Hominin Evolution Flashcards
Dating, classification, evolutionary processes
What are the 2 main types of dating in archaeology?
relative and absolute
define relative dating
gives a sequence of “older” and “younger” without absolute times/dates
define absolute dating
provides calendar dates for sites
what is another name for absolute dating?
chronometric
what are the 2 types of relative dating?
stratigraphy and seriation
define stratigraphy
using the law of assumption
define seriation
based on the how much or how little we see patterns in artifact styles over time
what type of dating is based on the how much or how little we see patterns in artifact styles over time
seriation
what type of dating uses the law of assumption
stratigraphy
what are the 4 types of absolute dating?
-dendrochronology
-archaeomagnetism
-paleomagnetism
-radiometric
describe dendrochronology
using tree rings; the most precise method of absolute dating
describe archaeomagnetism
a type of absolute dating; study of remnant magnetism in artifacts
describe paleomagnetism
study of the changes in the earth’s magnetic field over time
describe radiometric dating
calculates age based on radioactive decay
what type of absolute dating is the most accurate?
dendrochronology
define half life (radiocarbon) dating
measuring the rate of decay in organic materials
measuring the rate of decay in organic materials is called what?
half life
define thermoluminescence dating
dating used when radiocarbon dating cannot be used (ceramic, stone)
Half life and thermoluminescence dating are examples of what type of dating?
radiometric
how far back can you use radiometric dating?
up to 50,000 years, after that it isn’t considered reliable
what does “BC’ stand for?
before christ
what does “AD” stand for?
anno domini- after Christ was born
what does “CE” mean?
common era
Is CE the same as AD in dating?
YES
what years are included in the “BC” period?
1 day after christ up to 5000 years ago
what does ‘bP’ mean and what does it signify?
before present; signifies the commencement of the dating scale, 1950 being the “standard” year
what does it mean for a period to be calibrated vs uncalibrated?
calibration represents evidence found in the form of radiocarbon concentration, which is then converted into years.
define uncalibrated dating
a rough estimate that still needs to be proven with carbon levels
define natural selection
“survival of the fittest”; acts on variation within populations
what is gene flow?
exchange of genetic information from one population to another
what is genetic drift?
small random changes in isolated populations
what is mutation?
main source of genetic variation
what is a hominin?
any creature believed to be in the direct line of evolution with humans
what is the one characteristic that separates hominins from other species?
Bipedal locomotion
what are some characteristics of primates?
-tendency for erect posture
-opposed thumb
-nails (not claws)
-stereoscopic vision (brain can create 3D images)
-live in groups/pairs with permanent males
-brachiation (branched on both sides)
-prehensile (able to grasp)
what does it mean to have stereoscopic vision?
your brain can create 3D images
what does brachiation mean?
to be branched on both sides (arms that are able to swing- form of locomotion)
what does it mean to be prehensile?
you are able to grasp with your hands
what is non-honing chewing?
grinding your food (molars) rather than slicing (incisors, canines)
what is an extinct species that was included in the early hominins?
austrolipiths
how were early hominins classified?
-bipedal locomotion
-bigger brain to body ratio
-generalized dentition
-non honing chewing
describe phylogeny
the evolutionary history of a species, using DNA & paleoanthropology, that involves comparing some genetic similarities of species
the evolutionary history of a species, using DNA & paleoanthropology, that involves comparing some genetic similarities of species is defined as what?
phylogeny
LCA means what?
chimp-human last common ancestor
between what years did the LCA exist?
6.3 and 5.4 AD
Cretaceous Period
90-65mya, Purgatorius (shrew like animals)
Euocene-Ogliocene Extinction
55-23mya; Aegyptopithicus (earliest possible ancestor of the old world monkey)
Aegyptopithicus
predates the divergence of old world monkeys and hominoids (apes); found in the euocene-ogliocene period
Fayum Depression
oldest/richest records of mammal fossils found in Egypt during the Miocene period
Why is the Miocene period significant for archaeology, specifically referring to the Fayum Depression?
it holds the oldest/richest sites for mammal fossils in the world
oldest/richest records of mammal fossils found in Egypt during the Miocene period..what place is this?
Fayum Depression
What did the Miocene period mean for early primates?
they moved from forest to savanna and there was a huge expansion in the hominoids superfamily
when did the Miocene period occur?
23-5mya
when was there a lack of fossils during the Miocene period?
11-5mya
All members of the human lineage after it splits to chimp lineage are called what?
Australopiths
What are some extinct hominin generas?
sahelanthropus, ardipithecus, australopithecus, paranthropus
what was the hominin that was first discovered to have been the closest in anatomy to modern humans?
Sahelanthropus tchadenisis
what was the one outstanding characteristic of Sahelanthropus tchadenisis that set him apart from other hominins?
the position of the foramen magnum (where the spinal cord enters the cranium)
what was significant about the foramen magnum in Sahelanthropus tchadenisis?
it sat more underneath the skull and was not at an angle like other hominins. This signified a more erect posture (bipedalism) and a need to balance the skull (something not seen in other apes aside from humans)
what was the name of the hominin that came after Sahelanthropus tchadenisis?
Ardipithecus Ramidus
what hominin was closely related to Sahelanthropus tchadenisis?
Ardipithecus Ramidus
what hominin likely evolved into the earliest Australopithicines?
Ardipithecus Ramidus
which hominin was as much in the trees as it was on the ground?
Ardipithecus Ramidus
what are some of the key characteristics of Ardipithecus Ramidus?
-smaller canines
-opposed toe with no arches
-prognathism (protruding jaw)
-bipedal over short distances
where did Ardipithecus Ramidus live?
Ethiopia
what hominin lived during the middle of the Pilocene period?
Australopithecus
what are some characteristics of Australopithecus?
-small brains
-bipedal
-smaller canines
-small stature (just over 1m tall)
Who had features similar to both apes and humans but was more human like?
Australopithecus
what species of hominin was separated into robust & gracile forms?
Australopithecus
what genus of hominids had/has a prognathous jaw?
almost all members of the hominidae family (the great apes)
what is the family of great apes referred to as?
Hominidae
what is the super family of all species of apes and humans called?
Hominoidea
Hominoidea refers to what members of the human lineage?
all apes, their ancestors and humans
what are the members of the Hominiae?
gorillas, chimps, humans & their ancestors
what is the tribe called that contains gorillini & panini?
Hominini
what are the species included in the “great apes”?
gorillas, orangutans, gibbons, chimps bonobos, humans & their ancestors
Australopithecines Include what members of early hominins?
Australopithecus Africanus, Australopithecus Afarenisis, Australopithecus Sebidia
Approximately how tall were the early Australopithecines?
between 3.5 and 5 feet tall
what were key features of the early Australopithecines?
-human like dentition
-smaller canines
-steeper forehead
-prognathous
-smaller temporal fossa
-less prominent sagittal crest
-lest robust zygomatic arch
what is a sagittal crest?
bone running lengthwise on the skull
what is a zygomatic arch?
cheekbone
what area of the skull is called the zygomatic arch?
cheekbone
what area of the skull is called the sagittal crest?
the bone that runs lengthwise down the middle of the skull
what is the temporal fossa?
a depression on either side of the skull
what are the depressions on either side of the skull called?
the temporal fossa
Paranthropus is also called what?
Robust Australopithecines
Robust Australopithecines are part of what genus?
Paranthropus
Paranthropus had what features?
-flatter forehead
-larger temporal fossa
-large zygomatic arches
-thicker skull & bones
-massive molars & muscles
-more pronounced sagittal crest
-510cc avg brain size
what genus of hominoids have a flatter forehead?
Paranthropus
what genus of hominoids have a larger temporal fossa & zygomatic arches?
Paranthropus
what genus of hominoids have thicker skulls/bones, massive molars & muscles?
Paranthropus
what does bipedal mean?
using lower/rear limbs for locomotion
what else evolved along with bipedalism?
larger brains
Bipedalism is restricted to what tribe?
hominins
what are some advantages of bipedalism?
-hands are free to carry & manipulate
-posture exposes less skin to sunlight & helps see further (see more land/protect self from predators)
-efficient function
what are traits of the bipedal skeleton?
-pronounced lumbar curve
-foramen magnum is centered
-pelvis is bowl shaped
-shift in body mass distribution
-enlarged ankle bones/arches
-no opposable toe
-pronounced lumbar curve
-foramen magnum is centered
-pelvis is bowl shaped
-shift in body mass distribution
-enlarged ankle bones/arches
-no opposable toe
…these are all traits of what?
bipedal skeleton
“Lucy” is what species of hominin?
Australopithecus Afarenisis
why were the footprints in Laetoli, Tanzania significant to learning about early hominins?
they had big toes in line with the rest of their foot (like humans) and they walked heel-strike first, then toe-off..this meant they were not only bipedal but also more human like than ape.
“Lucy” was found at what Australopithecine archaeological site and how long ago?
Hadar, Ehtiopia 3.18mya
What was the child found in South Africa in 2mya called?
Tuang child
the Tuang child was a part of what genus of hominoid?
Australopithecus Africanus
who comes first in the Hominini branch? Australopithecus Africanus, Australopithecus Afarenisis, Sahelanthropus tchadenisis or Ardipithecus Ramidus?
Sahelanthropus tchadenisis
who came second in the hominini branch?
Australopithecus Africanus, Australopithecus Afarenisis, or Ardipithecus Ramidus?
Ardipithecus Ramidus
who came 3RD in the Hominini branch? Australopithecus Africanus or Australopithecus Afarenisis?
Australopithecus Afarenisis
who was the last out of these 4 in the Hominini branch:
Australopithecus Africanus, Australopithecus Afarenisis, Sahelanthropus tchadenisis or Ardipithecus Ramidus?
Australopithecus Africanus
what species lived at the same time as the Australopiths?
Homo Habilis
