EARLY HOMOS
Homo habilis Members of the genus homo have larger brains and a smaller, ape-like faces. What distinguished them from their predecessors was is ability to make stone tools. “Homo erectus” was the first species to expand into Asia and Europe. “Homo” is Latin for "human." [Sources: Homo erectus, National Geographic, May, 1997; Homo erectus, Rick Gore, National Geographic, July 1997]
Claims to the oldest “Homo” fossils include a 2.4-million-year- old mandible from Uraha, Malawi, a 2.4-million-year-old skull fragment from Lake Baringo, Kenya and a 2.3-million-year-old upper jawbone from Hadar, Ethiopia. For the most part though the period between two million and three million years ago there is little data and few fossils.
“Homo” species had longer bodies than the short and stocky “Australopithecus “ species. Since about 1.8 years hominins have been within the size range of modern humans. Male and females size differences characteristic of Australopithecus species decreased. The brain volume of Australopithecus species ranged between 400 and 500 cubic centimeters while the brain volume of early “ Homo” species was between 600 and 750 cubic centimeters.
Categories with related articles in this website: Early Hominins and Human Ancestors (23 articles) factsanddetails.com; Neanderthals, Denisovans, Hobbits, Stone Age Animals and Paleontology (25 articles) factsanddetails.com; Modern Humans 400,000-20,000 Years Ago (35 articles) factsanddetails.com; First Villages, Early Agriculture and Bronze, Copper and Late Stone Age Humans (33 articles) factsanddetails.com.
Websites and Resources on Hominins and Human Origins: Smithsonian Human Origins Program humanorigins.si.edu ; Institute of Human Origins iho.asu.edu ; Becoming Human University of Arizona site becominghuman.org ; Talk Origins Index talkorigins.org/origins ; Last updated 2006. Hall of Human Origins American Museum of Natural History amnh.org/exhibitions ; Wikipedia article on Human Evolution Wikipedia ; Human Evolution Images evolution-textbook.org; Hominin Species talkorigins.org ; Paleoanthropology Links talkorigins.org ; Britannica Human Evolution britannica.com ; Human Evolution handprint.com ; National Geographic Map of Human Migrations genographic.nationalgeographic.com ; Humin Origins Washington State University wsu.edu/gened/learn-modules ; University of California Museum of Anthropology ucmp.berkeley.edu; BBC The evolution of man" bbc.co.uk/sn/prehistoric_life; "Bones, Stones and Genes: The Origin of Modern Humans" (Video lecture series). Howard Hughes Medical Institute.; Human Evolution Timeline ArchaeologyInfo.com ; Walking with Cavemen (BBC) bbc.co.uk/sn/prehistoric_life ; PBS Evolution: Humans pbs.org/wgbh/evolution/humans; PBS: Human Evolution Library www.pbs.org/wgbh/evolution/library; Human Evolution: you try it, from PBS pbs.org/wgbh/aso/tryit/evolution; John Hawks' Anthropology Weblog johnhawks.net/ ; New Scientist: Human Evolution newscientist.com/article-topic/human-evolution; Fossil Sites and Organizations: The Paleoanthropology Society paleoanthro.org; Institute of Human Origins (Don Johanson's organization) iho.asu.edu/; The Leakey Foundation leakeyfoundation.org; The Stone Age Institute stoneageinstitute.org; The Bradshaw Foundation bradshawfoundation.com ; Turkana Basin Institute turkanabasin.org; Koobi Fora Research Project kfrp.com; Maropeng Cradle of Humankind, South Africa maropeng.co.za ; Blombus Cave Project web.archive.org/web; Journals: Journal of Human Evolution journals.elsevier.com/; American Journal of Physical Anthropology onlinelibrary.wiley.com; Evolutionary Anthropology onlinelibrary.wiley.com; Comptes Rendus Palevol journals.elsevier.com/ ; PaleoAnthropology paleoanthro.org.
Development of Australopithecus Into Homo
Homo habalis skull from Koobi Fora
scientists have different theories about which hominins evolved into more developed species and which lead to evolutionary dead ends. Some scientists believed that the “Homo” genus evolved from “Australopithecus afarensis” . Others believe it developed from “Australopithecus afarensis” . “Bosei” and “robustus” are believed to be evolutionary dead ends because they lived at the same time as “Homo” species. The various theories are difficult to prove.
There is some debate as to whether the Homo genus evolved in East Africa or evolved in southern Africa and migrated north. Proponents of the southern Africa theory believe that the earliest “Homo” species evolved from “A. africanus “ (Taung Child) and base their argument on the facts that arrangement of her teeth and brain size are similar to that of “Homo habilis “ (the earliest “Homo” species), their fingers are humanlike and their brains were of similar size to “ Homo habilis” .
In southern Africa, the oldest-known hominin species is Australopithecus africanus. The four-foot-tall hominid with long arms for tree climbing lived in the region 3.3 million to 2.1 million years ago, when the area was partly forested. As the climate became drier, the forests gave way to more open grasslands, and new hominids evolved. Paranthropus robustus— famous for its massive jaw and giant molars, which allowed the species to chew tough plants—inhabited the area 1.8 million to 1.2 million years ago. It lived alongside the taller, more modern-looking Homo erectus, which also came onto the scene about 1.8 million years ago before disappearing from Africa 500,000 years ago. [Source: Erin Wayman, Smithsonian Magazine, January 2012]
One of the primary outstanding mysteries of human evolution is the origin of our genus, Homo, between two million and three million years ago. Jamie Shreeve wrote in National Geographic: “On the far side of that divide are the apelike australopithecines, epitomized by Australopithecus afarensis and its most famous representative, Lucy, a skeleton discovered in Ethiopia in 1974. On the near side is Homo erectus, a tool-wielding, fire-making, globe-trotting species with a big brain and body proportions much like ours. Within that murky million-year gap, a bipedal animal was transformed into a nascent human being, a creature not just adapted to its environment but able to apply its mind to master it. How did that revolution happen?/+\ [Source: Jamie Shreeve, National Geographic, September 2015 /+]
“The fossil record is frustratingly ambiguous. Slightly older than H. erectus is a species called Homo habilis, or “handy man”—so named by Louis Leakey and his colleagues in 1964 because they believed it responsible for the stone tools they were finding at Olduvai Gorge in Tanzania. In the 1970s teams led by Louis’s son Richard found more H. habilis specimens in Kenya, and ever since, the species has provided a shaky base for the human family tree, keeping it rooted in East Africa. Before H. habilis the human story goes dark, with just a few fossil fragments of Homo too sketchy to warrant a species name. As one scientist put it, they would easily fit in a shoe box, and you’d still have room for the shoes.” /+\
Lee Berger, a paleoanthropologist at the University of the Witwatersrand, “has long argued that H. habilis was too primitive to deserve its privileged position at the root of our genus. Some other scientists agree that it really should be called Australopithecus. But Berger has been nearly alone in arguing that South Africa was the place to look for the true earliest Homo. And for years the unchecked exuberance with which he promoted his relatively minor finds tended only to alienate some of his professional colleagues. Berger had the ambition and personality to become a famous player in his field, like Richard Leakey or Donald Johanson, who found the Lucy skeleton. Berger is a tireless fund-raiser and a master at enthralling a public audience. But he didn’t have the bones.” /+\
Several Homo Species Lived at the Same Time
Although modern humans are the only members of the Homo genus alive today, other human species that belonged to the genus lived in the past. The earliest Homo specimen found so far lived about 2.8 million years ago. About a dozen Homo species have been identified although there is still intense debate as to how they all fit on the evolutionary tree or even whether they are unique species. Some of them, including Neanderthals, lived at the same as modern humans around 50,000 years. Others lived when modern humans were emerging around 300,000 years ago. And others still lived at the same time as Australopithecines more than 2 million years ago.
Valerie Ross wrote in Discover: “The big-brained, upright primates of the genus Homo—the group to which we modern-day humans belong—evolved in East Africa around 2.4 million years ago. By half a million years later, Homo erectus, from whom we’re directly descended, was walking the plains near Lake Turkana in what is now Kenya. But anthropologists have increasingly come to believe that Homo erectus wasn’t the only hominin around. Three newly discovered fossils, detailed in Nature in August 2012, confirm that at least two other Homo species lived nearby—providing the strongest evidence yet that several evolutionary lineages split off in the genus’s early days. [Source: Valerie Ross, Discover, August 9, 2012 )=(]
“These new discoveries bolster the idea that the human family tree wasn’t, as scientists once thought, a steady climb upward; even within our own genus, life was branching out in several directions. As anthropologist Ian Tattersall told the New York Times, “it supports the view that the early history of Homo involved vigorous experimentation with the biological and behavioral potential of the new genus, instead of a slow process of refinement in a central lineage.”“ )=(
Complexity of the Hominin Scene 3 Million Years Ago
Pete Spotts wrote in Christian Science Monitor: “New fossils from Ethiopia are providing fresh evidence that some 3 million to 4 million years ago, ancestors to modern humans may have been more diverse than previously thought. That diversity would have led to an inadvertent test to see which species was best able to weather changes in climate and habitat during that period, some researchers suggest. So far, that would appear to be Australopithecus afarensis, represented by its most famous example, Lucy, discovered in 1974 by Donald Johanson and Tom Gray. [Source: Pete Spotts, Christian Science Monitor, May 27, 2015]
range of homo habilis
“But Lucy and her species were not the only Australopithecines on the block. Over the years, researchers have reported uncovering two additional species from this period. If this latest discovery holds up, it would bring to four the number of known Australopithecus species living within this million-year span. These species range from Ethiopia to Chad. The research team that found the new fossils – upper and lower jaws that included teeth – have classified the find as belonging to a new species of hominin, a subset of hominins that includes modern humans and our direct ancestors. The researchers suggest that the new species, which they have dubbed Australopithecus deyiremeda, was a close relative to A. afarensis. The team's analysis appeared the journal Nature.
“A. deyiremeda's remains were found at a site in Ethiopia's Afar region known as Woranso-Mille, about 22 miles north of another site rich in A. afarensis fossils – pointing to the possibility that the two species roamed the same general region at about the same time. With several Australopithecus species living in eastern and central Africa in the same general period, "we're looking at hominins who are potential candidates as human ancestors," says Henry Bunn, a paleoanthropologist at the University of Wisconsin at Madison. During this period, known as the middle Pliocene, the climate was getting cooler and drier. Vegetation and food resources were changing.
“Looking at these Australopithecines, "you could almost think of them as ecological experiments as populations try to exploit new habitats and new resources successfully," says Dr. Bunn, who was not a member of the research team. "Most of those species went extinct."
In the past, researchers had broken the last 5 million years of hominin evolution into blocks of 1 million to 2 million years, he explains. Based on the fossil evidence available at the time, "you only had one species per block of time," he says. At about 2 million years ago, with the emergence of the genus Homo, hominins became more diverse.
With Lucy and subsequent discoveries, it now appears that the middle Pliocene also hosted a diverse array of hominins that included at least one additional group beyond Australopithecines – a group represented by Kenyanthropus platyops. The newly discovered jawbones and teeth – dated to between 3.5 and 3.3 million years ago – shared some characteristics with A. afarensis and others with K. platyops. This period also coincides with the appearance of the earliest stone tools yet found, a discovery announced last week in another paper in Nature.
“The new species is yet another confirmation that Lucy’s species, Australopithecus afarensis, was not the only potential human ancestor species," according to Yohannes Haile-Selassie, curator of physical anthropology at The Cleveland Museum of Natural History who headed the team making the discovery. “Current fossil evidence from the Woranso-Mille study area clearly shows that there were at least two, if not three, early human species living at the same time and in close geographic proximity,” he said in a prepared statement.
Homo habilis
Homo Habilis skulls “Homo habilis”, meaning "handy man," was dramatically different from his predecessors. Homo habilis appeared around the same time as the first stone tools. Some scientists suggest the transformation from Australopithecus to Homo habilis was brought about by climatic changes.
Geologic Age 1.4 million to 2.5 million years. Very few “H. habalis” remains have been found, but scientists speculate he survived about a half a million years. He lived at same time as Australopithecus boisei. Linkage to Modern Man: Seen as direct ancestor. Not clear what Australopithecus species he evolved from.
Discovery Sites: Eastern and southern Africa. Discovered at Olduvai Gorge, Tanzania in 1959 by Mary Leakey and found near Lake Turkana at Koobi Fara, Kenya by B. Ngeneo and the Sterkfontein and Swartkrans in South Africa. Leakeys. The Lake Turkana remains are housed at National Museum of Kenya in Nairobi.
Homo habilis Body Features and Size
Size: Small compared to modern humans. males: 4 feet 4 inches; females: 3 feet 10 inches, 71 pounds. Skull Features: Primitive face, back teeth narrower. Larger brain and smaller human-like jaws and teeth than those found on Australopithecus species. Body Features: More similar to modern man.
Homo Habilis tooth Brain Size: 630 cubic centimeters, significantly larger than predecessors. Although half the size of modern man's brain, it's brain was large relative to body size and almost the same relative size as the brain of modern man. There was a pronounced bulge in the area of the brain associated with speech. Scientists say it probably didn't speak because it's vocal chords were not developed enough. A human brain is about 1,350 cubic centimeters. A chimpanzee’s brain is 390 cubic centimeters.
A February 2009 article in Science announced the discovery of 1.53-million -year-old footprints found at Ileret, Kenya. The footprints, likely made by early “Homo habilis” or “Homo ergaster”, were heralded as the earliest evidence of modern upright walking. The large toe was parallel to the other toes, indicating an upright posture. The 3.6-million-year-old prints found in Tanzania and attributed to an Australopithecus species indicated an upright posture but had a shallower arch and an apelike divergent toe. The discovery was announced by a team led by Matthew Bennet of Bournemouth University in Britain.
Homo habilis Tools
“Homo habilis” appeared around the same time as the first stone tools, which included cobbles and choppers made from lava. Some of the tools were made of materials not found in the area where the tools were found. This implies the materials were carried to the area where they were found from a distant site, which in turn implies the transportation of goods of even trade.
“Homo habilis” consisted mostly fist-size hammerstones and small, sharp flakes. Scientists believe that “Homo habilis “ and his tools were too small too hunt large prey. The tools, they theorize, were used mainly to fight off competing scavengers for the large carnivores such as lions and cut the hides and break open the bones of their scavenged meals. “Homo habilis “ deliberately hammered and shaped rocks into these tools.
Homo Habilis and Homo Erectus
In an August 2007 article in Nature, Maeve Leakey of the Koobi Fora Research Project announced her team had found an upper jawbone of a “Homo habilis” east of Lake Turkana in eastern Kenya dated to 1.44 million years ago, making it much more recent than other fossils from the species.
Homo ergaster It had previously been theorized that “Homo habilis” and “Homo erectus” lived at different times and “Homo erectus” evolved from “Homo habilis”. The discovery by Leakey’s team however seems to counter this finding, suggesting that the two hominins lived together for around a half million years, which in turn makes it unlikely that “Homo erectus” evolved from “Homo habilis”.The finding does not challenge the theory that “Homo erectus” are the direct ancestors of modern humans but it does call into question whether “Homo habilis” was.
Scientists now theorize that “Homo habilis” and “Homo erectus” had a common ancestor that lived between two million and three million years ago, a period in which there is little data and few fossils. Leakey told the New York Times that the finding of her group suggests “Homo habilis” and “Homo erectus” “had their own ecological niche thus avoiding direct competition...Their coexistence makes its unlikely that Homo erectus evolved from Homo habilis.” Fred Spoor, a Leakey colleague from the University College of London, said the finding contradicts previous theories that present human evolution “as one strong single line from early hominins to us” and supports the revised interpretation of “a lot of bushiness and experimentation in the fossil record.”
The 1.44 million-year-old “Homo habilis” fossils were found several years before but extra care was taken identifying the species and dating the fossils, which was done from volcanic ash deposits, to make sure they got it right since the implications of the finding are so dramatic.
Homo rudolfensis and Homo ergaster
homo ergaster Nariokotome Boy “Homo rudolfensis” , is a hominin species that lived between 2.5 million and 1.9 million years ago. Little is know about this hominin which sprung up about a half million years before “Homo habilis” died out. Many scientists regard “Homo rudolfensis” as a member of the “ Homo habilis” species. If not it is the earliest known homo species. Skull Features: Long, broad face with flatter browridges and a larger, rounder braincase that “Homo habilis” . Discovery Sites: Eastern Africa. Omo, Ethiopia; Koobi Fora at Lake Turkana, Kenya; Uraha, Lake Malawi.
“Homo ergaster “ is a hominin species that lived between 1.8 million and 1.4 million years ago. Many scientists regard “Homo ergaster “ as a member of the “Homo erectus “ species. Skull Features: smaller jaws and a more projecting nose than earlier Homos. Body Features: Arm and leg proportions more similar to modern man. Discovery Site: Koobi Fora at Lake Turkana, Kenya.
"Turkana Boy" is a nearly complete skeleton and skull from a 12-year-old boy that lived 1.54 million years ago and was discovered in 1984 near the shores of Lake Turkana not far from Nariokotome, Kenya. Some scientists think he is “Homo erectus”. Others regard him as distinctive enough to be regarded as a separate species — “homo ergaster”. Turkana Boy was about 5-foot, 3-inches tall when he died and probably would have reached a height of about six feet if he reached maturity. Turkana boy is the most complete skeleton of a hominin more than a million years old.
See 1.7-Million-Year-Old Hominin Fossils in Georgia
Three Homo Species Living at Same Time: Homo Erectus, Homo Habalis and Homo Rudolfensis?
Homo Rudolfensis endocast
Seth Borenstein of Associated Press wrote: “The Leakey scientific team contends that other fossils of old hominins - not those cited in their new study - don't seem to match either erectus or 1470. They argue that the other fossils seem to have smaller heads and not just because they are female. For that reason, the Leakeys believe there were three living Homo species between 1.8 million and two million years ago. They would be Homo erectus, the 1470 species, and a third branch. "Anyway you cut it there are three species," study co-author Susan Anton, an anthropologist at New York University. "One of them is named erectus and that ultimately in our opinion is going to lead to us." [Source: Seth Borenstein, Associated Press, August 8 2012]
Both of the species that Meave Leakey said existed back then went extinct more than a million years ago in evolutionary dead-ends. "Human evolution is clearly not the straight line that it once was," Spoor said. The three different species could have been living at the same time at the same place, but probably didn't interact much, he said. Still, he said, East Africa nearly 2 million years ago "was quite a crowded place"
“And making matters somewhat more confusing, the Leakeys and Spoor refused to give names to the two non-erectus species or attach them to some of the other Homo species names that are in scientific literature but still disputed. That's because of confusion about what species belongs where, Anton said. Two likely possibilities are Homo rudolfensis -which is where 1470 and its kin seem to belong - and Homo habilis, where the other non-erectus belong, Anton said. The team said the new fossils mean scientists can reclassify those categorized as non-erectus species and confirm the earlier but disputed Leakey claim.
“But Tim White, a prominent evolutionary biologist at the University of California Berkeley, is not buying this new species idea, nor is Milford Wolpoff, a longtime professor of anthropology at the University of Michigan. They said the Leakeys are making too big a jump from too little evidence. White said it's similar to someone looking at the jaw of a female gymnast in the Olympics, the jaw of a male shot-putter, ignoring the faces in the crowd and deciding the shot-putter and gymnast have to be a different species. Eric Delson, a paleoanthropology professor at Lehman College in New York, said he buys the Leakeys' study, but added: "There's no question that it's not definite." He said it won't convince doubters until fossils of both sexes of both non- erectus species are found. "It's a messy time period," Delson said.
Body Structure of Early Homo Species Very Diverse
Research in the mid 2010s has revealed that not only did early Homo species Homo rudolfensis, Homo habilis and Homo erectus have significant differences in facial features, they also differed throughout other parts of their skeletons and had distinct body forms. According to the University of Missouri-Columbia, a research team found 1.9 million-year-old pelvis and femur fossils of an early human ancestor in Kenya, revealing greater diversity in the human family tree than scientists previously thought. "What these new fossils are telling us is that the early species of our genus, Homo, were more distinctive than we thought. They differed not only in their faces and jaws, but in the rest of their bodies too," said Carol Ward, a professor of pathology and anatomical sciences in the MU School of Medicine. "The old depiction of linear evolution from ape to human with single steps in between is proving to be inaccurate. We are finding that evolution seemed to be experimenting with different human physical traits in different species before ending up with Homo sapiens." [Source: University of Missouri-Columbia, Science Daily, March 9, 2015 /~/]
“Three early species belonging to the genus Homo have been identified prior to modern humans, or Homo sapiens.Homo rudolfensis and Homo habilis were the earliest versions, followed by Homo erectus and then Homo sapiens. Because the oldest erectus fossils that have been found are only 1.8 million years old, and have different bone structure than the new fossil, Ward and her research team conclude that the fossils they have discovered are either rudolfensis or habilis. /~/
homin skull comparison
Ward says these fossils show a diversity in the physical structures of human ancestors that has not been seen before."This new specimen has a hip joint like all other Homo species, but it also has a thinner pelvis and thighbone compared to Homo erectus," Ward said. "This doesn't necessarily mean that these early human ancestors moved or lived differently, but it does suggest that they were a distinct species that could have been identified not just from looking at their faces and jaws, but by seeing their body shapes as well. Our new fossils, along with the other new specimens reported over the past few weeks, tell us that the evolution of our genus goes back much earlier than we thought, and that many species and types of early humans coexisted for about a million years before our ancestors became the only Homo species left." /~/
“A small piece of the fossil femur was first discovered in 1980 at the Koobi Fora site in Kenya. Project co-investigator Meave Leakey returned to the site with her team in 2009 and uncovered the rest of the same femur and matching pelvis, proving that both fossils belonged to the same individual 1.9 million years ago. /~/
Journal Reference: Carol V. Ward, Craig S. Feibel, Ashley S. Hammond, Louise N. Leakey, Elizabeth A. Moffett, J. Michael Plavcan, Matthew M. Skinner, Fred Spoor, Meave G. Leakey. Associated ilium and femur from Koobi Fora, Kenya, and postcranial diversity in early Homo. Journal of Human Evolution, 2015; DOI: 10.1016/j.jhevol.2015.01.005
2.8-Million-Year-Old Fossil Found in Ethiopia: the First Human?
In 2015, scientists said they had unearthed the jawbone of what they claimed was one of the very first humans. The 2.8 million-year-old hominin is 400,000 years older than what had been previously described as the oldest “Homo.” The discovery also hinted that climate change might have played a part in transition from living the trees to walking upright. Prof Brian Villmoare of the University of Nevada in Las Vegas told the BBC that the discovery may be linked with “Lucy,” the iconic 3.2 million-year-old hominin found in the same area in 1974. Could Australopithecus afarensis (Lucy's species) have evolved into the first primitive humans? "That's what we are arguing," said Prof Villmoare. But the fossil record between the time period of Lucy and the emergence of Homo erectus — a “Homo” species,, with a relatively large brain and humanlike body proportions, that lived two million years ago — is thin.[Source: Pallab Ghosh, BBC News, March 4, 2015 |::|]
Pallab Ghosh wrote for BBC News: “The 2.8 million-year-old lower jawbone was found in the Ledi-Geraru research area, Afar Regional State, by Ethiopian student Chalachew Seyoum. He told BBC News that he was "stunned" when he saw the fossil. "The moment I found it, I realised that it was important, as this is the time period represented by few (human) fossils in Eastern Africa." |::|
“The fossil is of the left side of the lower jaw, along with five teeth. The back molar teeth are smaller than those of other hominins living in the area and are one of the features that distinguish humans from more primitive ancestors, according to Professor William Kimbel, director of Arizona State University's Institute of Human Origins. "Previously, the oldest fossil attributed to the genus Homo was an upper jaw from Hadar, Ethiopia, dated to 2.35 million years ago," he told BBC News. "So this new discovery pushes the human line back by 400,000 years or so, very close to its likely (pre-human) ancestor. Its mix of primitive and advanced features makes the Ledi jaw a good transitional form between (Lucy) and later humans." |::|
“A computer reconstruction of a skull belonging to the species Homo habilis, which has been published in Nature journal, indicates that it may well have been the evolutionary descendant of the species announced today. The researcher involved, Prof Fred Spoor of University College London told BBC News that, taken together, the new findings had lifted a veil on a key period in the evolution of our species. "By discovering a new fossil and re-analysing an old one we have truly contributed to our knowledge of our own evolutionary period, stretching over a million years that had been shrouded in mystery," he said.” |::|
Hominin brain sizes
Significance of 2.8-Million-Year-Old “Human” Fossil Found in Ethiopia
Pallab Ghosh wrote for BBC News: “The dating of the jawbone might help answer one of the key questions in human evolution. What caused some apes to climb down from the trees and make their homes on the ground. A separate study in Science hints that a change in climate might have been a factor. An analysis of the fossilised plant and animal life in the area suggests that what had once been lush forest had become dry grassland.As the trees made way for vast plains, apes found a way of exploiting the new environmental niche, developing bigger brains and becoming less reliant on having big jaws and teeth by using tools. [Source: Pallab Ghosh, BBC News, March 4, 2015 |::|]
Prof Chris Stringer of the Natural History Museum in London described the discovery as a "big story". He says the new species clearly does show the earliest step toward human characteristics, but suggests that half a jawbone is not enough to tell just how human it was and does not provide enough evidence to suggest that it was this line that led to us. He notes that the emergence of human-like characteristics was not unique to Ethiopia. The jawbone was found close to the area where Lucy was discovered. "The human-like features shown by Australopithecus sediba in South Africa at around 1.95 million years ago are likely to have developed independently of the processes which produced (humans) in East Africa, showing that parallel origins are a distinct possibility," Prof Stringer explained. |::|
“This would suggest several different species of humans co-existing in Africa around two million years ago with only one of them surviving and eventually evolving into our species, Homo sapiens. It is as if nature was experimenting with different versions of the same evolutionary configuration until one succeeded. Prof Stringer added: "These new studies leave us with an even more complex picture of early humans than we thought, and they challenge us to consider the very definition of what it is to be human. Are we defined by our small teeth and jaws, our large brain, our long legs, tool-making, or some combination of these traits?"”
Oldowan Tools
Oldowan chopper
The earliest stone tools believed to have been made by the genus Homo are tools from or of the type of found in Olduvai Gorge, Tanzania, where they were discovered in large quantities. Oldowan tools were characterized by their simple construction, predominantly using core forms. These cores were river pebbles, or rocks similar to them, that had been struck by a spherical hammerstone to cause conchoidal fractures removing flakes from one surface, creating an edge and often a sharp tip. The blunt end is the proximal surface; the sharp, the distal. Oldowan is a percussion technology. Grasping the proximal surface, the hominid brought the distal surface down hard on an object he wished to detach or shatter, such as a bone or tuber. [Source: Wikipedia +]
The earliest known Oldowan tools date from 2.6 million years ago and were in Gona, Ethiopia. After this date, the Oldowan Industry spread throughout much of Africa. Archaeologists are currently unsure which Hominin species first developed them, with some speculating that it was Australopithecus garhi, and others saying it was Homo habilis. Homo habilis used them for a long period. About 1.9-1.8 million years ago Homo erectus inherited them. The Industry flourished in southern and eastern Africa between 2.6 and 1.7 million years ago, but also spread out of Africa and into Eurasia with homo erectus, who took Oldowan tool as far east as Java by 1.8 million years ago and Northern China by 1.6 million years ago. +
Oldowan Tool-Making Site at Lake Victoria, Kenya
Popular Archaeology reported: “At a site in the Homa Peninsula of Lake Victoria, Kenya, scientists are uncovering stone tools and fossils that are shedding new light on their manufacture and use, as well as early human habitat and behavior. Led by co-directors Dr. Thomas Plummer of Queens College, City University of New York and Dr. Rick Potts of the Smithsonian Institution, excavations at the site, called Kanjera South, have revealed a large and diversified assortment of Oldowan stone tools, fossil animal remains and other flora and faunal evidence that is building a picture of hominin, or early human, life and behavior in a grassland environment about 2 million years ago. Oldowan stone tools represent the earliest known human or hominin stone tool industry, named after the Olduvai Gorge, where Louis Leakey first discovered examples in the 1930’s. This early industry was typically composed of simple “pebble tools” such as choppers, scrapers and pounders, a type of technology used from about 2.6 to 1.7 million years ago. [Source: Popular Archaeology, June 12, 2012 /+]
“According to Plummer, the site “has yielded approximately 3700 fossils and 2900 artifact...This represents one of the largest collections of Oldowan artifacts and fauna found thus far”. But more significant than the numbers is what the analysis of the finds and the site has revealed. Says Plummer, “the 2 million year old sediments at Kanjera South…..provide some of the best early evidence for a grassland dominated ecosystem during the time period of human evolution, and the first clear documentation of human ancestors forming archaeological sites in such a setting”. /+\
“The site thus shows clear evidence that early humans of this time period were inhabiting and utilizing a grassland environment, in addition to other types of environments, a signal of critical adapation that led to evolutionary success. Moreover, analysis of the makeup of the tools and the geography and geology of the area suggested that these hominins were transporting what they must have considered to be the highest quality materials from relatively distant locations to produce the most effective and efficient tools for butchering animals. /+\
“Cut marks made by stone blades on fossil bones, particularly small antelopes, showed signs that the animals may have been hunted, or at least encountered first, by the early humans before other preying animals reached the carcasses. “The overall pattern of hominin access to the complete carcasses of small antelopes may be the signal of hominin hunting”, writes Plummer. “If so, this would be the oldest evidence of hunting to date in the archaeological record”.
“Use of stone tools by these early humans apparently went beyond butchery. “Thus far, the use-wear on the quartz and quartzite subsample of Kanjera artifacts confirms that animal butchery was conducted on-site, but also demonstrates the processing of a variety of plant tissues, including wood (for making wooden tools?) and tubers. This is significant, because the processing of plant materials appears to have been quite important, but would otherwise have been archaeologically invisible”. /+\
Homo Gautengensis
Homo gautengensis is a hominin species proposed by biological anthropologist Darren Curnoe in 2010 based on the analysis of a partial skull found in 1977 at Sterkfontain Cave near Johannesburg, South Africa. Some scientists had earlier classified the fossils as Homo habilis or Homo ergaster. Others said they belonged to an Australopithecus species. Curnoe has argued that Homo gautengensis is the earliest species in the genus Homo. The view is controversial to say the least. Many scientists dismiss the idea that Homo gautengensis is a unique species.
Homo Gautengensis
According to the Bradshaw Foundation: “Further identification of Homo gautengensis was based on partial skulls, several jaws, teeth and other bones found at various times and cave sites in South Africa’s Cradle of Humankind. The oldest specimens are those from Swartkrans between 1.9 and 1.8 million years ago. The Sterkfontain specimen is dated between 1.8 and 1.5 million years ago, and the Gondolin Cave 1.8 million years ago. The youngest specimens from Swartkrans are dated to sometime between 1.0 and 0.6 million years ago. [Source: Bradshaw Foundation \=]
“According to Curnoe, Homo gautengensis had big teeth suitable for chewing plant material, was small-brained and large-toothed, and was probably an ecological specialist, consuming more vegetable matter than Homo erectus, Homo sapiens and probably Homo habilis. It apparently produced and used stone tools and may even have made fire, as there is evidence for burnt animal bones associated with Homo gautengensis' remains. Standing just over 0.91 meters tall and weighing about 50 kg, it walked on two feet when on the ground, but probably spent considerable time in trees, perhaps feeding, sleeping and escaping predators. It probably lacked speech and language skills. \=\
“Homo gautengensis was a close relative of Homo sapiens but not necessarily a direct ancestor. It would have lived at the same time and in the same place as Australopithecus sediba, the latter being more primitive [and therefore less likely to be the ancestor of humans]. Indeed, there would have been a number of distinctive, perhaps short-lived, species of proto-humans living in both eastern and southern Africa in the period between 2 and 1 million years ago.” \=\
Skull 1470 and Recent Fossils Finds by Meave Leaky
In 2012, Meave Leakey announced that her team had found facial bones from the time of Homo erectus that didn’t belong to Homo erectus, proving that more than one hominin lived at that time and perhaps meaning that there was more than one common ancestor for man. Leakey’s team found facial bones from one creature and jawbones from two others between 2007 and 2009 about 10 kilometers away from a an old fossil-rich site in Lake Turkana region. [Source: Seth Borenstein, Associated Press, August 8 2012]
Valerie Ross wrote in Discover: “In 1972, researchers found a partial skull in the fossil beds near Lake Turkana. Its big cranium—with room for a large brain—made clear it was a member of the genus Homo. Its unusual face, flat and long, led some scientists to believe it represented a new species, dubbed H. rudolfensis; others felt the skull could just be an odd-looking specimen of a known species, H. erectus or H. habilis, an example of natural variation in action. With the skull’s entire lower jaw missing, it was impossible to make a definitive classification. Just a few years ago, researchers found fossils of a complete and partial lower jaw and of another face, dating from 1.78 million to 1.95 million years ago. The newly discovered jaws fit well with the earlier skull, as shown above, and are different from those seen in before, confirming that the 1972 find is a new species. The other find, the fossil face, was from a juvenile, and clearly mirrored the other skull’s features and shape. [Source: Valerie Ross, Discover, August 9, 2012]
Seth Borenstein of Associated Press wrote: The “finding has led the researchers to conclude that man's early ancestor had plenty of human-like company from other species. These would not be Homo erectus, believed to be our direct ancestor. They would be more like very distant cousins, who when you go back even longer in time, shared an ancient common ancestor, one scientist said. But other experts in human evolution are not convinced by what they say is a leap to large conclusions based on limited evidence. It is the continuation of a long-running squabble in anthropology about the earliest members of our own genus, or class, called Homo - an increasingly messy family history. And much of it stems from a controversial discovery that the Leakeys made 40 years ago.
“In their new findings, the Leakey team says that none of their newest fossil discoveries match erectus, so they had to be from another flat-faced relatively large species with big teeth. The new specimens have "a really distinct profile" and thus they are "something very different," said Meave Leakey, describing the study published online in Nature. What these new bones did match was an old fossil that Meave and her husband Richard helped find in 1972 that was baffling. That skull, called 1470, just did not fit with Homo erectus, the Leakeys contended. They said it was too flat-faced with a non-jutting jaw. They initially said it was well more than 2.5 million years old in a dating mistake that was later seized upon by creationists as evidence against evolution because it indicated how scientists can make dating mistakes. It turned out to be two million years old.
For the past 40 years, the scientific question has been whether 1470 was a freak mutation of erectus or something new. For many years, the Leakeys have maintained that the male skull known as 1470 showed that there were more than one species of ancient hominins, but other scientists said it wasn't enough proof. The Leakeys' new discoveries are more evidence that this earlier "enigmatic face" was a separate species, said study co-author Fred Spoor of the Max Planck Institute in Germany.”
Are Hobbits Evidence That Homo Habalis Left Africa?
The origin of Homo floresiensis (the hobbits of Indonesia) raises some interesting questions, one being that they could be descendants of predecessor of homo erectus —homo habalis or even a Australopithecus species — and this in turn could mean homo habalis or Australopithecus species could have emerged from Africa before Homo erectus.
Deborah Netburn wrote in the Los Angeles Times: “One hypothesis posits that Homo floresiensis descended from the large-bodied hominin Homo erectus that lived between 1.89 million and 143,000 years ago. Scientists say it is possible that Homo erectus may have arrived on Flores from Java, perhaps after being washed out to sea by a tsunami. Over time, this species began to shrink on its new island home – a relatively common phenomenon known as island dwarfism. “Lots of animals that end up on islands get smaller for a variety of reasons like limited food sources, or because there are no large predators to stay big for,” said Karen Baab, a paleoanthropologist at Midwestern University in Glendale, Ariz., who was not involved in the study. “We even see it in modern humans in certain environments that are home to pygmy populations.” [Source: Deborah Netburn, Los Angeles Times, June 8, 2016 */]
“The other hypothesis states that Hobbits descended from smaller and more ancient hominins like Australopithecus africanus or Homo habilis that were already diminutive at the time they reached the island. Both theories have challenges. One might accept that Homo erectus grew smaller in stature by two-thirds over time. After all, a smaller body is easier to feed. But for some scientists, it is hard to believe that it made evolutionary sense for its brain to shrink by half. Losing brain power doesn’t seem like a likely evolutionary development. On the other hand, if you buy that Homo floresiensis was descended from Australopithecus or Homo habilis, then you have to explain how either of these species made their way to Indonesia when their remains have never been found outside of Africa. */.
A bone study published in 2017 in the Journal of Human Evolution showed there was nothing to support claims that Homo floresiensis evolved from Homo erectus, which scientists say was an ancestor of modern humans, and thus did not have any direct links modern humans. Teeth similarities had been suggested as evidence that homo erectus and hobbits were linked.
Melissa Davey wrote in The Guardian: “The study, led by the Australian National University researcher Dr Debbie Argue from the school of archaeology and anthropology, found there was no evidence Homo floresiensis evolved from the much larger Homo erectus, the only other early hominin known to have lived in the region. It was one of several theories about the origins of the “hobbit” species. Since it was discovered, researchers have tried to determine whether Homo floresiensis was a species distinct from humans. [Source: Melissa Davey, The Guardian, April 21, 2017]
“The findings add support to the theory that the species evolved from one in Africa, most likely Homo habilis, and that the two species shared a common ancestor. It was possible that Homo floresiensis evolved in Africa and migrated, or the common ancestor moved from Africa and then evolved into Homo floresiensis somewhere, the researchers concluded. Prof Mike Lee of Flinders University and the South Australian Museum used statistical modelling to analyse the data collected by the researchers. He said the findings were clear. Homo floresiensis occupied a very primitive position on the human evolutionary tree,” Lee said. “We can be 99 percent sure it’s not related to Homo erectus and nearly 100 percent it isn’t a malformed Homo sapiens.” |=|
There is a good evidence that a relatively large human that lived 700,000 years ago and shrunk quickly and stayed that size ago is an ancestor of Homo floresiensis according to two studies published in Nature in June 2016. Marlowe Hood of AFP wrote: “A modest haul of teeth and bones from an adult and two children has bolstered the theory that Homo floresiensis arrived on Flores island as a different, larger species of hominin, or early man, probably about a million years ago. And then, something very strange happened. These upright, tool-wielding humans shrank, generation after generation, until they were barely half their original weight and height. [Source: Marlowe Hood, AFP, June 9, 2016 \^/]
Image Sources: Wikimedia Commons
Text Sources: National Geographic, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Nature, Scientific American. Live Science, Discover magazine, Discovery News, Natural History magazine, Archaeology magazine, The New Yorker, Time, Newsweek, BBC, The Guardian, Reuters, AP, AFP and various books and other publications.
Last updated September 2018