Exam Flashcards
What are the five forces of evolution?
Natural selection Random genetic drift Mutation Population mating structure Culture
Natural selection details
- Since the environment can’t support unlimited population growth, not all individuals get to reproduce to their full potential
- some traits make it more likely that a species will survive
- but we interfere with that with things like IVF and modern medicine which means it’s not the same anymore hence the massive ⬆️ in population size
- environment adaptation = competition over food, water, mates and living space
Genetic drift details
Changes in allele frequencies by chance
Population mating structure details
- e.g. chimpanzees = patrilineal- when the females hit sexual maturity they leave the group and find another one this creates gene emmergration b/c they bring new genes to the new group
- mate preference = no consensus on how important it is e.g. giving food/grooming
Mutation details
Error in copying the DNA
Culture details
- The development of an ability from simple to complex
- e.g. nut cracking in chimpanzees - when the females move groups they adopt the new way the new group crack nuts
What modern world advances will effect future evolution
- Social and religious attitudes towards population growth, birth control, abortion
- social attitudes about who to marry/not marry
- military culture
- domestication
- travel and transport improvements
- internet (e.g. online dating)
- genetic engineering
We are currently in the Tertiary Period which is made up of 5 epochs, which are called?
Palaeocene epoch 65-54 ma Eocene 54-38 ma Oligocene 38-24 ma Miocene 24-5 ma Pliocene 5-1.8 ma (Anthropocene)
Details of the Quaternary period
Beginning of the ice age - 1.8 ma
Includes the Holocene 11,000 ya -present
What do these stand for? KNM WT ER OH D
KNM = Kenya National Museums WT = West (lake) Turkana ER = East Rudolf (former name for Lake Turkana) OH = Olduvai Gorge specimens D = Dmanisi specimens
Details of the Olduvai Gorge (OH)
- in Northern Tanzania
- a steep sided ravine in the Great Rift Valley
- one of the most important palaeoanthropological sites in the world - excavated by the Leakeys
- homo habilis (1.9 ma)
- Paranthropus boisei (1.8 ma)
- homo erectus (1.2 ma)
- homo sapiens (17,000 ya)
The Cradle of Human Kind details
- South Africa
- an area with many limestone caves
- Malapa cave - Australopithecus Sediba
- Paranthropus, homo habilis
- Rising Star cave - homo naledi
Dmanisi cave details
- location Georgia
- 5 homo erectus skulls (1.8 ma) found but large morphology of skulls varies - not classified as different species because they are the same age and found in the same place
- oldest one outside of Africa
4 characteristics of hominins
1) Increased brain size
2) Decrease tooth size
3) Bipedal
4) Increased tool use
3 Ardipithecus groupings
1) Sahelanthropus
2) Orrorin
3) Ardipithecus kaddaba and ramidus
What makes Ardipithecus group different from later hominins
They are the earliest Hominins who lack the features of later Hominins
Sahelanthropus tchadensis details
- Ardipithecus group
- location = Chad
- found (small) Cranium , (large) jaw fragments, (large) teeth
- 7.6-6 ma
- small brain size
- oldest known hominin
- more downwardly orientated foramen magnum = suggested upright posture and locomotion
Orrorin tugenensis details
- found in Kenya
- found arm + leg bones + teeth
- lived 6.1-5.8 ma
- unknown brain size
- Size and shape of femur suggests bipedalism
Ardipithecus Kaddaba details
- found in Ethiopia
- jaw fragments found
- lived 5.8-5.2 ma
- Brain size unknown
- leg bone and foramen magnum suggest bipedalism
Ardipithecus Ramidus details
- found in Ethiopia
- lived 4.4. ma (because it was found in two volcanic strata)
- has reduced canine size + presence of adaptations which could be bipedal (not habitually bipedal)
- very complete skeleton found
Australopithecus group 5 species
- Australopithecus anamensis
- Australopithecus afarensis
- Australopithecus garhi
- Australopithecus africanus
- Australopithecus sediba
What are the features of the australopithecus
1) bipedal
2) similarity structure to humans
3) Brain size similar to modern apes
Australopithecus anamensis details
- found in Kenya
- 4.1-3.9 ma
- arm bone(chief specimen), ear canal piece, jaw joint found
- Brain size unknown
- lower leg bone (knee joint surface) indicates bipedalism
Australopithecus afarensis “Lucy”
- Discovered Ethiopian Afar region
- most complete and well preserved A. Afarensis fossil
- 3.8-3.0 ma
- completeness = scientists could understand bipedalism in early humans
- Brain size ape like
- no evidence of toolmaking
- Habitat = woodland + open areas - known through isotope analysis
- diet soft fruit + leaves - but teeth adapted to eat hard foods as well
Australopithecus garhi details
- Central Ethiopian
- 2.5 ma
- Brain size 450 cm3 - no average because only one skull found
- Limb proportions = more human-like
Australopithecus africanus “Taung child”
- South Africa
- 3.0-2.0 ma
- Brain size ape like
- bipedal (Likely to be arboreally proficient)
- thicker teeth than A. Afarensis -suggests eating harder foods still
Australopithecus sediba details
- found in Malapa Cave, South Africa
- 2 ma
- Over 220 fragments from species found
- Wide range of features and post-cranially
- teeth, arm + leg length + narrow up a chest resemble Australopithecus
- Tooth traits + broad lower chest resemble Homo
Paranthropus group
- P. aethiopicus
-P. Boisei
-P. Robustus
(Also calls Australia)
Skull structure of Paranthropus in general
- Heavy chewing
- Large muscle attachments
- Large molars
- large jaws
Paranthropus aethiopicus details
- discovered Ethiopia + Kenya
- toothless lower jaw found (“black skull” because they of high levels of manganese)
- 2.5-2.3 ma
- Brian size 410 cm3
- skull + teeth adapted for eating tough foods
Paranthropus robustus details
- discovered Sough Africa
- found damaged skull + half jawbone
- 2-1 ma
- brain size 530 cm3 (slightly bigger than previous Paranthropus)
- considered a dead-end branch of the human family
- very robust jaw (masticatory features) which set it apart from Australopithecus & homo lineages
Paranthropus Boisei (“nutcracker man”)
- discovered Olduvai Gorge + Tanzania
- found many compleat skulls
- 2.3-1.3 ma
- brain size 400-550 cm3
- large chewing muscles
- “nutcracker man” b/c large posterior teeth + jaws made it look like vintage nutcracker
Homo group
- genus hominids includes modern Homo sapien + closely related species
- genus between 2.3-2.4 ma
- difference between early Australopiths + homo = increased cranial capacity in homo
- H. Habilis
- rudolfensis
- erectus
- heidelbergensis
- floresiensis
- naledi
- sapiens
Homo habilis (“handy man”
- Discovered Tanzania (most primitive homo)
- 2.4-1.4 ma
- brain size 510-687 cm3
- Large brain
- Smaller face and teeth
- “Handy man” = home-made tools found along with fossils
Homo erectus (“upright man”)
-Discovered in Java, Indonesia, Kenya
-“Java man“, “speaking man“ and “Turkana boy“
-1.8 ma - 50,000 ya
-Brain size = 600 -1200 cm³
-oldest known early human to have human-like posture (elongated legs, shorter arms compared to torso
-Ability to walk/run long distances (efficient bipedalism)
-generally considered the first species to leave Africa
-
Homo heidelbergensis
- discovered Germany
- found lower jaw (others found in Africa + Europe)
- 500,000-200-000ya
- Brain size 1274 cm³
- Big brained
- Big bodied
- sophisticated hunter
- Probably ancestor to Neanderthals and modern humans
Homo floresiensis (“the hobbit”)
- Discovered island of Florence, Indonesia
- “Hobbit“ Scholl, jaw and limb bones found
- 95,000 - 12,000 ya
- Brain size 400 cm³
- 3.5 feet tall
- Small body and brain
- Unknown if they are a species distinct from modern humans
- hypothesis e.g. Down’s syndrome, insular dwarfism or microcephaly
Homo sapiens
-
