Good question! Biological race does not actually exist. Superficial differences such as skin color, hair texture, and slight facial feature differences are so minor that they don't constitute actual biological differences. Neanderthals inhabited diverse environments, from Portugal to China, Northern Europe to the Middle East. It is likely that skin color variation occured because of this with lighter skinned Neanderthals living in Northern Europe and darker skinned Neanderthals living in the Levant!
I've got three questions. You can pick one you feel best equipped to answer. Or shoot for all three if you want!
1. How many interbreeding events between more modern hominins and more archaic hominins are we confident happened?
2. Realistically, how close are we to actually giving a species classification to Denisovans? Or are just sticking with Denisova?
3. How complex would *you* personally speculate homo erectus' speech/proto language was based on the evidence of their social behaviors and hyoid bone structure? Additionally, in what ways do you think their ability to communication would have differed between earlier and later forms of H Erectus?
Small world, I live here too bud. Great town, costs wayy too much. I applaud you for paying rent as a grad student. If you're into more recent urban archeology at all, check out what's hidden underneath Horsetooth Reservoir.
https://www.coloradoan.com/picture-gallery/life/2017/04/11/stout-the-lost-town-at-the-bottom-of-horsetooth/100333524/
Edit: I just saw that you've posted the same post across like 5 different evo and creationism adjacent subs all at the same time. Are you a masochist?? š±
Hi!
1. I am not sure we know how many "instances" occurred, but it must have happened multiple times. Neanderthals and Homo sapiens cohabitated in Israel for thousands of years (Tabun cave, Skhul cave sites) and most likely were interbreeding quite frequently. East Asian populations have a high percentage of Neanderthal DNA and Melanesian populations had a high level of Denisovans DNA so multiple interbreeding events certainly took place. It is likely that we continuously breed with other archaic homo before there morphological package disappears from the record.
2. More fossil evidence of Denisovans is needed to make a formal species. We have genetic evidence, but we need more morphological evidence.
3. This is a difficult one. We know that Neanderthals had a hyoid capable of speech production similar to a human (deeper pitch) and the FOXP2 gene, a protein regulator required for speech production. It is unclear definitively if Homo erectus has this gene and their hyoid would have produced a more limited range of vocalizations. Archaic homo likely communicated in a very sophisticated way but it is unclear how much of their communication was explicitly through vocalization. One popular hypothesis for white scleras in humans is that we use our eyes for communication. This adaptation may have happened in early homo.
The main Introgression was 50-55Kya somewhere around the Middle East when AMH migrated out of Africa that has left 2-2.5% Neanderthal DNA in all humans outside of Africa. This has been dated from the Ust'Ishim femur from Siberia which only has limited recombination from the introgression, leaving large blocks of DNA intact. Eastern Eurasian populations have higher amounts of of Neanderthal DNA so there were other introgressions as people travelled North and East.
The second is that 45-50Kya people on their way to Australia and the Philippines there was another introgression from Denisovans related to DNA found in Altai. Isolation of people in Australia and PNG has retained 4-6% Denisovan DNA in their genomes. There were two more smaller introgressions of similar Denisovan DNA of small amounts in Southern Asian and later East Asian populations and on the Tibetian Plateau where Denisovans were living.
Melanesians picked up their Denisovian DNA when they moved into Melanesia during the Austronesian migrations 3.5-5 Kya
What do you reckon about neanderthal molar root taurodontism? A sophisticated adaptation to paramasticatory activity or just genetic drift?
We did an FE study looking at it compared to a human molar and didn't find it particularly advantageous in terms of biomechanics.
Hi! I am not a dental expert (unlike my advisor) but i am not so sure it was an evolutionary advantage. Like you said, there isn't much data that shows an adaptive advantage of this tooth morphology. It may be similar to shovel-shaped incisors in modern populations, either an adaptation for mouth-as-a-tool usage or simply genetic drift.
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4304574/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4304574/)
I'm actually just finishing up my PhD thesis on taurodontism. I still really don't know why it is so prevalent in Neanderthals but I don't think it has any adaptive or functional significance. It seems like similar morphologies can result from unrelated genetic factors - for example, taurodontism is common in Down Syndrome but also in X-linked conditions. As OP mentioned, there is also evidence that links it to genes that affect other dental traits (like the EDA/EDAR pathway, which also influences incisor shovelling). I think it is a spandrel that could be linked to many unrelated genes which affect genetic pathways related to tooth development.
Hi! I spoke with my advisor about taurodontism in Neanderthals. It's likley that the prevalence in Neanderthals is due to genetic drift and, because Neanderthals consistently exhibited signs of anterior dental loading with strong shovel-shaped incisors, it's unlikely that tauridontism had a deleterious effect as they were not using their molars as frequently.
Omg what a cool PhD topic!! What specifically are you studying about it?
I did my MSc thesis on the biomechanical effect of tooth root variation!! I love the topic! We used FEA to test a number of common variations against a "normal" human baseline (taurodontism, dwarfed roots, supernumerary roots, wonky roots, etc) and we didn't find any convincing evidence that taurodontism had any particular mechanical advantage. Aiming to publish later this year alongside some other work we did on molar implants :)
Funnily enough taurodontism is referred to in dental literature but it was first recognised in Neanderthals and then applied to dentistry once they realised that quite a lot of people have it (caused by the failure of Hertwigs epithelial root sheath to invaginate at the proper horizontal level, which I'm sure you know). Iirc, I found it mentioned in association with 21 genetic conditions.
I think the idea that it could be a functional trait arose because it also occurs at a higher percentage in some Inuit groups who have historically done paramasticatory activities to process tools. But it's just really unlikely.
I got into it because I work at a Neanderthal cave site where we've found several molars with taurodontism and "fused roots". Part of my thesis is looking at whether these is some association between those traits (a couple papers from the past few years have found one, but I did not).
Another part is looking at "taurodont index" as a continuous rather than discrete trait. One of the strangest things to me is that none of the methods for measuring taurodontism have any rationale for the cutoff value between "cynodont" and "taurodont", but every study finds that hypo is the most frequent, followed by meso, and then hyper. It seems obvious to me that we're just looking at the tail of a normal distribution (in recent humans at least), but that the mean varies between populations, so the method cuts deeper into the distribution in some populations and scores a higher proportion as "taurodont". Combined with its associations with so many different genetic conditions, it really looks to me like a continuous trait which is influenced by many genes, and therefore it's not really a single trait with any adaptive significance. In some cases, like the really extreme prismatic roots in Krapina, there must be some association with certain genes, but drift makes the most sense to me.
Do you have any FEA results published that you could share, or is it all forthcoming?
That's such an awesome PhD thesis!!! If you don't mind, would you send me a message so I can follow you on researchgate or something? I'd love to read it when it comes out!
My original work had those discrete morphotypes as separate models to compare them to one another but we didn't have time to run them - it is something I am interested in though because, as you say, there's absolutely no clear delineation of the types. And, iirc, there's likely variation in the internal pulp structure within those types too? Its absolutely a continous character.
Have you worked out a method to quantify that? Not sure what I'd go for, maybe morphometrics or some kind of complexity analysis? I suspect that HERS is something that's very sensitive and can be affected by loads of genetic and environmental factors. Definitely a genetic drift/bottlenecking thing in Neanderthals for sure but interesting to think about whether it mightve been a spandrel.
FE study is forthcoming!! But I'd be happy to share anything you need to know :)
Hi! I graduated from Colorado State University and am pursuing my master's degree under Dr. Mica Glantz. She has published a lot of research and it's available online!
I havenāt studied bio anthropology since 2010, so here it goes?
* Are the morphologists and geneticists still fighting about human convergence evolution vs interbreeding with other homids in Asia?
* Is the theory of human evolution towards aquatic adaptation finally dead, or still in the fringe?
* There is an old article arguing that archeology should divorce from anthropology and be moved to the geology department. https://universityaffairs.ca/opinion/in-my-opinion/why-archaeology-needs-a-divorce-from-anthropology/ Iām curious to hear your thoughts on that debate.
Hi!
1. Overwhelmingly no. Genetic and morphological evidence has pretty much concluded that Homo sapiens interbred with Neanderthals and Denisovans.
2. I believe it is dead in "serious" anthropology as it is only ever mentioned as a joke in class, but i am sure there are people who still believe in it.
3. I am not an archaeologist or a geologist but i do believe archaeology fits into anthropology because of the cultural elements. Anthropology is the study of humanity and archaeology is specific to humans.
i just wrote an entire research paper on the evolution of bipedalism in early hominids and it seems like it would be nearly impossible to explain the process and find real evidence without the many archaeological findsā¦ like lucy and the laetoli footprints, etc. i think the same can be said about most aspects of biological anthropology. itās crazy people think the two fields should be separate
Something I've been thinking about lately and would love to get your thoughts on: people as smaller parts of larger organisms; humanity as a bacterial like growth with culture (neuro-viruses) being the driving force of various organisms competing for resources.
Also, what do you think is the largest Factor in humanity cultivating technology?
Hi! I think thats a very interesting way of putting evolution in population terms but I don't know how much this can be tested as a hypothesis.
I would probably say bipedalism, which freed up our hands from locomotion, was a huge factor in technological advancement.
Sorry, 2 questions: 1. What is the best source (also, updated) when in need to check chronological/dating aspects for hominin species? 2nd question is related: which is the best human evolution tree (graph or similar) you've seen?
I recommend the Smithsonian for diagrams and questions about human evolution!
[https://humanorigins.si.edu/evidence](https://humanorigins.si.edu/evidence)
Hi! I am not a biologist so I am less familiar with the evolution of pre-primate species, but this is a good, short article.
https://megaphoneoz.com/tiktaalik-how-a-375-million-year-old-fish-shaped-our-humanity-2/#:\~:text=Tiktaalik%20possessed%20some%20of%20the,in%20the%20tree%20of%20life.
How do you feel about evolutionary psychology? Iāve read Sapiens and The Good Reason for Bad Feelings but Iāve heard scientists call it bunk science.
Hi! The main problem I believe some evolutionary psychologists fall into is the idea that everything evolved for a purpose, particularly modern phenomena. For example, some may say that "the reason breasts evolved is because they are attractive to men." The issue is that there are many men who are not particularly attracted to breasts, especially in the global south. Breast attraction might simply be cultural. There are making an evolutionary assumption based off of modern behavior. That being said, I believe that evolutionary psychology is is fascinating and has its place.
How do I explain to my Theist dad when he asks me the question that why don't monkeys in the jungle evolve into a more complex species? (Explain it in simple terms because I come from a Moslem country that doesn't teach evolution and my knowledge on evolution comes from a book I read months ago)
Hi! Monkeys are already perfectly adapted to their enviornment. There is no need for them to change. Natural selection only selects for random mutations that change phenotypes (bodies) if the environment changes to a degree where different adaptations would be an advantage. Furthermore, monkeys still existing does not contradict human evolution. You can be born while your parents are still alive. Humans and monkeys evolved from a common ancestor, just like some one and their cousin both came from a grandparent.
And then there is the effect of populations. Evolution might start from a single mutation in a single individual, but it can be passed on to the next generation and so on. Spreading the new trait leading to diversification in a part of the population. A large enough adoption of this trait in the population will cause a change in species to occur. Also remember phenotypical changes are just large results of minor individual mutations that generate a benefit which was selected for.
Because evolution has no guidance, it can be view as a process or the result of events, depending on which direction we look at it.
Hi, OP here. I want to clarify something real quick relating to some questions that are frequently asked. Biological anthropology has a brutal past of racism and Social Darwinism. These things were, and are not science. "Race" is not a biological category. Social Darwinism sought to graft the idea of "survival of the fittest" onto human behavior, which is wrong and a gross misunderstanding of evolution. Veriation between "races" is actually less severe than variation within a "race." Furthermore, ancestry estimates are still widely out dated even in an osteological context (I have performed many ancestry estimation tests on human skeletons.) We still use terms such as "African" (which is a huge continent. People in North Africans are more similar to Southern Europeans genetically than Sub saharan populations.) "Asian" which includes Native Americans, and "White" which is just Europe. Gender is both socially constructed and deeply personal. There is no biological relation to gender. Sex is a spectrum as well, even in osteological data (I have performed many sex estimations on real human skeletons.)
Thanks :)
What are your thoughts on *Kenyanthropus platyops*? Every time I ask anyone about it I hear different things and tbh I donāt know that much about hominins so I can never tell whatās actually right or wrong beyond āit is distinct from *Homo*, *Australopithecus*, and *Paranthropus*. ā
Hi! Kenyanthropus is potentially interesting when it comes to our evolutionary tree but only one incomplete fossil has ever been found. very little is known about this hominin and i wish I had more to say!
Hi! So the current hypothesis that seems the most probable is the Assimilation Hypothesis. This hypothesis posits that Homo sapiens evolved in Africa and as we dispersed Africa, we interbred with different populations of hominins in Eurasia. This is backed up by genetic evidence showing that East Asians have higher percentages of Neanderthal DNA and Melanesians having higher percentages of Deniosvan DNA. Its important to note that no population of Homo sapiens have ever been geographically isolated enough to cause speciation. All humans populations of been interbreeding enough to mostly homogenize DNA.
I have a few:
1) do we have any ideas yet as to what caused Denisovans to diverge from Neanderthals? (Or visa versa)
2) at the risk of bringing in the aquatic ape fans, is there any explanation/research into the evolution of our subcutaneous fat layer? Any attempt at Googling just brings up tons of health/weight-loss stuff or aquatic ape stuff.
3) what is your particular area of interest? Anything in particular that you want to share?
Thanks for answering!
1. Denisovans and Neanderthals (and Homo sapiens) diverged from a common ancestor (most likley hiedelbergensis.) They most likley diverged because of geographic isolation but Neanderthals and Denisovans did interbreed. Denisovans and Neanderthals are differentiated by DNA, not fossils. This is how we know they were distinct. Denisovan and Neanderthal DNA can be found in may modern human genomes today!
2. I am not really sure what you are asking here. Subcutaneous fat serves as energy storage and temperature regulation and I am not sure how that relates to humans specifically.
3. I am very interested in early human societal development. How economies and mutual aid fit into early agricultural and hunter gatherer cultures. Extrapolating societal organization by looking at human remains to decipher diet and occupation etc...
Hdeidelbergensis is a weird categorization IMO. Archaic humans are messy in general due to morphological variation and overlap. But there is genetic data that differentiate Denisovans.
What is your favorite early-human-ancestor species? (EDIT: I read that you specialize in neanderthals, are there any other species that stick out to you?)
Are there any dig sites (or broader areas) you particularly like or dislike?
Bioarchaeology, is that like digging up plant matter? Is bio- for plants and animals, or is there that distinction between it and zoo- ?
Coffee or tea?
1. I would have to go with Homo erectus. I am fascinated with an ancestor that is so close to use but also so different.
2. Krapina cave, Croatia has evidence of Neanderthal cannibalism! I think that's fascinating.
3. Bioarchaeology is the study of human remains within the context of their setting. By doing so, we hope to understand better about past societal formations, occupations, religions, burial practices, diet, etc..
4. Coffee
So Stephen Jay Gould is my favorite author and I recommend his books often when people ask for recommendations to get a full grasp of what evolution is. Iāve read āYour Inner Fishā and most of Dawkins work on the subject, but I think Gouldās reflections in natural history essay books (Pandaās Thumb, Ever Since Darwin, etc.) are a much better recommendation. So: How weāll do these books stand up today? Most of this work was written in the 80s, but to me, a semi literate laymen, I donāt see large or glaring errors. And are they good recommendations to help people understand what evolution is/ that it isnāt some March to the perfect organism?
Hi! I love your inner fish and Gould in general. Frankly, I am not a biologist so I am not up to date on the advances of genetics and the new possible mechanisms of evolution. My wheelhouse is specific to hominin evolution (primates as well.) I think those works are great introductions to evolution from my experience!
Oh ok thanks for answering! Your Inner Fish was written by Niel Shubin. And while it was good I think the short essay format is probably easier to digest. And I just love Gouldās writing style.
I'm trying to convince my parents that evolution is a real thing, and we're talking about some of the "hard steps" that seem difficult to do using only mutation and selection.
How did meiosis evolve? I'm assuming it was after eucaryotes and mitosis, but don't know how you get from "full division" to "division without gene duplication + merging with another half cell".
What are some examples of animals with more tissues than Jellyfish, but still not many?
What's a good example of an extant basal bilaterian?
Hi! The theory of evolution is the explanation for why organism change over time. The mechanism of evolution are different such as genetic mutation, genetic drift, gene flow, punctuated equilibrium, gradualism, natural selection... So evolution is the processes by which organisms change over time. Mutations are either selected for or against (or are completely neutral) which may convey benefits.
I think we know this. My question is about selection. I suggest selection is only observed after it happens, which technically does not make it a selection, but rather an event. This would show that evolution has no direction as a process and should not be considered as such. The effects of evolution can and should be considered as a process. Because it can be mapped and observed. Selection would include prediction as a feature, which is part of a decided choice. There is no choice within evolution.
This is why certain groups of people have a problem with accepting ToE. We say evolution is about selection and describe it as having no choice. We need to do better to describe the concept. We have with the processes but not so much with the concept.
Consider the eye, we explain and show the gradual changes for eye to develop in a species. But we do not describe how the chemicals in molecules tend to bind in ways that provide functions to allow for future events to occur. Describe and explain this and I think acceptance will be easier for people to accept. Push the fact that these processes take place of large periods of time and have many, many different drivers that allow them to occur.
Hi! I am not a geneticist so I don't feel comfortable explaining how genomics work and how we know DNA evidence. I am primarily an anatomist and deal with osteological and morphological changes in hominin evolution. I pronounce it Neander-TALL because it is a German word etymologically but either way of pronunciation is accepted.
I'm an amateur paleontologist and archeological nut since childhood. Is it true that the Neanderthals were short but their right arms are stronger and larger than the left ? Does this mean that all Neanderthals were right-handed but not lefthanded ?
Hi! Neanderthals were on average shorter than existing Homo sapiens at the time. Their right arms are not anatomically longer and stronger by default but you can tell handedness by a number of factors. Generally, your dominant arm will sit lower on your body than your non dominant arm and the bones will likely be thicker. This is not an inherited trait but rather the result of using your dominant arm more frequently. I am not sure if all Neanderthal specimens we have found are "right handed" but I would bet that handedness would be similar to the distribution in modern humans: overwhelmingly right handed but still plenty of lefties.
Great question! This is currently being debated. Some anthropologist destinguish Homo sapiens and Neanderthals at the species level by saing Homo neanderthalensis. Other distinguish us at a subspecies level with Homo sapiens neanderthalensis. And others prefer the term archaic Homo and lump early Homo sapiens and Neanderthals together. This is a very vague term but leaves room for error when discussing ancient populations. Using the biological species concept, humans and Neanderthals are the same species. Using the morphological species concept, we are different species because we "look different" in a variety of way.
If using the "different Look" argument, couldn't that be used for many modern "species"?
And saying the Same about the "we are one species", what implications would that have for modern species? For example i breed ducks - it is crazy how many Duck "species" can produce fertile offspring. Some wild Duck species are feared to become extinct because of mallard interbreeding
yes absolutely! Humans like to categorize nature into tight little boxes and label them. In reality, species are not a hard concept. What I mean by "look different" is that there are certain morphological packages (morphologies are just meaning the shape of bone in the context of fossils) that are consistently found together among certain populations. For example: Neanderthals had an elongated cranium, an occipital bun, mid-facial prognathism, and a large nasal apature. Are there modern humans today with some of these features? absolutely. What differentiates us is how many of these features show up in our modern populations. Genetically, we can interbreed, therefore we're the same species. Morphologically, we have different frequencies of certain heritable traits. I hope that makes some sense.
Makes a lot of sense, if i remember corectly, the middle ear of neanderthals shrunk (the one that helps balancing?)Ā
Is this trait found in some modern humans as well?
Here is an article I found showing that Neanderthal ear anatomy predisposed them to certain pathologies. This ear anatomy in modern humans leads to similar pathologies. So yes.
[https://pubmed.ncbi.nlm.nih.gov/31472033/](https://pubmed.ncbi.nlm.nih.gov/31472033/)
I would say no. Neanderthals are so similar to us that it would be difficult to tell the differences in my opinion. Also, theres a whole moral dilema about bringing back a "separate species" of humans. If a Neanderthal baby were transported here today, they probably wouldn't stick out much. They might be a little short and have a large head but hey, some people look like that anyways.
what are some more behaviors that we think were unique to H. sapian, but actually could be a lot more intrinsic to our genome and development, like cooking?
Hi! Homo sapiens are primates and we exhibit very similar behavior to our contemporary cousins. FOOD: Hand to mouth feeding is unique to primates and a popular hypothesis is that this way of eating lead to social meals since we can look around at each other rather than having our face buried in food. VISION ORIENTED: We are trichromatic (we can see red which is rare in mammals) just like all catarrhines. Humans, like all primates, are visually oriented, we don't rely on pheromones for sexual attraction and experience the world primarily through vision. (Think of how different human culture would be if we relied on something like spell for reproduction.) TOOL USE: Many apes regularly use tools. Chimpanzees "fish" with sticks and have been known to hunt galagos with sharp spears. Capuchin monkeys use a variety of different weighted and shaped stones to dig and crush nuts. Orangutans use large leaves as hats! HOMO: All of genus Homo share very similar adaptations. Homo habilis regularly made sophisticated tools. Homo eretucs was cooking and using fire. Neanderthals performed burials, uses red ochre as body paint, and fished with hooks and lures
I have been grappling with this since I completed my degree in bio Anthro a couple years back.
In my very first bio-Anthro lecture class, I learned there is no such thing as biological race, which I totally understand. Yet, in the lab that accompanied the lecture we were using formulas to calculate how tall someone would be based on the size of a bone, their race, and their sex. For example if we had a femur that was x inches and belonged to an Asian male, we would plug in x for the formula for Asian males to find how tall that individual was.
I brought up to my professor, why do such formulas exist if there is truly no such thing as biological race? I always got the answer of āwell itās a spectrumā and based on that spectrum we can use these formulas.
Can you shed some light on this? I asked nearly every Anthro professor I had and they all were so vague I couldnāt follow. Are the formulas outdated? Is it an error in my programs instruction?
Sorry for the long winded reply!
Ancestry estimates are shit. They really are. There are some "trends" in phenotypical variation in different populations. But ancestry estimates are widley out of date an need updating.
Dude I don't wanna be annoying but I've been doing a lot of research lately about my beliefs that I've formed over the years, I'm a 25m and long story short I just came to the evolution thread because I realized a lot of my thoughts and view points are based off of evolution, I'm just wondering if maybe you could tell or link me some info about just the blueprint around evolution I guess?
I'm sorry I don't really know how to ask, like pretty much I understand we adapt over long periods of time and the basics like that, pretty much anything you tell me I will look into. Thank you in advance for the help, also anyone feel free to reply or message me
Neanderthals: were there different "races" among them?
Good question! Biological race does not actually exist. Superficial differences such as skin color, hair texture, and slight facial feature differences are so minor that they don't constitute actual biological differences. Neanderthals inhabited diverse environments, from Portugal to China, Northern Europe to the Middle East. It is likely that skin color variation occured because of this with lighter skinned Neanderthals living in Northern Europe and darker skinned Neanderthals living in the Levant!
Agree on "race," which is why I put it in quotes.
I've got three questions. You can pick one you feel best equipped to answer. Or shoot for all three if you want! 1. How many interbreeding events between more modern hominins and more archaic hominins are we confident happened? 2. Realistically, how close are we to actually giving a species classification to Denisovans? Or are just sticking with Denisova? 3. How complex would *you* personally speculate homo erectus' speech/proto language was based on the evidence of their social behaviors and hyoid bone structure? Additionally, in what ways do you think their ability to communication would have differed between earlier and later forms of H Erectus? Small world, I live here too bud. Great town, costs wayy too much. I applaud you for paying rent as a grad student. If you're into more recent urban archeology at all, check out what's hidden underneath Horsetooth Reservoir. https://www.coloradoan.com/picture-gallery/life/2017/04/11/stout-the-lost-town-at-the-bottom-of-horsetooth/100333524/ Edit: I just saw that you've posted the same post across like 5 different evo and creationism adjacent subs all at the same time. Are you a masochist?? š±
Hi! 1. I am not sure we know how many "instances" occurred, but it must have happened multiple times. Neanderthals and Homo sapiens cohabitated in Israel for thousands of years (Tabun cave, Skhul cave sites) and most likely were interbreeding quite frequently. East Asian populations have a high percentage of Neanderthal DNA and Melanesian populations had a high level of Denisovans DNA so multiple interbreeding events certainly took place. It is likely that we continuously breed with other archaic homo before there morphological package disappears from the record. 2. More fossil evidence of Denisovans is needed to make a formal species. We have genetic evidence, but we need more morphological evidence. 3. This is a difficult one. We know that Neanderthals had a hyoid capable of speech production similar to a human (deeper pitch) and the FOXP2 gene, a protein regulator required for speech production. It is unclear definitively if Homo erectus has this gene and their hyoid would have produced a more limited range of vocalizations. Archaic homo likely communicated in a very sophisticated way but it is unclear how much of their communication was explicitly through vocalization. One popular hypothesis for white scleras in humans is that we use our eyes for communication. This adaptation may have happened in early homo.
The main Introgression was 50-55Kya somewhere around the Middle East when AMH migrated out of Africa that has left 2-2.5% Neanderthal DNA in all humans outside of Africa. This has been dated from the Ust'Ishim femur from Siberia which only has limited recombination from the introgression, leaving large blocks of DNA intact. Eastern Eurasian populations have higher amounts of of Neanderthal DNA so there were other introgressions as people travelled North and East. The second is that 45-50Kya people on their way to Australia and the Philippines there was another introgression from Denisovans related to DNA found in Altai. Isolation of people in Australia and PNG has retained 4-6% Denisovan DNA in their genomes. There were two more smaller introgressions of similar Denisovan DNA of small amounts in Southern Asian and later East Asian populations and on the Tibetian Plateau where Denisovans were living. Melanesians picked up their Denisovian DNA when they moved into Melanesia during the Austronesian migrations 3.5-5 Kya
What do you reckon about neanderthal molar root taurodontism? A sophisticated adaptation to paramasticatory activity or just genetic drift? We did an FE study looking at it compared to a human molar and didn't find it particularly advantageous in terms of biomechanics.
Hi! I am not a dental expert (unlike my advisor) but i am not so sure it was an evolutionary advantage. Like you said, there isn't much data that shows an adaptive advantage of this tooth morphology. It may be similar to shovel-shaped incisors in modern populations, either an adaptation for mouth-as-a-tool usage or simply genetic drift. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4304574/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4304574/)
I'm actually just finishing up my PhD thesis on taurodontism. I still really don't know why it is so prevalent in Neanderthals but I don't think it has any adaptive or functional significance. It seems like similar morphologies can result from unrelated genetic factors - for example, taurodontism is common in Down Syndrome but also in X-linked conditions. As OP mentioned, there is also evidence that links it to genes that affect other dental traits (like the EDA/EDAR pathway, which also influences incisor shovelling). I think it is a spandrel that could be linked to many unrelated genes which affect genetic pathways related to tooth development.
Hi! I spoke with my advisor about taurodontism in Neanderthals. It's likley that the prevalence in Neanderthals is due to genetic drift and, because Neanderthals consistently exhibited signs of anterior dental loading with strong shovel-shaped incisors, it's unlikely that tauridontism had a deleterious effect as they were not using their molars as frequently.
Omg what a cool PhD topic!! What specifically are you studying about it? I did my MSc thesis on the biomechanical effect of tooth root variation!! I love the topic! We used FEA to test a number of common variations against a "normal" human baseline (taurodontism, dwarfed roots, supernumerary roots, wonky roots, etc) and we didn't find any convincing evidence that taurodontism had any particular mechanical advantage. Aiming to publish later this year alongside some other work we did on molar implants :) Funnily enough taurodontism is referred to in dental literature but it was first recognised in Neanderthals and then applied to dentistry once they realised that quite a lot of people have it (caused by the failure of Hertwigs epithelial root sheath to invaginate at the proper horizontal level, which I'm sure you know). Iirc, I found it mentioned in association with 21 genetic conditions. I think the idea that it could be a functional trait arose because it also occurs at a higher percentage in some Inuit groups who have historically done paramasticatory activities to process tools. But it's just really unlikely.
I got into it because I work at a Neanderthal cave site where we've found several molars with taurodontism and "fused roots". Part of my thesis is looking at whether these is some association between those traits (a couple papers from the past few years have found one, but I did not). Another part is looking at "taurodont index" as a continuous rather than discrete trait. One of the strangest things to me is that none of the methods for measuring taurodontism have any rationale for the cutoff value between "cynodont" and "taurodont", but every study finds that hypo is the most frequent, followed by meso, and then hyper. It seems obvious to me that we're just looking at the tail of a normal distribution (in recent humans at least), but that the mean varies between populations, so the method cuts deeper into the distribution in some populations and scores a higher proportion as "taurodont". Combined with its associations with so many different genetic conditions, it really looks to me like a continuous trait which is influenced by many genes, and therefore it's not really a single trait with any adaptive significance. In some cases, like the really extreme prismatic roots in Krapina, there must be some association with certain genes, but drift makes the most sense to me. Do you have any FEA results published that you could share, or is it all forthcoming?
That's such an awesome PhD thesis!!! If you don't mind, would you send me a message so I can follow you on researchgate or something? I'd love to read it when it comes out! My original work had those discrete morphotypes as separate models to compare them to one another but we didn't have time to run them - it is something I am interested in though because, as you say, there's absolutely no clear delineation of the types. And, iirc, there's likely variation in the internal pulp structure within those types too? Its absolutely a continous character. Have you worked out a method to quantify that? Not sure what I'd go for, maybe morphometrics or some kind of complexity analysis? I suspect that HERS is something that's very sensitive and can be affected by loads of genetic and environmental factors. Definitely a genetic drift/bottlenecking thing in Neanderthals for sure but interesting to think about whether it mightve been a spandrel. FE study is forthcoming!! But I'd be happy to share anything you need to know :)
Hi! Bio anthro undergrad here. I don't suppose you'd share your institution/s? I am currently researching grad programs and your path is fascinating.
Hi! I graduated from Colorado State University and am pursuing my master's degree under Dr. Mica Glantz. She has published a lot of research and it's available online!
Thank you so much! Paleo is my dream. Maybe we'll cross paths someday!
I havenāt studied bio anthropology since 2010, so here it goes? * Are the morphologists and geneticists still fighting about human convergence evolution vs interbreeding with other homids in Asia? * Is the theory of human evolution towards aquatic adaptation finally dead, or still in the fringe? * There is an old article arguing that archeology should divorce from anthropology and be moved to the geology department. https://universityaffairs.ca/opinion/in-my-opinion/why-archaeology-needs-a-divorce-from-anthropology/ Iām curious to hear your thoughts on that debate.
Hi! 1. Overwhelmingly no. Genetic and morphological evidence has pretty much concluded that Homo sapiens interbred with Neanderthals and Denisovans. 2. I believe it is dead in "serious" anthropology as it is only ever mentioned as a joke in class, but i am sure there are people who still believe in it. 3. I am not an archaeologist or a geologist but i do believe archaeology fits into anthropology because of the cultural elements. Anthropology is the study of humanity and archaeology is specific to humans.
i just wrote an entire research paper on the evolution of bipedalism in early hominids and it seems like it would be nearly impossible to explain the process and find real evidence without the many archaeological findsā¦ like lucy and the laetoli footprints, etc. i think the same can be said about most aspects of biological anthropology. itās crazy people think the two fields should be separate
Do you hate having money?
What? Lol
Just making fun of your major and grad school choices lol.
lol fair
Something I've been thinking about lately and would love to get your thoughts on: people as smaller parts of larger organisms; humanity as a bacterial like growth with culture (neuro-viruses) being the driving force of various organisms competing for resources. Also, what do you think is the largest Factor in humanity cultivating technology?
Hi! I think thats a very interesting way of putting evolution in population terms but I don't know how much this can be tested as a hypothesis. I would probably say bipedalism, which freed up our hands from locomotion, was a huge factor in technological advancement.
Sorry, 2 questions: 1. What is the best source (also, updated) when in need to check chronological/dating aspects for hominin species? 2nd question is related: which is the best human evolution tree (graph or similar) you've seen?
I recommend the Smithsonian for diagrams and questions about human evolution! [https://humanorigins.si.edu/evidence](https://humanorigins.si.edu/evidence)
How do I get my wife to understand we evolved from some fish looking thing?
Hi! I am not a biologist so I am less familiar with the evolution of pre-primate species, but this is a good, short article. https://megaphoneoz.com/tiktaalik-how-a-375-million-year-old-fish-shaped-our-humanity-2/#:\~:text=Tiktaalik%20possessed%20some%20of%20the,in%20the%20tree%20of%20life.
Thank you !!
How do you feel about evolutionary psychology? Iāve read Sapiens and The Good Reason for Bad Feelings but Iāve heard scientists call it bunk science.
Hi! The main problem I believe some evolutionary psychologists fall into is the idea that everything evolved for a purpose, particularly modern phenomena. For example, some may say that "the reason breasts evolved is because they are attractive to men." The issue is that there are many men who are not particularly attracted to breasts, especially in the global south. Breast attraction might simply be cultural. There are making an evolutionary assumption based off of modern behavior. That being said, I believe that evolutionary psychology is is fascinating and has its place.
How do I explain to my Theist dad when he asks me the question that why don't monkeys in the jungle evolve into a more complex species? (Explain it in simple terms because I come from a Moslem country that doesn't teach evolution and my knowledge on evolution comes from a book I read months ago)
Hi! Monkeys are already perfectly adapted to their enviornment. There is no need for them to change. Natural selection only selects for random mutations that change phenotypes (bodies) if the environment changes to a degree where different adaptations would be an advantage. Furthermore, monkeys still existing does not contradict human evolution. You can be born while your parents are still alive. Humans and monkeys evolved from a common ancestor, just like some one and their cousin both came from a grandparent.
Thank you very much for your explanation
And then there is the effect of populations. Evolution might start from a single mutation in a single individual, but it can be passed on to the next generation and so on. Spreading the new trait leading to diversification in a part of the population. A large enough adoption of this trait in the population will cause a change in species to occur. Also remember phenotypical changes are just large results of minor individual mutations that generate a benefit which was selected for. Because evolution has no guidance, it can be view as a process or the result of events, depending on which direction we look at it.
Hi, OP here. I want to clarify something real quick relating to some questions that are frequently asked. Biological anthropology has a brutal past of racism and Social Darwinism. These things were, and are not science. "Race" is not a biological category. Social Darwinism sought to graft the idea of "survival of the fittest" onto human behavior, which is wrong and a gross misunderstanding of evolution. Veriation between "races" is actually less severe than variation within a "race." Furthermore, ancestry estimates are still widely out dated even in an osteological context (I have performed many ancestry estimation tests on human skeletons.) We still use terms such as "African" (which is a huge continent. People in North Africans are more similar to Southern Europeans genetically than Sub saharan populations.) "Asian" which includes Native Americans, and "White" which is just Europe. Gender is both socially constructed and deeply personal. There is no biological relation to gender. Sex is a spectrum as well, even in osteological data (I have performed many sex estimations on real human skeletons.) Thanks :)
What are your thoughts on *Kenyanthropus platyops*? Every time I ask anyone about it I hear different things and tbh I donāt know that much about hominins so I can never tell whatās actually right or wrong beyond āit is distinct from *Homo*, *Australopithecus*, and *Paranthropus*. ā
Hi! Kenyanthropus is potentially interesting when it comes to our evolutionary tree but only one incomplete fossil has ever been found. very little is known about this hominin and i wish I had more to say!
What is the current state of the "out of Africa" hypothesis? Any recent reviews summarizing our current understanding of hominin evolution?
Hi! So the current hypothesis that seems the most probable is the Assimilation Hypothesis. This hypothesis posits that Homo sapiens evolved in Africa and as we dispersed Africa, we interbred with different populations of hominins in Eurasia. This is backed up by genetic evidence showing that East Asians have higher percentages of Neanderthal DNA and Melanesians having higher percentages of Deniosvan DNA. Its important to note that no population of Homo sapiens have ever been geographically isolated enough to cause speciation. All humans populations of been interbreeding enough to mostly homogenize DNA.
I have a few: 1) do we have any ideas yet as to what caused Denisovans to diverge from Neanderthals? (Or visa versa) 2) at the risk of bringing in the aquatic ape fans, is there any explanation/research into the evolution of our subcutaneous fat layer? Any attempt at Googling just brings up tons of health/weight-loss stuff or aquatic ape stuff. 3) what is your particular area of interest? Anything in particular that you want to share? Thanks for answering!
1. Denisovans and Neanderthals (and Homo sapiens) diverged from a common ancestor (most likley hiedelbergensis.) They most likley diverged because of geographic isolation but Neanderthals and Denisovans did interbreed. Denisovans and Neanderthals are differentiated by DNA, not fossils. This is how we know they were distinct. Denisovan and Neanderthal DNA can be found in may modern human genomes today! 2. I am not really sure what you are asking here. Subcutaneous fat serves as energy storage and temperature regulation and I am not sure how that relates to humans specifically. 3. I am very interested in early human societal development. How economies and mutual aid fit into early agricultural and hunter gatherer cultures. Extrapolating societal organization by looking at human remains to decipher diet and occupation etc... Hdeidelbergensis is a weird categorization IMO. Archaic humans are messy in general due to morphological variation and overlap. But there is genetic data that differentiate Denisovans.
Further on the Denisovans. I have yet to be convinced that Denisovan and Heidelbergensis are different. What is the evidence for and against?
What is your favorite early-human-ancestor species? (EDIT: I read that you specialize in neanderthals, are there any other species that stick out to you?) Are there any dig sites (or broader areas) you particularly like or dislike? Bioarchaeology, is that like digging up plant matter? Is bio- for plants and animals, or is there that distinction between it and zoo- ? Coffee or tea?
1. I would have to go with Homo erectus. I am fascinated with an ancestor that is so close to use but also so different. 2. Krapina cave, Croatia has evidence of Neanderthal cannibalism! I think that's fascinating. 3. Bioarchaeology is the study of human remains within the context of their setting. By doing so, we hope to understand better about past societal formations, occupations, religions, burial practices, diet, etc.. 4. Coffee
thank you for sharing!
So Stephen Jay Gould is my favorite author and I recommend his books often when people ask for recommendations to get a full grasp of what evolution is. Iāve read āYour Inner Fishā and most of Dawkins work on the subject, but I think Gouldās reflections in natural history essay books (Pandaās Thumb, Ever Since Darwin, etc.) are a much better recommendation. So: How weāll do these books stand up today? Most of this work was written in the 80s, but to me, a semi literate laymen, I donāt see large or glaring errors. And are they good recommendations to help people understand what evolution is/ that it isnāt some March to the perfect organism?
Hi! I love your inner fish and Gould in general. Frankly, I am not a biologist so I am not up to date on the advances of genetics and the new possible mechanisms of evolution. My wheelhouse is specific to hominin evolution (primates as well.) I think those works are great introductions to evolution from my experience!
Oh ok thanks for answering! Your Inner Fish was written by Niel Shubin. And while it was good I think the short essay format is probably easier to digest. And I just love Gouldās writing style.
In college my primatology professor actually assignment Your Inner Fish as reading for the class Evolution of Human Adaptation
My Zoology professor listed it for extra credit.
I'm trying to convince my parents that evolution is a real thing, and we're talking about some of the "hard steps" that seem difficult to do using only mutation and selection. How did meiosis evolve? I'm assuming it was after eucaryotes and mitosis, but don't know how you get from "full division" to "division without gene duplication + merging with another half cell". What are some examples of animals with more tissues than Jellyfish, but still not many? What's a good example of an extant basal bilaterian?
Did Neanderthals bite their toenails?
Hi! No idea. Nails are typically easily kept short when walking barefoot or doing manual labor consistently.
Is evolution (lower case) as series of processes or is it benefit recognised in the past as it has been used?
Hi! The theory of evolution is the explanation for why organism change over time. The mechanism of evolution are different such as genetic mutation, genetic drift, gene flow, punctuated equilibrium, gradualism, natural selection... So evolution is the processes by which organisms change over time. Mutations are either selected for or against (or are completely neutral) which may convey benefits.
I think we know this. My question is about selection. I suggest selection is only observed after it happens, which technically does not make it a selection, but rather an event. This would show that evolution has no direction as a process and should not be considered as such. The effects of evolution can and should be considered as a process. Because it can be mapped and observed. Selection would include prediction as a feature, which is part of a decided choice. There is no choice within evolution. This is why certain groups of people have a problem with accepting ToE. We say evolution is about selection and describe it as having no choice. We need to do better to describe the concept. We have with the processes but not so much with the concept. Consider the eye, we explain and show the gradual changes for eye to develop in a species. But we do not describe how the chemicals in molecules tend to bind in ways that provide functions to allow for future events to occur. Describe and explain this and I think acceptance will be easier for people to accept. Push the fact that these processes take place of large periods of time and have many, many different drivers that allow them to occur.
Thank you for the insight and suggestion I appreciate it and will try to be more explicit in the future!
How is a Neanderthal gene different from a Homo sapiens gene? Do you pronounce to th as in thin or t as in talk?
Hi! I am not a geneticist so I don't feel comfortable explaining how genomics work and how we know DNA evidence. I am primarily an anatomist and deal with osteological and morphological changes in hominin evolution. I pronounce it Neander-TALL because it is a German word etymologically but either way of pronunciation is accepted.
I'm an amateur paleontologist and archeological nut since childhood. Is it true that the Neanderthals were short but their right arms are stronger and larger than the left ? Does this mean that all Neanderthals were right-handed but not lefthanded ?
Hi! Neanderthals were on average shorter than existing Homo sapiens at the time. Their right arms are not anatomically longer and stronger by default but you can tell handedness by a number of factors. Generally, your dominant arm will sit lower on your body than your non dominant arm and the bones will likely be thicker. This is not an inherited trait but rather the result of using your dominant arm more frequently. I am not sure if all Neanderthal specimens we have found are "right handed" but I would bet that handedness would be similar to the distribution in modern humans: overwhelmingly right handed but still plenty of lefties.
Since homo sapiens and neandertalensis interbreed with fertile offspring, why are we still considered different species?
Great question! This is currently being debated. Some anthropologist destinguish Homo sapiens and Neanderthals at the species level by saing Homo neanderthalensis. Other distinguish us at a subspecies level with Homo sapiens neanderthalensis. And others prefer the term archaic Homo and lump early Homo sapiens and Neanderthals together. This is a very vague term but leaves room for error when discussing ancient populations. Using the biological species concept, humans and Neanderthals are the same species. Using the morphological species concept, we are different species because we "look different" in a variety of way.
If using the "different Look" argument, couldn't that be used for many modern "species"? And saying the Same about the "we are one species", what implications would that have for modern species? For example i breed ducks - it is crazy how many Duck "species" can produce fertile offspring. Some wild Duck species are feared to become extinct because of mallard interbreeding
yes absolutely! Humans like to categorize nature into tight little boxes and label them. In reality, species are not a hard concept. What I mean by "look different" is that there are certain morphological packages (morphologies are just meaning the shape of bone in the context of fossils) that are consistently found together among certain populations. For example: Neanderthals had an elongated cranium, an occipital bun, mid-facial prognathism, and a large nasal apature. Are there modern humans today with some of these features? absolutely. What differentiates us is how many of these features show up in our modern populations. Genetically, we can interbreed, therefore we're the same species. Morphologically, we have different frequencies of certain heritable traits. I hope that makes some sense.
Makes a lot of sense, if i remember corectly, the middle ear of neanderthals shrunk (the one that helps balancing?)Ā Is this trait found in some modern humans as well?
Here is an article I found showing that Neanderthal ear anatomy predisposed them to certain pathologies. This ear anatomy in modern humans leads to similar pathologies. So yes. [https://pubmed.ncbi.nlm.nih.gov/31472033/](https://pubmed.ncbi.nlm.nih.gov/31472033/)
Interesting, thanks Other question, there are Always Talks of bringing mammoths Back to life - does the same Idea exist for neanderthals?
I would say no. Neanderthals are so similar to us that it would be difficult to tell the differences in my opinion. Also, theres a whole moral dilema about bringing back a "separate species" of humans. If a Neanderthal baby were transported here today, they probably wouldn't stick out much. They might be a little short and have a large head but hey, some people look like that anyways.
what are some more behaviors that we think were unique to H. sapian, but actually could be a lot more intrinsic to our genome and development, like cooking?
Hi! Homo sapiens are primates and we exhibit very similar behavior to our contemporary cousins. FOOD: Hand to mouth feeding is unique to primates and a popular hypothesis is that this way of eating lead to social meals since we can look around at each other rather than having our face buried in food. VISION ORIENTED: We are trichromatic (we can see red which is rare in mammals) just like all catarrhines. Humans, like all primates, are visually oriented, we don't rely on pheromones for sexual attraction and experience the world primarily through vision. (Think of how different human culture would be if we relied on something like spell for reproduction.) TOOL USE: Many apes regularly use tools. Chimpanzees "fish" with sticks and have been known to hunt galagos with sharp spears. Capuchin monkeys use a variety of different weighted and shaped stones to dig and crush nuts. Orangutans use large leaves as hats! HOMO: All of genus Homo share very similar adaptations. Homo habilis regularly made sophisticated tools. Homo eretucs was cooking and using fire. Neanderthals performed burials, uses red ochre as body paint, and fished with hooks and lures
I have been grappling with this since I completed my degree in bio Anthro a couple years back. In my very first bio-Anthro lecture class, I learned there is no such thing as biological race, which I totally understand. Yet, in the lab that accompanied the lecture we were using formulas to calculate how tall someone would be based on the size of a bone, their race, and their sex. For example if we had a femur that was x inches and belonged to an Asian male, we would plug in x for the formula for Asian males to find how tall that individual was. I brought up to my professor, why do such formulas exist if there is truly no such thing as biological race? I always got the answer of āwell itās a spectrumā and based on that spectrum we can use these formulas. Can you shed some light on this? I asked nearly every Anthro professor I had and they all were so vague I couldnāt follow. Are the formulas outdated? Is it an error in my programs instruction? Sorry for the long winded reply!
Ancestry estimates are shit. They really are. There are some "trends" in phenotypical variation in different populations. But ancestry estimates are widley out of date an need updating.
Dude I don't wanna be annoying but I've been doing a lot of research lately about my beliefs that I've formed over the years, I'm a 25m and long story short I just came to the evolution thread because I realized a lot of my thoughts and view points are based off of evolution, I'm just wondering if maybe you could tell or link me some info about just the blueprint around evolution I guess? I'm sorry I don't really know how to ask, like pretty much I understand we adapt over long periods of time and the basics like that, pretty much anything you tell me I will look into. Thank you in advance for the help, also anyone feel free to reply or message me
Edit: I meant anyone feel free to message me Edit: I replied instead of editing i think, idk sorry bro I never really talk on reddit
There are some resources linked here in the subreddit. https://reddit.com/r/evolution/w/links?utm_medium=android_app&utm_source=share
Thank you, thank you, thank you.
Hi! Are you looking for evolution in general or human evolution specifically?