For exam, lecture 1 Flashcards
when did hominids show up
Pliocene
why did hominids show up in the pliocene
is the start of the change in climate that resembles more modern climate… have a cooling and doing out of the vegetation… conditions that are favourable to the hominin line are showing up
what is significant about the East African Rift System
facilitated the fossilization of a number of known hominin specimens.
where is the East African Rift System
The rift runs from the Afar Depression in NE Ethiopia, south to Malawi, and is typified by rift valleys and both active and inactive volcanoes
how is a rift valley created
A rift valley is created by magma forcing tectonic plates apart, creating a collapsed area between the flanks of the plates
Over time, the walls of the rift valley continue to erode, encouraging fossilization through periodic inundation and collapse
what is believed to be our direct ancestral line
Australopithecines
where are Australopithecines fossil remains are found
Their fossil remains are found only in East and Southern Africa
is there evidence Australopithecines migrated into Eurasia
no
how many species are included in the genus Australopithecus
5
which species are included in the genus Australopithecus
Au. anamensis (4.2–3.9 mya) Au. afarensis (3.6–3.0 mya) Au. garhi (2.5 mya) Au. africanus (3.0–2.2 mya) Au. sediba (1.98 mya)
what are the two areas Australopithecus are found
in east and southern africa
which species are found in east africa
Au. anamensis (4.2–3.9 mya)
Au. afarensis (3.6–3.0 mya)
Au. garhi (2.5 mya)
which species are found in south africa
Au. africanus (3.0–2.2 mya)
Au. sediba (1.98 mya)
when did Australopithecus anamensis exist
4.2-3.9 mya
wh first described Au. anamensis
Mary Leakey
where was Au. anamensis found
northern Kenya’s Great Rift Valley in 1994
what is the name Au. anamensis derived from
derived from “anem,” which means “lake” in Turkana.
what are the notable specimens of Au. anamensis
- part of an upper palate with canine teeth;
- part of a mandible with teeth;
- proximal and distal ends of a tibia (lower leg bone).
so far how man specimens and individuals have been recovered from the Lake Turkana area in Kenya and from Middle Awash, Ethiopia of Au. anamensis
than 80 specimens from around 20 individuals
what is the earliest known member of the genus Australopithecus
Au. anamensis
what is the Dentition of Au. anamensis
Dentition is generally primitive, and indicates a diet of fruits, nuts and roots. Molar rows are parallel, and the dental arcade is U‐shaped. Canine teeth are small, overall, but still show sexual dimorphism. Dental enamel is thick
what is the upper pallet like in Au. anamensis
The upper palate is shallow compared to later hominins and humans
what is the external auditory meatus (ear canal) like in Au. anamensis
is elliptical –- an ape-like trait.
what is important about ear canals in fossils
that you can see on the outside of the cranium… one of the traits that helps to put the species in the phylogeny with other hominis
how did Au. anamensis move and what proof Is there
Evidence for bipedalism is strong, but indirect. The proximal tibia shows signs of excess weight bearing. The distal tibia is wide and thick, acting as a shock absorber.
The arms are relatively long, indicating strong climbing ability.
The shape of the lower tibia suggests the femurs were angled, a feature of bipeds
what is Au. anamensis’ relationship to Ardipithecus
undetermined
Most researchers believe Au. anamensis is a direct ancestor of what
Au. afarensis
A minority of researchers believes the known Au. anamensis specimens should actually be re-‐ classified as what
Au. afarensis
when did Australopithecus afarensis exist
3.6-3.0 mya
what is is easily the best-documented australopithecine in the fossil record
Australopithecus afarensis
what is Australopithecus afarensis named for
The species is named for the “Afar” depression in which Hadar is situated