Describe which general fossil primate groups appear and radiate during the following geological epochs: Eocene, Miocene, Pliocene, Pleistocene. For each of the geological epochs, identify the general primate group that first appears and radiates during that epoch. In addition, give the time range in millions of years for each epoch and provide at least one example of a specific primate genus and/ or species that is representative of each general primate group.
2. List and briefly describe at least five elements of the post-cranial anatomy found in humans, but not in apes, that facilitate efficient bipedal locomotion. Provide specific elements of post-cranial anatomy (specific anatomical features that make efficient bipedal locomotion possible). DO NOT simply list legs or feet. You must include particular anatomical features of the legs, feet, spine, hips, etc. in your answer.
Over time, the early man evolved to a modern man with elongated feet and short arms in comparison to ancestors. This is attributable to increased weight and needs to move fast and far in search of food. Addi tonally, the foot in modern man bears more body weight while walking. In contrast, apes have shorter and lighter feet used for grasping and hanging on trees. This was a feature in homnidis. Still, the human toe is small and aligned with the foot as compared to their bipedal predecessors that had big and separated toes since their walking position was not perfectly upright. Lastly, there is an arch in human foot compared to flat patch in apes to support bipedal locomotion.
Hip
Notably, modern human feet has hip joints that are shorter, larger and broader shaped in comparison to its predecessors that were quadrupedal spieces. This is important to afford support to body weight passing through them during locomotion activity. Moreover, this evolution led to closing in of vertebral column to provide stability for the upper body when walking. It is important to note that walking requires one to balance on a rather unstable ball and socket joint; therefore, the proximity of vertebral column closer to the hip joint gives this balance with less amount of muscular effort. Again, change of hip shape from elongated and narrow part to broad and short hip shape decreased extension degree consequently increasing energy efficient while walking. Likewise, it gives support when standing due to the enlarged area of gluteus muscles.
Knee
Here, knee joints enlargement over time in comparison to earlier human ancestors serve the same purpose as broad hip discussed above. Additionally, decreased knee extension is important in reducing energy lost through vertical movement as a result of the force of gravity. Therefore, a human can walk for faster and long distance without feeling too much exhausted. This has changed human appearance as they walk in comparison to earlier predecessors. Notably, as human walk, their knees are directly under their body since knees are kept straight and thigh bent inward. However, in earlier human predecessors their knees are outside their body line as while in locomotion activity.
Limbs
Particularly, human legs became elongated while the hands evolved from hanging body parts to shorter arms. As such, longer legs enable a human to walk upright using natural swing and not muscled as used by earlier ancestors. This leaves forelimb for other purposes such as carrying, holding and experimenting with items around with higher precision than apes. Consequently, forelimbs strength decrease about human body weight in comparison to apes that use forelimb to crawl and hang on trees. Still, that forelimb is shorter than legs allow them to walk upright. This evolution let the knees come close and under the body lining in human, hence upright walking position without getting tired quickly.
Skull
Lastly, in modern human the skull balances on the vertebral column. Notably, foreman magnum is loosely joined under the skull, thus allowing the upper weight to be shifted behind the spine. Additionally, flat face in human is essential in striking a balance on the occipital condylynes. Hence, it allows maintaining an erect head position without causing supraorbital ridges and strong muscles lining as in apes. As such, muscles on the forehead are solely used in making a facial expression. Moreover, a human has larger brain capacity which is the source of drive in human evolution and development. Indeed, the human brain is estimated to three to four fold the capacity of a chimpanzee.
3, Explain the concept of mosaic evolution and how this is demonstrated in the evolution of hominins from the Late Miocene to the Middle Pleistocene. Provide specific examples to support your answer.
Mosaic Evolution is a concept in evolutionary changes that argues that changes occur in stages. Indeed, the evolution of hominins from the Late Miocene to the Middle Pleistocene was slow and gradual, and it did not follow any certain chronology. For instance, the brow ridges that extended to the eyes reduced from Miocene to the Middle Pleistocene. Additionally, the size of their forelimbs reduced from one stage of evolution to the next due to change of climate necessitating movement for the search of food. Still, the fingers and toe size reduced from one stage the next and the toe aligned with the foot as hominins evolved to human-ape. The size of pelvic-reduced while the thickness and size of enamel progressively increased. As these, distinct part evolution took place; hominin improved their locomotive ability.
4. Describe the significance of each of the following early hominin specimens and site areas to the study of hominin evolution: Ardi of the Middle Awash, Lucy at Hadar, Selam at Dikika, the Taung Child of South Africa, and the fossil footprints of Laetoli, Tanzania. For each be sure to provide dates and why it is important.
Ardi of the Middle Awash
Ardipithecus ramidus was first discovered by a team led by famed American paleontologist Tim White in Middle Awash area of Ethiopia. This was the partial skeleton of foot ‘Ardi' in Afar language; it indicates that early human had a divergent large toe with a rigid foot, and it was estimated to be 4.4 million years old. Additionally, a recreation of crushed pelvis specimen indicates adaptations to tree climbing as well as bipedal activities among these early humans. Thus, this discovery confirms an existence of a human-like ape that was different from a chimpanzee. Indeed, their male and female canine size and formation had very little difference.
Lucy at Hadar
This is a 3.2-million-year-old ape named "Lucy" and also the first Australopithecus afarensis ever to be discovered. The hominin specimen was discovered in 1974 by Donald C. Johanson in Hadar, Ethiopia. That Lucy was both ape-like and had human features illuminated a lot of light to human evolution theories. For instance, this hominin sapien had long hanging arms though the pelvic, spine, foot and leg formation enabled the hominin to walk upright. However, the head was an ape-like with low and heavy forehead with brain size similar to that of a chimpanzee.
Selam at Dikika
Selam is a name given to remains of hominin specimen believed to be a child discovered in Ethiopia. The discovery is a landmark in advancement to fill many gaps in evolution theory. Notably, the discovery of Selam provides insights on important stages of evolution that transpired to more advanced homo sapiens. Notably, Selam remains made an almost complete girl child classified as Australopithecus afarensis. The anatomical features of this remain lie between ape and human in regard walking adaption, climbing and hanging on trees. Indeed, it is believed that Selam was among the first human ancestors that walked on two legs. These remains are estimated to be about 3.3 million years old. However, brain case indicates that Selam was more ape-like than human regarding brain size.
Taung Child of South Africa
Taung Child is a three years old hominin specimen skull discovered in Tang, South Africa in 1924 by Raymond Dart with the assistance of local quarrymen (Haviland and William p.142). The specimen is estimated to be about 2.8 million years old. The fora magnum of this skull indicates that the hominin was bipedal. Additionally, its spinal cord hole was positioned in front of its skull remain, which is linked to bipedal locomotion in human. In comparison, cord hole of other apes are further back which retrains bipedal locomotion. This allows head balance; therefore, the discovery of this remains helped researcher in mapping out the chronological path of evolution.
The fossil footprints of Laetoli, Tanzania
These footprints are suspected to be made by Australopithecus afarensis that fossils were found in same layer sediments as the footprints. About 70 hominin footprints were stretching for a length of 27 meters. Researchers estimate that they were made about 3.6 million years ago when volcanic ash covered two early humans from an erupting mountain. Subsequent eruption covered these remains which were discovered by Paul Abell in 1978 while accompanying Mary Leakey and her team that had noted animal tracks in the area in 1976. The discovery indicated that at that time early human was bipedal with a big toe that aligned with their foot. Additionally, the distance between footprints was close implying that the bearers had short strides, hence shorter legs. Notably, human developed long legs later on which enabled them to walk fast and far in a unit time as compared to predecessors.
5. Describe why many paleoanthropologists now see the hominins formerly referred to as "robust australopithecines" as forming a separate genus group (Paranthropus). In your answer be sure to describe the specific anatomical features or characteristics that distinguish the robust forms (Paranthropusaethiopicus, Paranthrousboisei, and Paranthropusrobustus) from the gracile Pliocene hominins (e.g. Australopithecus africanus, Australopithecus garhi, Australopithecus sediba etc.)
The most distinct characteristic in Paranthropus is very large megadont cheek teeth, with thick enamel. Notably, their chewing occurred at the back of their jaws while their large cheek bones made it possible to pass large chewing muscles. As such, they had a wide, dish-shaped face that is quite different from gracile Pliocene hominins. Additionally, they had a large sagittal crest that provided large surface to anchor chewing muscles to the skull; therefore, they could grind down tough and fibrous food. However, their body size was relatively small compared to their large size face and teeth.
6. Explain why Homo erectus is a particularly important or significant species for understanding human evolution. In your answer be sure to describe qualities that HOMO ERECTUS possessed (such as behavioral, technological, and anatomical traits or characteristics) that earlier hominins did not (important "first" of Homo Erectus)? Provide at least four examples to substantiate your answer and be sure to make reference to particular fossil/ and or archaeological sites.
Notably, the earliest Homo erectus that possessed a modern human body position, long legs, and shorter arms, lived in Africa. The features exhibited by homo erectus give an advanced process of adaptation possibly due to changing climatic conditions necessitating early humans to walk for long distance in search of food. Here, there is clear indication of brain case expansion in comparison to the face size. The perfect hominin specimen is ‘Turkana Boy' that was discovered in Kenya (Regal p.114). The remains are well preserved, though both hands and leg bones are missing. The fossil dates back to 1.6 million years ago, and studies reveal that his growth rate is similar to other apes that developed to modern humans. Discovery of Homo erectus is a turning point in the process of human evolution due to its features, behaviors as well as the discovery of other sapiens across the globe as illustrated in the discussion below.
Homo erectus had emotional behavior that is linked to advanced human. Thus its discovery brought new aspect in the human evolution. For instance, there is enough evidence to indicate that Homo erectus cared for sick and weak in the society. Here, there is an impression of community and family life that focused on the common good of all the members. Additionally, that remains of Homo erectus were found on the African continent yet again brought other dimensions into the evolution processes and theories. Many researches attributes strong sense of adaptation fueled the ability of this spices to move out of Africa through inventions. For instance, Homo erectus used fire for its needs. This was followed by the development of hand tools that would help early human to deal with surroundings to their advantage. As such, controlling fire ushered in a new skill, tool technology in the human evolution process. In fact, there are hand axes made by these sapiens, which was a landmark improvement in tool technology. A tool used by Homo erectus are collectively referred as the Acheulean industry that comprises of hand axes, cleavers. These tools were used for butchery and hunting among other household activities.
Apart from Acheulean industry that was used by Homo erectus, the discovery of this species revolutionized theories of human evolution. In fact, a branch of researchers argued that early human came from Africa and migrated to Asia, particular to eastern Asia. For instance, there have been discoveries from Java in the 1890s and China, remains named ‘Peking Man' in 1920s that show similar characteristics to Homo erectus found in Africa. Clearly,=Homo erectus had many variations species that lived in Asia and Africa. Notably, Homo erectus is considered the longest-lived species that had a resemblance to modern man. Therefore, its lengthy existence is important since it provides tons of information that aided in filling gaps in human evolution theory in more than one continent such as variations of gender in early human-like apes. Consequently, this has led to the invention of tools and cut edge technology that will lead to more information on this subject in future. As such, Homo erectus discovery connected the past with the future in the field of human evolution.
7. Describe the key differences in anatomay (cranial and post-cranial) between Neandertals and anatomically modern humans (Homo sapiens)
Generally, Neanderthal had huge bones and was heavily built in comparison to modern man; however, they were shorter compared to modern human beings (Andrews, and Chris p.44). Compared to an anatomically modern human who have a smaller toe that aligns with feet formation, Neanderthal man had robust fingers and toes. This is attributable to the fact that they were still undergoing development and evolution at the time. Additionally, that they used their hind limb for other purposes rather than carrying and holding explain the large size of fingers compared to a modern human. It is also evident that they had shorter legs than what we have today. This inhibited their movement for long since their strides are a bit shorter. Moreover, this made the degree of extension large and thus they used more muscle force in locomotion and not natural swing as human do. Still, their knee caps were larger than of modern human leading to knees formation outside body line. This was also caused by flaring pelvis in Neanderthal. On the other hand, anatomically modern human knees are inside the body and under their body.
It is also evident that Neanderthal heads long, front to back length in comparison to a modern man. Additionally, the back of their head had a bulge normally referred as the occipital bun. Their faces were large with big noses and brow ridges stretching to their eyes and did not have pointed chin common in modern man. Still, their brain capacity was less compared to modern. The larger body and build body stock helped them survive in cold climates. Indeed, large head and compact body are associated with high energy.
8. Provide a basic overview for the origins and spread of anatomically modern humans (Homo sapiens). In your answer be sure to describe the specific genetic, fossil, and archaeological that lead paleoanthropologists, geneticists, and archaeologists to believe that anatomically modern humans (Homo sapiens) first evolved in Africa and then migrated out of Africa to colonize the rest of the world.
According to “Out of Africa” Theory, modern human originated in Africa and migrated to the rest of the world. There is tangible evidence that support this theory, though there are disputes from a branch of researchers; particularly Chinese researchers who argue that there is evidence of modern human presence as early as 80,000 years ago. This theory indicates that first batch of Homo sapiens migration took place between 130,000-115,000 years ago via northern Africa; however, this group either retreated or died while on the course. Later, a second group took Southern Route by around 50, 000 years ago, which causes disputes from Chinese researchers due to time of migration that is earlier than age of modern human remains in China. In other research, it is believed Aborigines of Australia constitute descendant of Homo sapiens that migrated through south eastern coastline.
However, “Out of Africa” Theory argues that despite multiregional origin of modern humans, Homo sapiens from Africa interbred with Homo erectus in other parts of the world, hence colonization. This theory is supported by several research findings. Firstly, earliest Homo sapiens lived in East Africa around 200,000 years ago. Specifically, there were Omo remains dated 195, 000 years ago. Additionally, there was idaltu dated 160,000 years ago discovered at Middle Awash in Ethiopia. In comparison, fossils found outside Africa date ,much earlier; remains found Qafzeh, Israel (80,000 to 100,000 years), modern human remains discovered in Manot Cave Israel (54,700 years), fossils from Lake Mungo Australia (42, 000 years ago) as well as remains Tianyuan Cave China (38,000 and 42,000 years) among others.
9. Explain why it is that while anthropologist recognize the existence and importance of biological variation in human populations, most do not believe that distinct biological races of modern humans exist. In your answer be sure to describe how and why the genotypic and phenotypic evidence tends not to support the notion of distinct, clearly demarcated biological racial groups and why it that race is a mostly social phenomenon ("social race" as opposed to "biological race")
Race is more of social phenomenon than a biological distinction for several reasons. Firstly, it is purely categorization of human to suit varied desired ends; as such, its meaning differs among locations. For instance, in America the term race was predominantly used in discussions to determine whether blacks were either animals or men following earlier assumptions and stereotypes. Additionally, it is evident that scientists use science to proof existence of biological differences among people with different colors for purpose of oppressions and institutional marginalization. Anthropologists challenge existence of biological races arguing that 19th and 20 race classifications were entirely based on physical traits such as skin color, face size, shape and size of human head and body as well as their skeletons. These appearances were coupled with social constructions of race. Yet again, Anthropologists observe that all human belong to single species, Homo sapiens, and thus share common descendants. Additionally, all humans in any geographic regions across the world evolved from Homo sapiens over the same amount of time; therefore, none of human categorization is superior to rest in terms of biological aspects. Indeed, biological differences result from interaction of hereditary causes and natural and social environment. However, human differences such as genetic variations occur even within a similar classification, say white people. Besides, all human despite their color complexion can interbreed leading to reduction of human population differences.
Some of the differences among human such as body size occur due to nutrition variances, way of life and other environmental factors in a particular geographic area. Moreover, according to anthropologists, complexity of genetic variations and inadequacy of human classification cannot be used as a based to create absolute boundaries in human population. Lastly, human species have continually been involved in major events such as migrations, population and territorial expansions as well as contractions due to war and famine, leading to variations. Consequently, human have adapted to these adversities and environmental factors to create some variations among the particular group involved in these events. As such, human race is merely social phenomenon to advance certain interests.
10. Humans respond to environmental stresses through genetic adaptation ( as population evolves), acclimatization ( of individuals), developmental adjustment ( of individuals), and cultural practices and technology ( as a population). Draw ng from chapters 14,15,16 of your text book "Introduction to Physical Anthropology (Jurmain et al 2014) and lectures material describe how each of these allows for human responses to environmental stresses and provide at least one specific example of each to support your answer.
Genetic adaptation
This occurs due to natural selection after a constant and lengthy environmental stress that lasts many generations. For instance, climatic change led to expansion of savanna and desert in Africa leading to emergence of new plants and diet components. As such, this diet shift led to genetic change. Still due to migrations, human had to go through genetic changes to be more resistant to new disease in their destinations; those that did not adopt were wiped out by outbreaks and persistent conditions such as malaria in certain areas.
Acclimatization
This is a change that occurs in an organism due to changes in environment such as temperatures and humidity within a short period of time and they are reversible. For instance, change in temperatures because of migration to cold areas increased number of red blood cells to boost oxygen carrying capacity.
Developmental adjustment
These are changes in growth patterns caused by changes in environmental conditions such as expansion of deserts. This necessitated more movement among homonins in search of food; therefore improving locomotion activities. Eventually, Homo sapiens became bipedal.
Cultural practices and technology
These are changes that occur due human interactions and use of appliances to perform daily activities. For instance, cultural exchanges led to change of diets and dressing codes across the world human populations. On the other hand, adoption of technology has reduced group tasks and human are now more independent than they were before wide application of technology in their workplace and homes. 11. Chapter 17 of your textbook Introduction to Physical Anthropology (Jurmainetal. 2014) is titled the HUMAN DISCONNECTION. Explain what is meant by this and provide examples.
Human disconnection in anthropology implies those human beings are failing to recognize the relationship of all lives in nature and their essence. For instance, there is increased loss of biodiversity due to such activities as forest clearing, mining and other human projects that cause harm to other living organism. This disconnection will result harm on humans.
Works Cited
Andrews, Peter, and Chris Stringer. Human Evolution: An Illustrated Guide. London: British Museum (Natural History, 1989. Print.
Haviland, William A, and William A. Haviland. Evolution and Prehistory: The Human Challenge. , 2014. Print.
Regal, Brian. Human Evolution: A Guide to Debates. Santa Barbara, Calif. [u.a.: ABC-Clio, 2004. Print.
