Introduction to Anthropology Textbook Chapter 5 The Genus Homo and the Emergence of Us

CHAPTER The Genus Homo and the Emergence of Us Figure Liang Cave on the island of Flores in Indonesia . A potentially new species of the genus Homo , Homo was discovered in this cave in 2003 . credit Flores to by , BY 20 ) credit Flores by Ryan , BY ) CHAPTER OUTLINE the Genus Homo Tools and Brains Homo habilis , Homo , and Homo erectus The Emergence of Us The Archaic Homo Tracking Genomes Our Human Story Unfolds INTRODUCTION Our human story continues with the rise of the genus Homo which at one time represented at least different species in our human lineage with only sapiens surviving . The genus Homo displays some of the most diverse and complex examples of both australopithecine and Homo characteristics , which has made the of species in this genus challenging . In this chapter we take a look at how have Homo and at attempts to answer the question , What does a species of the genus Homo look like ?

the Genus Homo LEARNING By the end of this section , you will be able to Describe the time periods and geological context of the genus Homo . Identify some key differences between the genus Homo and . some of the limitations of and challenges in the of species in the genus Homo . Explain the concept of as it relates to early evolutionary development and as a tool for . Putting Homo into Context Before learning about the species that make up the category genus Homo , it will be helpful to become familiar with the key archaeological time periods with which Homo is associated . The species and cultural developments mentioned below will be explored in greater detail in the sections that follow . Lower Paleolithic ( from roughly million years ago to approximately ) This period includes habilis and the tool industry , followed by and the tool industry . Middle Paleolithic ( approximately ) This period includes continued use of tools by , followed by and the tool industry . Upper Paleolithic ( approximately ) The Upper Paleolithic saw the emergence of cave art like that found in the famous Cave in France ( Figure , Venus Figure , and an increased use and antler in tools and jewelry . The most recent ice age occurred during this time , with glaciers covering huge parts of the planet . The emergence of and the use of Clovis points , which were used to kill large game such as mastodons and mammoths , occurred near the end of this time period . Neolithic ( Agricultural Age ) New innovations appear during the agricultural age , or Neolithic revolution , as sapiens set up permanent settlements . Humans begin to transition from being hunters and gatherers to growing grow crops , owning land , and domesticating animals . The Challenge of the Genus Homo The previous chapter introduced the , who were diverse in their physical characteristics ( gracile and robust ) with and teeth and small brain size . A key characteristic shared by both the and the genus Homo is . The transition to is linked with various anatomical changes , including longer legs , changes in spinal curvature , and the development of arches in the feet to conserve energy and increase balance when walking . What criteria other than might be used to classify a species under the genus Homo ?

Many anthropologists have attempted to establish criteria to use in determining a of Homo . Mary , Louis , and John , as well as Phillip Tobias , were among the to extensively study the fossils of Homo , considered to be one of the earliest species in the genus Homo . had a brain size of around , which was larger than the , with hands that were capable of the dexterity needed for making tools , clue to bone structure changes and a repositioning of the thumb , which allowed for better grip . The type specimen OH of dated between and and was found in 1960 at Gorge by Jonathan and Mary . It was described by Louis in 1964 . Type specimen refers to a specimen that serves as the standard for the taxon or group for that species . OH is the or accession number of this specimen and stands for Hominid . The specimen consisted of a partial juvenile skull , hand , and foot bones . It possessed teeth that were much smaller than those of any australopithecine and was possibly in coexistence with the robust ( Based on an endocranial cast ( an imprint of the interior of the brain case ) it was determined that habilis may have possessed what is called a area in the brain . area , which includes two areas ( referred to as 44 and 45 ) is located in the middle of the left cerebral cortex of the brain and is especially important for speech development ( Figure ) Some scientists have suggested that habilis started to

develop the neural networks necessary for human speech , while others argue that probably already had speech . FIGURE Position of the area in the brain , consisting of areas 44 ( yellow ) and 45 ( blue ) area is associated with speech development and may have been present in the brain of habilis . credit , Sonia , Richard Commons , BY ) The features ( skeletal structures in the body other than the skull ) of Homo habilis are not as well established , as is the case for many other early fossils . This can be problematic , as many species coexisted with overlapping traits . Likewise , it can be problematic to have material and not the cranium or skull . The skull often serves as a diagnostic tool when materials do not provide enough evidence or provide confusing evidence . Based on their research on habilis , Mary , Louis , and John proposed the following criteria for classifying Homo a brain size over 600 a round , globular skull tool use reduced prognathism ( protrusion of ) and and mandibles humanlike features and feet that are fully adapted for walking ( Tobias , and 1964 ) While this list established and fairly comprehensive guidance , the diversity of traits and the ways in which they overlapped didn always line up with the criteria . habilis has been at the center of several debates regarding their taxonomic position and relationship with other early archaic Homo species . For example , habilis was initially believed to have been a direct human ancestor through the lineage of Homo erectus and then modern humans . This viewpoint is now debated and has resulted in a divide between those supporting habilis and those suggesting another Homo species , as being the ancestor of erectus . is an archaic Homo dated to about , which coexisted with other Homo species during that time period . A cranium was discovered in 1972 along Lake in Kenya by Bernard , a local . The specimen was later described by paleoanthropologist Richard . There is a lot that is not known about this species scientists are missing materials , and as no tools have been found . There are hypotheses that propose that might be a habilis male , exhibiting a larger cranium than that seen in a female . Others suggest it is a completely different species . Another controversy centers on tool use . While Homo habilis was long regarded as the earliest to use stone tools , it has been determined , based on evidence of , that at least one australopithecine ( used stone tools before , at around ( et al . 1997 )

FIGURE The specimen of on the left is noticeably different from that of habilis on the right . credit Commons , BY ) While there are still questions as to the phylogenetic relationship of habilis and , there is general agreement that Homo did evolve from . The timing and placement of the split between and Homo , however , is still debated . was determined to not be an due to its smaller teeth , a humanlike foot , and hand bones that suggested an ability to manipulate objects with precision . One of the main considerations in classifying habilis as a Homo and not an was its cranial capacity , which is a measurement that indicates brain size . With some exceptions , cranial capacity can serve as an indicator of where a fossil might belong in the phylogenetic tree . refers to a progressive increase in brain size over time . In human evolution , we can observe beginning with Homo habilis and progressing more rapidly through erectus . correlates with an increase in behavioral , cognitive , and cultural complexity . Cognitive developments correspond with our ability to construct and form ideas , including the ability think in and communicate via symbolic and abstract language , such as that used in storytelling , ritual , and art . There are always exceptions , however , such as the , who will be introduced later in this chapter . In spite of having a very small brain , made and used tools and built . This discovery has challenged what we thought we knew about the correlation of brain size and cognitive development in human evolution . The quotient ( can serve as a good indicator ( with some exceptions ) of within the genus Homo . The quotient is a calculation arrived at by comparing the ratio between actual brain size ( determined with either a mass or volume calculation ) and expected brain size . Body size is a factor in these measurements as expected brain size the relationship between brain and body size for a given taxonomic group ( 1973 ) The larger the brain weight relative to the overall body weight , the more likely that the brain was used for more complex cognitive tasks . Harry ( 1973 ) was the to develop measurements . The formula he used for calculating in birds and mammals is brain ( body mass ) Other formulas have also been proposed , such as brain mass ( body mass ) Martin 1981 ) While is a strong tool for studying brain size in early , there are always potential margins of error when dealing with fragmentary fossils , and increasingly alternative forms of measurements are being proposed . One study proposes that should no longer be used as a tool in calculating brain size in primates and other vertebrate species , based on the premise that cognitive performance does not depend on body size and so body size should not be included in the formula ( et al . 2021 ) Other theories consider the number of cortical neurons and neural connections as most important when considering cognitive ability ( Roth and 2012 ) According to this approach , the density of the cortex

is more associated with intelligence than is brain size . These alternate approaches would perhaps better explain those exceptions in the fossil records , such as . Other interesting research is looking at potential levels of cognition and memory as it relates to levels of tool complexity ( Read and van der 2008 ) In spite of these criticisms , many see measurements as providing fairly consistent results . Modern humans ( Homo sapiens ) have an of roughly ( meaning that their brain mass is six to seven times greater than what one would expect to in a comparable mammal of the same body size ) erectus has an of , while for an australopithecine is around to ( 2012 , 227 ) Figure shows increases in average brain sizes for various species over time . mom Volume Time FIGURE After remaining steady for millennia , average brain size increases noticeably in the last two million years . Wu , and Norton 2007 ) credit Garcia , artist ( brain images ) BY ) Tools and Brains Homo , Homo , and Homo erectus LEARNING OBJECTIVES By the end of this section , you will be able to Compare and contrast the anatomy and material culture of habilis , erectus , and . the term tool industry and describe the tools typified by the and industries . Identify possible correlations between the environment , diet , new behaviors , and brain growth . The Archeologists use the word describe a or assemblage of stone tools . The tool industry is the oldest known stone tool industry . It dates from around to . Because there were several in Africa during this time , it is unclear whether these tools were created and used by habilis or by , or by both ( 1991 ) tools are fairly crude and primitive in appearance , which can make it to and identify them in the .

146 The Genus Homo and the Emergence of Us FIGURE An tool . This chopper is made of quartzite and dated to the lower Paleolithic period . credit Commons , Public Domain ) Mary was the to create a system to classify , basing her on utility , or how the tools were used . Later efforts were made to classify tools based on how the tools were made . All tools were created by using hard hammer percussion , in which are chipped away from a stone , resulting in a core . These cores served as basic tool that could have been used for killing game , cutting meat and plants , and possibly woodworking . toolmaking is the earliest evidence of , a technique that became more complex over time , resulting in more sophisticated tools ( Figure . FIGURE Demonstration of flint , an ancient technique for shaping stones into useful tools . credit Demonstration National , BY ) Handedness , or brain lateralization ( whether one is or ) is a cognitive development that can be inferred through evidence of the use of a dominant hand in creating and using tools . The use ofa dominant hand suggests a possible reorganization of the brain . It is believed that about 90 percent of humans are , which differs from apes , which are closer to 50 percent . David ( 2016 ) an anthropologist from the University of Kansas , has concluded that the brain lateralization of Homo habilis was more like that of modern human than that of apes . found striations on the teeth of a old Homo habilis fossil that indicate . He concluded that meat was pinched between the teeth and held in place with the left hand , while the right hand cut the meat with a tool . Brain lateralization , increasing brain size , and tool use are just some of the key developments we see in the genus Home . Access for free at

Homo Homo is the first Homo that looks much like sapiens . A key difference between and earlier is that exhibits substantially less sexual dimorphism in body size . males were only 20 percent larger than females . Likewise , modern human males are only 15 percent larger than females . This contrasts sharply with all other previous , such as the , in which males were 50 percent larger than females . It is well established that in mammals , dimorphism is associated with polygyny , and a lack is associated with a monogamous mating system . It has been suggested that the reduction in dimorphism seen in may indicate less competition for access to females and perhaps a shift toward a monogamous mating system , with substantial parental investment in offspring . Other similarities between and modern humans are seen in the teeth and features . The average cranial capacity of is , which is just a bit smaller than that of modern humans , who average . There is a very important specimen of bears mentioning , the Boy . This specimen was discovered in 1984 by paleontologist near Lake in Kenya . It is dated to approximately . The specimen is believed to represent a boy of about 12 years old , determined by various dental and cranial features . He was about feet inches tall , roughly the same height as a modern boy of the same age Figure ) It has been estimated that his adult height would be around feet 10 inches , with an estimated cranial capacity of 900 . The Boy looks tremendously modern in appearance despite being million years old . FIGURE This specimen of Homo known as the Boy . It is believed to be the remains of a boy who was about 12 years old at the time of death . credit Homo ( fossil hominid ) Lower , to Ma , Lake area , Kenya ) by James , BY ) Home Technology Homo continued to use stone tools , but they also began to construct much more complex tools , referred to as the industry ( Figure . These tools have been found throughout Africa , Europe , and the Middle East and are noted as appearing approximately to years ago . These types of tools are rarely found in Asia . It is currently unclear whether this is because the industry had not yet been developed when erectus migrated to Asia or because bamboo ( a plant found in

abundance in Asia ) was found to be a more versatile resource than stone . As wood and bamboo are biodegradable , no remains of tools constructed from these materials would exist today . FIGURE This hand axe , found in the province , Spain , displays the form and construction techniques typical of the industry . credit Commons , Public Domain ) Unlike tools , tools actually look like tools . tools are distinct from tools in that they were on both sides , resulting in a symmetrical tool with two faces , also known as . One end of the tool was tapered , while the other end was rounded . The creation of symmetrical objects from stone materials is believed to represent an increase in cognitive ability as well as motor skills in the tool maker . These were struck from large , which had themselves been struck from boulder cores . This required a more delicate technique than banging one rock into another . tools were typically created used the soft hammer technique . In this technique , hard rock such as is chipped by striking it with a softer material such as bone or wood . The gentler blows detach small that leave smooth , shallow scars , creating a straighter and more uniform cutting edge . The main advantage of technology is that it allowed to get a better grip on their tools , as they were shaped to the hand . This tool type was used primarily as a hunter knife but also for chopping , scraping , and even piercing . The most common type of tool is a hand axe . Note that even though these tools are called axes , they are held in the palm of the hand . Another type of used by Homo is called a cleaver ( Figure ) The cleaver had a wide cutting edge across the end instead of a point and was best suited for hunting or hacking wood . Another tool is the side scraper , used to scrape hides that could then be turned into simple clothing .

, cleaver . More than 500 FIGURE Map of cleaver dated to the Lower Paleolithic ( Note the concentration of artifacts found in certain areas of Africa and in Spain . attribution Copyright Rice University , under BY license ) Evidence of an Increase in Meat Eating In 1973 , a specimen of as ER 1808 was found in Fora , Kenya . Dated to about , this is the most complete specimen ever found . Analysis of ER 1808 suggests that may have been eating carnivore liver , which is high in Vitamin A . This may indicate a dietary shift toward increased meat eating by . Homo erectus A Success Story Homo erectus is the species in the genus Homo . For almost two million years , erectus existed and evolved . Also known as the Upright Man or Java Man , erectus was found in Indonesia in 1891 by Eugene , a professor of anatomy at the University of Amsterdam . At a site called , he found a skull cap and a femur . He named the specimen erectus . The most current dates for Homo erectus are million years ago . erectus exhibits a cranial capacity averaging 900 and several distinguishing characteristics . These characteristics include a slightly projecting nasal spine , incisors , a nuchal crest ( a ridge in the back of the skull that supported strong neck muscles ) very thick skull bones , and pronounced brow ridges . They also had longer legs , evidence that they were utilizing energy much more when walking and becoming effective hunters . We also see a diminishing of the ( or prognathism ) that was so prominent in the .

150 The Genus Home and the Emergence of Us FIGURE This Homo erectus cranium exhibits a number of features , projecting nasal spine , thick skull bones , and pronounced brow ridges . credit Commons , Public Domain ) There is evidence that erectus was using around , which would make it the or one of the to do so . Ancient hearths , charcoal , and charred animal bones have been found in , China . This evidence suggests that erectus was hunting , cooking , and eating meat . Also found at are a number of fossil skulls that were once thought to display evidence of cannibalism . However , recent research evidence suggests that the remains of these erectus were prey to animal scavengers such as hyenas ( et al . 2004 ) The Smithsonian Institution has created an interactive tool ( that visually illustrates the between an increasingly variable and colder climate , and new technologies and tool use . These correlations align with fossil evidence indicating changes in diet and caloric requirements in response to a colder and changing climate , which ultimately fueled a growing brain . The expensive tissue hypothesis proposes that maintaining a brain is expensive and that , in order to meet the energy requirements of a larger brain , our digestive system became smaller and shorter , making it more suited for , food such as meat ( and Wheeler 1995 ) The list below summarizes some of the key evolutionary changes seen in erectus from to possibly as recent as years ago , which provide further support for these correlations ( 2020 ) There is a progressive increase in brain size in erectus , from about 550 to . There is evidence of increased use of and of eating cooked meat at erectus sites . erectus would have needed as much as 35 percent more calories than previous ( Fuentes 2012 ) The eating of softer foods as a result of cooking meat and plants alleviated the need for large chewing teeth and jaws . Over time teeth became smaller , which resulted in thicker enamel . There is a gradual decrease in prognathism , and as in habilis , skulls provide evidence of smaller teeth , which would have made room for larger brains . erectus is taller than any other previous , with longer legs that provided the ability to run great distances and chase prey . New research is shedding some additional light on the possible of running in early The fossil evidence suggests that endurance running is a derived adaptation of Access for free at

The Emergence of Us The Archaic Home the genus Homo , originating about two million years ago , and may have been instrumental in our evolution ( Bramble and 2004 ) The Homo and Home erectus Debate There is great debate as to whether Homo and Homo erectus are one species or two . Some refer to as the early erectus . Their differences are largely geographical is associated with Africa and erectus with Asia . Yet some researchers have concluded that and even should be referred to as erectus . Whether to lump or split the diverse species in the genus Homo is an ongoing challenge in the community . While there are some anatomical differences between erectus and , they are fairly minimal . FIGURE Homo erectus ( left ) has a sagittal keel ( ridge on top of head ) a shorter forehead , and a shaped skull than Homo , seen on the right . credit ( left ) Commons , BY 20 ( right ) free Creative Commons licensed Commons , BY ) The diversity and number of evolutionary changes seen in erectus indicate that erectus set the stage for the arrival of the archaic Homo , which we will cover in the next section . The Emergence of Us The Archaic Homo LEARNING OBJECTIVES By the end of this section , you will be able to Describe the context , time frame , and key anatomical characteristics of archaic Homo . Explain the potential environmental conditions that led to evolutionary change in anatomy and material culture seen in archaic Homo . Compare and contrast the current hypotheses regarding the extinction of the Neanderthal . the Archaic Homo There is no universal consensus on what is included within the term archaic Homo . The term is used as an umbrella category encompassing all the diverse Homo species after erectus . species as archaic Homo typically have a brain size averaging to , which overlaps with the range of modern humans . Archaic Homo are distinguished from anatomically modern humans by the characteristics of a thick skull , prominent supraorbital ridges ( brow ridges ) and lack of a prominent chin . Archaic Homo are viewed as transitional between erectus and sapiens and display many overlapping and varied traits . It has been proposed that archaic Homo may have been the first species to use language , based on the size of their brains 151

and the fairly large social groups they lived in . Archaic Homo species as presented here will be divided into two groups the Early Archaic ( KYA ) and the Late Archaic ( KYA ) Early Archaic Homo Homo antecessor Homo been found in Spain , France , and England and dates to around to 800 KYA . These specimens represent the oldest fossil evidence for the presence of the genus Homo in Europe . Some scientists have suggested that this species is the ancestor of Homo , while others suggest that antecessor is the descendent of . Homo first found at the Sima de los site of the Sierra de region in Spain . Within this site is a cave known as the Pit of Bones , where more than fossils of 28 individuals have been found that date at or before years ago . The site is an important one that stretches over a long period of time and displays the emergence and divergence of various Homo physical characteristics that later appear in the Neanderthal . Evidence from nuclear DNA suggests that early at this site were related to the Neanderthal and not the , indicating divergence earlier than years ago ( Meyer et al . 2016 ) The section on the Neanderthal will explore further the interbreeding and of the , and modern Homo sapiens . Homo almost six feet tall and males weighed about 200 pounds , well within the range of variation for modern humans . Other anatomical features of this species include a protruding occipital bun ( a bulge found in the occipital area of the skull ) a low forehead , no strong chin , and a cranial capacity of about . It has been suggested that the purpose the occipital bun is to balance the weight of the anterior portion of the skull and face . One very modern trait exhibited by this species is the presence of a facial depression above the canine tooth called the canine fossa , which is also found in modern humans . The best preserved fossil is a maxilla ( ofa individual . In addition to the fossil bones , 200 stone tools an 300 animal bones were also found at Gran Dolina , another location at the site , along with a carved stone knife . Stone tools at this site were predominantly style and constructed from local raw materials . Tools included cutting and cores . It has been suggested that the absence of retouched tools at this site indicates that these tools were created primarily for processing and eating meat . are present on the majority of animal remains . One of the most intriguing observations about this site is that there are numerous large animal carcasses ( mostly deer ) that are believed to have been transported to the site rather than consumed where they were killed . Some scientists have suggested that the practice food back to the site is evidence of social cooperation , suggesting both a division of labor and a custom food sharing . Many of the bones of Homo antecessor show the same evidence of as the animal bones , indicating that was removed from the bones with the goal of dismemberment . Some scientists have taken this to mean that cannibalism . However , humans have also been known to remove the from bones during funerary rites . Whether the made by antecessor represent cannibalism , a funerary rite , or another yet unknown practice is still being debated . Homo Homo is an incredibly variable group . Many archaic Homo species are included in this group because they possess features that can best be described as a mosaic between , erectus , and anatomically modern humans ( This section looks a few of the specimens that are regularly attributed to Homo . One of the most important Homo specimens is known as . It was found in 1907 in Germany and is represented by a mandible ( that is dated to approximately years ago . It has a robust mandible and a receding chin like earlier Homo has very small molars like anatomically modern sapiens . The jaw is so big and the teeth are so small that there is plenty of space for additional teeth to develop behind the wisdom teeth . Given that the third molar ( the wisdom tooth ) has already erupted , it has been suggested that this individual was between 20 and 30 years at death .

The Emergence of Us The Archaic Homo FIGURE This jawbone from a Homo specimen was found in Germany in 1907 and is dated to approximately years ago . credit Commons , BY 30 ) Another important specimen of Homo is known as the cranium . It was found in 1960 in Greece . Dates are uncertain but believed to be in the range of to years . Animal fossils found with the specimen indicate is between and years old . It combines Homo traits , such as massive brow ridges and thick cranial bones , with a cranial capacity of , which is similar to anatomically modern sapiens . A third specimen of Homo is known as . It is very possibly the oldest archaic human specimen from Africa and was found in Ethiopia in 1976 . It is dated to approximately years and has a relatively large cranial capacity of , which is again within the range for modern humans . It is a robust cranium with very thick bones and two separate brow ridges . Homo Technology and Culture is associated with bifacial hand axes . Some scientists have suggested that butchered animals because hand axes have been found with animal bones . There are on the cranium that resemble those made by cutting fresh bone with stone tools . It has been suggested that the cranium is the earliest evidence of the removal of immediately after death using a stone tool . The were made symmetrically and with patterns on the cranium , which is interpreted as strong evidence that the was done purposefully for funerary practices . Once again , others have suggested that the indicate that may have been practicing cannibalism . In addition to their use of stone tools from the tool industry , Homo is also believed to have used spears . The earliest known spears have been found in , Germany , and are dated to about years ago . The spears were made either from spruce or pine wood and are believed to have had a range of about 35 meters . Probably the most important technological achievement evident in these spears is the use of technology . involves attaching stone points to a handle made of another substance , such as wood , metal , or bone . The spears found at represent one of the known instances in which united separate elements into a single tool . gives stone tools more utility , as they can now be thrown ( as with a spear ) shot ( as with an arrow ) or used with more leverage ( like an axe ) These stone points are able to be used with increased force and effectiveness , allowing people to hunt and kill animals more . This increased in hunting and killing animals is believed to have created a situation in which had regular access to 153

meat and other foods . Some have suggested that the presence of spears represent evidence that could hunt herd animals that can run faster than a human , and that they had sophisticated hunting strategies requiring cognitive skills like anticipatory planning . Like Homo Homo erectus , Homo occupied both caves and sites . However , they did notjust use the sites as is , they them . One of the most interesting aspects of the cultural behavior of Homo is that they are associated with clear archeological evidence for dwellings . For example , in the Czech Republic there is a dwelling that consists of a stone foundation that is approximately years old . Most likely , this dwelling had a roof constructed of thick branches . Other dwellings have been found in Germany and France . Evidence of controlled has been found at most reasonably preserved Homo sites . The oldest established continuous site for Homo is from Israel and is dated to around years old . Key Maximum sea level ice age Homo sapiens Neanderthal Homo mill on years ago Homo mill on years ago . Central FIGURE Phylogenetic tree and proposed migration routes of genus Homo and later and Neanderthals . attribution Copyright Rice University , under BY license ) Late Archaic Homo Homo A Rising Star The most recently described archaic Homo is known as Homo . They were found in the Rising Star cave system in South Africa in 2013 and 2014 ( Figures ) and are dated to approximately years old . Over bones from as many as 15 individuals were recovered from the cave , which is possibly the largest assemblage ofa single species yet discovered . Despite their relatively recent date , they have exceptionally small cranial capacities , comparable to the robust and gracile , which are around 560 . The quotient of is estimated at , which is the same as but notably smaller than all other Homo ( contemporary Homo are all above ) The presence of this at the same time that Neanderthals and Homo were around is further evidence that multiple lineages were coexisting and evolving at the same time . The of proved to be a challenge , as the specimens presented a mosaic of traits and characteristics associated with an array of other species .

The Emergence of Us The Archaic Homo FIGURE Maps showing the location of the Cradle of Humankind World Heritage Site in South Africa , where Homo were found in the Rising Star cave system . credit Hawks et al . 2017 ) BY ) Only entrance into chamber is a 12 vertical shaft . coming out CHAMBER ( i I . I Unit ( FIGURE The Rising Star cave system , showing geological features and the location of the excavation area where numerous Homo have been found . credit Paul et al . 2015 ) Commons , BY 40 ) 155

FIGURE . It is apparent in these images that this species had rather pronounced prognathism ( Credit John Hawks , Marina Elliott , Peter et al . 2017 ) Commons , BY ) FIGURE were much like those of modern humans . credit , Churchill , Berger ( 2015 ) Commons , BY )

FIGURE The hands of curved bones and large thumbs , indicating that it still had an adaptation for climbing trees . credit Lee Berger et al . 2015 ) Commons , BY ) relatively high mi small small bum min , a . ma volume volume small mew , molars increase back Homo habilis Homo erectus Homo Homo FIGURE Comparison of some of the most commonly known Homo species ( credit Chris Stringer , Natural History Museum , United Kingdom ( 2015 ) Commons , BY ) Homo Did They Bury Their Dead ?

Homo has not yet been found in association with any stone tools . Despite a lack of established tool use , there is fairly convincing evidence that may have used the cave system as a place to bury their dead . The hypothesis that had a ritualistic mortuary practice is based on several observations , such as the bones appearing to lack evidence of gnawing marks from predators and the lack of evidence of layers of sediment that would suggest the bones were deposited by ( et al . 2015 ) In 2017 additional fossil remains were found in a second chamber in the Rising Star cave system ( Hawks et al . 2017 ) but these remains do as yet appear to offer additional evidence to support the hypothesis of an intentional burial . Some scientists believe that there is evidence to conclude that were involved in funerary ritual practices . They have noted that the preservation of specimens are similar to that of dwelling baboons that have died natural deaths . At Sima de los , remains of about 28 Neanderthal and fossils were found in a cave dated to about years ago . Researchers who examined the scattering patterns of the remains at both the Rising Star cave system in Africa and the Sima de los site in Spain ( et al . 2018 ) concluded that the sites showed evidence of having been scavenged but that this does disprove the possibility that they may also be deliberate burials . The verdict is still out on this . Lee

Berger and other scientists are conducting further investigations of the skeletal deposits to further explore the possibility they might be evidence of something more deliberate than the actions of predators . Rethinking the Neanderthal Homo The word Neanderthal might conjure up stereotypical images ofa brutish creature holding a club in one hand and dragging supper with the other . No one said entertainment had to be accurate , but media can create false perceptions and stereotypes about the past . This section takes a closer look at who the Neanderthal people were and the role they played in the human story . ASIA La Le EUROPE La Quina I La El . Pech de ' i FIGURE Distribution map of Neanderthal sites . The red squares mark locations of Neanderthal remains and the shaded area represents the supposed territory of Neanderthal people in Europe and Asia . credit of work Neanderthal distribution by Commons , Neanderthals have been found only in regions of Europe and the Middle East and are dated to between about and years ago . The fossils , which were found in the Valley , were believed to be the remains of an extinct kind of human . The Germans called them the Neanderthals , the people of the Valley . FIGURE The Neanderthal skull on the left is noticeably different from the sapiens skull on the right . credit ( left ) Commons , Public Domain ( right ) Image from page 27 of Human physiology ( by , William Archive Book , Public Domain ) Neanderthals possess several distinctive anatomical characteristics the skull and brain is larger than that of

humans , with an average size in Neanderthals of compared to modern humans . Does the Neanderthal larger brain size mean that it was more intelligent than modern humans ?

As mentioned earlier in this chapter , while there does seem to be a correlation between brain size and complex cognitive skills , the brain in some may have been organized differently than that of modern humans , with different anatomical areas of the brain emphasized . It is believed that in the Neanderthal brain , the frontal region , which is the center of speech and language , was less developed , while the back of the brain , which deals with the senses , was more developed . This greater development in the back area of the brain could be a survival adaptation found in Neanderthals who had to hunt in often harsh and conditions . Philip , a cognitive scientist at Brown University , argues that Neanderthals lacked the anatomy necessary for humanlike speech . He drew this conclusion based on a reconstruction ofa Neanderthal throat , which indicated that the neck could not accommodate the vocal apparatus of modern humans ( 2007 ) While there is evidence ofa hyoid bone , a small bone in the front of the neck , that would have able to anchor the tongue muscles , other anatomical evidence suggests that the larynx in was placed high in the throat . A highly placed larynx limits an animal ability to produce many sounds , as vowels . In humans , the larynx is positioned further down into the throat . The Neanderthal has been determined to have possessed the gene , which is linked to the ability to understand complex language , but the verdict is still out as to whether they were able to produce complex language . It is believed by some researchers that the ability to produce complex speech gave sapiens a edge over the . Other skull characteristics of the Neanderthal include an occipital bun at the back of the skull ( as also seen in antecessor and erectus ) large brow ridges ( which are not solid bone and create an air cavity ) a large nasal cavity , and incisors that show a rounded pattern of wear , especially in older individuals . Their large front teeth typica ly show excessive wear . Chipping and pitting on the incisors are believed to have been caused by chewing on . The bones show that they had a broad scapula , which indicates that their rotator cuff muscles were well developed . They possessed a robust humerus with a massive head and the ability to rotate their arms , which suggests they were capable of throwing projectiles and using spears . Some of the Neanderthal specimens come from a place called Cave in Iraq . Within this cave , various skeletal remains of eight individual Neanderthals were found . These remains are as , which were discovered between 1957 and 1961 , and 10 , which was discovered in 2006 . Nearly all the skeletal remains show some evidence of trauma , suggesting that hunting was risky business . At various Neanderthal sites it has been observed that men and women exhibit similar cranial injuries , suggesting that women might have also engaged in hunting activities . However , the number of injuries in women were fewer than those found in men ( et al . 2008 ) In a comparative study , it was established that during the Upper Paleolithic , modern sapiens sustained similar injuries as the Neanderthal , but interestingly , these injuries were less likely to result in death ( et al . 2008 ) features a Neanderthal man who suffered a rib injury , potentially as the result of an encounter with an animal , and suggests healing as a result of care from others . called the Old Man ( years old was old in Neanderthal terms ) had multiple traumas to his body , one of which resulted in blindness in one eye . He was also missing the lower part of his right arm and hand , which suggests the earliest amputation on record . Although he did heal from this amputation , it may have left him paralyzed on the right side of his body . He also had no teeth . It is believed he was kept alive by taking food that had been chewed by others for him . There is evidence of many of these individuals healing from their injuries , which suggests that compassion and a sense of social responsibility for disabled members of the community existed .

160 The Genus Home and the Emergence of Us FIGURE This cave is the site of the Neanderthal flower burial site . Evidence found here and at other sites indicates that the Neanderthal practiced intentional burials of their dead . credit Cave , Iraqi by Sammy , BY ) The Flower Burial Hypothesis The remains found at in Iraq suggest that the Neanderthal practiced intentional burials , or deliberate placing of the dead in a ritualistic manner . At , the individual is placed on his left side with his legs drawn up in a position . Pollen analysis of the soil surrounding the corpse suggests that spring had been placed in the grave , possibly indicating that the Neanderthal had a belief in an afterlife and established mortuary practices . However , there has been a lot of debate as to whether there is evidence to conclude that that the pollen found at some of the Neanderthal sites was a result of ritualistic placement of . Opposing hypotheses propose that the pollen was brought into the cave and deposited by burrowing rodents ( 1999 ) In spite of these , the consensus supports the theory that the Neanderthal did practice intentional burials . This is largely based on evidence such as the careful placement of bodies in specially dug shallow pits . Recent research at both Cave and other sites now support the claim that the Neanderthal did practice ritual and intentional burial . FIGURE This reconstruction of a Neanderthal grave is housed in the Israel Museum in Jerusalem . credit Neanderthal Burial , Cast by Gary , Public Domain ) Neanderthal Creativity and Material Culture Neanderthals have been labeled , perhaps unjustly , as a species with a limited ability to communicate in symbolic or abstract forms . Until recently , the Neanderthal had been assumed to lack the cognitive skills Access for free at

associated with the practice of ritual and art . However , cave paintings discovered in Spain in 2012 by Alistair Pike , an archaeologist at the University of , UK , challenge that assumption . These paintings , which have been dated to around years ago , before the arrival of sapiens in the region , have been determined to be the creative works of the Neanderthal and are currently considered the oldest cave art ever found . This discovery may change what people have previously thought about Neanderthal cognition and their ability to express symbolic thought . It should be acknowledged that the ability to depict the world evident in these paintings does not compare with that in the artwork from sapiens sites like and in France ( to be discussed later in this chapter ) Neanderthals created more technologically advanced tools than those produced by erectus and seen in the tool industry . The tool industry associated with the Neanderthal is called the tool industry or the Middle Paleolithic tool industry . Archeological sites that date to the Neanderthal period are dominated by tools . This means that the Neanderthal struck from cores and then used the as their tools instead of the core . This resulted in smaller and sharper tools with increased utility . What Happened to the Neanderthal ?

What Gave Modern Humans the Edge ?

The Neanderthal went extinct around to years ago . There have been various hypotheses as to what caused this , many connected to the fact that Neanderthal coexisted with sapiens in regions of Europe and Asia for an estimated years . These hypotheses include an inability to adapt to a changing climate and colder temperatures , the spread of disease , competition for food with sapiens , and even aggressive takeover by the sapiens , who may have been better able to adapt to environmental changes due to more complex technology and language skills . Another theory points to evidence that the Neanderthal tended to live in small , scattered groups with limited genetic diversity and low birth rates , which potentially impacted the ability of the Neanderthal to be competitive . A low gene pool can result from reduced birth rates and low survival rates of young children . New genetic evidence shows that the Neanderthal were genetically ess diverse and more isolated than sapiens . And then some argue that the Neanderthal did go extinct at all because some people still have Neanderthal genes in them . Are You a Neanderthal ?

Recent genetic evidence indicates that ( was happening as far back as years ago . From one Neanderthal toe bone found in the cave in Siberia Russia , the Max Planck institute has been able to produce a whole genome which revealed evidence of inbreeding amongst the Neanderthal , along with interbreeding with their cousins the ( discussed in next section ) as well as a mystery yet to be species , as well as Homo ( 2013 ) The genetic evidence is most prominent in people of East Asian descent , accounting for between and percent of their DNA . Various mutations and diseases are linked to this Neanderthal DNA , including diabetes , addictions , depression , allergies , and disease . One study suggests that Neanderthal genes gave people some level of protection from getting a severe case of ( 2018 ) although a ater study ( and 2020 ) proposes that Neanderthal genes may have increased the risk of respiratory failure as a result of the virus . Such differences may have to do with different genetic clusters in Neanderthal populations in different geographical regions ( et al . 2021 ) Neanderthal genes are believed to have provided immunity to some viruses that sapiens , arriving from Africa , would not lave had time to build up an immunity against . On the reverse side , sapiens may have brought diseases rom Africa that the Neanderthal did not have resistance to , possibly playing a role in their extinction . As Janet Kelso , a computational biologist at the Max Plank Institute for Evolutionary Anthropology , states , Viral challenges , bacterial challenges are among the strongest selective forces out there ( 2019 ) The The , like Homo , are archaic Homo . There are not a lot of one bone , three teeth , some long bone ( Long bone ) fragments , a , and a parietal bone ( Parietal bone ) skull fragment . Because of this lack of evidence , very little is known of their anatomical features . Some of the specimens come from Cave in Siberia , Russia , and are dated to between and years ago . These dates are arrived at based on the few fossils that exist , inferences made from genetic studies , and sediment analysis . More recently another specimen was found on the Tibetan plateau . In 1980 and two teeth were uncovered in the Karst Cave by a

monk , but it was until 2010 that scientists were able to study the jaw . Dating placed the specimen at approximately years ago . Protein analysis determined the jaw to be of origin and from a member of a population who were most likely well adapted to living in high altitudes ( Chen et al . 2019 ) Because so few bones have been found , most understanding of this species comes from genetic analyses . According to nuclear DNA studies , and Neanderthals were more closely related to each other than they were to modern humans . DNA evidence suggests that the with modern humans and with local Neanderthal populations over multiple time periods . Tracing the male chromosome , one study indicated that interbreeding between early humans and Neanderthals actually replaced the ancient chromosome once found in Neanderthals . The time of divergence of the is estimated to be around years ago , with modern humans diverging from the Neanderthal around years ago ( et al . 2020 ) is typically considered to have been the direct ancestor and Neanderthals , and sometimes also of modern humans . One specimen is a hybrid , Denny us Denny hybrid had a father and a Neanderthal mother ( Slon et al . 2018 ) 11 was found in Cave in Russia and provides evidence that Late Homo species when the groups met . Comparison of the DNA of these three groups suggest that most Europeans and Asians inherited about percent of their DNA from Neanderthals , with no ancestry in Europe and percent in China . The genetics found in Tibetans , and Indigenous Australian are currently being challenged originally , they were thought to be about percent and percent Neanderthal . Statistical geneticist Ryan and his team have investigated the percentages of extinct DNA in modern humans . They concluded that Neanderthals and are not the whole story and that there could be a third group yet unknown contributing to the Islander genome ( Rogers , and Huff 2017 ) Statistical and genetic evidence can serve as indicators of the existence of a group for which no fossils have yet been found . These are referred to as ghost populations . For example , there are indications that percent of the DNA of four West African populations may have come from an unknown archaic that split from the ancestor of humans and Neanderthals between 360 KYA and ( and 2020 ) The hypothesis of a third lineage in the genus Homo appears to have received further with a discovery in China . New Homo Genus Discovery Homo , or Dragon Man Recently a new archaic Homo fossil surfaced in , China , dated to about years ago ( Ji et al . 2021 ) Given the name , it has also been called Dragon man ( as its origins were determined to be in the province of the Black Dragon River . The fossil ( referred to as the cranium ) was donated to the GEO University museum after being hidden away in a well in the during the construction of a railway bridge . The verdict is still out as to whether represents a lineage of the or a new species , but it is clear it was robust and able to adapt to one of the coldest regions of China . It had a large brain , thick brow ridges , and fairly large teeth , similar to what is found in the . Regional Evolutionary Adaptations Homo The Hobbit of Flores Homo , also known as the Hobbit or Flores Man , was discovered on the island of Flores in Indonesia in 2003 . The species has been dated to approximately years ago . What was surprising about this species is its size . An adult individual stood about feet inches tall . Liang , the cave where was found , shows evidence of the use of for cooking and contains bones with . Since the initial discovery , partial skeletons of nine individuals have been found . like the earlier , did not possess a chin , and its leg bones are thicker than those of modern humans . They had feet that were relatively long in comparison to the rest of their bodies . As a result of these anatomical differences , it is believed that their was quite different from that of modern humans , with a high stepping gait and slower walking speed . also had substantially more mobility in the , which suggests that they were tree climbers . Their small brain size is not believed to have affected their intelligence . This challenges the view that larger

cranial capacity equals higher cognitive skills . Although has a brain size ofjust 380 , equal to the size of an orange , evidence indicates that they made tools , used , and hunted very much like erectus . The brain of does contain a area , which is associated with cognitive abilities , that is the same size as that found in modern humans . Some have suggested that is a sister species of Homo habilis that branched off before or shortly after the evolution of Homo . Other hypotheses suggest that they were the descendants of erectus who became stranded on the island after arriving via water , possibly on bamboo rafts . Another Homo species similar in size to was , found on the island of in the Philippines and dated to at least years ago . displays a hybrid of australopithecine traits ( including curved hands and feet ) and Homo characteristics , yet lived alongside modern sapiens . Clearly the genus Homo is more diverse and complex than was originally thought , especially within the special evolutionary pressures of island environments . FIGURE This skull is on display at the , a Natural History Museum in Germany . credit Commons , Public Domain ) Island as an Evolutionary Explanation Numerous hypotheses have been proposed to account for the small brain size found in both and . One initial theory was that had microcephaly , which is a genetic condition creating an abnormally small head . This was discounted as an explanation once additional specimens were found exhibiting the same size . Perhaps the most convincing explanation is an evolutionary theory called island , which notes that the evolutionary pressures on islands can be very different from those found on the mainland . Island posits that mainland small animal species that colonize islands might evolve larger bodies if the island does not contain key predators . On the other hand , larger species may become smaller due to more limited resources in an island environment . According to the island hypothesis , erectus made its way to Flores , where its descendants became isolated and grew progressively smaller to make the most of limited resources in the island environment . This theory is supported by the fact that there are unique sizes displayed by other animals found with , including a dwarf species of primitive elephant called a . As body shrank , its brain may have undergone neurological reorganization to fit a smaller cranial space while maintaining its ratio . The only

164 The Genus Homo and the Emergence of Us potential large predator that may have been a threat to was the Komodo dragon , which ate most of the large mammals on the island . Nevertheless , predation pressures for the little people were likely quite is , until sapiens arrived . The Emergence of Us Homo sapiens Modern sapiens appeared about years ago in Africa . Anthropologists generally classify these people as anatomically modern sapiens , which is a way of noting that while their bodies are the same as modern humans , they had not yet developed the cultural traditions , symbolic behaviors , and technologies that are seen among later sapiens , including people of today . Probably the most feature of anatomically modern sapiens is their chin . Modern sapiens is the first to exhibit a projecting chin . One of the most common explanations for this anatomical feature is that the chin evolved in response to human speech and protects against stresses produced by the contraction of certain tongue muscles . Sometime around years ago there was an abrupt change in tool technology , subsistence patterns , and symbolic expression among sapiens . These changes seem to have occurred almost simultaneously in Africa , Asia , Europe , and Australia . While there is evidence of some creative artistic activity in earlier groups like the Neanderthal , they were not on the same scale as that seen during the Upper Paleolithic , which is also referred to as the human revolution . The level of cultural changes associated with this period has been compared to the level of change that occurred during the Industrial Revolution of the century . Among these changes , sapiens began assembling a much more elaborate tool kit by constructing tools from a wider variety of materials including antler , ivory , and bone . During the Upper Paleolithic , humans shifted from the manufacture of round to the manufacture of blade tools . This construction method is known as the blade tool industry . Blades are stone that look like a modern knife are long , thin , and , and they have a sharp edge . They have a much longer cutting edge than do and are thus more than older technologies . The technique of the that provided was and extended to create blades . FIGURE This Upper Paleolithic burin tool has a much longer cutting edge than anything that came before it and was much more efficient than previous technologies . credit Large Knife Upper Paleolithic or later Africa by Mary , BY ) Access for free at

Over the years of the Upper Paleolithic , there were many distinctive tool industries within the larger category of the blade tool industry , including the , and . The most tool during the Upper Paleolithic was the burin . The burin is a capable of scraping narrow grooves in bone . Scraping two parallel grooves would allow a sliver to be detached as stock for a needle , pin , or awl . The tool industry lasted from approximately to years ago . During this tool industry , there are many instances of animal remains being used for both decorative and traditional tool purposes . For example , the teeth of arctic foxes were used for decoration , while their arm bones were used as and barbs . Some animal bones such as mammoth tusks and bones were used to not only create tools , but also to make art , as seen in the Lion in Figure . This could be the earliest example of a having both human and animal characteristics , a form often associated with shamans or priests . Some have proposed that the lion man is actually a woman due to the lack of a lion mane . FIGURE An ancient of a lion sculpted from a mammoth tusk . This was discovered in a German cave in 1939 and dated to around years ago , making it one of the oldest sculptures yet discovered and the earliest example of an . credit Commons , Public Domain ) The tool industry utilized techniques not seen before . It produced worked bifacial points made with lithic reduction percussion rather than . Lithic reduction is the process of fashioning stones or rocks into tools or weapons by removing some parts . The lithic core , such as a partially formed tool or naturally formed rock , is held in one hand and struck with a hammer or percussor with the other hand . As are detached , the original mass of stone or lithic core is reduced . In addition to stone tool innovations , the is characterized by the appearance of the , or spear thrower . An atlatl is a long stick used to propel a spear or dart . Functioning as an extension of the arm , this stick or antler added kinetic energy , and therefore range , to a short spear tipped with or bone . The earliest archeological evidence for this tool innovation comes from France , where a atlatl was found constructed out of reindeer antler . It is believed that the atlatl was used by humans to hunt large fauna .

166 The Genus Homo and the Emergence of Us FIGURE Contemporary man using an atlatl , a tool for launching a spear or a dart that is at least years old . credit Atlatl throwing demonstration by Hannah , Public Domain ) By years ago , the tool industry was replaced by a new tool industry known as the tool industry . During this period , bone and ivory continue to be used , as well as stone . Unlike tools , tools are made not only from nearby rocks , but also from rocks that have been transported over relatively long distances . Keep in mind that this required not only transporting the selected rocks , but also and extracting them . The tool industry is best known for carved Venus portraying a woman , typically made from ivory or limestone . Most have small heads , wide hips , and large breasts . Most researchers believe that they served a ritual or symbolic function . Some have suggested that they represent an expression of health and fertility . FIGURE Venus of Fels . This is considered to be the earliest known depiction of a human being in prehistoric art . credit Commons , BY ) Access for free at

The Emergence of Us The Archaic Homo 167 During the Upper Paleolithic , a great deal of cave art . More than 350 cave painting sites have been discovered , the majority located in France and Spain . Cave art seems to have been created continually from to years ago and then disappeared around years ago , likely due to climate change . As temperatures increased , underground shelters were gradually replaced by surface settlements . The most cave sites in France are the ( years ago ) Figure ) and Caves ( years ago ) The art in both caves features common subjects , such as bison , horses , and deer , as well as tracings of human hands . Most of the animals depicted were commonly hunted but were not always found with associated deposits of bones . The cave art produced during the Upper Paleolithic show a level of sophistication and even sacredness not seen previously in human history . A FIGURE These drawings of lions from the Cave in France are dated to years ago . credit Commons , Public Domain ) FIGURE Handprints found in the de las Manos upon Rio , near the town of Argentina . Hand stencils on cave walls have been found in many locations around the world . credit by , BY 20 )

Cave paintings were made with natural pigments created by mixing elements , such as dirt , red ochre , hematite , manganese oxide , and animal blood , with animal fat and saliva . Paint was applied using twigs formed into brushes and blow pipes made from bird bones , through which paint was sprayed onto the cave wall . Hand stencils on cave walls can be found in many locations around the world including Africa , Argentina , Europe , and Australia . Anthropologist Dean Snow ( 2013 ) conducted research at eight cave sites in France and Spain to determine who the artists might be . Based on calculated measurements of the handprints , he concluded that 75 percent of the ochre stenciled handprints in the Paleolithic caves were made by women . Trucking Genomes Our Human Story Unfolds LEARNING OBJECTIVES By the end of this section , you will be able to how sheds light on early human migrations and explain the Out of Africa model . Explain how genomes and of lice can fill current gaps in the human fossil record . the origin of human variation from an evolutionary perspective . Mitochondrial Eve Begun in 1990 and concluding in 2003 , the Human Genome Project was an ambitious international effort that about 99 percent of the human genome with an accuracy of percent . Genetics has thus far largely the Out theory , which proposes that early humans left Africa around years ago and migrated to diverse areas of the world . When early humans left Africa and moved into Europe , they not only lived alongside but also with species such as the Neanderthal , who were already in the region . Molecular anthropologists have an interest in determining when living human populations began diverging from one another . This has been to do using nuclear DNA because it mutates much too slowly for accumulations to occur in years . Many of the genetic studies that have been conducted are thus based on genetic material carried in the mitochondria ( which are passed on maternally . There is no recombination in , so unless the mitochondria carries a novel mutation , a child has exactly the same mitochondrial genes as its female genetic contributor ( which may be its mother , egg donor , or someone in a similar genetic relationship ) The mitochondria of every living person is a copy , only by rare mutations , of the mitochondria passed down via matrilineal descent from a population in our ancient past . This population is referred to as Mitochondrial Eve or ( mitochondrial most recent common ancestor ) believed to have lived in southern Africa years ago . As discussed in Chapter , the longer ago two populations share a common ancestor , the more time there is for mutations to occur and for adaptations and change to take place . Although genetic variation is small among the world human populations , it is greatest in Africa . This indicates that the human populations in Africa have the longest established genetic lineage . While multiple hypotheses exist as to human origins and new evidence could change the current views , the consensus is an Out model traced back to the matrilineal descent of a population living in Africa about years ago . How the Genome of Lice Con Fill in the Gaps While perhaps not a pleasant thought , lice have long been a part of human history . Studying the relationship between humans and lice has shed much light on human story . David Reed , the Curator of Mammals and Associate Director of Research and Collections at the University Museum , has been studying the of humans and lice , an area of research that has developed only within the last 20 years . Reed groundbreaking research has the potential to in some big gaps in humans rather sketchy fossil record and provides important data that might have applications in medicine and biology . Two questions that this research has already begun to ask are when did we become less hairy and when did we start wearing clothes .

( FIGURE There are three types of lice associated with humans ( a ) crab or pubic louse ( body louse ( head louse . The of humans and lice is a developing area of research . credit ( a ) Commons , BY ( Janice Carr , Centers for Disease Control and Commons , Public Domain ( Dennis , Centers for Disease Control and Commons , Public Domain ) Figure shows three types of lice associated with humans the head louse ( the body louse ( and the crab louse or pubic louse ( Body lice infest clothing and lay their eggs on in the fabric . Head and pubic lice infest hair , laying their eggs at the base of hair . The human head and body lice ( genus ) share a common ancestor with chimpanzee lice , while crab lice ( genus ) share a common ancestor with gorilla lice . By tracking louse variations , scientists have been able to determine when the head louse and pubic louse diverged , enabling estimates as to when we lost our extra hair and when we started to wear clothes . It is interesting to note that the divergence of the genus ( head and body lice ) correlates with the divergence of the human lineage from chimpanzees about six million years ago . Research on lice also provides further support for the Out model of human migration . Reed has observed that the genome of African lice shows a higher degree of genetic diversity than that of lice found elsewhere in the world , supporting the hypothesis that both humans and lice existed in Africa . Many hypotheses about what may have triggered the loss of hair in humans point to thermoregulation , the need to control body temperature in extreme conditions . Living in the heat of the savanna , humans needed a cooling mechanism to enable them to be better hunters . Other evidence of adaptation to the heat includes the appearance of sweat glands , which are more numerous in humans than in other primates . Another theory about the cause of the loss of hair among humans suggests that it was an adaptation to control parasites on the body . Did people immediately throw on clothes after losing all of that extra body hair ?

Reed research suggests that the wearing of clothes was not something that happened quickly . Humans lost body hair about a million years ago and did start wearing clothes until around to years ago . That about years living in their birthday suits ! When humans began to wear clothes , the body louse adapted structures that enabled them to attach to clothes instead of hair .

FIGURE Humans lost most of their body hair about a million years ago . credit Neanderthal by Eden , Janine and , BY ) PROFILES IN ANTHROPOLOGY Molly A FIGURE Molly ( holding skull ) leading a study session . credit Molly , Public Domain ) Personal History From the time Molly was young , she knew she wanted to be an anthropologist . She took an archaeology class at the local community college when she was a high school student and went to school over the summer . In college , she completed a double major in archaeology and anthropology , with a minor in Museums and Society . She later gained experience working with different museum collections and held internships at the Baltimore City Medical Examiners Office and the Smithsonian Museum of Natural History . After completing her undergraduate degrees , she knew that she wanted to pursue anthropology as a career and began working towards her master and doctorate in biological anthropology .

Area For Molly the most interesting thing about biological anthropology is the information that bones can tell us . Initially she was interested in what the history of disease could tell us about the lives of people in the past , but as she worked with biological anthropologists , her focus shifted to understanding how evolution can impact the shape of different bones . She received her undergraduate degree from Johns Hopkins University in Baltimore , Maryland , and her Masters degree from the University of Florida , where she is currently a candidate . Her research interests include comparative anatomy , cranial morphology , and anatomical sciences education . She is most interested in how cranial morphology varies within and between species and how it is impacted by factors such as evolution and selective breeding practices . Her earlier research focused on the differences in cranial morphology in dogs created by selection for facial reduction . Her dissertation research currently focuses on a comparative study of facial reduction across bats , primates , and dogs . Accomplishments in the Field For Molly her most important accomplishment in the of anthropology has been in education and outreach . Throughout her time in graduate school , she was involved in school visits , working with teachers to facilitate the inclusion of human evolution into existing science curricula . She has focused on helping educators teaching materials that are culturally inclusive and responsive . She has led multiple professional development workshops for teachers on the same topic and has visited over two dozen classrooms and interacted with over students in the last four years . Making science accessible to educators is an extremely important part of being a researcher , and she believes everyone in academia should strive to be effective science communicators . Studying biological anthropology helps us better understand our origin story as a species . It helps us recognize why our anatomy is the way that it is , how morphological changes over time can take place , and why we have such a diversity of life on earth . Just being able to recognize and identify our anatomy is only half the important is our understanding why various traits are adaptive , how structure relates to function , or why leftover anatomical traits still persist in our body to this day . Natural Selection and Human Variation Are Humans Still Evolving ?

Human variability is attributed to a combination of environmental and genetic factors , including social status , ethnicity , age , nutrition , quality of life , access to healthcare , work and occupation , etc . As mentioned in Chapter , anthropology contributes many insights into both the social construct of race and the impacts racial categories have on people lives . The focus in this chapter is the role of natural selection in human variation . A number of changes are associated with the Neolithic era and the rise of agriculture around to years ago . Many have noted that changes during this time period did not have positive effects on human and environmental health . The evolutionary mismatch hypothesis proposes that our bodies are best suited to the environments we have spent much of our evolutionary history in , which are very different from the environments we inhabit today ( Li , van , and 2018 ) Humans evolved for one million years as . Today , human bodies are still trying to adapt to the largely diet brought about by agriculture , a diet characterized by less diversity and lower levels of nutrition than that ofa typical . Incomplete adaptation to this change has made people susceptible to a number of diseases and nutritional . Lactose intolerance is a prime example . The domestication of cattle and the drinking of cow milk began during the agricultural age , not very long ago in evolutionary history . Currently 65 percent of humans are unable to digest cow milk . Dental caries ( cavities ) are another problem linked to the change in diet associated with agriculture . The and diets associated with agriculture are very different from the diet of . Neither our bodies nor the bacteria in our mouths have had time to fully adapt to this change . Another adaptation that took place during the Neolithic era is related to variation in skin pigmentation . Humans who left Africa and settled in Europe about years most likely had dark skin with high levels of melanin , which provides protection against ultraviolet radiation New data that about years ago , early in Spain , and Hungary also had darker skin . Skin pigmentation is an adaptation to ultraviolet radiation , with different tones offering different advantages , depending on one

172 The Genus Home and the Emergence of Us distance from the equator . As humans migrated to the Northern Hemisphere , they were exposed to less ultraviolet radiation , which also meant less absorption of the Vitamin needed for strong bones and other important immune functions . In order to compensate for this loss and to allow for greater exposure to ultraviolet radiation , skin pigmentation became lighter . Another example of human variation as a result of adaptation to the environment can be seen in Indigenous populations in the Andes , Tibet , and the Ethiopian highlands . Each of these three groups faces the same environmental challenge , living in a environment , and they have responded with unique adaptations . Tibetans compensate for low oxygen levels by taking more breaths per minute than people who live at sea level . Those living at high altitudes in the Andes have been found to have higher concentrations of hemoglobin in their blood than other people . Ethiopians living at altitudes of to feet have neither of these adaptations . The explanation as to how the Ethiopian highlanders thrive in their environment is still a mystery . FIGURE A valley in the Andes near , Peru . Indigenous peoples living at high altitudes in the Andes have been found to have higher concentrations of hemoglobin in their blood than other people . credit Snows of the Andes by David , BY 20 ) This chapter has some of the immense biological and cultural diversity of the genus Home . This diversity has emerged in response to highly complex and variable environments connected to factors such as exposure to UV radiation , low oxygen levels at high altitude , changes in diet as a result of hunting or agricultural practices , geographic isolation in island populations , and climate variability and temperature . The genus Home has proven to be resilient and adaptive in response to whatever environment or challenge it has faced . Variation is the key to survival . While scientists recognize that biological and cultural variation has greatly contributed to our human evolution , the human species is now facing a moment in which we must contemplate a question To what extent has our success as a species jeopardized the survival of other species and the health of the planet we all call home ?

ACTIVITY Identify the Fossil Imagine that you have just discovered a fossil with some of the characteristics listed below . Write each of the characteristics on a card and them together . Then , working in a group , decide which characteristics belong in the Homo group and which belong in the group . What name ( would you give it , and what criteria did you use ?

Note This is an actual fossil ! Access for free at Brain similar in shape and structure to modern human brains Hands suited for tool use Small jaws and teeth Third molar larger than other molars ( found in and some early Homo species ) Skull shaped more like erectus or habilis A sagittal keel ( as seen in erectus ) small raised ridge on top of the skull Bipedal and walked with a human gait Humanlike feet with arches and ankles Flaring blades of the pelvis ( primitive ) Broad rib cage Lower part of pelvis like modern humans Small ( Skull shows prognathism ( protruding face ) Primitive shoulder position suggests suitability for climbing and swinging Curved ( What would that suggest ?

Additional Resources Visual timelines and maps The Atlas ofHuman Evolution has put together a user friendly interactive map on the development of Homo sapiens . The Smithsonian Human Evolution Interactive Timeline ( provides an interactive overview of major milestones and species ranges . of lice and humans David Reed , associate curator of mammals at the Florida Museum of Natural History , offers an explanation of his research ( for a general audience . The Smithsonian Magazine explores possible causes and ( of the human loss of hair .

Key Terms tool industry the production of more complex tools , including hand axes , by erectus from million to years ago . archaic Homo the period of time that precedes the emergence of the earliest early modern humans ( Homo sapiens ) around years ago . tools a type of tool characteristic of the tool industry , with both sides worked . area a region in the frontal lobe of the brain ( which includes two areas ) found in habilis and connected with the production of speech . canine fossa a facial depression above the canine tooth found in modern humans . an interaction between different species that each species evolution the simplest case of this is relationships . cranial capacity the volume of the interior of the cranium or skull , providing an approximate size of the brain . increased brain size over time . quotient a measurement as the ratio between brain and body size . endocranial cast an impression taken from the inside of the cranium ( frequently used by to determine the shape and approximate size of the brain in and other primates . evolutionary mismatch a hypothesis that disease and nutritional result when are unable to adapt to an environment that they have not spent most of their evolutionary in . genome the complete set of genes or genetic material present in a cell or organism . ghost population proposed group for which no evidence has yet been found . the process of attaching stone points to a , which increases a tool effectiveness for . handedness the use ofa dominant hand , suggests of the brain and cognitive development . intentional burials evidence of placing the dead in a manner , suggesting ritualistic practice . Summary In this chapter we have explored our as a member of the genus Homo , following a trail of adaptations and change that ultimately led to us . island mainland small animal species that colonize islands might evolve larger bodies if the island does not contain key predators . On the other hand , larger species may become smaller due to more limited resources in an island environment . lithic reduction the process of fashioning stones or rocks into tools or weapons by removing some parts . melanin substance that determines the color of skin pigmentation and protects people from ultraviolet radiation . Skin will have higher levels of melanin the closer to the equator one lives . Mitochondrial Eve genes traced through mitochondrial DNA that represent the female genetic originator of all humans who lived years ago in Africa . tool industry a complex stone tool technology largely associated with the Neanderthal . the DNA located in the mitochondria that can be passed down unchanged from female genetic contributor to child . mitochondrial most recent common ancestor , or Mitochondrial Eve , representing the common ancestor of sapiens around years ago . occipital bun an anatomical feature seen in the Neanderthal skull that appears in the rear of the skull . tool Industry the oldest and most primitive tool industry production and use are largely in association with habilis . Out of Africa theory theory that proposes that Homo sapiens developed in Africa and then spread around the world between and years ago . features skeletal material found in the body that is not related to the skull ( cranial bones ) sexual dimorphism differences in physical characteristics other than reproductive organs that appear between males and females of the same species . thermoregulation an adaptation that allows the body to control and regulate body temperature . First on the scene were the , who were already walking on two feet and paved the way for the evolutionary changes and cultural

achievements that were to follow . A colder climate with drastic changes in climate were associated with an increased reliance on cooked meat , which may have contributed to a growing brain . A brain with highly developed cognitive skills gave humans the capacity to solve problems and create tools that enabled better hunting and survival skills . Adaptations provided and erectus the ability to walk and run longer distances , to more effectively track and follow game , and to explore nearby continents . Genetic information provided by indicates that all humans shared common ancestors who lived in Africa years ago . Studies of genetics shows examples of and how even small organisms such as lice can shed light on the human story . The rise of agriculture created new challenges for humanity , with evolutionary mismatch still Critical Thinking Questions . What are some of the key anatomical differences between and one of the species in the genus Homo ?

What criteria would you use to a species belonging to the genus Homo ?

What are some of the limitations in using the currently known criteria for classifying a species under the genus Homo ?

What are some of the explanations or hypotheses for the increasing brain size ( seen in the genus Homo ?

Bibliography impacting people today . From the earliest to the cave art of the Upper Paleolithic to the modern computer age , the predominant theme of human history has always been about change . The ability to adapt to this change is why humans are still here . Humans evolutionary story , however , does not end with the emergence of the species . Today humans are faced with numerous challenges as they adapt to an increasingly changing environment as a result of climate change , loss of habitat , and decreasing biodiversity . In 2020 , Darwin theory of natural selection played out in real time as people began an arms race with a mutating and evolving COVID virus . Evolutionary change is not something that happened to in the is very much still happening today , and it will continue to be part of the future . Based on current evidence , form a hypothesis as to what you think caused the extinction of the Neanderthal . What gave modern humans the edge ?

In what ways has genetic research enabled modern humans to track their story ?

What are some similarities between Homo , Homo , and Homo , and what makes them so unique ?

In what way are humans still evolving today ?

Can you provide an example ?

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