Robin May appeared on the latest episode of our podcast 'Any Further Questions?' to answer all the questions we didn't have time to get to. Listen on Spotify and Apple now!

What I really love in these science based presentations is that they always say..."maybe", "perhaps", "based on current knowledge".......and so on, unlike some others who claim to know everything, here and now. You know what I mean. ; )

Fst is as high as .46 between Mbuti and New Guineans which is staggering considering the distinction between two different species like Coyotes and Red Wolves is only .08- .1. It seems a lot of animal 'species' should actually be reclassified as belonging to the same species if we use the same universal standard for judgment. Edit: In fact, after doing some more research, domestic cattle (bos taurus) and buffalo (bison bison) are even more closely genetically related (Fst of at most .368) than those two human groups, even though they aren't even classified as the same genus let alone the same species. Something seems to be screwy with our classification system.

We ate the competition.

If species is defined by the ability to have viable offspring and modern humans have Neanderthal DNA, then wouldn’t that make Neanderthals the same species as humans?

I do have a question about the categorisation of species. You noted that there are different species of butterflies that look very similar but are different species. Is that based on your definition of the same species reproducing together? The reason I ask is, do we know that these different species of butterfly can’t reproduce, or is it that they won’t reproduce, which I think are very different things. If they choose not to reproduce with each other but in actual fact could technically reproduce, would they then be the same species? I suppose it’s also very hard to tell because I’m assuming you can’t force two butterflies to reproduce with each other.

In my lifetime, there's been sp much advancement of knowledge on the evolution of our and other species. It's so humbling when someone finds a very distant "ancestor." We're always surprised, too. I find it delightful. Thank you for this great lecture. I love going to class. ❤

Very interesting and thorough, Thank you very much.

thoroughly enjoyed that, thanks

This is very interesting! Thanks for a great lecture, really fascinating!

I have ‘watched’ this video but realised it was one of those i played right before sleep. … but the title is actually interesting. So i will watch again, this time for real

35:14 -- I think science is overlooking one potential reason why the Lion Man was created: Because it's really **cool.** Think about it. Imagine a twelve year-old boy living with his people on the grasslands of East Africa. "Bro, what if I had the head... of a **LION.** That would be so cool!"

Dogs and wolves have traditionally been considered separate species, but Alaskan huskies have been successfully interbred with wolves by native Alaskans for thousands of years.

I love how he's so clear and humble at the same time.

Physically speaking there are at least 12 species of humans. As species of elephants there are three. Check out other animal species, for we are just one of them.

This was awesome. I love this format. Very informative and kept my attention. More like this please

Pretty cool info. Thanks for the lesson

Interesting lecture, thank you : )

Wonderful presentation!!! I love this!!!! We have some interesting information on behavioral patterns of our extinct sister species. I wonder if we could look at if there is a relationship between some aspects of human diversity and our genetic heritage from those sister species? Such as do some neurodivergent people, like ASD people such as myself, have perhaps a higher percentage or a certain marker from our Neanderthal ancestors? I thinking this could be an interesting study for any relationship. I suspect, that we will find some interesting beneficial genes from our sister species that actually jumpstated cultural development and it is going to relate back to neurodivergent traits.

How does one distinguish an interbred human (sapiens x denisovan, or sapiens x neanderthalensis) from a human from an intermediate evolutionary branch???

Thanks for a very interesting and informative lecture!

Whenever one of these lectures posts, I get a big grin on my face and figure out how to carve some time for great presentations and education. Can't wait for the next one!

I have a question for Dr. May. I am a Historian with a huge interest in Anthropology and Genetics. Your lecture is excellent! I wonder - what research is being done that might shed light on *when* Sapiens began to appear different from their other relatives? We have a bit of a basis for wondering of course - given that we can see the changes in horses over time as well and more recently, the domestic dog. Yes, I know this is selective, but have a look at films of London and NYC at the turn of the century and keep a keen eye on the dogs in the footage. You can see how we have brought about a rapid change in them , and I think that in a natural way, it must have clearly happened when we began to *realize* that we were different. I wonder if you have thoughts on what that might have looked like and when?

Odd that as broad as the human species is, a scientist can get a ladybug with an extra dot it’s own species.

45:55 Dogs (canis lupus familiaris) aren't "a single species", they are a sub-species of Gray Wolves (canis lupus lupus), they aren't genetically distinct enough to be their own species. The difference between a "dog" and a "wolf" is also purely semantic.

Thank you so much for this, I loved it from the very beginning to the very end and for once to get a much clearer overview of how things came to be maybe perhaps….. seriously, excellent

Great presentation with substance and amazing clarity. Thank you!

Very interesting lecture. Thank you.

I understand the question(s): why are the Denisovans, Neanderthals and Floriensians extinct? But, I don’t understand your more general question. “There is one species of humans” seems to be a tautology. Chimpanzees are like humans but are not human. Chinese, Europeans and Africans are different from one another but are all human. How could the situation be different? Could there be a species with human attributes (which?), with whom we could not interbreed? Although, the connection between “species” and the ability to interbreed is troublesome, since we could breed with Neanderthals and the others mentioned.

Great lecture. One thing confuses me though. Early on we choose a definition of species to use. One of the parts of that definition is no successful cross breeding. Yet later we discuss all the interbreeding between the sapiens, neanderthal, and denisovians. Am I missing something or does the second half of the lecture betray the choice of “best” definition of species?

It seems to me the human capacity for intentional travel has had the consequence of halting speciation which was already underway 100,000 years ago. I would guess if, as a thought experiment, geologically separate populations of humans were left to themselves on separate continents for another million years, some of those populations would not be regarded as recognizably human by the end of this epoch.

Very articulate, well spoken. An Absolutely outstanding communicator.

Could the florensians be denisovians stuck on an island, becomome small because of that, since they were on that side of th Wallace line?

Awesome lecture. Thank you for the upload. ;-)

I would be curious of your thoughts of future human species when people get specialized for living on the moon and mars. Will our adaptation create separate species especially if radiation may play a dominate play in those that will live there.

“I am quite conscious that my speculations run beyond the bounds of true science. It is a mere rag of an hypothesis with as many flaws and holes as sound parts.” -C. Darwin

_"Why are we the only species of human?"_ Because we make the conscious decision to taxonomically classify ourselves that way.

during the segment about sister species I'm wondering why if bonobos and chimps are considered different species then why wouldn't humans with the same genetic difference of 0.4% also be considered different species?

Surely there is a distinction between species pairs and congeners? Two species can be congeners without being a species pair. Robin May cites genetic evidence to show that Chimpanzees and Bonobos are more closely related to each other than either is to us, but does that justify our being put in a separate genus? Is there a consistency across taxonomy as to what level of genetic diversity constitutes putting a species in a separate genus to another? I ask because I've read Jared Diamond say that there is a greater genetic difference between a Chiffchaff and a Willow Warbler than between the two Chimpanzees and ourselves.

Brilliant Lecture watched the whole thing absolutely engrossed

I would be interested in how the four blood types fit in with the evolution and the migration. The blood type AB is said to be started as less than 1000 yrs ago. Thanks..

What a great presentation 👍

My friend suggested, coming down from trees, changing conditions, reaching up the thumb eventually fully stretched away from index finger, complete flexibility of hands, sounds reasonable, “ our destiny all in our hands “

Very interesting and informative video. Thank you.

Very interesting...much like The Silmarillion (sp?) or Out of the Silent Planet. I have always been amused at how anthropologists can describe entities by a fossilized tooth. Of course gene study will enhance the validity of the results. 50 years ago when I studied Anthro. the defining characteristics of a specimen were the physical characteristics alone. By this the Irish were supposed to exhibit more Neanderthal features than other Europeans. (A long ways from their African roots).

I absolutely LOVED that lecture. The subject is fascinating and Robin May is a really engaging presenter. I would definitely like to hear more from him. Loved it.

We say that all humans are a single species and some even go as far to say that the term "race" is just a construct that shouldn't be used anymore. But when we classify other animal species we split them into separate species and sub species based on sometimes miniscule physical differences that have arisen through spacial isolation of individual groups.

I echo comments below by @bernard 2735. By the lecturer's own use of Mayr's biological species theory with his assumption that Sapiens successfully and often interbred with Neanderthals and Denisovans, it seems most logical to regard all three as members of a single species.

Great lecture. Appreciate hearing some of the Q&A; some rather insightful questions asked.

46:48 "Biologically race is completely meaningless. Doesn't mean anything at all." Different races have different susceptibility to certain diseases. This is basic knowledge to all medical practitioners for effective diagnosis. Sickle cell, alpha-thalassemia, cystic fibrosis, SMA, beta-thalassemia, gaucher diseases, tay-sachs disease, fam. dysautonomia, canavan disease, just to name a few.

I want to know his thoughts on populations in Antarctica. Who they were where they came from and where they traveled to and who they merged with later or does he think they went extinct.

"Why is there only one species of Human?" 1min 45 secs into the video..."We don't really know why." Thanks for not waiting until the end of the video to say that.

Thank you for a very interesting lecture, though I have a question about the definition of species. You define a species as a group of individuals that can reproduce successfully together. I understand that enough H. sapiens and H. neanderthalensis interbred that many of us carry some of their genetic material. Does that mean that the definition is incorrect or is H. neanderthalensis better characterised as H. sapiens neanderthalensis? Note, I am not a zoologist so forgive any glaring misunderstanding 😊

Really loved watching this video and learning more about evolution. Thank you and Robin May for the lecture and ability to watch it!

Really Enjoyed that Lecture.......Many Thanks 🤘

But if they were interbreeding, doesn't that mean we aren't distinct species?

As alluded to, defining a species is a complex task in biology and there are several factors that scientists consider when doing so. He mentioned some, but for those who might be interested (maybe you're watching this video to research for a paper or something) more such factors include, but surely aren't limited to: Morphological Characteristics: Physical traits such as size, shape, coloration, and other observable features. This traditional method of species identification relies on visual cues. Genetic Variation: Examination of genetic differences between individuals within a population or group. DNA analysis, particularly through techniques like DNA sequencing, can reveal genetic diversity and help distinguish between species. Reproductive Isolation: Species are often defined as groups of organisms that can interbreed and produce fertile offspring within their own group but cannot do so with individuals from other groups. This concept is known as the Biological Species Concept. Ecological Niche: The role an organism plays within its ecosystem, including its habitat, behavior, and interactions with other species. Species may occupy distinct ecological niches, which can contribute to their differentiation. Evolutionary History: Consideration of the evolutionary relationships between organisms, including their ancestry and the divergence of traits over time. This is often studied through methods like phylogenetics and cladistics. Geographic Distribution: The geographic range in which a species is found. Populations of the same species are often connected by a continuous distribution, although geographic barriers can lead to isolation and speciation. Behavioral Characteristics: Behavioral traits such as mating rituals, communication methods, and social structure can also play a role in defining species boundaries, especially in organisms where these behaviors are highly specific. Hybridization: Instances where individuals from different species interbreed and produce viable offspring can complicate species boundaries, especially in cases of recent divergence or ongoing gene flow. To conclude, these factors are often considered together and different species concepts may prioritize certain factors over others depending on the organisms being studied and the goals of the research. Additionally, the definition of a species is not always clear-cut and can vary depending on the context and the specific organisms involved.

Great and engaging lecture. Thank you.

I often wondered (as undergraduate anthropology student) if humans were on the road to speciation. If not for exploration or migration might not speciation have occurred. Given phenotypic variation amongst even current populations could different, yet very similar species have developed?

Fascinating, thank you very very much.

Arguably, there may be only "one species" of any species. It goes with the word. At the same time, biologists do recognize some subordinate levels of classification within a species, but they are commonly still considered one species. Designations such as subspecies, variant, and landrace all address recognizable variations within a particular population. The fact is that until a strange mix of racism and political correctness came along arguing that Neanderthals could not be H. sapiens, or that it was unfair not to regard Neanderthal as its own species, Neanderthal was often referred to as _H. sapiens neanderthalensis_, a subspecies of _H. sapiens_.

@40:00 it is said that interbreeding was going on with different human species, but wouldn't that mean that these different species were actually one?

I have heard the theory about disease from an arriving population. are there any cases where an arriving group is wiped out by the locals, and if not why not? love the lecture.

Loved loved loved this lecture!

That was a wonderfully illustrative presentation.

Some (native american) people have started to claim that indigenous Americans are not actually the same species and that they originated in North America, and not in Africa like the rest of us. Could you do a video evaluating their claims?

i really love the fact that these species were interbreeding so much. like, yes, we're different, but not that different. and thanks to that interbreeding, their dna has survived to today

Also this lecture didnt even go into the several other ghost species which our evolution even more complicated

From the original definition of species in this video, surely you could make the argument that sub-species already exist through geographic separation of population centres throughout the majority of human history.

@ 39:00 I had heard of this, but my question is: if we were truly two seperate species, how would we be able to enter breed with them? Honest question. I'm enjoying this lecture quite a bit. Thanks for posting.

Needs to be way longer, or of course many more videos on this.

It would interesting to get a DNA sample from an individual from North Sentinel Island to how development has varied compared to the rest of us if at all

Excellent!

I would love to see the other lecture he alluded to, where he mentions the topic was the future evolution of humans!

"The genetic difference between two very different humans is the same as the genetic difference between bonobos and chimpanzees. 0.4%" So if it wasn't for the requirement of 'species' to be able to interbreed we would be different species of humans today. Edit: Then again. Neanderthals were a different species but ancient humans interbred with them. It is all a little vague.

Great lecture! Thank you.

When he says "we know from dating", he isn't talking about pre-diluvian Tinder.

In the Galápagos, it was found the speciation happens after as little as three generations. It's not just a matter of being physically able to breed with another species but also, do you want to breed with that other species?

Africa has the highest levels of genetic diversity on the planet. While the out of Africa theory is well proven the inner African human evolution story has never been researched. Continual references to Europe and Asia makes no sense because you're only getting a fraction of the story. Surely if human life started in Africa it would make more sense to focus research on that part of the world. This avoidance is a deliberate one. What are they hiding?

There used to be many hominids. The ice ages caused mass movement towards the tropics and sub tropics multiple times which caused the hominids to interbreed and reach what we consider anatomically modern humans

Species live in niches so when they are in the same niche as another there is competition. The fittest species in an area in a particular niche will out compete all others in the particular niche there can only be one. To accommodate this similar species must adapt to or change to live or occupy a different if similar niche. If different species are able to reproduce then repeated mating between species groups will dissolve the differences in variation and thus the relative competitive advantages associated with either species selective niche occupying advantages respectively. Thus two species in similar or overlapping niches will either outcompete one or the other, or interbreed and dilute differences down to one species.

How can you see what is clearly a denisovan in papua and claim there’s only one species?

Excellent lecture. Really cogent explanation of a complex subject. Thanks.

If we found a gracile skeleton of a person from Thailand, and the robust skeleton of an Australian Aboriginal would we conclude they were the same species? How can we be a different species from Neanderthals if we share a common ancestor and had fertile children? It strikes me that this is more of a political question than a scientific one.

I believe we are a hybrid. A hybrid made up of at least 8 other human speices. Some people have more or less dna of a speices than others which is why we have differnt colors and features.

It feels that our ability to interbreed with Neanderthals muddies the whole theory a little.

Currently, humans are respeciated. Several times throughout history, several groups have, through natural barriers and seplf imposed restriction, have expeciated. Prior to the period of european exploration, it was very common for entire civilizations to be cut off from the rest of the world for centuries. The ability to hybridize and for those hybrid species to continue producing ofspring is how respeciation has occoured. Humans are, after all, just animals, so if we are to define speciation by specific clasification criteria, those same criteria also apply to humans.

Im not sure we are alone, i known a lots of nearthentals and pitetcantropus in my country😊

I haven't watched this yet. I hope you address the fact that there is a far greater genetic variance amongst humans than many other multiple species animals. If we were viewing earth from afar I think we would have labelled 4 to 6 species of humans. It's all to PC and devisive now. But hey once I've finished watching, maybe I'll change my mind.

I enjoyed that immensely... Thank you!

It's very simple, species is not a fact, instead it's a poorly defined notion based on skeletons which are snap-shots of human development in time and space! In point of fact EVERY human IS an intermediate form, and each individual IS a separate species!! What we call our species is merely the cluster of these individual sub-species who could hypothetically breed with one another! Species did not magically succeed one another, one dying off and another magically appearing, the newer were the previous population's offspring!!

Thanks for making this very interesting exploration of our human evolution and interwoven roots. Very clear explanation of biological, genetic and social understanding of race.

Ive always wondered that there were multiple 'human species' and were over time mixed together and got the best outcome

Traditionally, the distinction between species is supposed to be the ability to successfully breed as you laid out here, but you also mentioned that humans can be as different from one another genetically as bonobos and chimpanzees. This got me wondering and sure enough, bonobos and chimpanzees can successfully mate in captivity. In fact, the only thing keeping them from regularly mating in the wild is the fact that they are separated by an uncrossable (for them) river. But assuming the river dried up overnight, they would likely start mating and blend as species. So what is to say that humans aren't just a blend of separate species and that the most different humans genetically today may in fact be humans that are closest genetically to their respective species?

Just a thought, but has anyone tried in vitro fertilisation of very similar species? Maybe it's possible, but they just don't choose to do it?

Who is the lecture convenor at the end? She asked some interesting questions.

I just saw the question and straight away I thought of the answer. There are two, us and all these pathological narcissistic psychopaths running the show

We have subspecies though... I think if there were other human species it would still seem completely normal to us, it would just be a more extreme form of what we have now with the different subspecies, except interbreeding may not be possible.

I heard a theory some time ago which appeared quite feasible. That is, that modern man may well be the first war like human. Not that they killed other humans en masse but perhaps drove them out, off to less habitable lands. Considering that that is exactly what we have been and are throughout recorded history

If you want to get into Darwin and positive seelection and a sister species, alls you have to do is look at the fact Neanderthals from certain areas were heterozygous for what became Rh negative and it was protective against Toxoplasmosis Gondii. Hence, there WAS Natural selection for the pre-cursor to Rh negative, and, like sickle cell anemia, the positive selection resulted in homozygotes who actually had Rh negative blood type. The Rh negative blood type is a reproductive barrier, and signifies a speciazation event. Many Autistic people are Rh negative blood type. Most Neurotypical "humans" are not.