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.
