturing!
This is the best explanation I've heard, yet. So basically, Eukaryotes are known to hoard materials and parts for later use. Sounds like my parents.
If both your parents are Eukaryotes, chances are that you're eukaryotic!
😂
first off - love the Sub-Pop sticker affixed to the laptop......as much as i was able to grasp - which was definitely more than i expected - i found this talk absolutely fascinating. thank you for sharing Mr. Pettitt...
When clicking on this I guessed it was going to focus on mutation rate/ population size stabilization and was very happy to find out it was on introns and translation. He presented the information very well, hope to see more like this, Cheers.
Can you tell me, please, what is the minimum number of individuals that must be present in order for the group to be considered a population?
@@thankmelater1254 Have never considered the difference in number, but I suppose it is two. My understanding of a population is a discrete gene pool; as such, it would only require isolation from others of the species, and the ability to interbreed. Minimum viable population is based a number of variables both internal and external. Hope that helps, but really I’d ask the channel directly, I kinda assume you meant to. Cheers.
@@aaronbedell3753 Thank you. When a whole science refuses to answer the most basic of questions it sucks.
Try to get a climate science priest to answer how much weather data it takes to make climate data.
All they do is excoriate those who talk about the weather right after they talked about the weather.
@@aaronbedell3753"it would only require isolation from others of the species, and the ability to interbreed."
"Species" needs definition in that case. Also "Interbreed"... necessarily must have fertile offspring?
@@thankmelater1254 I guess "species" would be individuals which could interbreed and therefore effect the gene pool, and "interbreed" would be, yes, creating fertile offspring. But this definition doesn't make the assumption that the population is healthy or will even survive, only that the gene pool made up via the individuals can be measured and has a defined boundry. Makes it useful for trying to collect data on the effects of other variables on that gene pool. Again, I understand it as a discrete geel pool, not a collection of individuals. kinda like I don't see individual ants as individuals, but rather parts or a single hive. And not all ants everywhere just this group of ants, all those individuals rise and fall togeather as one thing. I know using an animal as a metaphor here is kinda silly, but as I understand it (especially for a genetics perspective) it's a discrete gene pool. Hope my thoughts helpful. Cheers
Brilliant! Love learning the history of introns and complexity and evolution, drift, selection.
What exactly did you love about it?
Seriously though, labeling a blue line, a green line, an orange line, a red line, and a purple line as "the red variant" is not an optimal data presentation strategy. Especially right after showing a graph of the "red variant" represented by a red line.
Lol that was a bit of an oversight but still understandable enough with the commentary
That was a confusing moment
Yep. Completely lost me.
I was so glad that this is a youtube video so I could pause and rewind until I got it xD
Welcome to the confusing world of the colourblind, it ain't easy. Lol. Apart from that. Did you enjoy the talk?
I really enjoy listening to someone with amazing insight, explain something extremely complex in a clean, simple way that I can actually understand.
I disagree.
But I guess it is just ok...
@@caseypalmateer4515
You disagree that I enjoy listening to someone with amazing insight...
🤣
@@caseypalmateer4515 I agree with your disagreement. We have seen better…
It’s content like this that keeps me subscribed to the RI channel. Thank you.
Far better than some of the earlier “buy my book” talks
You mean «Why Dogs Live in a Multiverse?» I agree with you.
People have to make a living.
@@savage22bolt32 yes, but there’s ending a talk with “I’ve only touched on the subject here, if you want to in-depth I do so in my book that is described in the comments” and having a copy on the table and constantly showing it like some sort of infomercial.
@@KribensaUK yes, I semi-agree with you.
I'm almost on a guilt trip for not buying some of the stuff that great creators are selling. But I know I can't support everyone.
And it's not as intrusive as all the GD commercials YT foists on us.
@@KribensaUK I'm sorry you feel that way about authors who talk about their books. I, of course, feel differently: I actually like it if the speaker has published a book about the subject.
- It always adds to your credibility when you have a published book. Particularly for a scientist, publishing a popular-science book (not just technical papers) shows that they're a science *communicator* as well.
- If the talk interests you and you want to delve deeper, the book becomes a great starting point. (Otherwise I don't even watch the full lecture-I have other things to do.) Indeed, I have read many books only because I watched the corresponding talk first and got hooked.
Remember, it's not required that you buy the book-that's completely optional.
I mean, sure-most of the time you eat the free samples at the supermarket without thinking twice. But once in a while, you do like that chicken in teriyaki sauce. And you say to yourself, yeah, I could eat more of that.
It's nice to have that option available.
If you have Amazon Prime, then-in most cases-you don't even have to pay extra-you can read the ebook for free.
Thank you! It was amazing 🤗
Thanks a lot. This was highly informative and there were quite a lot of surprises.
I’m really impressed by the amount of views this video has. If at least 20 % of the people who clicked on it viewed at least half of it without being biologists, I can now say I have faith in humanity. Me, being a theoretical biologist, struggled sometimes to understand the intricacies of this talk, but it was definitely worth it.
I'm a software engineer and was keeping up and enjoying until somewhere after 14:46. The _What is genetic drift_ section alone was worth the click and answered the title's question.
'theoretical biologist' and didn't already know this stuff - pffft
Dave, how do you know that 20%+ watched >1/2, & that they're not biologists?
@@savage22bolt32 Because YT has all your stats and info 😂
I know nothing of biology, I'm uneducated and I believe I may have got something, learned something from watching this. I could be wrong, It definitely makes me yearn for formal education. I suppose I'm grateful I have the internet at least.
please more technical talks like this 😇
"Evolution is nothing if not making the best of a bad job" - Amen to that!
The most positive proof of the 'Theory of Evolution' known is the fact that Primates (monkeys, apes, baboons, etc.) evolved from Liberal Democrats. 🇺🇸 😎👍☕
all r bad apple but pick the least bad
Thank I learned a lot and this was to great help.
That was very interesting. Thanks.
So it's all "lost in transcription".
Nicely delivered.
Interesting to see chance and opportunism and natural selection all being part of the mix that creates the biology we see around us.
So interesting! Wow. Though lots of complex words and explanations I still got the gist of this lecture and it is mindblowing how nature works so hard to survive and evolve.
And because of the gender pay gap, Mother Nature has to work through her lunch break to support her kids!
"mindblowing how nature works so hard to survive and evolve." Nature=God.
@@thedarkmoon2341 even if a deity started everything. They are not physically present now and nature has taken action
@@thedarkmoon2341 Actually nature = nature
@@thedarkmoon2341 Tests in religious schools must be easy to ace. Every answer = God did it.
Note: The yellow arrows near the blue gear DO NOT demonstrate what is stated. They both point in the same rotary direction. A better diagram would have ONE arrow per gear, at first a bidirectional arrow, then a unidirectional arrow.
I have been teaching and presenting information in many different formats and settings for many years. I love science and science presentation. My major was in education, with a science focus.
I'm begging you, RI...I'm down on my knees here. Please please please get someone who knows how to do audio so we can get talks that aren't saturated with mouth noises. I can't watch more than about a minute of these before I'm grossed out to the point where I have to turn it off.
I totally agree. The speaking has a INCREDIBLY DRY MOUTH, and the mouth sounds drive you batty. You should listen to the RI lecture by Nick Lane. It was impossible to listen to him.
Mouth sounds are the bane of my existence. It’s a shame that this comment didn’t get popular.
Interesting topic, especially for a math guy like me who was never as interested in studying biology. It's really great to have information presented by an expert :)
Biologists could likely use your help. Biomathematics began with statistics in the 1700s but has come long ways in the 20th Century. Theory of games of strategy is one imperative for making predictions of aggregate behavior but I've been curious about knot theory in orgonometry. I prefer orgonometry, because like trigonometry, it dispenses with theory and relies purely on measure.
How many dimensions does it take to screw in a lightbulb?
Three that we perceive and countless others for theoreticians to milk our tuition money⸮
Ask a sailor: it's two dimensions, a dimension of insertion and a dimension of yaw!
Biology bores me to tears.. another math guy here
@@LL-wc4wn statistics (again, an earliest historical record of biomathematics) is held among the most boring realm of maths.
Ironically, it's also held among the most useful maths for liars, and case in point, maybe the maths of predators and parasites, the most deceptive of life forms⸮
Non zero sum games of strategy are downright useful for people who want to succeed in life, score with a mate, earn an honest living, reduce system noise.
@@LL-wc4wn I am the reverse
Excellent lecture! I only disliked his equivocation of "complex" with "complicated"... I understand they are synonymous in ordinary language, but they couldn't be more different in scientific parlance.
Excelente Dr Pettitt, excellent lesson. Truly good! I am at the "ending line" of your research (the mind brain selection and drift) and philosophy. Thanks. (Btw your English is very peculiar. I believe your idiomatic origin is peculiar maybe not native British?).
Brasil
He uses a few americanisms here and there, but his English is very much British. His accent is a bit difficult to place, the way he pronounces a few words (such as 'father') sounds vaguely north of England, but his general pronounciation is more southern. He may have grown up with a northern or midlands accent which he modified through education - which is pretty common in Britain.
No American pronounce IMPORTANT and ECONOMICAL this way,, open vowels.
Thank You! This was really interesting. But I think some small changes to some "slides" would have done a world of good. Without the laser pointer some things got kind of lost. I think.
"All eukaryotic ... most eukaryotes... start their translation wiith AUG."
As you suspected, that's now known not to be the case:
"... it was long thought that eukaryotic translation almost always initiates at an AUG start codon, recent advancements in ribosome footprint mapping have revealed that non-AUG start codons are used at an astonishing frequency."
See Kearse and Wilusz, "Non-AUG translation: a new start for protein synthesis in eukaryotes", 2017
doi: 10.1101/gad.305250.117
He doesn't address creationism directly, but parts of this talk explain how evolution produces "irreducibly complex" systems, something which creationists argue is impossible. The end result in his example is a system where you can't remove any of the parts without the system breaking, and yet it was possible for evolution to build the parts of that system and then tie them together step-by-step.
Yes, but why, some of these IDers think, God would tinker about with evolution for so long?
(I'm not sure if my grammar was right.... )
That was fascinating.
I found the key word to be "substrate": neutral genetic drift generates a background of biochemical complexity that natural selection might use to solve a problem somewhere down the road. But doesn't this resemble the basic relationship selection has with the environment in general? Can't this "substrate" be seen as just another feature of the world that selection adapts to and seizes opportunity from? A feature of the genome's environment that just happens to reside within the cell?
My ears pricked up when he mentioned leishmania. I've had Leishmaniasis and the current treatment is brutal and can be fatal if the patient cannot tolerate the drug.. If this research identifies an Achilles heel that can produce an alternative treatment it would be a boon to the millions of people (largely in developing countries) that have exposure to this disease.
Graphs were not clarifying to me. I can see the wilder swings for a small population, which would be expected. But why something died out or didn't, and whether it was blue, or green or whatever, and why, no, totally opaque. The rest was interesting. Unsure I got it all but maybe another viewing would help.
During that part of the talk he was discussing random chance over time. There’s no “why” to be had, which is why he ran the simulation many times and showed several of the measured outcomes.
That's my lecturer from University of Aberdeen!
at this point ive learned so much from the royal institute! Love spreading free information!
Really enjoyed the lecture and learnt something new!
Learned* 👍
@@donaldmcronald8989 No, we are international and its just preference.
However l learned you don't have autocorrect and are pedantic..
Just jesting, stay fit sharpwit
@@donaldmcronald8989 Learnt: past simple and past participle of learn
Check before you correct someone...
I love this guy, he even says kephalopod (the right pronunciation) 👍🏽
Wouldn't the introns affect the likelihood of exons being separated by crossover?
This is a harder lecture to follow than some RI lectures I've viewed. I did get a bit lost I confess. I have a medical degree (from over 50 years ago), and I'm not a complete science dummy but I think Jonathan Pettit tried to cover too ground much here. Darwin did indeed have a problem, his theory of evolution was developed without the knowledge of Mendel's experiments, that showed the independent and random inheritance of genetic characters, and gave the mechanism by which organisms could maintain genetic differences and change over all future generations (which is the puzzle that Darwin wasn't able to solve). Fast forwarding to the subject of this lecture, so much more more detailed and fascinating knowledge, but the basic principle remains the same. Still, thanks for the effort Jonathan, hopefully others found the lecture more illuminating than I did.
Population Genetics = Genetics + Statistics!
Each science is quite complex and when both of them are fused together make "Population Genetics" extremely complex!
A recessive mutation like blue eyes would remain hidden for many generations before the first blue eyed person was born. An interesting dynamic
@@davepowell7168 I also have the blue eye mutation. Does it produce any advantage that would account for its popularity?
@@petergleeson295 Well there's the Nordic master race possibility and the probability that some women just love blue eyes?
No vision advantage from iris color l know of yet
All albino have blue eyes, it is a deletion of pigmentation genes. The blue colour is just an effect of light instead of blue pigments.
The leucistic humans walk amongst us but are penalised for being truthful , Julian Assange is imprisoned as if he had been a traitor to an armed force which he was not part of. The guy was a journalist, that's all
@@davepowell7168 probably some men too
I'd like to hear more evidence that the variation advantage of introns wasn't present from pretty early on. Seems like it's just an assumption that "then" they were unilaterally harmful.
So many assumptions here…
great subject but
I did not hear the why or how of the drifting started between the 10 and 10.000, 😢
only a lot of assumptions,
would like to understand that better before I can go on to the rest of assuming after, to get the rest followed and understood all with in my brain, and space time
Why did they exist at all?
13:15 I know this as "It's not the Better, which is the fiercest enemy of Good, it's Good Enough."
The perfect is the enemy of the good. The good enough keeps species alive.
Does anyone have a good resource for a more in-depth explanation of the trans-splicing concept?
Also, did he not say that animals both did and did not use trans-splicing?
It looks like many do, but a lot of them (us included) do not. Considering how many animal species there are, this is not surprising. It must also mean that animals are one of those 14 groups that came up with trans splicing themseves, otherwise all animals would have the capability
@@thenasadude6878 There's something wrong with your post. If "animals are one of those 14 groups that came up with trans splicing themse[l]ves, otherwise all animals would have the capabilit" then we would have [at least, have had] it, since we are animals.
@@gandydancer9710 if all animals had trans ability, then it would mean animals inherited the trait from a common ancestor.
Since a sizeable portion of animals don't have the trait, they've either lost it (because it never became necessary, which is unlikely - it would mean no damage ever to the introns) or the common ancestor lacked the capability.
If the ancestor lacked the trait, then some animal must have at some point "invented" it
He used the word "animal" in two different contexts: C. elegans is a member of Kingdom Animalia, so obviously there is at least one "animal" that uses trans-splicing; later, when he was talking about targeting trans-splicing as treatment against things like schistosomiasis, he casually referred to "animals" being unaffected by counter trans-splicing agents--I suspect he meant creatures such as cats and dogs and livestock, which don't trans-splice.
Could someone please please break the 5-6 main points of this lecture down, for someone who doesn't have a deep background in molecular biology?
Main point: zero cost neutral genetic drift happens. Later, something may break, or become advantageous, and then the neutral protein/system gets "locked in the population". Also, at low population sizes, chance may cause a slightly hurtful mutation to become fixed in the population,because "eh, good enough".
@@TomiTapio What is the significance of something neutral getting fixed in the population? Thanks!
@@greggeisenberg9196 It justifies genetic drift as the default setting. A big data nugget for diversity and isolation induced speciation.
@@greggeisenberg9196 Neutral mutations becoming fixed in different populations can help trace the ancestry of the populations.
I absolutely love your shirt. Sorry I love your discussion as well. I live in the county where Wilkesboro Elementary is located.
I too grew up there. I don't recall Jonathan in any class of mine! Must be a story that goes with that tee....
Great content as always say 🌍💖
There are some older videos showing this working in computer models. It's amazing what can suddenly change when a new mutation joins forces with an old mutation. Suddenly, a new variant is dominant and rules the world.
I clicked on this thinking it was another TH-cam creationist telling us "how the Theory Of Evolution is wrong" by misunderstanding it or misrepresenting it. Instead I got a very edifying lecture that gave me a lot of details I didn't know. That's all I need after a day of programming to make the day worthwhile.
What did you learn from it really?
@@szymonbaranowski8184 Several things including how population size affects evolution.
Eh, does it need to be explicitly said? The fact that we have literal code embedded within us should be enough to tell you...
@@kinetic7609 It shouldn't need to be but I like answering science deniers so I get a lot of their videos popping up in my feed. This was much more pleasant.
Funny guy. In a very small circle. Loved it!
Jonathan does more to PROVE evolution than anyone I've seen before. Thanks.
@@gregoryt8792 → The probability of your being correct is 10^-100 (inverse of a googel). You don't have a clue.
I'm a computational physicist who works in genomics and I believe this theory is wildly incorrect. I think there is a very clear, testable and evolutionarily sound reason for the existence of introns in our genomes, further that the larger and more complex an organisms genome is, the more "spacers" it needs to self-organize in a way that supports computation. In order for cells to compute reliably the chromatin in our differentiated cells needs to be highly structured to be systematically accessible to computation. We know that the way that large bodies of chromatin self-organize is to form helix's of helix's wrapped around 4 types of constant diameter structures called histones. According to information theory, we can't predict how or when a given piece of code will complete a useful calculation. Another way of stating this is that we can't predict how long a program will need to be to solve a given problem without writing the code. Gene's come in arbitrary lengths that need to be fully accessible for transcription. They must be organized by being wrapped around constant diameter structures, which are all in turn tightly coiled up inside the cell. In order for our epigenetic machinery to systematically access complete (arbitrary length) genomes wrapped around constant diameter histones, we need spacers. Our man-made programs are full of spacer data which is usually just zero bits for similar reasons. In a biological system, these spacers would probably need to have more specific hydrophilic or hydrophobic properties represented by longer runs of certain nucleotides in order to provide "handles" for epigenetic machinery to systematically unwind the coiled up chromatin, identify the relevant coding sequences and ignore the spacer data.
What's strange to me about modern biology is that you don't hear this said clearly anywhere and yet the field of information theory tells us that in order for DNA to compute, there MUST be some amount of spacer data to facilitate decoding. Some or all of what we call Introns MUST be spacers. Over the years I read and heard many of these really extreme and highly implausible explanations for what has been called "junk DNA". If you're going to wind a 3 mile long strand of DNA around a nucleus that fits inside a single cell and need to access a gene in the middle of it, you need enormously complex machinery and padding to untangle that gene and expose it in a systematic way.
In this video, the "expert" is portraying genetic drift as a cause of junk DNA, and presumably various genetic infirmities. The idea of "genetic drift" has a very close analog in modern AI learning systems. In order to train a neural network to "think", it needs a certain amount of noise to enable it to learn efficiently. If we don't add noise to a neural network, it will tend to overfit the sample of data it is trained to. The same is probably true of evolution. If you want evolution to "LEARN" the optimal genetic solution to maximize the survival of a population you DON'T want it to overfit one new genetic trait. Like neural network training, you want each new (locally beneficial) mutation to be tested in the context of an entire population of different environmental and genetic circumstances to select the overall NETWORK of genes that collectively maximize for survival. This is how modern neural networks have achieved such incredible advances in learning speed. In the context of this video, it means that evolution works best and as intended in large populations. If the population set is low.... then survival is an emergency and spreading a new incrementally beneficial new mutation rapidly may be essential to avoiding extinction. All of this would be an explanation for how evolution is incredibly efficient and intelligent about how it innovates rather than a rationale for why it must be sloppy and broken. This kind of analysis smacks of anthropomorphic bias. If a scientist encounters inexplicable natural phenomena, it's the phenomenon that must be stupid, not the scientist who can't figure it out.
Starting from the end, there is not a single proof that supports DNA changes are natural nor random. They could be much easier artificially made, which would explain things like changes at embrionary stages much easier.
While I think you have a point, your theory is more complex in the sense that the genetic drift is always the h0 hipotesis while the natural selection hipotesis requires to be proven.
Great perspective thanks
What is the minimum number of individuals needed for a group for it to be called a population? One?
Disappointing lack of beavers.
Thank you for your video.
@ 17:00 I might have got hold of the wrong end of the stick here but I don't think Eukaryotes are single celled organisms at all, they contain many organelles inside their cytoplasm from what I have read. Or does he mean that eukaryotes are single cells which is pretty obvious really.
Can't help but feel this is exactly how data transfer and compression works in a computer system.
it is
Really? Can you explain the computer version to me? I couldn’t understand the biological one…
This was a great talk. What it led me to think is that if we do discover life elsewhere in the Universe, there is a fairly decent possibility of it having things about it vastly different from what we've come to expect of life here on Earth.
It's fairly guaranteed that life elsewhere in the Universe won't resemble anything we are familiar with on Earth. And they will be carnivorous with a taste for human flesh! 😜
@@supertubemind But having a taste for human flesh would resemble not a few creatures on planet Earth, including, in rare cases, some with human flesh themselves ; _o_
This is confirming my armchair hypothesis - why do we so few transition fossils - because in a time of transition, populations had to be small, to fix changes, and therefore the probability to fossilize must have been small... In big populations, you see just slow and small changes... fascinating.
Very enlightening lecture. Evolution at the fundamental cell level.
My admiration for evolutionary theory and Darwin, , who developed it when genes were not heard off.
There is no evolution
Darwin died 140 years ego. It's like saying What Newton won't tell you about gravity. PS: I found the talk really interesting and informative. PSS: you shouldn't take me serious. I'm not a scientist. I work in IT.
Yeah, you have a problem with this nonsense too. We didn't know anything about DNA until long after Darwin was dead. This guy is a clown.
A more apt title may be "What Darwin's model doesn't cover"
Yeah..you probably best turn the Darwin book off and On again.. new chapters will be updated then...
@D R Lamarck was a little bit right. Epigenetics does not quite work the way he imagined... a Giraffe child having a longer neck because momma Giraffe had to pick tall fruit.
@@jjackomin Are you an expert on circus performers? Wow, didn't know you get a degree in that! Did a google search, nothing came up? Please tell us where you go to get it.
I came for the population genetics, stayed for the memes. 😀
13:00 - coś czego w sumie mozan by sie domyślec w podstawóce. :)
31:00 - to jest piekne w nauce; ta niepewność ;)
43:10 - objawy dysleksji ?
😂😂
...and so they make a "choice".
Despite just correcting himself on using that terminology. I know we're all conditioned to speak in this way but it makes it difficult for those who regularly follow the science to separate processes from agency when we use words like choice and want, etc. To describe things that aren't capable of making choices or having desires.
I find myself in the position of Dr. Pettitt's imagined student, rolling my eyes at his obscuration of the obvious. Yes, if the numbers are small the Laws of Large Numbers won't apply, and chance can swamp natural selection... but regarding this as some alternate method of evolution seems like a category error. And saying that it's a matter of population size is obtunded. It's not the size of the overall population that matters to calculate the chance of a trait's extinction, but the absolute number of individuals who possess it. Then he wanders off into material that doesn't seem to be on point, whatever that point was.
It's not necessarily true that the absolute number of individuals is most important. Being a smaller percentage means that group will have less access to resources
@@olbluelips There is no general reason that I can see why a Darwinian-fitter subset should have less-than-average access to resources, and nothing in Pettitt's account suggested that, that I can recall.
You were nicer than I would be - I managed fifteen minutes and lost the will to live.
yes, rather like the Darwin original, 'On the Origin of Species', which waffles for 450 pages and does not explain the origin of even a single species, not one
Full disclosure, i have not watched this video yet so don’t have much context. But as someone who has studied population genetics, I can say that it is true that population size directly influences the probability that an allele will become “fixed” in a population (either completely lost or completely ubiquitous). The phenomena where chance events overpower natural selection is called genetic drift, and some say is actually the dominant mode of evolution. Genetic drift becomes more probable with lower population sizes, and selection is much stronger in large population sizes, because selection coefficients are often extremely small and so therefore the population needs to be large for them to have an effect. This is all well established and really more rooted in statistics than biology. I really enjoyed population genetics in undergrad because it almost entirely abstracts away all of the biology, and allows the calculation of things like fixation probability and directions of evolution solely based on allele frequency and selection coefficients.
While undoubtedly a good teacher, I get the feeling there wasn't a lot of time spent adapting the material for the situation of under an hour general information. One of the least appealing presentations I've seen here.
Yes, cheers to the students who said this was boring and badly taught. I concur.
Sounds like you are looking for pop-science.
Excellent talk
He suggested that changes in organisms move from simpler to more complex. Does it ever move from more complex to simpler?
All of the time. Many parasites are simplified versions of more complex animals. They may have complex life cycles, though.
Isn’t it called devolution? For kicks, read Vonnegut’s “Galapagos,” where humans just go dumb with a vestigial brain.
Clickbait title implying this has something to do with the Darwin's field of research.
Darwin was a naturalist, not a biochemist.
You know what else Darwin won't tell you about - blockchain technology. So what? Not his field.
In an abundant environment nature has an opportunity to do many experiments.
In an environment of scarcity nature relies on the most reliable methods of perpetuating a species.
Aside: In humans abundance brings selfishness. Scarcity brings cooperation.
Transitioning from scarcity to abundance brings joy. Transitioning from abundance to scarcity brings strife.
Your equation is based on what? Too many situations where scarcity sparks egotism to an extent we find harrowing. The fear of scarcity remains in times of abundance and could trigger egotism as a preventive measure. Not that I approve of it.
@@annelbeab8124 there is a big difference between perceived scarcity and very real scarcity where shelter, food and water availability is uncertain.
@@ArtII2Long I think you have that backwards as when water and food are scarce people are going to want the last drops for themselves, not others.
17:55 the funnest of the fun facts.
Nick Lane makes us see the evolution of the Earth with fresh eyes.
Jonathan: "Evolution is not going to the trouble of building ..." What does that mean? It was not Darwin as far as I know, who believed that evolution can perceive troubles. Evolution has no direction, no intention, does not avoid trouble or all these sorts of things. Evolution is the result of surviving specimens over a long period of time.
It's just a more digestible way of saying "Evolutionary pressures will favor mutations with fewer superfluous features, and the result will be niche optimization".. So, evolution will not abide superflous eyes or complexity of eyes based on the niche. "The survival of that which does not suck too badly." --Holly Dunsworth
Evolution results in 90% of species becoming extinct.
@@deathbykindnes you use words like complexity and superflous. Is an elephant more complex than a bacterium? If so, why do we have elephants if bacteria are sufficient? If not so, what does complexity then mean?
that, and all the use of "invented"... nobody invented noting here
An elephant and a bacterium are as complex as they need to be in order to be fit enough to continue performing in their niche...
So what is the green line? Where does it come from?
Possibly jumping genes.
Fascinating enough to listen to all the way through and yet too complicated for this Eukaryotic mind.. Perhaps enough to note another’s comment that ponders whether this is similar to the way data transfer and compression works on computers. I’ll go with that.
I wonder how many folks in the audience 'get' the "this is fine" meme at 23:00 :)
More at 25:14 - wonderful :D
I would've expected a more professional, non-sensationalistic post title than this.
It's not *that* sensationalist imho. Darwin was just early, so there're plenty of things he couldn't tell you about evolution. He was obviously right about natural selection, but we're many years ahead in research
@@olbluelips Yes, but if you look at the actual talk, Darwin is barely mentioned at all.
@@KaiHenningsen lol that's a fair point honestly. But I think the "Darwin" part of the presentation was when we were under the simpler assumption that Selection's influence on determining genetics was about the same regardless of the population size.
Seeing the disadvantageous trait totally outcompete the advantageous trait due to random factors at population 100 was interesting. Not because it's super surprising that unlikely things happen randomly, but because it affects the way you look at traits in populations. If some trait arose when the population was relatively small, selection might not explain its presence as well as you thought!
@@KaiHenningsen on the other hand, if it’s a talk about things Darwin didn’t know, then Darwin’s relevance to the discussion would be very small! 😊
14:50
Top: DNA
Middle: Caveman
Bottom: Elvish
Genetic drift is a concept we use when we can't actually track the directionality of selection ('random') so we call it drift. It's just selection.
That was bloody interesting. But the audience seems to have had a sense of humour bred out of them.
Were there jokes?
@@Autists-Guide only if you were clever enough to get them ;-P
@@MarkDibley
Too distracted by the "so"s and "m'kay"s.
The audio for many recorded talks like this is either just the lapel-mic or the lapel + ambient mics but with the ambients cranked way low in the mix. This is because audiences are surprisingly loud. A result of this, though, is that audience laughter is basically impossible to hear (and always leads to TH-cam comments mentioning the 'unlively' audience). I think this is what the RI is doing - If you listen to the QA sections, they pass a microphone around, and you can't hear the person talking until right when they bring the mic up to their face.
@@Autists-Guide imagine not automatically ignoring these
Darwin is dead … Darwin can’t tell you anything.
but for language and literacy
@@chrishoover4888 which is still a crock, because anti-evolution nitwits still think evolution is verbatim what Darwin originally wrote about.
Watched all of it 48:08
If there is a creationist watching this, I would be curious to read your take on this lecture.
To be sure, I'm not trying to set you up to poke fun at you or to humour you.
I'm genuinely curious what you think.
Creationists do not actually think. They just "believe".
Some people must now think their "imaginary friend" made things so unnecessarily complicated.
Yes, he/she/them was/were _very_ sloppy...
Clickbait title. You lost a view for this. Next time you'll lose a subscriber.
You boosted engagement by leaving a comment. Too bad!
@@olbluelips I like the channel. I just hate clickbaits. The only thing I can do is let them know.
@@k1ry4n Good to see you focussing on what is important like a real science enthusiast.
@@godfreypigott Being a little more than a "science enthusiast" I like scientific rigor. The fact that this is "science communication" channel aimed at the general public doesn't excuse the authors when they use this kind of cheap tricks.
@@k1ry4n If that is your idea of rigour then you are probably a denier of climate change and covid.
H.Dunsworth's quote, at 13 in, is roughly what I often ascribe to Wikipedia. Both with love, and not.
This seems very related to the law of large numbers.
There are so many unknowns that all our current theories are almost certainly wrong. It's like physics in 400 BC.
More realistically like physics around maybe 1800, I'd say.
Possibly wrong, but incomplete
The old axiom - the more you know about a subject, the more you realize how much you don't know.
How about a button-down shirt, a jacket, maybe...God forbid...a tie?
So disrespectful to such an institution!
Saltationism held that new species arise as a result of large mutations. It was seen as a much faster alternative to the Darwinian concept of a gradual process of small random variations being acted on by natural selection.
I am unsure of the infestation argument: "more infestation less survivability", because having more mitochondria made those ancient eucaryotes much more energy productive. In fact, aerobic respiration gives 18 times more energy than anaerobic respiration. Mitochondria could use oxygen, meanwhile, the host cell only had anaerobic respiration at its disposal. Perhaps the chaos of a larger infestation was more than compensated by energy production?
I think he meant the amount of infestation of the introns, not of the amount of mitochondria.
You should speak more carefully and outline the conditions of your simulations more completely. I found this to be a bad enough fault that before 10 minutes I had had it and quit watching. I have taken population genetics and enjoyed it very much. Your lecture I did not enjoy at all.
Darwin won't tell me a lot about evolution. He's dead, and knew nothing about genetics or cell biology.
Too bad that my downvote isn't visible.
Ah, a literalist. Uses English like a computer programming language-assumes that what is said is what is meant. Isn't aware-or tends to forget-that human language is a social construct, and that figurative usage is the more common form in human-to-human communication.
As Darwin would say, this organism hasn't evolved higher language faculties.
Is it fair to say that population genetics determines the choices that natural selection has to choose from?
I loved him in Elephant Man
Let’s go brandon 🍦🍦🍦
The neutral theory of molecular evolution, proposed by Motoo Kimura in 1968, holds that at the molecular level most evolutionary changes and most of the variation within and between species is not caused by natural selection but by genetic drift of mutant alleles that are neutral. A neutral mutation is one that does not affect an organism's ability to survive and reproduce. The neutral theory allows for the possibility that most mutations are deleterious, but holds that because these are rapidly purged by natural selection, they do not make significant contributions to variation within and between species at the molecular level. Mutations that are not deleterious are assumed to be mostly neutral rather than beneficial.
Neutral mutations might not affect an organism in it's lifetime but it could affect the population later on, especially if the environment changes. What is neutral now might not be neutral in the future. It could be beneficial
Isn't that what's called chance? The genome is an ordered set. And subjected to the random mutations there ordered set gradually degrades and becomes disordered. The natural selection fights this natural degradation and keeps the set in order. Evolution is needed not just to progress, but just to maintain the current order.
Contemporary biologists accept that mutation and selection both play roles in evolution; the mainstream view is that while mutation supplies material for selection in the form of variation, all non-random outcomes are caused by natural selection.[77] Masatoshi Nei argues instead that the production of more efficient genotypes by mutation is fundamental for evolution, and that evolution is often mutation-limited.[78] The endosymbiotic theory implies rare but major events of saltational evolution by symbiogenesis.[79] Carl Woese and colleagues suggested that the absence of RNA signature continuum between domains of bacteria, archaea, and eukarya shows that these major lineages materialized via large saltations in cellular organization.[80] Saltation at a variety of scales is agreed to be possible by mechanisms including polyploidy, which certainly can create new species of plant,[81][82] gene duplication, lateral gene transfer,[83] and transposable elements (jumping genes).[84]
Drift is random changes. It's not adaptive evolution. Natural selection fights maladaptive changes.
The smaller the population, the longer it takes, that is if the species survives at all.
How does genetic drift and population genetics apply to self reproducing organisms?
At 12:19 "blue variant has a reproductive DISadvantage" - I spent 5 minutes baffled, until I assumed this was a mistake. Isn't it?
What are the *assumptions* in the selection model?
The title attracted me, then the decision or perceived need to explain what complicated means, quickly turned me off.
Perhaps I'll watch another time when I'm feeling more forgiving.