The Early Hominins Flashcards
What percentage of humans genes are shared with chimpanzees?
98.7%
What does the small genetic difference between humans and chimps result in?
results in enormous differences between us as species
How many species of Homo do we have on this planet?
We are unique – for all our diversity, there is only one species of Homo on the planet – that is us, Homo sapiens
What makes humans unique?
- Habitual bipedalism
- Large brain size (relative to body size)
- Large capacity for planning and problem solving (thinking in the abstract)
- Tool making
- Great social complexity
- Complex language
When did human lineage split from chimp lineage?
Molecular evidence suggests that the lineage that led to modern humans split from the chimp lineage only about 5-7 Mya.
Whats a chimp?
Chimpanzee
What has happened to humans in the 5-7 million years since we split from the chimps?
the human lineage underwent some profound evolutionary changes to bring us to where we are today
Define hominid.
the group consisting of all modern and extinct Great Apes (i.e. modern humans, chimpanzees, gorillas and orang-utans plus their immediate ancestors)
Define hominin
the group consisting of modern humans and extinct species on the human lineage since our divergence with the apes
Why is the hominin lineage confusing?
- It is more of a ‘bush’ with numerous branches than it is a simple linear progression from earliest hominin to modern human
- The dates of the various important fossil discoveries do not reflect the timeline of hominin evolution
- The paucity of fossil evidence in many cases and over certain time periods
- Species are reclassified and renamed
What was Raymond Dart presented with in South Africa in 1924?
the immature skull of a small-brained creature extracted from a South African mine. This was named the Taung child.
What was the first discovery of an early hominin ?
The Taung child
Whats the Taung child?
The skull found by Raymond Dart in 1924 in south africa in a mine.
Why was the Taung child named the Taung child?
It was named the Taung child, after the site where it was found.
What did Raymond Dart call the Taung child?
Australopithecus africanus (“southern ape from Africa“)
Whats the Taung child also known as?
Australopithecus africanus (“southern ape from Africa“)
What was Australopithecus africanus contested to be?
originally this was hotly contested as being a precursor to humans.
What were researchers convinced of about human evolution?
Researchers were convinced humans evolved in Asia (Eurocentric), not Africa (despite little evidence from either region)
What were there preconceived ideas about?
There were preconceived ideas about what characteristics a human ancestor would have.
What did Australopithecus africanus look like?
Some features quite ape-like -
it had a protruding face and small brain.
Other features were not ape-like (e.g. dentition)
What features of Australopithecus africanus were ape like?
protruding face and small brain.
What features of Australopithecus africanus were not ape like?
dentition
What do the anatomical features of Australopithecus africanus show?
Anatomical features (position of the foramen magnum) indicated it walked upright on two legs (bipedal)
Define bipedal.
Walking upright on two legs.
What are key anatomical features of Australopithecus africanus?
position of the foramen magnum.
What was the estimated age of the Taung child?
3.3 to 2.1 million years
Was Taung child / Australopithecus africanus bipedal?
Yes.
Describe the anatomical features of Australopithecus robustus (later Paranthropus robustus).
- much more heavily built
- They had large, heavy jaws and teeth, no forehead and low cranial dome
When was Australopithecus africanus found?
1924
When was Australopithecus robustus (later Paranthropus robustus) found?
1938
Whats the estimated age of Australopithecus robustus (later Paranthropus robustus)?
1.8 - 1.2 million years.
What was Australopithecus robustus later renamed as?
Paranthropus robustus
What was accepted in 1947 by the European scientific community?
- Australopithecus africanus was finally accepted as a hominin by the European scientific community in 1947
- Africa was also accepted as the probable origin of the human lineage
What did Louis and Mary Leakey discover in 1959?
discovered a robust hominin and called it Zinjanthropus boisei (“Zinj”) but it was later renamed Paranthropus boisei.
What was Zinjanthropus boisei renamed as?
Paranthropus boisei.
What did Paranthropus boisei inhabit?
inhabited the dry savannah grasslands of Eastern Africa from 3.2 - 1.2 mya
How long ago did Paranthropus boisei exist?
3.2 - 1.2 mya
Describe the skull of Paranthropus (Australopithecus) boisei.
had a skull highly specialized for heavy chewing
What was Paranthropus (Australopithecus) boisei believed to be responsible for?
Because some remains were found in the same stratigraphic layers, it was originally thought to be the species responsible for making the stone tools found in Olduvai (now known as Oldowan tools and the oldest known). It is now known that this is not the case.
What were the tools found in Olduvai called?
Oldowan tools
What were the oldest kind of tools made?
Oldowan tools
When was Australopithecus afarensis found?
1974
How was Australopithecus afarensis found?
- a large part of a female hominin skeleton was found.
- The skull was missing but there was part of the lower jaw and about 40% of the post cranial skeleton.
Who found Australopithecus afarensis?
Don Johansen
What was missing from the Australopithecus afarensis fossil?
The skull was missing but there was part of the lower jaw and about 40% of the post cranial skeleton.
What did the Australopithecus afarensis fossil become known as?
Became known as “Lucy”
Where was Australopithecus afarensis fossil found?
in the Awash River valley, Ethiopia
How old was Australopithecus afarensis (Lucy) estimated to be?
3.0 – 3.9 Millions years old
What did the Prehistoric autopsy on Lucy show?
Lucy was a small adult female, about 1.5 m tall, weighed about 30kg and had a brain capacity of 380 – 500cc (modern H. sapiens about 1300cc)
When was Australopithecus anamensis found?
1995
Where was Australopithecus anamensis found?
at Allia Bay and Kanapoi, Kenya.
What did the Australopithecus anamensis findings from Kanapoi include?
The Kanapoi finds included upper and lower jaws, cranial fragments, and the upper and lower parts of a tibia.
How old is Australopithecus anamensis estimated to be?
Dated at 3.9 – 4.2 My old.
What was discovered in August 2019 in Ethiopia?
A complete skull was discovered in Ethiopia. The skull was attributed to A. anamensis, a species for which only a few fossils have previously been found.
Was A. anamensis or A. afarensis more primitive?
A. anamensis is more primitive than Lucy but it appears the two species were contemporaries for about 100,000 years.
When was Australopithecus bahrelghazali found?
1995
How long ago did Australopithecus bahrelghazali live?
Estimated to have lived 3.5 Mya
Why is so little known of the Australopithecus bahrelghazali?
Findings comprises only a portion of the lower mandible
What do some argue about the Australopithecus bahrelghazali?
Some argue it is actually A. afarensis and its status as a separate species is questioned but can’t be substantiated because there are so few remains.
Why is the finding of the Australopithecus bahrelghazeli fossil so significant?
Significant because:
- It was the furthest west a fossil hominin had been found.
- If it is a different species, it
suggests that A. afarensis was not the only hominin living at this time
When was Ardipithecus ramidus found?
1994
How were the remains of Ardipithecus ramidus?
The remains were fragmentary
and fragile but some anatomical
features suggested that A. ramidus was a hominin.
Fifteen years of excavation and study have now uncovered remains representing …
…110 specimens
What do the Ardipithecus ramidus
specimens include?
The specimens include a partial female skeleton
What did the partial female skeleton of Ardipithecus weight and how tall was it?
weighed about 50 kg and stood about 1.20 m tall.
How old is A. ramidus estimated to be?
A. ramidus is dated at 4.4 million years old
Is A. ramidus or A. afarensis more primitive?
This species is substantially more primitive than Australopithecus afarensis (Lucy).
What was Ardipithecus Ramidus nicknamed?
Ardi
What is the most significant find since lucy?
Ardi
What did Ardi shed light on?
shed light on numerous questions about the anatomy, habitat, diet and behaviour of the earliest hominins.
When was Australopithecus garhi found?
1996
Where was Australopithecus garhi found?
Ethiopia.
What size was A. Garhi brain?
450 cc (small-brained)
How old A. garhi?
estimated to be 2.5 My old.
Describe the dental features of A. garhi.
Some dental features are quite human-like
What may A. Garhi have used?
may have used the world’s earliest known stone tools. Although there is no direct evidence for this.
What is the evidence for A. garhi being the species that used the earliest stone tools?
There is no direct evidence that A. garhi did use stone tools, but the cut-marks on antelope bones found in association with A. garhi do provide circumstantial evidence.
What might A. garhi represent?
A. garhi may represent the evolutionary step between A. afarensis and Homo.
When was Homo habilis found?
Early 1960s
Where was Homo habilis found?
Olduvai Gorge
What does Homo habilis mean?
handy man
What did leaky become convinced of about Homo habilis?
Leakey was convinced he had finally found the maker of the Oldowan tools.
WHats the estimated age of H. habilis?
Dated at 2.4 - 1.4 M years old
What is H. habilis considered to be?
considered to represent the beginning of the Homo line (where hominins that led to Homo sapiens branch off from the Australopithecines).
Why is homo habilis considered to represent the beginning of the Homo line.
This is partly because it is with H. habilis that we begin to see a trend toward increasing brain size in hominins.
When was Homo rudolfensis found?
1972
Where was Homo rudolfensis found?
Lake Turkana (formerly Lake Rudolf - hence the name)
How old are the Homo rudolfensis specimens?
H. rudolfensis specimens have been dated at 2.4 - 1.6 my old.
What was Homo rudolfensis a contemporary with?
possibly contemporary with H. habilis and the distinction between the two is not always clear.
What are Non- Australopithecine specimens from Olduvai generally considered to be?
H. habilis.
What are Non- Australopithecine specimens from Turkana generally considered to be?
Divided between H. habilis and H. rudolfensis
Are H. habilis and H. rudolfensis ancestral to humans or is this unclear?
It is not clear which of them (if either) was ancestral to humans
When were the first findings of homo erectus fossils?
in the late 19th and early 20th century. At the time, they were not recognised as early hominins.
What does Homo erectus mean?
upright man
Where were fossils of Homo erectus found?
Indonesia and China (“Java man” & “Peking man”)
Where have discoveries of Homo erectus fossils been made since the 1950s?
Since the 1950s, discoveries of H. erectus fossils have been made in Africa (Algeria, E. Africa & S. Africa) and also in Asia.
Whats the most famous example of H. erectus?
“Turkana boy” (‘Nariokotome boy’), an almost complete skeleton found in 1984 by Leakey’s team near Lake Turkana.
WHats the brain capacity of Homo erectus?
880cc
Whats the body of H. erectus like?
his stature (tall, thin, long arms and legs) are typical of humans adapted to open, tropical environments.
Estimated age of H. erectus?
1.6 my old.
Whats one of the most oldest specimens of H. erectus?
Turkana boy is one of the oldest specimens of H. erectus.
What is identified 1.6 mya?
1.6 million years ago, an advance in stone tool technology is identified with a species called Homo ergaster, from Africa.
Anatomically, H. ergaster is similar to…
Homo erectus.
When was Kenyanthropus platyops found?
1999
HOw old is Kenyanthropus platyops ?
3.5 my old
How old is Orrorin tugenensis fossil?
5.8 - 6.0 my old.
When was Orrorin tugenensis found?
the year 2000
What might Kenyanthropus platyops represent?
a completely new genus and species of early human ancestor.
What does Kenyanthropus platyops mean?
“Flat-faced man from Kenya”.
How old is the Sahelanthropus tchadensis fossil/cranium believed to be?
Close to 7 my old.
What was Sahelanthropus tchadensis nicknamed?
Toumai
What is debated about Orrorin tugenensis?
SOme say its a hominin but not all experts are convinced.
Where was Sahelanthropus tchadensis found?
Chad, southern Sahara.
Where was Orrorin tugenensis found?
Tugen Hills in northen Kenya.
When was Sahelanthropus tchadensis found?
2001
Whats the brain size of Sahelanthropus tchadensis?
320-380 cc.
What exactly was the fossil of Sahelanthropus tchadensis?
a mostly complete cranium with a small brain (320 - 380cc)
WHat features did Sahelanthropus tchadensis
have?
Human like and ape like features.
What were the ape like features of Sahelanthropus tchadensis?
It has some ape-like features (low-domed and elongated skull, small brain size.
What were the human like features of Sahelanthropus tchadensis?
It has features considered to be more advanced (small canines and thick tooth enamel - a human characteristic) and a relatively short face.
What does Brunet think about Sahelanthropus tchadensis?
Brunet considers Toumai to be a hominin (i.e. the human side of the chimp-human split) but this is not at all certain at this stage.
Have their been post-cranial findings of Sahelanthropus tchadensis?
There are no post-cranial remains to date. Just the mostly complete cranium.
How does the discovery of Sahelanthropus tchadensis affect the hominid lineage?
The discovery of Sahelanthropus pushes the homind lineage back close to the estimated human-chimp divergence.
When was Homo floresiensis fossil found?
2003
Where was Homo floresiensis fossil found?
Island of flores.
What did the findings of Homo floresiensis consist of?
a nearly complete female skeleton of a tiny human that lived about 18,000 years ago
How long ago did Homo floreiensis live?
18,000 years ago.
What was Homo floreiensis nicknamed?
the Hobbit
What is the origin of Homo floreiensis?
Their origin is unknown (they are possibly a remnant population of Asian H. erectus) but how they got to Flores is a mystery.
When was Autralopithecus sediba found?
2008
Where was Autralopithecus sediba found?
Malapa fossil site in South africa.
What did the fossil of Autralopithecus sediba consist of?
Full skull pieced together. Clavicle and mandible initally found, then skull found following year.
What was the body of Autralopithecus sediba like?
1.27 meter tall, juvenile male.
Estimated age of Autralopithecus sediba?
2 million years old.
A. sediba shows features suggested by Berger to be…
…transitional between the australopithicines and Homo
What species showed features which are suggested to be transitional between australopithicines and Homo?
Autralopithecus sediba
Describe the physical features of Autralopithecus sediba?
- The arms and shoulder features are primitive and suggest a predominantly arboreal lifestyle but the hand has features that would allow a precision grip suggesting it might have been a tool-makingAustralopithecine.
- Dentition appears most similar to early Homo
- Lower limbs have features that suggest it could walk upright
- Grapefruit brain size: so was starting to develop more advanced neural circuits.
- Ankle joints mostly like humans, but heel and shin bone are mostly ape like.
- Pelvis suggetss that biomechanics of walking played a bigger role in development than demands of child birth and the need to accommodate larger brained infants.
What was A. sediba considered to be in human evolution?
A unique experiment in human evolution.
Where was Australopithecus deyiremeda
found?
near Hadar (Ethiopia)
When was Australopithecus deyiremeda
found?
2011
What Australopithecus deyiremeda fossils were
found?
two lower jaws and some bone fragments of
What does Australopithecus deyiremeda mean?
“close relative”
Estimated age of Australopithecus deyiremeda?
between 3.3 and 3.5 my old
What might Australopithecus deyiremeda
have been a contemporary of?
A. afarensis (Lucy). Or may be the same species?
What are the most likely contenders for the ancestor of early Homo and humans?
- Until recently, Lucy.
- Now?? Kenyanthropus platyops, Australopithecus sediba?
- Or something else still waiting to be discovered?
Describe body of Sahelanthropus tchadensis?
Adaptations for walking bipedally.
Smaller canine teeth.
Describe body of Australopithecus aferensis.
Enlarged cheek, teeth, and jaws
Describe body of Paranthropus.
- Massive cheek, teeth, and jaws.
- Enlarged chewing muscles.
Describe body of homo habilis.
- Slightly larger brain (600 cc).
- More vertical face
- No snout
- Fingers with precision grip
- Ability to make simple stone tools for processing food eg meat
Whats the brain size of Homo habilis?
600 cc
Describe body of Homo erectus.
- Smaller jaws and cheek teeth
- long legs and arched feet, well suited for long-distanced running and walking
- Larger brain (650 cc - 1200 cc) than homo habilis
What was brain size of homo erectus?
650 cc - 1200 cc
Describe body of Homo neanderthalensis and Homo hefdelbergensis.
- Sophisticated stone flakes
- Could make tools for hunting
- Larger brain size (1200 cc) than homo habilis and homo erectus.
Describe body of Homo sapiens.
- Large brain (1400 cc), larger than any other Homo.
- Small face tucked below brain case.
- Rounded cranial vault
- Small brow-ridges
- Capacity for art
- Symbolic thought
- Full blown language.
Whats the brain size of Homo neanderthalensis and Homo hefdelbergensis?
1200 cc
Whats the brain size of Homo sapiens?
1400 cc
