okay so we are in week 9 of the semester which is wild because it's a 16 week semester so we're already past the hump we're already uh more than halfway through the course and we are moving into the final part of module two so if I scroll down a little bit further don't want to frighten anybody on the early Monday morning but exam number two is coming up on um uh pretty soon so that's a schedule for November 7th okay so let's have a look uh first of all our readings that we have coming up this week we have a reading and videos and so this particular topic is prime origins and evolution and these are our learning objectives so that's from chapter eight from our book Explorations and you'll notice a few things about this chapter first of all this chapter is long and so it will take probably about an hour to get through the reading so just in terms of time management make sure that you're setting aside time also it's pretty dense stuff it's not easy going the reading there's a lot of new vocabulary there's a lot of names of strange species you've never heard of before my suggestion is for this particular chapter to break it up into more manageable um readings so maybe rather than doing one straight hour and just plowing through this chapter divide it into two or three sessions I mean you could get through it in one reading but it wouldn't be my uh suggestion um the other thing I want to highlight is like other chapters we've done before you don't need to read the entire chapter read the parts which are highlighted here so I highlighted the headings and subheadings that I want you to read through so rather than reading through all of chapter A's which is already long it's already dense I just want you to read through the highlighted sections and then I think it's helpful to have a look at our learning objectives so that we know what we're looking out for in this chapter because as you're reading you want to pay more attention to certain things than other things in this chapter so one learning objective is to understand the major Trends in climate Evolution from the origin of primates to the origin of our own species so we're going to start at the very earliest primates all the way through to the point where right before our species appears because the next module in this course is going to deal with the origin of our species and then human evolution so this is going to take us right up to that point looking at primate evolution you're you're going to learn about primary adaptations and how they characterize major primary groups so what are some of the primary adaptations we've talked about some of these already but we're going to look at them in more detail the characterize say straps rides what are the characteristics of New World monkeys and how are new world monkeys different than all World monkeys why are car seers classified as haplorines rather than straps around so we're just going to go into a little bit more detail on these primary adaptations because the primary adaptations themselves are going to allow us to better understand the evolutionary history of primates discuss the kinds of evidence the primatologists use to find out how extinct primates are related to each other and to live in primates so how do we know that what we're looking at are first of all even primates and then second of all how do we know they relate to certain groups so when we find the fossil skeleton of a primate how do we know for instance it's a catarine a relative of all World monkeys and apes or how do we know it's a platarine uh relative of New World monkeys so how are anthropologists able to make those determinations also recognizing how the change in geography and climate of Earth have influenced where and when primates thrived or have gone extinct so as we'll see in this course many early primates are found in places that you wouldn't expect given their current modern geographic location for instance many early primates were very common in North America one of the places where anthropologists go looking for fossils of some of the earliest primates in the world is Wyoming that's surprising right nobody came to this class expecting that we would be talking about primates in Wyoming but that's where some of the earliest fossils of primates have been found similarly during the myosin period right before humans come on the scene or human ancestors what we call hominins we find many Apes living in Europe and Asia today we find most Apes well we find all Apes in Africa and Southeast Asia so how is it that their distribution changed over time and so we're going to explore changing geography and also the climatic changes that led to a redistribution of where we find primates and then I say this chapter is particularly dense read and there are a lot of taxonomic groups that are mentioned it can be a little bit overwhelming especially since all of these names are going to be very new for you so here are the ones that are most important for you to remember and they're also the ones that we'll spend time in class going over which are places that performs purgatories carpalesta simpsonai adipoids omamayids necro lemur Egypt epithecus Victoria piskus proconsul plybedes shivapithecus you're already a little overwhelmed just hearing that list but we're going to go through each one in turn and so between what we covered this weekend lecture and also going through the reading these names will become more familiar and then as you're reviewing and going over SI material in this class as well as the Quizlet it'll help reinforce um these different taxonomic groups so just in case anybody is already feeling a little bit overwhelmed by what we're going to jump into well so is everybody else but you got this just a matter of going through it multiple times doing the readings listening to either this live session or the recording of it and then doing some self-testing we have some videos that we'll be watching uh one is this one evolution in Reverse which we'll look at during today's class we also have this video of a floating island in Panama I'll explain why that is pertinent as we go through the lecture it's probably not very obvious right now and then there's another video which is the evidence for evolution and um this video is a great overview of how biologists as well as anthropologists are able to figure out which groups are related based on um different characteristics adaptations traits and so on so that's where we are headed let me jump back to our modules for this week so we're in week nine and one of the assignments we have this week is a discussion assignment it's the second of our scientist Spotlight assignments the first scientist Spotlight assignment focused on student scientists and I wanted to give you a sense of what the Journey of scientists looks like and scientist Spotlight one and scientist Spotlight 2 looks up more kind of mid-career scientists within our discipline within the field mid late career so once again you're going to have options and I want you to read through each of the blurbs under each of the scientists to get a better sense of who they are and then based on their mini biography you can click through and you can learn more about the particular scientist so let me read through these really quickly Dr William Montague Cobb is a contender for the most impactful biological Anthropologist of the 20th century his teaching research and activism are legendary and his legacy lives on in around 6 000 medical students he he taught um over 1 000 Publications sky was a giant in our discipline so if you're interested in reading more about Dr Cobb you can just click on the link and you have this article which is a PDF article which is a retrospective about his life let me just click on that really quickly this is the article and I've highlighted sections that I want you to read so rather than reading through the whole article if you have time you definitely should it's a it's a wonderful article but these are the sections that I want you to read through so that you're not reading through the entire article itself I've also uh made a let me go back up and close this out uh text to speech it's 11 minutes long of the highlighted portions of the article so if you prefer to listen you can do that and then once you've read a biography you can return to the assignment page and just click on back to discussion link and it'll shoot you back to the discussion assignment the second of our assigned to spotlights is Dr Sheila atreya she is an Asian American biological Anthropologist who has published her research on various topics related to human Origins and human evolution she's been an advocate for elevating the voices of marginalized people within anthropology particularly Asian Scholars and once again you can click through to read her biography and I link to an article here it's a quite a short article it's only um really two and a half pages long and it's called but you're not a real minority the marginalization of Asian voices and paleoanthropology and so you can have a look through that and the third of our scientist spotlights is my dear friend Dr Stephanie Meredith um Stephanie was a part-time professor of biological anthropology here at SMC for um a few years and then she got a full-time job at West LA College and she is the founding member of gay ABA which is a subcommittee of the American Association of biological anthropologists committee on diversity which serves lgbtqia Plus members and allies she's a trained as an primatologist she has centered queer perspectives in her Research into topics ranging from evolutionary history of human gender to human and primary growth and development she has been in demand as a consultant and panelist on a range of topics including sex and gender and diversity and lgbtqia plus visibility in stem inner all the biography she speaks about the academic challenges she faced and so you can click through and read um Dr Stephanie murditz autobiography so this is her self-written autobiography that she shared with us and she outlines her story and I also link to a short article that she has co-written with um Christopher Schmidt and it's called the outliers are in the queer perspectives and investigating variation in biological anthropology um once again it's a very short article it's only about a page and a half long and so it won't take too long to get through that and then uh we have Dr Ventura Perez he's an anthropologist who's written extensively on how violence both visible and invisible has been used to elevate the voices and opportunities of the few at the expense of the many within biological anthropology his lived experience as a Mexican-American man informs much of his research on violence and prompted prompted him to find the academic Journal Landscapes of violence and interdisciplinary Journal devoted to the study of violence conflict and Trauma of which he is editor and Chief and you can click through you can read more about Dr Perez and his research once again there is a short article which is called until the brains run out white privilege physical anthropology and co-opted narratives and there's also a link to his biography which you can read here it's a really fascinating story and then finally we have Dr Johannes highly Selassie who I had the privilege to meet when I was an undergraduate student we were visiting the Natural History Museum in Cleveland where he was the curator at the time and he was awesome he set aside time to meet with a bunch of nobody undergraduates and he explained his research to us and to this day he remains one of my heroes and uh uh human evolutionary research he's one of the biggest names out there as far as human evolutionary research goes much of his research has focused on early human fossils from his native country of Ethiopia he has been instrumental in the discoveries of important human fossils including ones that we'll highlight in this course that include artipithicus ramidus australopithecusgari Australopithecus afarensis Homo rectus as well as some of the earliest Homo sapiens he's currently director of The asu's Institute for human Origins and you can click through and learn more about Dr Hailey Selassie and you you can read his bio which is linked here and you can watch his Ted talk so there's a link to a TED Talk that he gave so he talks about um the or the title of his Ted Talk is searching for our ancestors in the afar desert of Ethiopia so that's the scientist Spotlight assignments so once again have a read through each of these uh decide which one resonates the most with you and then you have your prompts which scientists did you decide to read about why did you pick that particular scientist what particularly resonate personally what if anything did you feel was relatable be as specific as possible how did this person challenge others to think differently about our discipline and how we do research what are their major contributions why are their contributions important what in what way were dissimilar or different two ideas you had about scientists do they remind you of anybody you know if so how and then what did reading their story tell you about the types of people who do science so once again um it's a 200 word response you can always do a recording if you prefer so if you're more comfortable um using your voice you can do a voice recording if you prefer to do that and then um you can comment to a classmate explaining why you enjoyed their post okay any questions about our upcoming assignments all right let's Jump Right In so as we start thinking about devolutionary history of primates in other words where do primates come from one way to start is to look at primates today to look up Prime adaptations and then use those adaptations that we see today to make inferences about primates in the past so imagine uh a world in which we don't have any fossils to work of if fossils didn't exist thankfully we do have a quite a rich fossil record but fossils didn't exist we would have to rely on looking at traits or adaptations that exist today in order to make inferences about the past and so one of the earliest hypothesis as to the origin of primates is called the arboreal hypothesis and the arboreal hypothesis says that the many characteristics or adaptations that we see in primates today are as a result of primates being adapted to life in the trees that's what this word arboreal means arboreal means forest or um in this context adapted to the trees so what are some of these characteristics well one is primates rely quite heavily on sense of vision so Vision being one of those primary senses for things like color vision depth perception foreign mammals rely more on different senses like hearing for instance or sense of smell but these senses are more minimized in primates relative to the sense of vision and that kind of makes sense right as you're moving through the canopy high up into trees that's a very complex environment also it's really important that as you're swinging from Branch to French that you're judging distances accurately and that you're able to very clearly see where the branches are as you're making leaps through the trees so having high visual Acuity seems like a really good adaptation to have in that particular environment the other trait is what I call here prehensility prehensilities just ability to grasp so it's one of the things that we do really well right that your um pet dog can't do for instance right we're able to grasp onto objects really easily right I can grab this um this cup for instance and I can even grab it with more of a Precision grip foreign some of you are riding with a pen right now while you're taking notes and those are all examples of prehensibility and those are traits that are emphasized in primates more than they are in many other mammals and that makes sense when you're having to grasp onto branches and to this list we could also add having flexible limbs for instance the fact that we can raise our shoulder high above our head that's something that's typical of primates but not typical of many other species you don't see your dog for instance putting its Paul up over its head into the ear and so having a flexible limb structure once again makes a lot of sense when you think of the context of living in the forest environment however these set of traits while they are useful in this particular environment having the visual Acuity being able to grasp onto objects having that flexible limb structure is all well and good but it's not the only way to be adapted to life in the forest perfect example are these guys that we see foreign that I took just down the street right I think all of us see squirrels about at least once a day if you're out and about and nobody would argue the squirrels are not well adapted to trees they're incredibly well adapted to to life in the trees in fact it kind of blew my mind right like we live here in Los Angeles and I can see in some of your um um video screens right I could see palm trees in the background and just seeing the squirrel climbing up a palm tree think about how hard that would be for you to do and they just shoot up there like it's nothing and they can jump many times their body size as jumping from tree to tree or as is often the case in LA from tree to car roof to wall to roof of the house there are incredible climbers yet they're very different than primates right they don't rely as heavily on sense of um sense of sight for instance they don't have fall color vision like primates do so they don't see all of the range of colors that we do second of all the if you notice their eyes are kind of more to the side of their skulls that means that they have left less depth perception so they're not as good at judging distances also they don't have grasping limbs quite as dexterous as primates do they can grasp right but their limbs their digits are not as mobile as ours are they don't have true opposable thumbs for instance yet they're well adapted to life in the trees so maybe there's more to primate traits than just emporial hypothesis so one of the things I mentioned about the squirrel for instance was the squirrels tend to have eyes which are more to the sides of their heads and that's true of many mammals it's true of many mammals it's true of many birds in fact most birds I Know Have Eyes which are to decide of the head there's a few Birds you're going to see more of in our city than these guys right here Rock pigeons and rock pigeons have eyes which are oriented more to the side of the head and what that means is that a pigeon is pretty much able to see all the way around its head this is what I call the teacher's dream you know how teachers always talk about I wish I had eyes on the back of my head you know when they're up at the the Whiteboard and the writing or parents for instance right parents would like to have eyes on the back of the head but we don't right our eyes are oriented to the front of our skulls and so there's trade-offs involved because pigeons they're able to see all around them almost almost all the way around them they have very few blind spots just at the very back of the head but it comes at a cost of having very little binocular vision and this binocular vision that allows us to better judge distance and depth owls on the other hand Have Eyes which are oriented to the front of this the head and so while they don't have the same visual range in other words they can't see all around them they have a high degree of visual acuity in the binocular range in other words they're really good at judging distance they're really good at depth perception so there's a really interesting observation there so think about animals that you might consider more as Predator animals animals that go out and Hunt other animals like cats for instance cats tend to have eyes which are forward-facing owls are predators but owls are not just the only example we can think of other Raptors Hawks Eagles kites Falcons these are all birds of prey that Have Eyes which are more forward-facing whereas animals that tend to be preyed upon like pigeons like squirrels like dare tend to have eyes which are more to the sides and so this brings up another interesting hypothesis as to Prime adaptations called the visual predation hypothesis and that says that most primates Have Eyes which are forward-facing because at some point in our evolutionary history we were predators and so our eyes have oriented towards the front because we hear that characteristic in common with other predators we can think of at least one good example among primates which are Tarsiers Tarsiers are 100 carnivorous in fact they're the only primate that is 100 carnivorous they rely entirely on insects for foods for food and they catch insects by hunting and they're aided in this process by their forward-facing eyes from however there are a few problems with the visual predation hypothesis kind of like the arboreal hypothesis it can explain some things but doesn't explain everything for instance many persimians including Tarsiers rely little on visual information for predation in fact this mouse lemur relies as much on that sense of hearing and that sense of smell as it does on its Vision because many of these persimmians go out and hunt at night time and so nocturnal Hunters generally rely on other senses especially auditory senses for hunting in the dark also it doesn't make sense from the perspective of the fact that most primates with the exception of Tarsiers are not generally massive carnivores were certainly not carnivores the way dogs are or cats are and in fact the preferred food for most primates is fruit and so most primates say chimpanzees even though chimpanzees will periodically hunt and eat meat did comprises a very small proportion of their diet around 80 percent of their diet consists of fruit and that fruit is supplemented with leaves grasses nuts berries and so on and so the visual predation hypothesis doesn't really explain the overall eating habits of most primates foreign video with you and a link to this video can also be found in our reading and videos um section of our modules for this week but I'll copy and paste the link into the chat and you can take a couple of minutes to click on the link and to watch the video so I'll pause the recording so we just watched a video that explains the evolution of color vision among primates and it's really fascinating because primates are the only group of mammals that have full visual acuity and so most primates and most mammals lost the sense of fall color vision during the time when most mammals were found underground or living nocturnally but one group re-evolved folk color vision and that group being primates and so another hypothesis that has been proposed to explain the evolution of primary adaptations is called the angiosperm primate coevolution hypothesis that's quite a mouthful an angiosperm is a fruit bearing tree so it's another name for uh fruit bearing or flowering plant and so it says the primates co-evolved with fruit-bearing plants and one of those pieces of evidence for that co-evolution is the reacquirement of full color vision because plants that are fruit-bearing signal to their primary pollinators to eat the fruit based primarily on the color and so birds for instance know when berries are ripe based on the particular color of those berries and so the same is true of primates in the same way we saw in the video the monkey preferred the fruit that was ripe rather than the fruit which was still unripe and so for instance it's what allows us to know for instance if a banana is ready to eat right um bananas have a short window of ripeness from ranging from Green on ripe to Brown over ripe bananas which at that point are just good for basically banana bread and so I know there's probably weirdos in our class because there always is that prefer green bananas and then there's other weirdos that prefer Brown bananas but ripe for a banana is yellow and that's a hill that I'm willing to die here's here's our problem our problem is that all primates all live in primates today share a common ancestry you and all other primates share a common ancestors that live tens of millions of years ago but Dan itself doesn't tell us much about the common ancestor nor does it tell us what that common ancestor was like what they look like were they primates were they primate like or the word is something totally different primates in the modern sense are incredibly hard to pin down and Define because primates while sharing a lot in common with one another also share a lot of differences we have a lot of diversity within the primate order so if we look at primates today well the common all shapes and sizes and they have different adaptations some primates are vertical clingers and leapers While others are terrestrial quadrupeds some may move through brachiation suspending below branches for instance others prefer like the weirdos that we are humans we prefer to walk on two legs we're bipedal uh some primates like um strep surrounds lemurs and lawrences have specialized incisors that make up what's called a dental comb that they use for grooming but it's not found in any other groups are primates in fact that many of the persimmians have nail or claw like nails that are called um grooming claws or sometimes called toilet claws because they have a dual function of using for both grooming and cleaning themselves after they go to the bathroom that's found in some groups but it's not found in other groups um most primates give birth to a single Offspring at a time but some primates like marmosets and tamarinds give birth to multiple Offspring at a time and as we saw last week different primates have different social structures some are one male multi-female some are multi-female single male some uh or sorry um uh one uh uh one female multi-male some are multi-male multi-female some are um uh pure bonded or monogamous and some have more flexible social structures so as soon as we start to Define and try to pin down pyramids we start to see that there's quite a lot of variation among this group and so if modern primates are difficult to pin down that must mean that early primates are even more difficult and they're more difficult because they're going to have fewer derived primary characteristics undergoing to have more primitive or ancestral characteristics by waiving example I want to introduce you to dicodexes and this is what diocodexes look like dicodex has lived around 45 to 55 million years ago and today there is um group of mammals that are ancestral or descended from diacodexes anybody guess what these mammals are so just in the chat I'm going to be looking in the chat just type in the chat what you think the modern relative of diocode access is all answers welcome of course zebra there horse but with a w alpaca horse antelope these are all great guesses and it makes sense right because that's what it looks like right it looks like an animal that's either adapted to living in an open Woodland environment or maybe open Plains it's hoofed like horses and so it had similar adaptations on dens of the limbs and based on this artist's reconstruction of what it looked like it Bears a strong resemblance to something like an alpaca or a deer so I think these are all strong gases and they are so incredibly wrong this is the modern relative of diocodexes whales and you're all shaking your heads going no way you're a big liar Professor we don't trust you we've lost any ounce of trust we have in you in this class but I'm telling the truth and of course I set up that question as a kind of trick question in a way but it's to emphasize a really important point what ancestral ancestors look like in the past may not reflect what their descendants may look like today or vice versa the reason that we know diacondexis is ancestral to whales is because we can trace the evolutionary history of whales we have every step in The evolutionary chain that we can look at and we can see the transition from diocodexus which would be adapted just like a dare in the forest and in fact they lived in Forest habitats until those forests became more swampy and wet and as a result of natural selection they adapted they changed their bodies to these more muddy habitats and these muddy habitats then became more lake-like habitats kind of like Everglades in which they took on the form of a body that resembles more like an alligator or crocodile and as we know crocodiles and alligators kind of have adapted about life on the the land and life in the water but at some point in the evolutionary history of Wales their ancestors decided Well screwed land we're going to be adopted full time to life in the water as a result the limbs shrunk in size they were co-opted into uh flippers to help them move more easily through the water and over time they adapted even further by growing in size having greater insulation um emphasizing Mobility through the water buoyancy and so on and so as we go back in time and as we look through the fossil record which fossil is going to be more ancestral or to put it another way as we move forward in time traits that we see or adaptations we see are more derived remember ancestral means traits that are retained from an earlier ancestor derived means traits that have changed from an earlier ancestor well when we look at whales have whales changed from the nearly your ancestor heck yeah extraordinarily so that's a significant amount of evolutionary change in about 50 million years or so the reason I'm mentioning whales in this conversation is because as we start to think about primates and primate ancestors we have to be mindful of the fact that primates if we go back as long ago as the time of diocodexes or earlier well primates are not going to look like primates today because modern primates by definition are derived they have derived traits traits that have changed over time from their earlier ancestors so much like when we go looking for whale ancestors we shouldn't expect something that looks like a whale 50 100 million years ago when we go looking for primates we shouldn't go seeking out something that looks exactly like a modern primate because so much Evolution has occurred in that period of time so as we go all the way back to between 37 65 million years ago we meet a group that's at the root or potentially close to the root of the primary tree and that group is called plesiadapaforms and plesiadapa forms are best known from fossils there are a few sites in Europe but most of these early primate ancestors are found in and throughout North America and so as you can see the world was quite different back then right due to continental drift as the plates are moving over time where we find the continental plates today is different than where we find the plates 50 million years ago we can see for instance the Indian subcontinent is moving through the Indian Ocean and will eventually collide with the Asian continental plate creating the largest mountain range in the world the Himalayas we can see North and South America are yet to connect with one another we can also see that South America is connected to Antarctica in fact one major group of mammals marsupials are native to Australia which you probably know and also South America and in fact the earliest marsupials were not found in Australia but are found in South America and so if you're wondering how marsupials kangaroos koalas wallabies and so on got to Australia it's through this land bridge that connected South America to Antarctica to Australia so as we're understanding changes in evolutionary history we have to understand where the continents were and what the world looked like and what the climate and environment looked like at the time foreign forms unlike primates they didn't have any post-orbital closure one of the characteristics of primates is that they either have a bony bar or completely enclosed eye orbit but these guys did not they also have quite small brains and very large faces and snouts which are also kind of on primate like [Music] they have very spiky teeth which is something that's not typical of primates except for Tarsiers would which tells you something about the adaptation spiky Teeter typically found in insect eaters and they also had claws at the end of their digits and so at this point you're probably looking at all of these traits and going well none of these really sound like primary characteristics well we can turn that question on its head and say well were any of the diocodexes adaptations whale like adaptations and the answer will be no so we're looking at a very ancestral prime it however some groups of plesiadapta forms have Clues to suggest that they are indeed related to the earliest primates for instance some have cusps that are bunodont which means Roundup molars that word bun means rounded and so bunodont means round the teeth and so if we look at our teeth our molars the cusps are more rounded which is typical of 3 liters which is what most primates are so this may be the group that led to the fruit eating primates and so some of these places that performs were omnivorous with forgivers and insectivorous adaptations which is something we see also in modern primates and the interestingly one group of plesiadapt performs called carpalesta simpsonai had long digits and long fingers and a nail on a Divergent and opposable big toe and so one of the characteristics of primates is that we have opposable thumbs and opposable toes with one exception of humans we've lost the adaptation through bipedal locomotion but all other primates have an opposable big toe and we find this one characteristics in one species of plesi that performs called carpales The Simpson eye and so for that reason many anthropologists and primatologists believe that please adapter forms may have been the earliest ancestors of primatology or of later primates however it's not until around 50 55 million years ago that we start to see primates that look like primates and the word for this group of eerily primates is called you primates U is the word which means good or true in Greek like the word eulogy or the word euphemism eulogy means you logos which means speak well or speak good or good words depending on how you translate and so you in this context means true and in fact the name you alternatively say for you primates are true primates and these U primates are true primates are found in the early eocene period around 50 or so million years ago and are found in multiple continents North America Europe Africa and Asia and these true primates they appear in the early Asian period and they consist of two major family groups under two family groups are they other pits and the alma Mayas are the Pitt day and Amma Maya Day and they represent an early adaptive radiation so that just means a diversification and evolution of early persimmians okay let's let's do a little bit of recap on primate taxonomy so among primates we have two main groups we have the strepsilines and the haplorines strep sarons consist of lemurs and lorises within a gradistic taxonomy this group would also include Tarsiers so we would call that group persimmians persimmians or lemurs lorises and Tarsiers within a gradistic taxonomy but here we're looking at a Cloud District taxonomy and within the classics cladistic taxonomy strep surrounds are lemurs and lorises and Tarsiers fall into this group the haplerides the haplorines consisting of Tarsiers platerini which are new world monkeys means flat nose which is a characteristic of the monkeys that are found in the New World South and Central America and katarini consists of the circuits which are the old world monkeys and the hominois which are the Apes and so really the taxonomies are very similar except for where Tarsiers fall according to gradistic taxonomy their place with the Lemurs and lorises according to cladistic taxonomy based on shared derived characteristics rather than the degree of evolutionary change they fall in with monkeys and apes and so if we compare our two groupings strepsilons and haplorines and we use lemurs and Tarsiers as two examples of or examples of each we see some differences first of all lemurs have a long snout which tells us that they retain this ancestral characteristic so they still rely heavily on the sense of smell in fact they have a rhinerium at the end of the snow which is a wet nose they also have a post-orbital bar which is a semi-closed bony bridge at the side of the eye orbit and this arrow is kind of showing that you could stick your finger through the skull of the eye socket it would come out the other side so it's open at the back so that bony Bridge just runs along the side of the eye orbit if we look at tarsier on the other hand well Tarsiers they have really large eyes because they are nocturnal and the eye socket is enclosed which is a haplorine trait so rather than the post orbital bar we can describe this as a post-orbital plate or post orbital closure also the snout is much reduced in size which is also a haplorine trait so that's a trait that we find not only in Tarsiers but other haplorines you for instance have a shortened snout other monkeys other Apes also share this characteristic Tarsiers having that bony enclosure around the eye you monkeys and the Apes all share this characteristic in common and so if we look at our two earliest groups of true primates that other points and Alma Mayans we see those characteristics already show up the other points have a long snout the alma mites have a shortened snout the other points have small eyes the alma mites have large eyes So based on these characteristics we can already be we can already start to reconstruct information about the environment and about Behavior for instance we might assume that the alma miyads which have large eyes were probably nocturnal that's kind of cool when you think about it right that we can look at the skeleton of a fossil um we can actually reconstruct something about Behavior we can say because I had a large eye socket it probably had large eyes and if I had large eyes it was probably nocturnal not artists had smaller eyes and that tells us that or um sorry the adipoids had smaller eyes and that tells us that they were probably diurnal they were adapted to being active during the daytime and so here is an example of an adipoid and this is the skeleton of natartis which this photograph is one I took at the Natural History Museum in downtown L.A down by USC and we can see that notartis resembles very much a modern lemur in fact if I put up a picture of a modern lemur next to not artists which lived about 40 million years ago we see that they're practically identical to one another the similarities are striking right down to even the post-orbital bar the long snout the rhinerium that would have said at the end of this opening the curved forearm bones which tell us that they had a lot of strength in the forearms along with the long digits that facilitated vertical clinging and leaping which is still a behavior that's practiced by modern lemurs the flexed knees elbows ankle joints which facilitate this type of locomotion the longer lumbar vertebrae that allow them to flex down and to LEAP great distances all of these traits are present in this early ancestor are also found in modern lemurs and this is why we say that lemurs are the most ancestral of the living primates because they have changed very little foreign this is a photograph I took uh the Natural History Museum in Vienna of a very famous fossil and this is a fossil that's nicknamed Ida it was discovered um not so long ago and it crazed a lot of stir and not just the scientific Community but the community at large in fact there was a high profile documentary mad about it it was giving the uh kind of clickbait name of the missing link that's what they call the documentary it's not exactly the missing link for us but it is important Link in the chain of our evolutionary history and the reason why this fossil is so famous is because it's so incredibly well preserved this is a fossil that's close to 40 million years old you're unlikely to look this good in 40 million years time in fact the chances of you being fossilized in the first place are pretty slim fossilization is something that's relatively rare and it only occurs under certain conditions but at this particular location What's called the missile pits in Germany they have uncovered incredibly well-preserved fossils including this one of an early primate and here we're zoomed into the foot of this particular fossil of Ida which is uh other pit and looking at the thought of this fossil do you notice anything that stands out to you same pattern that we see in our hand and that we see in the photo of all living primates except for humans which is an opposable big toe and you can see that very clearly in this fossil also if we look at the rest of the fossil it's also really interesting first of all do you know this this black around the outside of the fossil that's actually decomposed tissue and fur so that normally doesn't preserve so that tells you how good the preservation is in this fossil that we still have some of the softer tissue still preserve um that's really really unusual another thing that we can infer from this particular fossil is what Ida at and we can defer for for two reasons one if we look at the teeth I'd have had really Roundup molars at the back and really large incisors at the front these are all the Hallmarks of a fruit eater and if the evidence from the teeth isn't enough to convince you scientists actually found remnants of seeds down here in the stomach so they found remnants using um High magnification and they were able to identify that these were the seeds of fruits so we have evidence of Ida's Last Meal which was being digested by the stomach which were fruit so either was a fruit eater a characteristic that she shares with later primates and this is one artist's reconstruction of what Ida looked like or to give her her species name darwinius maselia