Venture into the world of our ancestors and explore the epic saga of human evolution. From the primal steps of our ape predecessors to the triumphant rise of Homo sapiens, this journey through time reveals the incredible twists and turns that led to our existence. Join us as we unravel the mysteries of our origins and uncover the awe-inspiring story of humanity's remarkable journey. Human evolution, the process by which human beings developed on Earth from now extinct primates. Viewed zoologically, we humans are Homo sapiens, a culture-bearing, upright walking species that lives on the ground and very likely first evolved in Africa around 315,000 years ago.
We now stand alone as the only living members of what zoologists refer to as the human tribe, Hominini, but there is abundant fossil evidence to indicate that we were preceded for millions of years by other hominins such as Ardipithecus and the Australopithecines and our species also lived for a time contemporaneously with other members of our genus such as the Neanderthals, Denisivans, Homo floresiensis and many more. In addition, we and our predecessors have always shared earth with other ape-like primates from the modern-day gorilla to the extinct Poranthropus robustus. All apes extinct and living are all related. This is accepted by anthropologists and biologists all over the world.
Yet the exact nature of our evolutionary relationships has been the subject of debate and investigation since the great British naturalist Charles Darwin published his monumental books On the Origin of Species in 1859 and The Descent of Man in 1871. Surprisingly, Darwin never claimed As some of his Victorian contemporaries insisted he had, that man was descended from the apes, and modern scientists would view such a statement as a useless simplification, just as they would dismiss any popular notions that a certain extinct species is the missing link between humans and the apes. There is, theoretically, however, a common ancestor that existed millions of years ago. This ancestral species does not constitute a missing link along a lineage, but rather a node for divergence into separate lineages. This ancient primate has not been identified and may never be known with certainty, because fossil relationships are unclear even within the modern human lineage, which is of course much more recent.
In fact, the human family tree may be better described as a family bush. within which it is impossible to connect a full chronological series of species leading to homo sapiens that experts can agree upon. With the hominid line looking more like this than a straight line from one species to another like what most of us have seen all our lives, the latest common ancestor of humans and chimpanzees is estimated to have lived between 10 and 7 million years ago.
Speciation may have begun shortly after 10 million years ago. But later mixture between the lineages may have taken place until around 5 million years ago. Candidate hominini species which lived in this time period include Auronopithecus, a genus of Eurasian great ape represented by two species, Auronopithecus macedoniensis, a late Miocene hominoid from Greece, 9.6 to 8.7 million years old, and Auronopithecus turkey, also from the late Miocene of Turkey, 8.7 to 7.4 million years ago. The Ouranopithecus's shares derived features with some early hominins, such as the frontal sinus and a cavity in the forehead.
Graecopithecus, classified as a genus of hominid that lived in southeast Europe during the late Miocene around 7.2 million years ago. Their thick enamel and large molars are features that convince researchers that the specimen belonged to a hominid species. Sahelanthropus chadensis, an extinct species of hominid dated to about 7 million years ago.
Existing fossils include a relatively small cranium, five pieces of jaw and some teeth, making up a head that has a mixture of derived and primitive features. Arm and leg bones were also found, and in 2022 researchers analyzed the femur and ulna, and their results suggested that the description of the limb bones of Sahelanthropus confirms habitual bipedalism, but not exclusively. This may indicate Sahelanthropus is indeed the earliest known human ancestor. Another indication that Sahelanthropus was a human ancestor is that the Tumai skull has relatively small canine teeth. That's something seen in other human ancestors and modern humans, but not in other modern apes, and scientists think that it's a human ancestor.
it may be a sign of reduced aggression. More finds of this species is important for greater understanding in its position in our lineage. And finally, Aurorin tuganensis, a genus of primate within hominin A, fossils found are dated to 6.2 to 5.7 million years old.
Aurorin shares several apomorphic features with modern humans, as well as some with later Australopithecines, such as its leg bones being very modern human-like. Individuals of this species were approximately the size of a chimpanzee and had small teeth with thick enamel, again similar to modern humans. The most important fossil of this species is an upper femur, showing evidence of bone build-up typical of a biped. So, Aurorin tuganensis individuals climbed trees, but also probably walked upright with two legs on the ground. Because Aurorin tuganensis was a basal hominoid, it is more than likely a human ancestor, and very close to our last common ancestor with chimpanzees, that adapted an early form of bipedalism.
We can start to see from these fossils, the evolutionary pressures in Africa of that time for walking upright. The shift to bipedalism. or walking upright on two legs, likely occurred gradually over millions of years due to a combination of environmental and evolutionary factors.
There are many theories that attempt to explain why humans are bipedal, but none is wholly satisfactory. Increased speed can be ruled out immediately because humans are not very fast runners. Some theories suggest that changes in habitat, such as the transition from forests to more open savannas, may have incentivized our early ancestors to walk upright to see over tall grasses and cover longer distances more efficiently while foraging for food.
A study performed by three researchers from the University of Arizona, the University of California, and Washington University in St. Louis found that humans used 75% less energy walking upright than the chimps used walking on all fours. Essentially, walking upright seemed to be beneficial because it saved energy. Additionally, the ability to use objects and tools, especially tools for defense and hunting, while walking upright, could have provided an advantage for survival and resource acquisition.
Another theory proposed that walking on two legs freed the arms, which could then be used to collect food to bring to the family unit. If a primate walked on all fours, he couldn't carry much food back to the family without embarking on multiple hunting or foraging expeditions. It is likely all these factors, and probably more, are the reasons why humans started walking upright rather than on costly all-fours. As we go further into our evolutionary line, you can clearly see us becoming slightly more gracile but still very much ape-like, and still not looking very modern human-like just yet.
A species named Ardipithecus, a genus of an extinct hominin that lived during the late Miocene and early Pliocene epochs. in the Afar Depression, Ethiopia. Two fossil species are described in the literature, Ardipithecus cadaba, dated to approximately 5.6 million years ago during late Miocene, and Ardipithecus ramidus, which lived about 4.4 million years ago during the early Pliocene. Ardipithecus cadaba is known only from teeth and bits and pieces of skeletal bones.
The teeth show primitive morphology and wear pattern. which demonstrate that Kadaba is a distinct species from Ramidus, and so therefore it has been described as a probable ancestor of Ramidus. Ramidus existed more recently than the most recent common ancestor of humans and chimpanzees, and thus is not fully representative of that common ancestor.
Nevertheless, it is in some ways unlike chimpanzees, suggesting that the common ancestor differs from the modern chimpanzee. After the chimpanzee and human lineages diverged, both underwent substantial evolutionary change. Ardipithecus was arboreal, but with feet specialized for walking, showing adaptations that combined tree climbing and bipedal activity. It lived largely in the forest where it competed with other forest animals for food, no doubt including the contemporary ancestor of the chimpanzees.
The canine teeth of Ramidus are smaller. and equal in size between males and females, which suggests reduced male-to-male conflict, increased pair bonding, and increased parental investment. Thus, fundamental reproductive and social behavioral changes probably occurred in hominids long before they had enlarged brains and began to use stone tools.
But still, if we go by brain size for intelligence and cognition, Ardipithecus still only He had a brain size of between 300 and 350 cubic centimeters, which on average is actually smaller than the modern bonobo and chimpanzee brain. The size of the brain increased, along with presumed intelligence, came with the well-known Australopithecines, a group of extinct primates closely related to, if not actually ancestors of, modern human beings, and known from a series of fossils found at numerous sites in eastern, north-central. and southern Africa. The various species of Australopithecus lived roughly 4.4 million to 1.4 million years ago, during the Pliocene and Pleistocene epochs. The oldest australopithe was Australopithecus afarensis, found in East Africa.
It is thought that afarensis was ancestral to both the genus Australopithecus and the genus Homo. They had a brain size of 380 to 430 cubic centimeters and a prognathic face. The jawbone was quite robust, similar to that of gorillas. It was this member of the Australopithecines that left human-like footprints on volcanic ash in Laetoli, northern Tanzania, providing strong evidence of full-time bipedalism. The latest Australopith to live was Australopithecus sediba, who date to about 1.98 million years ago.
in the early Pleistocene in South Africa. It is known from a partial juvenile skeleton, the holotype MH1, and a partial adult female skeleton, the paratype MH2. MH1 has a brain volume of about 420 to 440 cubic centimeters, similar to other Australopithecines. The brain configuration appears to have been mostly Australopithecine-like, but the orbitofrontal cortex appears to have been more human-like.
which is involved in the cognitive process of decision making. The face of MH1 is also strikingly similar to Homo instead of other Australopithecines, with a less pronounced brow ridge, cheekbones, and prognathism, and evidence of a slight chin. The pelvis also points to Sediba being capable of a human-like stride. Australopithecines show clear signs of human-like adaptations from their ape-like ancestors.
Another hominin that lived near this time, and could possibly be ancestral to us, is a species called Kenyanthropus platyops, identified from the Lomekwi site by Lake Turkana, Kenya, during the Middle Pleistocene around 3 million years ago. Before its naming in 2001, Australopithecus afarensis was widely regarded as the only Australopithecine to exist during the Middle Pliocene, but Kenyanthropus evinces a greater diversity than once acknowledged. Kenyanthropus is most recognizable by an unusually flat face and small teeth for such an early hominin, with values on the extremes or beyond the range of variation for australopithecines in regard to these features.
Brain volume is uncalculable due to distortion of the brain case, but it was probably similar to that of australopiths and paranthropus. Kenyanthropus, Afarensis, and Deiremeda, another extinct australopithecine of the eight we know about, All coexisted in the same time and region, and because their anatomy largely diverges in areas relevant to chewing, they may have practiced niche partitioning and foraged for different food items. So out of Kenyanthropus and the Australopithecines, which species is our direct ancestor?
Many scientists think Afarensis is the ancestor of the later Homo species, and therefore us modern humans. But some scientists now feel Kenyanthropus's flat face and less pronounced brow ridges seem more closely related to Homo. Others in the scientific community believe more fossil evidence is needed before we can place Kenyanthropus within our lineage, as the only known skull from the species was found badly distorted.
These scientists believe Kenyanthropus platyops is no more than a variant of Afarensis. And remember, if they are in fact different species, Our family tree is more like a bush and therefore interbreeding between the two may have occurred and both of their genomes could have made their way down the line and into ours today. During the period from our split from the chimpanzee last common ancestor to the time of the Australopithecines, significant environmental changes occurred in Africa. These changes included a shift from predominantly forested habitats to more open and green areas.
grasslands and savannas due to factors such as climate change, tectonic activity, and the drying of the African continent. This transition likely influenced the evolution of our hominin lineage in several ways, such as our diet. The transition from forested habitats to grasslands may have led to changes in the changes in diet, with a shift towards more diverse and possibly harder to reach food sources, which could have influenced the development of tools and hunting strategies among early hominins.
Changes in habitat may have affected social structures and behavior also among early hominins. For example, the need to cooperate in group activities such as hunting or defending territory may have become more pronounced in open environments compared to dense forests. The challenges of navigating and surviving in changing environments may have also driven increases in brain size and cognitive abilities over time, as early hominins adapted to new ecological niches and social dynamics, and obviously bipedalism, as mentioned earlier in the video. Overall, the environmental changes during this period likely played a significant role in shaping the evolutionary trajectory of our hominin ancestors. Ultimately leading to the emergence of species more closely resembling modern humans.
Next, there are two potential hominin species that may be directly ancestral to us, a topic that continues to be debated among scientists. Some scientists even group them together as the same species. First up is Homo rudolfensis, who lived around 2.4 million years ago until around 1.8 million years ago in Eastern Africa, specifically northern Kenya.
northern Tanzania and Malawi. There is only one really good fossil of this Homo rudolfensis, and it has one really critical feature, a brain case size of 775 cubic centimetres, a big leap from their Australopithecus predecessors. And considerably above the upper end of the other debated human ancestor I will get to after this. Rudolfensis didn't have the heavily built jaw and strong jaw muscle attachments seen in robust early humans.
These anatomical differences likely indicate different diets between Rudolfensis and earlier Australopith species, capable of more powerful chewing. They lived in a predominantly a grassland environment. Although no associated archaeological evidence was found with any Homo rudolfensis remains, they were living at a time when it is known that human ancestors were making tools.
The next hominin is considered to be our direct ancestor over Rudolfensis and is regarded by some as the first human to walk the planet, hence the name Homo habilis, meaning handyman. The difference between the two to warrant being distinct species is Rudolfensis'larger brain case, longer face, and larger molar and premolar teeth compared to Homo habilis. Other than that, they are very similar in appearance. It is generally agreed upon that Homo habilis, who spanned from 2.3 to 1.4 million years ago, is descended from a species of Australopithecus. If Homo habilis evolved in East Africa, then Australopithecus afferensis and Australopithecus gahi are its possible ancestors.
But if habilis evolved in South Africa, then Australopithecus africanus and Australopithecus sediba are candidates. Future fossil discoveries will hopefully answer this question. This species, along with Homo rudolfensis, is one of the earliest members of the genus Homo. Many scientists think it is an ancestor of later species of Homo, and likely on our own branch of the family tree.
It had a slightly larger brain of 610 cubic centimeters, some actually as low as 500, but some as high as 800, and had a smaller face and teeth than in Australopithecus or older hominin species. But it still retained some ape-like features, including long arms, and a moderately prognathic face, which leads to some scientists to rather call it Australopithecus habilis rather than assign it to the genus Homo. A big reason why most scientists think it does belong in the genus Homo is because of habilis's increased cranial capacity and comparatively smaller molar and premolar teeth of the fossils, a human-like foot, and hand bones that suggested an ability to manipulate objects with precision. Furthermore, Scientists suggest they were also the first to manufacture the Alderwean stone tool industry.
Alderwean tools were a widespread stone tool archaeological industry style in prehistory. These early tools were simple, usually made with one or a few flakes chipped off with another stone. The system included choppers, scrapers and pounders.
They mainly used the tools in the butchering of animals, a massive step in human evolution. Although it is not thought habilis hunted the animals themselves, and instead are thought of as a scavenger hominin, Homo habilis lived in a predominantly grassland environment. The climate was becoming cooler and drier, and this may have been the impetus for new feeding streams. strategies that included scavenging and tool use. Chemical analysis suggests that this species was mainly vegetarian, but did did of course include meat in their diet.
Habilis groups are suggested to have have numbered 70 to 85 members. This configuration would be advantageous with multiple males to defend against open savannah predators such as big cats, hyenas and crocodiles of their time. Habilis coexisted with Paranthropus boisei.
a species of robust Australopithecine, but not thought to be in our own lineage, Homo rudolfensis, and most definitely our very own ancestor in some way, Homo erectus. But as they were living at the same time, how could erectus evolve from habilis, if habilis was still around when erected evolved, and co-existed for about half a million years? The theory being is a group of habilis may have been reproductively isolated, and only this group developed into Homo erectus.
This is called cladogenesis. This event usually occurs when a few organisms end up in new, often distant areas, or when environmental changes cause several extinctions, opening up ecological niches for the survivors, and causing population bottlenecks and founder effects, changing allele frequencies of diverging populations compared to their ancestral population. The events that caused these species to originally separate from each other over distant areas may still allow both of the species to have equal chances of surviving, reproducing and even evolving to better suit their environments while still being two distinct species due to subsequent natural selection, mutations and genetic drift. Homo erectus is the most long-lived species of human having survived for almost 2 million years and the first human ancestor to spread throughout Eurasia with a continental range extending from the Iberian Peninsula to Java.
They were also the first human to possess modern human-like body proportions, with relatively elongated legs and shorter arms, compared to the size of the torso. Unlike all hominins before, these features are considered adaptations to a life lived fully on the ground, with the loss of earlier tree climbing adaptations. They had the ability to walk and even run long distances. There is fossil evidence that this species cared for old and weak individuals, and why it is, in my opinion, the first true human.
They were the first human species to have exhibited a flat face, prominent nose, and possibly sparse body hair coverage to help regulate their body temperature in the scorching savannah heat. Like modern humans, Homo erectus varied widely in size, ranging from 4 feet 9 inches to 6 feet 1 inches in height and 40 to 68 kilograms in weight. thought to be due to regional differences in climate and nutrition.
Among primates, this marked of a response to environmental stressors called phenotypic plasticity is only demonstrated in modern humans. Also, like modern humans, and unlike other great apes and earlier hominids, there does not seem to have been a great size disparity between homo erectus males and females. Though the species brain size certainly exceeds that of ancestor species, Capacity varied widely depending on the population.
For example, the average brain size of Asian Homo erectus was about 1,000 cubic centimeters, while smaller-brained specimens have been found in Dmanisi, Georgia, averaging only 631 cubic centimeters, and specimens on the island of Java, averaging 780 cubic centimeters. Overall, Homo erectus'brain size varies from 546 to an astonishing 1,251 cubic centimeters, which is greater than the range of variation seen in modern humans and chimps, though strangely less than that of gorillas. 1,251 cubic centimeters also falls in line with the lower end of some modern Homo sapiens brains. While the cranial capacity of Homo erectus falls short of that of the average Homo sapiens, it far exceeds the capacities of the Australopiths. The difference between Australopithecus and Homo erectus is greater than that between Homo erectus and Homo sapiens.
The tall bodies and large brains of Homo erectus individuals required a lot of energy on a regular basis to function. Eating meat and other types of protein that could be quickly digested made it possible to absorb nutrients with a shorter digestive tract, another new adaption, making more energy available faster. Soon after we see evidence in the fossil record of the earliest Homo erectus, about 1.9 million years ago, we see evidence in the archaeological record for the first major innovation in stone tool technology, about 1.6 million years ago.
76 million years ago. Known as the Acheulean stone tool industry, it consisted of the creation of large cutting tools like hand axes and cleavers. Increased reliance on a broader set of tools may have helped Homo erectus survive during changing climates.
It is this, along with numerous butchering sites of large animals across Africa and Eurasia, that has led scientists to believe that Homo erectus was an apex predator, suggesting the development of predatory behavior and coordinated hunting. The brain, body size and manufactured equipment of Homo erectus were so superior to those of Australopithecus and Homo habilis that it is highly probable that food collecting techniques, including hunting, were also better. Many scientists hold that Australopithecus and habilis were more scavengers than hunters, perhaps at best opportunists who seized their chance when a weak, young, sick or aged animal crossed their paths.
Indeed, many of the animal bones found in Australopith deposits are of juvenile and old individuals. Although larger animal bones have been recovered from habilis deposits, these have exhibited tooth marks of non-human predators, as well as cut marks. Homo erectus, on the other hand, seems to have been a confirmed hunter whose prey included animals of all sizes and age groups. It is also postulated to have been the earliest human ancestor capable of using fire.
Evidence here lies in Kenya. at Kubi Fora as far back as 1.5 million years ago, and in South Africa, Wonderwork Cave, an astonishing 1.7 million years ago. These first firekeepers are thought to have simply transported to caves and maintained naturally occurring fires for extended periods of time, or only sporadically when the opportunity arose.
Seafaring evidence here is their Akyulean artifacts discovered on isolated islands of Flores, Timor and Roti in Indonesia, that were never connected to land. This is estimated around 800,000 to a million years ago, Homo erectus was the only known human capable of this at this time. Art, with evidence being engravings on a shell with geometric markings drawn into it.
They were also the earliest human to have intentionally collected red-colored pigments, namely ochre, found at Olduvai Gorge, Tanzania. Venus of Tantan and Venus of Berakat Ram are also postulated to being crafted by Homo erectus to resemble a human form. They were mostly formed by natural weathering, but slightly modified to emphasize certain grooves to suggest hairline, limbs and eyes. The former has traces of pigments on the front side, possibly indicating it was colored. Art-making capabilities could be considered evidence of symbolic thinking, which is associated with modern cognition and behavior.
And it looks like it started here with Homo erectus. And lastly, the capability of speech using some proto-language, but unfortunately, speech, of course, does not fossilize. The transition from Homo habilis, or Rudolfensis, to Homo erectus marks a significant leap in our evolutionary journey.
It is now we really start to see ourselves in the Homo lineage, but this is where the term, the muddle in the middle, gets its name. In paleoanthropology, this time period is often termed this because the species level classification of archaic human remains from this time period have and are still being heavily debated, just who is the ancestors of modern humans during this period in history. Several human species such as Homo heidelbergensis and Homo antisessa seem to have evolved from Homo erectus. With antisessa, there is still debate over how they are related to other Homo species. and where they sit on our evolutionary bush.
This is a controversial species designation. In 2020, Enrico Cappellini, a geneticist at the University of Copenhagen, completed a mass spectrometry study, a technique that can sort out a sample's chemical composition, including the peptides that make up proteins, to analyze proteins in a sliver of enamel from an 800,000-year-old Homo antisessar molar from Gran Dolina. And it was concluded Anticessor falls as a sister group, close, very close, to the branch that leads to us, and is not a direct ancestor of us or the Neanderthals. The most popular theory now is that modern humans are directly descended from Homo heidelbergensis.
Comparison of Neanderthal and modern human DNA suggests that the two lineages diverged from a common ancestor, most likely Homo heidelbergensis. sometime between 400,000 to 800,000 years ago, a fairly wide range, and it is still being debated by scientists. Between 600,000 and 200,000 years ago, the climates of Africa and Europe experienced a series of warm and cool phases. and the move from Africa to Europe subjected these people to generally colder climates. About 300,000 years ago, a severe cold-dry period began, and the Sahara became a barrier to movement between Africa and Eurasia, although movement may have been possible between Europe and Northern Asia.
At this time, populations in Africa and in Europe were isolated from one another, and regional differences began to appear. with the European Heidelbergensis branch leading to Neanderthals, and the African branch, sometimes called Homo Rhodesiensis, leading to Homo sapiens. Proponents of this wide concept of Heidelbergensis assert that the mosaic of primitive and derived features shared by this group of fossils is unique, with few traits linking them exclusively to either modern humans or Neanderthals. Homo Heidelbergensis is thus hypothesized to be the last common ancestor of both Neanderthals in Eurasia and Homo sapiens in Africa.
This scenario is the most popular and well-supported at present. Homo heidelbergensis is a species of human that is identified in both Africa and Western Eurasia from roughly 800,000 years ago onwards until as recently as 200,000 years ago. In comparison to early Pleistocene Homo erectus, Homo heidelbergensis had a much more modern human-like face, with larger brain case and flatter face than older early human species.
Some differences between Heidelbergensis and Homo sapiens were their large brow ridges and low foreheads. Their brain cases also were more elongated from front to back than in Homo sapiens. Their average brain size also took a slight leap from Homo erectus, averaging a volume of about 1260 cubic centimeters.
ranging from 1,100 to 1,390 cubic centimeters. They were in the same height and weight range as us. Males averaged 5 feet 9 and 62 kilograms, females 5 feet 2 and 51 kilograms.
Some experts believe that Heidelbergensis acquired a primitive form of language. Heidelbergensis had a modern human-like hyoid bone, which supports the tongue and middle ear bones capable of finely distinguishing frequencies Within the range of normal human speech, judging by dental striations, they seem to have been predominantly right-handed, and handedness is related to the lateralization of brain function, typically associated with language processing in modern humans. So it is postulated that this population was speaking with some early form of language, although of course this is impossible to verify, but it is likely they did. It was the first early human species to live in consistently colder climates. Their wide, robust bodies were likely an adaptation to conserving heat.
This early human also broke new ground. It was the first species to build shelters, creating dwellings out of wood and rock. Although a circle made by Homo erectus with volcanic rocks used to maybe support poles stuck into the ground, possibly to support a windbreak or a rough hut, was discovered in Olduvai Gorge.
so they might lose this title with more evidence of ancient human construction. The tools made by Homo heidelbergensis were mostly used for hunting and butchery. Most of their tools were of the type previously used by Homo erectus. These were large stone tools with flakes removed from two sides to produce the bifacial stone hand axes, cleavers, and carvers classified as Mode II technology.
But some later populations are known to have made tools from deer antler, bone and wood. These materials were modified into scrapers, hammers and sophisticated wooden throwing spears. These spears were made of soft spruce wood and were made to be between seven and eight feet long. These were used for hunting large animals for food, although the hides may also have been useful, especially in colder areas. The fossilized bones of these animals have shown that large animals including rhinos, hippopotamus, bears, horses and deer were targeted.
These animals were skillfully hunted then butchered in an orderly fashion that suggests that these people were working in advanced cooperative groups. No forms of sophisticated artifacts other than stone tools have been uncovered yet, although red ochre, a mineral that can be used to create a red pigment which is useful as a paint. has been found at Terra Amata excavations in the south of France.
There is evidence that Heidelbergensis was capable of controlling fire by building hearths or early fireplaces by 790,000 years ago in the form of fire-altered tools and burnt wood at the site of Gescher-Bergen. No Yaakov in Israel. One site in Atapuerca, northern Spain, dating to about 400,000 years ago, shows evidence of what may be human ritual, as scientists have found bones of roughly 30 Heidelbergensis individuals that were deliberately thrown inside the pit. Also known as the pit of bones, alongside the skeletal remains, scientists uncovered a single well-made symmetrical hand axe.
illustrating the improved tool-making ability of Heidelbergensis from earlier hominins. So as you can see from these advanced modern human traits, how we got to who we are today through millions of years of evolution, countless species that adapted, changed, developed and interbred with other human species, we get to us, Homo sapiens, the pinnacle of sophistication and advancement in the natural world. These crucial evolutionary adaptations enabled us to assert our dominance and influence over the world we inhabit today.
But let's not forget, our exact evolutionary line also led to our favorite cousins, the Neanderthals. While we are not descended from them, they have to be worth mentioning in our story. After all, we did interbreed with them numerous times over thousands of years, and everyone outside of sub-Saharan Africa can thank them for up to 4% of our genome. According to new studies, even inhabitants of sub-Saharan Africa have around 0.3% of Neanderthal genes. In all, about 20% of distinctly Neanderthal gene variants survive in modern humans today.
Some of the DNA is found in parts of the human genome that are associated with skin and hair, maybe giving our ancestors thicker hair and skin that help them cope better with the colder climate. Other DNA inherited from Neanderthals seems to be involved in boosting immunity, perhaps providing a quick fix against local infections. But it's not all good news.
Neanderthal DNA in modern humans seems to also be associated with diseases such as diabetes, lupus and Crohn's disease, which causes inflammation of the gut. The negative effects in modern humans may have been triggered by changes to our lifestyles over thousands of years. It seems that our Neanderthal inheritance has brought both benefits and disadvantages. The Neanderthals evolved slightly before us, the oldest potential. Neanderthal bones date to 430,000 years ago, compared to 315,000 for Homo sapiens.
Neanderthals lived life a lot like us, with very sophisticated technology. It includes the Mousterian stone tool industry, an array of advanced toolmaking techniques that produced hand axes, racloir, spearheads, and points. They had the sophistication and ability to create fire, Build cave hearths to cook food, keep warm and defend themselves from predators, make adhesive birch bark tar, craft clothing, weave, go seafaring through the Mediterranean, make use of medicinal plants, treat severe injuries, store food, and use various cooking techniques such as roasting, boiling and smoking. A number of examples of symbolic thought and Paleolithic art have also been attributed to the Neanderthals.
namely possible ornaments made from bird claws and feathers, shells, collections of unusual objects, including crystals and fossils, engravings, music production, indicated by the Divya Babe flute, and extraordinary cave paintings found in Spain. Neanderthals were likely capable of speech, possibly articulate, although the complexity of their language is not known, as, of course, language does not fossilize. Compared with modern humans, Neanderthals exhibited a more robust build and proportionally shorter limbs. Researchers often explain these features as adaptations to conserve heat in a cold climate, but they may also have been adaptations for sprinting in the warmer, forested landscape that Neanderthals often inhabited.
They had cold-specific adaptations, such as specialized body fat storage and an enlarged nose to warm air. Average Neanderthal men stood around 5 feet 5 inches and women around 5 feet. The brain cases of Neanderthal men and women averaged about 1,600 cubic centimeters and 1,300 cubic centimeters respectively, which is considerably larger than the modern human average of 1,260 and 1,130 cubic centimeters. Although brain size alone does not necessarily indicate higher intelligence.
It's probable their bigger, more robust body size may have necessitated a larger brain to control bodily functions and motor coordination. The Neanderthal skull was more elongated, and the brain had smaller parietal lobes and cerebellum, but larger tem... temporal, occipital and orbitofrontal regions.
Neanderthals and modern humans also appear to have interbred with the Denisivans, a different group of archaic humans, in Siberia and Southeast Asia. A 90,000 year old specimen named Denisova 11, or nickname Deni, was found that her father was a Denisivans, related to more recent inhabitants of the region, and her mother, a Neanderthal, related to more recent European Neanderthals at Vindija Cave, Croatia. Given how few Denisovan bones are known, the discovery of a first-generation hybrid indicates interbreeding was very common between these species.
As much as 17% of the Denisovan genome from Denisova Cave represents DNA from the local Neanderthal population. Comparison of the Denisovan genome to various modern human populations shows up to 4-6% contribution from Denisovan in non-African modern human populations. This concentration is highest in people from Papua New Guinea and Oceania. It makes sense that interbreeding would appear in these Southeast Asian and Pacific Island communities, as their ancestors migrated from mainland Asia, where Denisovan fossils have been found. DNA testing has revealed that all three of us shared a common ancestor around 800,000 years ago.
Once this ancestral population had split, our branch of the human family tree stayed in Africa while the Neanderthal and Denis-Ivan one moved into Eurasia. By roughly 430,000 years ago, the Eurasian branch had itself split, ultimately giving rise to the Neanderthals in western Eurasia and the Denisovans in the east. It isn't clear why the Denisovans and Neanderthals diverged.
But a new idea suggests that as the Arctic ice sheet expanded southwards to the Black Sea, cutting Europe off from Asia, it divided the early humans into the East and Westerly groups mentioned above. These splits weren't permanent though. After tens of thousands of years of independent evolution, members of the three populations met and interbred. It wasn't until 2010 that scientists announced that the Denisovan existed. So much about them remains unknown.
However, fossil and genetic evidence suggests the Denisovan lived across a wide range of areas and conditions, from the cold mountains of Siberia and Tibet to the jungles of Southeast Asia. It is speculated that Denisovan likely lived in a manner similar to Neanderthals. But a wealth of additional Denisovan finds is needed to further our understanding of their lifestyle and behavior. When we Homo sapiens arrived on the scene some 315,000 years ago.
We joined other human species, including Homo erectus, Heidelbergensis, Floresiensis, Naledi, Luzonensis, Neanderthalensis, and the Denisovans, and possibly more human species yet to be discovered. In Africa, archaic alleles, consistent with several independent admixture events in the subcontinent have been found. It is currently unknown who these archaic African hominins were.
Maybe it was one of these archaic humans, or another undiscovered human. Ancient DNA data from a 4,500-year-old Ethiopian highland individual, a 2,000-year-old South African individual, and a South Central African individual of an unknown time, someone in the last 8,000 years, has clarified that some West Africa populations have small amounts of excess alleles best explained by an archaic source in West Africans that is not included in the pre-agricultural Eastern African hunter-gatherers, Southern African hunter-gatherer populations, or the genetic gradation between them. The West African groups carrying the archaic DNA include Yoruba from coastal Nigeria and Mende from Sierra Leone, indicating that the ancient DNA was acquired long before the spread of agriculture and likely well before the Holocene.
11,600 years ago. Such an archaic lineage must have separated before the divergence of San ancestors, which is estimated to have begun on the order of 200 to 300,000 years ago. In Eurasia, hominin presence begun at least 2 million years before present. Genetic evidence shows that thousands of years later, when lineages of Neanderthals and Denisovan started to expand into Eurasia, The continent was still inhabited by descendants of these archaic hominins, and their genetic admixture made its way into the genome of Neanderthals and Denisovans through ancient interbreeding, then ultimately into us, Homo sapiens. Genetic studies show two major events of genetic admixture from superarchaics, suggesting that in the late Middle Pleistocene, scene, Eurasia was inhabited by at least two separate populations of ancient hominins.
An event of admixture occurred shortly after the common ancestor of Neanderthals and Denisovans began to spread into Eurasia. During this time they encountered a lineage of super-archaic hominins that had been isolated from African homo lineages for at least two million years. This interaction resulted in genetic contributions from this ghost species.
that eventually entered into our genome. This ghost species is believed to have been either a late form of Homo erectus, Homo antisessa, Homo heidelbergensis, or an undiscovered close relative. So after millions of years of evolutionary divergence from our last common ancestor with chimpanzees, with countless interbreeding with fascinating ancient hominins, we arrive at our own narrative, the story of Homo sapiens.
the last surviving species of the genus Homo. We are great apes, characterized by our remarkable adaptability, high intelligence, and advanced cognitive abilities, that allows us to develop highly complex tools and form complex social structures and civilizations. Homo sapiens living today have an average brain size of about 1350 cubic centimeters, which makes up 2.2% of our body weight.
Early Homo sapiens, however, had slightly larger brains at nearly 1500 cubic centimeters. It is not known why our brains have slightly shrunk. For at least 90% human history, we were nomadic hunter-gatherers, just like our ancestors.
Our bodies were thinner and less robust than earlier human species, and indicate a reduction in muscle size from earlier humans. Because of a big increase in intelligence, we simply may have not needed to be as strong as previous humans. The earliest Homo sapiens had a relatively simple culture, although it was more advanced than any previous species. Life for ancient hunter-gatherer tribe members was deeply intertwined with nature.
They had an intimate understanding of their surroundings, including the behavior of animals, plant cycles, and natural resources. Their knowledge was extensive and practical, essential for survival. They relied on hunting, fishing, and gathering edible plants for sustenance.
living in small nomadic groups that moved with the seasons in search of food and water. Their societies were often egalitarian, with shared responsibilities among members and a strong sense of community. For example, the modern hunter-gatherer tribe of the San people or Bushmen of southern Africa have social customs that strongly discourage hoarding and displays of authority and encourage economic equality via sharing of food and material goods.
The egalitarianism typical of human hunters and gatherers is never total but is striking when viewed in an evolutionary context. One of humanity's two closest primate relatives, chimpanzees, are anything but egalitarian, forming themselves into hierarchies that are often dominated by an alpha male. So great is the contrast with human hunter-gatherers that it is widely argued by paleoanthropologists that resistance to being dominated was a key factor in the development of human-hunter-gathering. driving the evolutionary emergence of human consciousness, language, kinship and social organization. Most anthropologists believe that hunter-gatherers do not have permanent leaders.
Instead, the person taking the initiative at any one time depends on the task being performed. Rare evidence for symbolic behavior starts to appear at a number of African sites about 100,000 years ago, but these artistic expressions appear more of a flicker of creativity. than a sustained expression.
It is not until about 40,000 years ago that complex and highly innovative cultures appear and include behavior that we would recognize as typical of modern humans today. Many researchers believe this explosion of artistic material in the archaeological record about 40,000 years ago is due to a change in human cognition. Perhaps humans developed a greater ability to think and communicate symbolically or memorize better. However, As there are obvious attempts at art before this, perhaps there are other reasons. One theory is that population size and structure play a key role as social learning is considered more beneficial to developing complex culture than individual innovations are.
Bigger populations often accumulate more cultural attributes than isolated groups. Then, within just the past 12,000 years, our species, Homo sapiens, made the transition to producing food and changing our surroundings. Humans found they could control the growth and breeding of certain plants and animals. This discovery led to farming and herding animals, activities that transformed the world.
transformed Earth's natural landscapes, first locally, then globally. As humans invested more time in producing food, they settled down. Villages became towns, and towns became cities. With more food available, the human population began to increase dramatically.
Our species had been so successful that it has inadvertently created a turning point in the history of life on Earth. Modern humans evolved a unique combination of physical and behavioral characteristics, many of which other early human species also possessed, though not to the same degree. The complex brains of modern humans enabled them to interact with each other and with their surroundings in new and different ways.
As the environment became more unpredictable, bigger brains helped our ancestors survive. They made specialized tools and used tools to make other tools. They ate a variety of animal and plant foods.
They had control over fire. They lived in shelters. They built broad social networks, sometimes including people they have never even met.
They exchanged resources over wide areas. And they created art, music, personal adornment, rituals, and a complex symbolic world. Modern humans have not only spread to every continent, but have also vastly expanded their numbers.
reshaping the world in numerous ways to their advantage. With advanced technology at our disposal, humans have not only conquered all continents, but have also ventured into outer space, leaving an indelible mark on the planet in ways that greatly benefit our species. We've journeyed from our shared ancestry with chimpanzees to the intricate tapestry of human evolution. This incredible odyssey highlights our resilience, adaptability, and the boundless curiosity that drives us forward.
As we conclude this chapter, remember, the story of human origins is not just about our past, but a beacon illuminating our future potential. Just carry on being nice folks and don't forget to like and subscribe if you enjoyed the video. Thank you for watching, goodbye.