ANTH 1001 Chapter : UNIT 3
UNIT 3 10/31/2012 3:28:00 PM
Terms
Lumpers – paleoanthropologist who wants to combine fossils into the
fewest # of species possible.
Splitters – they want to split the # of species into as many as possible,
emphasize the differences and increase the # of fossil species that are
named.
Gracile – a species that has small muscle attatchments. The areas where
muscle attaches tends to be smooth and rounded.
Robust – large muscle attachment areas. Sharp projections at attachment
points and they are bigger or thicker bone.
Does not necessarily talking about height, they are built differently.
Spoiler – referring to a fossil that is found that kinds of ruins the current
view (challenges that traditional understanding) of the fossil record.
Post-Orbital Constriction – POC, orbital refers to eye orbits and post is
behind. Refers to the narrowing of the skull immediately behind the eye
orbits. A high amount is associated with smaller brains, modern human
skuls do not have constriction.
Supra-Orbital Torus – SOT, an enlarged area of bone above the eye orbits.
Modern humans do not have, apes do. “brow ridge”.
Prognathism/Orthognathism - Anterior projection of the maxilla / a
vertical maxilla or a nearly vertical maxilla (more human trait).
Sagittal Crest – an enlarged area of bone that is located on the top of the
skull and it runs anterior to posterior (front to back). Primitive characteristic,
adult male gorillas, a muscle attachment site.
Nuchal Crest – an enlarged ridge of bone in the back of the skull. Where
neck muscles attach.
Paleoanthropology …
Most early fossils (Hominin) are found ONLY IN AFRICA.
EAST AFRICA: geology impacts the preservation and dating methods. They
have rift valleys (two continental plates together) so you have a lot of
volcanic activity and earthquakes. This is a good env for fossil preservation.
This impacts dating methods bc potassium argon can be used to find an
absolute (numberical) date.
SOUTH AFRICA: there is a lot of lime stone formation and below ground
caverns. Fossils have been found through quarrying activities . preservation
is good but difficult to extract bc they are found on Breccia (hard cement
like substance – sand, debris, lime stone, etc. ). There aren’t many absolute
methods that can be used, they use Biostratigraphy the most. D to use more
relative dating methods.
Miocene Fossils:
Sahelanthropus tchadensis – 7-6mya, (KNOW THIS DATE) this is the oldest
fossil that MAY BE associated with Hominins, it is definitely a hominid. Found
in central Africa. “Primative” cranium, it’s ape-like. Small brain, POC,
sagittal crest, nuchal crest, SOT. It has a relative flat maxilla and small
canine teeth making it less ape-like. This individual was possibly bipedal bc
of the positioning of the foramen magnum.
Ardipithecus ramidus – (Ardi) this species was named in the early 1990s.
they have at least 9 different individuals represented in this species but Ardi
was the most significant (40% complete) representation on the species. Mix
of ancestral and derived traits: anscetral = small (3.5 feet tall), small brain,
relatively gracile, more smooth nuchal region and almost no sagittal crest,
inbetween pelvis shape, opposable big toe, elongated arems. Derived = no
adaptation for knucklewalking, not a true brachiator, funky pelvis,. Definitely
a hominid, somewhat bipedal, wasn’t a good knucklewalker, doesn’t look
anything like a chimpanzee.
Miocene/Pliocene fossils
Ardipithecus ramidus (“Ardi”)
5.8-4.4 mya
“mix” of ancestral and derived traits:
-ancestral= small(3.5 ft tall), small brain, relatively gracile, more smooth
nuchal region and almost no sagittal crest, in between pelvis shape,
opposable big toe, elongated arms
-Derived: no adaptations for knuckle walking, not a true brachiator, a
hominid. Somewhat bipedal. Doesn’t look like a chimp
Interpretation- still up in the air
Pliocene Fossils
Kenyanthropus platyops
East Africa (Kenya)- anthropus (ape-man) Platyops (flatness in face)
“spoiler”- date and derived features make it a better candidate for a human
ancestor; More hominin-like
Australopithecus/ “southern ape”
• A. Afarensis
• East Africa around Ethiopia, and Kenya
• Characteristics:
o Cranial Traits- have a small brain and with there small brain
have post orbital constriction and have small to moderate size
crest. And Super orbital
▪ Prognothic
▪ Large molars and canines.
o Postcranail- Short, do not have flattened hips or rounded
hips. Somewhere in between. Long femoral neck, and wide
bicondylar angle. Have adaptation for knuckle walking. Long
arms compared to length of legs.
• “Lucy” (AL-288-1): A. Afarensis
1.completeness makes it important→ well represented.
2. adaptation for bipedalism (pelvis and femur)
• “Selam” (DK 1-1) A. Afarensis
Well represented skeletally (even more so than lucy)
-It is a skeleton of a child.
• Laetoli- site
-East Africa- Tanzania
-Foot prints of a biped walking across the savannah that was
preserved by volcaninc ash.
-Spoiler: Attributed as an Afarensis site because they were the only
bipeds walking around at the time- but could be a Kenyathropus
Platyops
Australopithecus
A. Africanus
Document Summary
Lumpers paleoanthropologist who wants to combine fossils into the fewest # of species possible. Splitters they want to split the # of species into as many as possible, emphasize the differences and increase the # of fossil species that are named. Gracile a species that has small muscle attatchments. The areas where muscle attaches tends to be smooth and rounded. Sharp projections at attachment points and they are bigger or thicker bone. Does not necessarily talking about height, they are built differently. Spoiler referring to a fossil that is found that kinds of ruins the current view (challenges that traditional understanding) of the fossil record. Post-orbital constriction poc, orbital refers to eye orbits and post is behind. Refers to the narrowing of the skull immediately behind the eye orbits. A high amount is associated with smaller brains, modern human skuls do not have constriction. Supra-orbital torus sot, an enlarged area of bone above the eye orbits.
