Early Ancestors Lucy in the Sky with Diamonds

World History E Napp Early Ancestors: Lucy in the Sky with Diamonds Name: Date: Historical Context: One fossil discovery above all has transformed views of how we became human But who was Lucy, and why is she so important to human evolution? Lucy was discovered in 1974 by anthropologist Professor Donald Johanson and his student Tom Gray in a maze of ravines at Hadar in northern Ethiopia Johanson and Gray were out searching the scorched terrain for animal bones in the sand, ash and silt when they spotted a tiny fragment of arm bone Johanson immediately recognized it as belonging to a hominid As they looked up the slope, they saw more bone fragments: ribs, vertebrae, thighbones and a partial jawbone They eventually unearthed 47 bones of a skeleton – nearly 40% of a hominid, or humanlike creature, that lived around 3.2 million years ago Based on its small size, and pelvic shape, they concluded it was female and named it ‘Lucy’ after ‘Lucy in the Sky with Diamonds’, the Beatles song playing on the radio when Johanson and his team were celebrating the discovery back at camp Like a chimpanzee, Lucy had a small brain, long, dangly arms, short legs and a cone-shaped thorax with a large belly But the structure of her knee and pelvis show that she routinely walked upright on two legs, like us This form of locomotion, known as ‘bipedalism’, is the single most important difference between humans and apes, placing Lucy firmly within the human family ‘Bipedalism is the most distinctive, apparently earliest, defining characteristic of humans,’ says Johanson, now director of the Institute of Human Origins at Arizona State University Johanson named Lucy's species Australopithecus afarensis, which means ‘southern ape of Afar’, after the Ethiopian region where Hadar is located 3.5 million years ago, Australopithecus afarensis foraged for fruit, nuts and seeds in a mixture of savannah and woodland It may also have obtained animal protein from termites or birds’ eggs In 1975, Michael Bush, one of Johanson’s students, found the remains of more than 13 afarensis individuals buried together following a natural disaster – possibly a flash flood The find yielded vital information about afarensis’ social organization ‘It is clearly a mixed sample of young and old, large and small – meaning several females and several males It looks very much like the composition of afarensis groups was like what we see in chimpanzees,’ Johanson explains ~ bbc.co.uk What are the main points of the passage? 12345678910While Lucy undoubtedly walked upright, some scientists, such as Randall Susman of Stony Brook University in New York, doubt that she walked with straight legs like humans Instead, they argue, she kept her hip and knees bent, like chimps when they walk upright Chimps usually walk on all fours, but occasionally walk upright for short periods of time Professor Robin Crompton of Liverpool University has used computer modeling to reconstruct how Lucy walked based on the proportions of her skeleton He assumed that Lucy could either have walked upright with a bent hip and knees like a chimp, or with straight legs like a human Crompton found it was mechanically effective for Lucy to walk like a human But there was an even closer match between Lucy's proportions and a type of bipedalism shown by orangutans This single finding could illuminate how our ancestors first started walking upright Orangutans live 20-40 metres above ground in the forests of Indonesia They spend most of their time in an upright position, but suspend themselves from branches with their long arms However, orangutans sometimes walk on branches without aid, raising their arms for balance Orangutans are not as closely related to humans as chimps But this behavior was recently observed in wild chimpanzees living in dense forest, suggesting it could be an ancestral trait common to all great apes Chimpanzees are our closest relatives Genetic studies show humans and chimpanzees shared a common ancestor that lived in the African rainforest 7-8 million years ago The descendants of this common ancestor split into two lineages – one that led to chimps and another that led to us It is thought that the human lineage developed routine bipedalism as a strategy for living on the ground when climate change decimated the forest, leaving wide belts of open terrain with no trees Crompton believes the forest canopy bipedalism shown by orangutans provided the kick-start for routine bipedalism when our ancestors came down from the trees and began living on the ground ‘This behavior is a good place to start in terms of what pre-adapted the hominid body, particularly the hip joint and knee joint, for the adoption of habitual (routine) bipedalism,’ Crompton explains Once our ancestors were forced to adapt to living on the ground, some drew on this behavior from their existing repertoire as a method of terrestrial locomotion The challenges of spending more time on the ground would have favored those hominids whose anatomy and behavior gave them a reproductive edge over their peers, however slight Hominids that were good bipedal walkers were clearly at an advantage in this terrestrial environment, because millions of years later, we walk on two legs instead of four ~ bbc.co.uk What are the main points of the passage? 1234567The Article: Tree Climbers, Wood Eaters, and More: The Top 10 Human Evolution Discoveries of 2012; Smithsonian Magazine, December 17, 2012, Erin Wayman As 2012 nears its end, one thing stands out as the major theme in human evolution research this year: Our hominid ancestors were more diverse than scientists had ever imagined Over the past 12 months, researchers have found clues indicating that throughout most of hominids’ seven-million-year history, numerous species with a range of adaptations lived at any given time Here are my top picks for the most important discoveries this year Fossil foot reveals Lucy wasn’t alone: Lucy’s species, Australopithecus afarensis, lived roughly 3.0 million to 3.9 million years ago So when researchers unearthed eight 3.4-million-year-old hominid foot bones in Ethiopia, they expected the fossils to belong to Lucy’s kind The bones indicate the creature walked upright on two legs, but the foot had an opposable big toe useful for grasping and climbing That’s not something you see in A afarensis feet The researchers who analyzed the foot say it does resemble that of the 4.4-million-year-old Ardipithecus ramidus, suggesting that some type of Ardipithecus species may have been Lucy’s neighbor But based on such few bones, it’s too soon to know what to call this species Multiple species of early Homo lived in Africa: Since the 1970s, anthropologists have debated how many species of Homo lived about two million years ago after the genus appeared in Africa Some researchers think there were two species: Homo habilis and Homo rudolfensis; others say there was just H habilis, a species with a lot of physical variation It’s been a hard question to address because there’s only one well-preserved fossil, a partial skull, of the proposed species H rudolfensis In August, researchers working in Kenya announced they had found a lower jaw that fits with the previously found partial skull of H rudolfensis The new jaw doesn’t match the jaws of H habilis, so the team concluded there must have been at least two species of Homo present New 11,500-year-old species of Homo from China: In March, researchers reported they had found a collection of hominid bones, dating to 11,500 to 14,300 years ago, in a cave in southern China Based on the age, you’d expect the fossils to belong to Homo sapiens, but the bones have a mix of traits not seen in modern humans or populations of H sapiens living at that time, such as a broad face and protruding jaw That means the fossils may represent a newly discovered species of Homo that lived side by side with humans Another possibility is that the remains came from Denisovans, a mysterious species known only from DNA extracted from the tip of a finger and a tooth Alternatively, the collection may just reveal that H sapiens in Asia near the end of the Pleistocene were more varied than scientists had realized Shoulder indicates A afarensis climbed trees: Another heavily debated question in human evolution is whether early hominids still climbed trees even though they were built for upright walking on the ground Fossilized shoulder blades of a 3.3-million-year-old A afarensis child suggest the answer is yes Scientists compared the shoulders to those of adult A afarensis specimens, as well as those of modern humans and apes The team determined that the A afarensis shoulder underwent developmental changes during childhood that resemble those of chimps, whose shoulder growth is affected by the act of climbing The similar growth patterns hint that A afarensis, at least the youngsters, spent part of their time in trees What are the main points of the passage? 1234567- Earliest projectile weapons unearthed: Archaeologists made two big discoveries this year related to projectile technology At the Kathu Pan site in South Africa, archaeologists recovered 500,000-year-old stone points that hominids used to make the earliest known spears Some 300,000 years later, humans had started making spear-throwers and maybe even bow and arrows At the South African site called Pinnacle Point, another group of researchers uncovered tiny stone tips dated to 71,000 years ago that were likely used to make such projectile weapons The geological record indicates early humans made these small tips over thousands of years, suggesting people at this point had the cognitive and linguistic abilities to pass on instructions to make complex tools over hundreds of generations Oldest evidence of modern culture: The timing and pattern of the emergence of modern human culture is yet another hotly contested area of paleoanthropology Some researchers think the development of modern behavior was a long, gradual buildup while others see it as progressing in fits and starts In August, archaeologists contributed new evidence to the debate At South Africa’s Border Cave, a team unearthed a collection of 44,000-yearold artifacts, including bone awls, beads, digging sticks and hafting resin, that resemble tools used by modern San culture today The archaeologists say this is the oldest instance of modern culture, that is, the oldest set of tools that match those used by living people Earliest example of hominid fire: Studying the origins of fire is difficult because it’s often hard to differentiate a natural fire that hominids might have taken advantage of versus a fire that our ancestors actually ignited Claims for early controlled fires go back almost two million years In April, researchers announced they had established the most “secure” evidence of hominids starting blazes: one-million-year-old charred bones and plant remains from a cave in South Africa Because the fire occurred in a cave, hominids are the most likely cause of the inferno, the researchers say Human-Neanderthal matings dated: It’s not news that Neanderthals and H sapiens mated with each other, as Neanderthal DNA makes up a small portion of the human genome But this year scientists estimated when these trysts took place: 47,000 to 65,000 years ago The timing makes sense; it coincides with the period when humans were thought to have left Africa and spread into Asia and Europe Australopithecus sediba dined on wood: Food particles stuck on the teeth of a fossil of A sediba revealed the nearly two-million-year-old hominid ate wood – something not yet found in any other hominid species A sediba was found in South Africa in 2010 and is a candidate for ancestor of the genus Homo 10 Earliest H sapiens fossils from Southeast Asia: Scientists working in a cave in Laos dug up fossils dating to between 46,000 and 63,000 years ago Several aspects of the bones, including a widening of the skull behind the eyes, indicate the bones were of H sapiens Although other potential modern human fossils in Southeast Asia are older than this find, the researchers claim the remains from Laos are the most conclusive evidence of early humans in the region What are the main points of the passage? 12345678910- ... bones, including a widening of the skull behind the eyes, indicate the bones were of H sapiens Although other potential modern human fossils in Southeast Asia are older than this find, the researchers... This single finding could illuminate how our ancestors first started walking upright Orangutans live 20-40 metres above ground in the forests of Indonesia They spend most of their time in an... growth is affected by the act of climbing The similar growth patterns hint that A afarensis, at least the youngsters, spent part of their time in trees What are the main points of the passage? 1234567-