Human Evolution:An interactive Learning Experience

Jim SanfordAdvanced Biology

Ed 205

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Human EvolutionHuman Evolution is an on-going field of Biological and

Anthropological Sciences.Research teams spend months in the field every year in

order to find more specimensLikewise, in labs previous discoveries are cataloged and

analyzedNew species are found and inserted into our family tree,

yet with out all the pieces, this is still an unfinished puzzle.

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Main PageThere are Three main branches in our Family Tree made up of the three predominant Genera: Homo, Gracile Australopithecines, and Robust Australopithecines (Paranthropus) as well as a page for new hominids

Paranthropus

HomoAustralopithecusNew Hominids

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Author’s Slide

• Jim Sanford is a Senior Biology Student, Chemistry minor, at Grand Valley State University, emphasizing in Secondary Education.

• Contact Jim at– Jim’s Email

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Resource Slide

• Information and images from http://human-evolution.com/species.htm 1999-2005 ArchaeologyInfo.com

• Supplemental Information from Humankind Emerging: The Concise Edition by Bernard G. Campbell and James D. Joy. Allyn and Bacon. Boston, Ma. 2002.

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HomoThe Genus Homo is were we find ourselves, this branch contains the most advanced primates to have ever lived. These species were the first to make stone tools and proliferate large areas, culminating in Our species which has become the dominant species on this planet. Highlighted are five major species within this genus.

Homo sapiensHomo neanderthanensis

Homo erectusHomo habilis Homo rudolfensis

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AustralopithecusThe Australopithecines are around the oldest ancestors to the Homo lineage. Highlighted are four Australopithecus species. These species mark the possible beginnings of our kind.

Australopithecus afarensis Australopithecus africanus

Australopithecus anamensisAustralopithecus garhi

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ParanthropusThe genus Paranthropus is a dead end along the evolutionary tree toward Homo sapiens. These robust Hominids are very similar and lived at a similar time as the Australopithecines, leading many to rename them as Australopithecus Robustus. Highlighted are the three main Paranthropus species

Australopithecus Robustus aethiopicus

Australopithecus Robustus boisei

Australopithecus Robustus robustus

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New Hominids

Ardipithecus ramidus

Kenyanthropus platyops Sahelanthropus tchadensis

This is a group of recently discovered hominids that do not immediately fall into one of the three main groups.

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H. habilis

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Homo habilis, or “handy man” is one of the oldest of the our genus. Its first naming was in 1964, after its discovery in 1960, and it was attributed to the earliest stone tools in Olduvai. With larger incisors, brain case, and shape and size of the hand, it was determined that this species had more in common with the genus Homo than Australopithecus. Dates from 2.2 to 1.8 million years ago.

H. rudolfensis

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Homo rudolfensis is a highly debate species. This is due to its age and features that some say are more consistent with Australopithecus. Discovered in 1972, its large brain size led to its designation as a member of the genus Homo. Most of the debates are based on the fact that there are no post cranial remains in order to compare it with other specimens, namely if its large dentition are in correlation to a large body. It has been said that this may be a link from Australopithecus to Homo.

H. erectus

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For many years only two species were attributed to the genus Homo other than us, Neanderthals, and Homo erectus. There is a wide body of specimens that are attributed to erectus from all over the world, including Africa, Asia, and Europe. Many call for a division of these based on geography, as there are subtle difference between these populations. These designations would split the European into heidelbergensis, the early African as ergaster, and leaving the most recent finds to be called erectus. Originally named in 1894, after the 1891 discovery of a mineralized skullcap. Now linked to material from 1.9 million years ago up to .2 million years ago, this species is the most far ranging hominid species other than ourselves. Due to the time, and indeed the place, where we see this species ends many believe H. erectus to be the direct ancestors of H. sapiens

H. neanderthanensis

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The Neanderthals developed as a species about the same time as fully modern humans. It is believe that this divergence happened about 700 thousand years ago, from an African population, most likely descended from H. erectus. Neanderthals had very few major difference from physically modern humans of the time. They were typically shorter and stockier that H. sapiens, and somewhat larger brains, suggesting that they moved out of Africa and into the colder European climate earlier than H. sapiens, leading to differentiation due to climate shift. Neanderthals used this time alone to spread across much of the European continent unopposed for several hundred thousand years. Their down fall likely came from direct contact and competition with H. Sapiens. Genetic studies have shown that Neanderthals did not contribute to the modern gene pool.

H. sapiens

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Fully modern humans arrived on the scenes about 200 to 250 thousand years ago. They came out of Africa and began to spread across lands that had been previously and currently occupied by Neanderthals. Fully modern humans took over as the last of the Neanderthals and some late ranging populations of H. erectus were forced into extinction. With out competition, fully modern humans were able to proliferate across the landscape in ways no other species has ever done. In a geologically short period of time, .1 million years or so, H. sapiens have become the dominant species on this planet. The difference that drove us to this point has been our use of technology, language, and culture. Beginning with the flint arrowhead, and ranging to the super computer, our species has been at the forefront of technology, leading us to the top of the food chain.

A. afarensis

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Quite possibly the best know early hominid species, due to the extent of samples attributed to the species as well as the nearly complete specimen of “Lucy”, which is one of the most complete specimens of an early hominid. This species in one of the first to be shown to be an obligate biped, due to the arrangement of the bones and the location of the foramen magnum. This species date from 3.9 million to 2.9 million years ago, making this one of the most successful hominid species. Like other early hominids, this species shows an ape-like face and dentition with a moderate sized brain case, and some advanced features as well. The famous Laetoli footprints are attributed to afarensis due to their proximity to afarensis specimens as well as the approximate age of the footprints.

A. africanus

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First named in 1925, many disputed the find as a possible human ancestor, as many expected to find true hominids in Europe, not in Africa, and appear to have a modern cranium with an ape-like maxilla and jaw. This was the first specimen to be named Australopithecus, which means “walking man” in a combination of Latin and Greek. Dates to approx. 2.9 to 2.4 million years ago.

A. anamensis

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Discovered in 1965, this fossil hominid was not recognized as a separate until more specimens were found in 1994. originally classified as a specimen of A. afarensis, it was reclassified in 1995 as a separate species due to differences in dentition form the typical afarensis specimens. Dates to approx. 4.0 million years ago

A. garhi

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This Australopithecine species was named in 1999, to much controversy. Dating from 2.5 to 2.0 million years ago. The lasting argument for this to remain a separate species is the fact that it come from East Africa, where very few fossils are found during this period.

A.R. aethiopicus

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The oldest of the Robust Australopithecines, this species has the most prominent cranial crest of all these robust species. Aethiopicus is dated to approx. 2.5 million years ago. This is a much debated species as so few specimens are attributed to it, and many will say that is an early form of other Robust Australopithecines.

A.R. boisei

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Discovered in 1959 in the Olduvai valley, boisei is the “youngest” or most recent evolution of the Robust Australopithecines, dating from approx. 2.3 to 1.2 million years ago. This is one of the most successful robust species both by longevity and by the spread of the species. This appears to be a highly specialized species with a very large mandible and dentition most likely used for hard foods such as nuts, berries and roots. A sudden change in environment may have caused their extiction.

A.R. robustus

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A.R. robustus was first discovered in 1938. Living at the same time and at the same region as A. africanus, many have speculated that these individuals may have interbred. Many theorize that these competing species may have specialized and grown apart due to competition for food and other resources. They are still considered by many to be separate species, due to the large number of differential traits. Like all robust australopithecines, robustus has a large and prominent crest atop the skull that is used as muscle attachment for its enlarged mandible.

Sahelanthropus tchadensis

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Little is known yet of this recent find, other that it was found in a layer of strata typical of the oldest hominid species. Yet unlike the oldest hominid fossils, tchadensis has many more modern features. Could this be the proverbial “missing link”?

Kenyanthropus platyops

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Discovered in 1998 on the shores of Lake Turkana, and first described in 2001, Kenyanthropus lived approx. 3.5 million years ago. This reconstructed skull shows a full range of traits that are both advanced and primitive, placing it in the line to be a possible human ancestor.

Ardipithecus ramidus

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Originally placed with other Australopithecines, this hominid has recently been placed into a genus of it’s own due to features not seen in other Australopithecines. Living between 4.5 and 4.2 million years ago, this could end up being one of our earliest ancestors. Mandible and post cranial skeleton fragments found.