For exam, lecture 2 Flashcards
what do We informally refer to Australopithecines as
the ‘gracile’ or omnivorous line, since their dentition indicates a more generalized adaptation to a broader diet (meat, plants, fruit)
in general, what is is defining feature of Australopithecines
molars and pre-molars are smaller than those we find with the Paranthropines, or ‘robust’ line
when did the genus Paranthropus exist
2.7-1.2 mya
where are the Paranthropus distributed
This genus includes three species, distributed throughout both East and Southern Africa
what species fall under Paranthropus and where were they found
In East Africa: P. aethiopicus (2.7 - 2.5 mya) P. boisei (2.3 – 1.2 mya) In Southern Africa: P. robustus (2 – 1.5 mya)
Paranthropines are likely descended from what
Au. afarensis
are Paranthropines believed to be on a direct ancestral line with the genus Homo
no
did Paranthropines branch out?
This hominin line is believed to have died out completely around 1 mya; there are no direct living primate descendants of the paranthropines
The morphological differences between paranthropines and australopithecines raises the question about what
how genera and species are defined
how could We choose to define species
according to the terms already discussed in this class: individuals capable of producing fertile offspring
or
Alternately, we could define species in more general terms: individuals sharing similar environments, behaviors and – by extension – genotypes and phenotypes
what are Lumpers vs Splitters
Informal terms that refer to opposing philosophies in any discipline that categorizes individuals
what is the Splitter Perspective
Emphasizes differences between individuals, resulting in a greater number of taxonomically defined species.
Should result in a phylogenetic tree that is more bushy, i.e. more branches
what is the Lumper Perspective
Emphasizes similarities between individuals, resulting in fewer number of taxonomically defined species.
Should result in a phylogenetic tree that is thinner, i.e. has fewer branches
what did Tim White argue
Tim White (2003) paper - “Early Hominids: Diversity or Distortion” argued that ALL fossils from 3.7 to 2.9 MYA represented only 1 species, A. afarensis
when did Paranthropus aethiopicus exist
2.7-2.5 mya
Fossil fragments of P. aethiopicus were first discovered where
in Omo, Ethiopia in 1967
what is P. aethiopicus sometimes referred to as
The species is sometimes (though not commonly) referred to as P. walkeri, after Alan Walker, the discoverer of its most significant fossil specimen: a partial cranium (well-‐dated to around 2.5 mya), known widely as ‘the Black Skull’ (KMN-‐WT 17000).
what is the cc of P. aethiopicus
410 cc
what is the Cranial Morphology of P. aethiopicus
A prominent sagittal crest (presumably only on males) anchors large temporalis muscles.
Cranial capacity is very low (around 410 cc) and the forehead is strongly sloping—indicating less development in the frontal part of the brain.
There is severe postorbital constriction.
The face is wide and flat.
The zygomatic arches are flaring, leaving ample room for the temporalis muscles.
There is a high degree of facial prognathism, though less than in the australopithecines.
Exhibits “post-canine megadontia” (i.e. great enlargement of the premolars and molars)
when did Paranthropus boisei exist
2.3-1.2 mya
who found the first P. boisei specimen and where
The first P. boisei specimen was found in 1959 by Mary Leakey at Olduvai, Kenya
It was the partial cranium of a male, more robust than any hominin that had been found in E. Africa to that point.
what was the largest and most robust of the paranthropines
P. boisei was by far the largest and most robust of the paranthropines
what are the Notable specimens include of paranthropines
- Olduvai hominin 5 (OH5), Leakey’s original cranium, dating to 1.8 mya;
- L74, a very robust jaw found at Omo, Ethiopia, dating to around 2.3 mya;
- A 1.8-million-year-old female skull from Koobi Fora, Kenya
what is the cc of paranthropines
Low cranial capacity (500-520 cc);
what is the Cranial Morphology of paranthropines
Severe postorbital constriction; Low vault elevation above orbits; Well-developed supraorbital tori; A wide, long, flat face; Flaring zygomatic arches; A moderate degree of facial prognathism; Very large molars
when did Paranthropus robustus exist
2.0-1.5 mya
who discovered Paranthropus robustus and where
Typified by a cranium discovered by Robert Broom in 1938, P. robustus is known from several specimens from the Southern African sites Kromdraai and Swartkrans
where do All P. robustus specimens come from
All P. robustus specimens come from cave sites, and have uncertain dates
Notable specimens of P. robustus (all recovered from Swartkrans) include
- An upper and lower jaw (from two separate individuals);
- A right adult innominate (pelvic half);
- Robert Broom’s partial cranium, which has been heavily disturbed by erosion, and (tenuously) dates to between 2 and 1.5 million years old
what is the cc of P. robustus
Low cranial capacity (~500 cc);
what is the cranial morphology of P. robustus
Severe postorbital constriction; Very low vault elevation above orbits; A wide, long, flat face; Flaring zygomatic arches; A moderate degree of facial prognathism; Very large molars with thick enamel; Relatively small incisors and canines
did P. robustus use tools
Possible evidence for tool use comes from Swartkrans, in the form of “digging sticks”
Use-wear analysis (i.e. traceology) suggests animal bones were used to access termites from mounds as a source of protein
what is the difference in cranial morphology between Australopithecus and Paranthropus
Australopithecus–
Narrow cranium, with moderate vault elevation above orbits.
Sagittal crest is generally absent in males.
Weak supraorbital tori and variable facial prognathism.
Molars are small or intermediate in size; canines are jutting and large.
Dentition is generally better suited to leaves, fleshy fruits and meat
Paranthropus–
Broad cranium, with very low vault elevation.
Sagittal crest is generally present in males. A flat face, strong supraorbital tori
and variable facial prognathism.
Molars are thick with strong enamel; canines are in line with the overall dental arcade.
Dentition is better suited to tough, fibrous vegetation, such as roots, tubers and nuts
when did Kenyanthropus platyops exist
3.5-3.2 mya
what is one of the most difficult hominins to classify.
K.platyops, described by Meave Leakey in 1999, is one of the most difficult hominins to classify
why is K.platyops so difficult to classify
Its cranial morphology combines traits of paranthropines and australopithecines
is the K.platyops its own genus?
Because of its unique combination of characteristics, it was somewhat controversially ascribed its own genus— Kenyanthropus (‘Kenya Man’). It’s species name, platyops, is derived from the Greek for ‘flat face.’
what is the cc of K.platyops
Low cranial capacity (~450cc);
what is the cranial morphology of K.platyops
Severe postorbital constriction;
Relatively high vault elevation above orbits;
Somewhat gracile supraorbital tori;
A narrow, but flat face;
Non-flaring zygomatic arches;
A moderate degree of facial prognathism;
Small molars
what do Scientists disagree over when it comes to Keynathropus
Scientists disagree over whether Keynathropus is a flat-faced species of hominin or just a distorted example of Australopithecus afarensis
what is the relationship between Keynathropus and Laetoli footprints
It’s been proposed that given the timing of Kenyanthropus in East Africa, it – and not Au. afarensis – may be responsible for the Laetoli footprints, which date to around 3.7 mya. The evidence for this is e n t i re circumstantial
what is the Paranthropine Legacy
Overspecialisation and reliance on hard-object feeding likely caused Paranthropines to go extinct.
Increasing climatic fluctuations in the Pliocene meant Paranthropines’ food sources became unpredictable
when did Homo (genus) exist
2.8 mya to present
what species go under homo
Traditionally, researchers have divided the genus Homo into three chronospecies:
H. habilis
H. erectus
H. sapiens
Of course, today, we know speciation within our genus has produced more than a handful of separate human species, of which we are the only surviving example
what is the association between tool creation/use and brains
There is a clear association between tool creation/use and higher brain function
Most (if not, all) tools fashioned and used by apes are what in nature
expedient in nature
Typically, the more time devoted to producing an artifact, what happens
Typically, the more time devoted to producing an artifact, the more apparent the object will be, if taphonomic processes haven’t interfered
what is the problem with Taphonomy and Preservation for tools
an unmodified tool with little-to-no usewear will not stand out as an artifact.
A more significant problem for our purposes is that the vast majority of very early expedient and possibly more complex tools are presumed not to have preserved, due to various taphonomic processes. Organic materials are especially susceptible.
We will refer to this as the preservation bias in hominin technology
what is preservation bias in hominin technology
an unmodified tool with little-to-no usewear will not stand out as an artifact.
A more significant problem for our purposes is that the vast majority of very early expedient and possibly more complex tools are presumed not to have preserved, due to various taphonomic processes. Organic materials are especially susceptible.
We will refer to this as the preservation bias in hominin technology
The earliest known stone tool technology dates to around what
3.3 mya—actually predating our genus (species undetermined)!
The earliest tool types were very rudimentary in design. They consisted of three general categories of tool type which are
- Cores (choppers, discoids)
- Unmodified flakes (scrapers)
- Hammerstones
what is Oldowan Tradition
tool industry
By around 2.3-2.1 mya, this basic style of production—known as the Oldowan Tradition—becomes widespread in E. Africa
In areas where conditions for fossil preservation are good, sites with Oldowan tools feature what
broken animal bones, or bones with butchery
There are two primary hominin suspects for the earliest habitual use of Oldowan technology, what are they
- Au. garhi (2.5 mya)
2. H. habilis (2.1-1.5 mya)
While the timing of the earliest Oldowan tools precludes H. habilis as a creator of the technology, what is clear
it is clear the species was a prolific user.
when did Homo habilis live
2.1-1.5 mya
where were specimens for H. Habilis live
First specimen (OH7) discovered at Olduvai Gorge, Tanzania Most specimens are from either Olduvai or Koobi Fora, Kenya
what is the nickname for H. habilis
Oldowan stone tools associated with H. habilis remains earned this hominin the nickname “handy man.”
what is the cc of H. habilis
500-600 cc, the first hominin with brain size expanded beyond known ape range
what is the cranial morphology of H. habilis
Rounded crania with a rising forehead, with cranial capacity of 500-600 cc, the first hominin with brain size expanded beyond known ape range
The face is narrow and small; reduced prognathism when compared to Australopithecines
Compared to Australopithecines, H. habilis had wider parabolic dental arcade, reduced canines, deeper palate, relatively small and narrow molars
why is the classification for H. rudolfensis difficult
The Olduvai H. habilis specimens all undoubtedly belong to the same species. The situation is more complicated further north at Koobi Fora, where a large number of hominins may have shared space between 2 and 1 mya.
One of these hominins was the habilis-‐like H. rudolfensis
when did Homo rudolfensis live
2.4-1.5 mya
where was Homo rudolfensis found
Found at Koobi Fora and (possibly) one site in Malawi
how tall was H. rudolfensis
About 1.5 m in height; limbs similar to modern humans
what is the cc of H. rudolfensis
Cranial capacity of 600-‐800 cc
what is the cranial morphology of H. rudolfensis
A flat, wide face with moderate facial prognathism.
Molars are thick and the jaw is robust, as with paranthropines
Though the classification of H. rudolfensis was at one time controversial, there is now consensus that the cranial morphology is unique enough to warrant a separate species designation
In addition to H. habilis and H. rudolfensis, Oldowan tools may have been utilized by what.
paranthropines living nearby
Today, we believe Oldowan tool makers/users were of what diet
both scavenging for meat and foraging, a broader concept of “gathering,” the collection of roots, leaves, fruits, nuts, seeds and insects.
why is scavenging a practical hypothesis
Scavenging would likely not have included driving predators off their kills, or competition over carrion with larger scavengers
This would have allowed access only to carcasses picked clean of large-to- medium sized packages of meat
what evidence is there that Oldowan tool makers/users scavenged
The evidence for this lies in the fact that at all known hominin sites with both Oldowan tools and preserved animal bones, the bones have been broken for marrow extraction. This would not necessarily have been done if other fat and protein was available
when and why did Animal fat and protein become more important to the diet
Animal fat and protein may have become more important to the diet at around 2 – 1.5 mya because larger brains require an increased amount of energy that can be obtained only through some dietary fats
