Evanth 101 Exam 2
cenozoic epochs
HPPMOEP Holocene (recent) Pleistocene Pliocene Miocene Ogliocene Eocene Paleocene
Do you expect the CLCA to have been a knucklewalker? Why or why not?
I do. Chimpanzees are knuckle-walkers, though humans are not. So it's likely that knucklewalking was lost somewhere along the human lineage
Who first observed tool making and tool use in chimpanzees, and what did they see?
Jane Goodall, dipping for ants & termites
miocene (23 mya - 5) -continental locales -climate -primates that arose/ radiated
-India moved into Asia (created Himalayas); Africa joined Eurasia -lil warmer - back to broadleaf evergreens; back to colder & arid at the end of the Miocene -evidence of suspensory locomotion & radiation of hominoids; but reduced hominoid diversity in Eurasia bc climate (chimp & gorilla ancestors survived the shift)
paleocene (65 - 54 mya) -continental locales -climate -primates that arose/ radiated
-NA more north; SA more south; India southeast and not attached to EA -warm & wet climate; broadleaf forests -plesiadapiforms (earliest lil shrew primates) in NA
ogliocene (34- 23mya) -continental locales -climate -primates that arose/ radiated
-at end of eocene; continents more or less like they are now but not all the way touching -major drop in temperatures bc cold currents formed around antarctica post SA & austr. separation; ALSO more variation in temp -euprimates from eocene radiated & to SA; New World monkeys appear
pleistocene (1.8 mya - .01) -continental locales -climate -primates that arose/ radiated
-basically modern -(lower, middle, upper = sharp cooling, warmer, warmest) -emergence & radiation in earnest of homo in Africa- Acheulian tools; then dispersal out of Africa and into Eurasia
pliocene (5 mya - 1.8) -continental locales -climate -primates that arose/ radiated
-basically modern -drier, more grasslands & woodlands -pioneering species moved down from trees - first evidence of bipedal apes with more modern dentition (lg posterior teeth, canine reduction) [ardipethicus, australopithecus, paranthropus, kenyanthropus, homo] - Oldowan tools
Can you give examples of non-human tool use? What types of tool use have been observed in monkeys? What about in all the ape species?
-chimpanzees, bonobos: dipping for ants, termites; toothpick, scratcher, rain hat -monkeys: hammers for cracking nuts,
plate tectonics and climate change
-continental drift is one of the engines of climate change (size and orientation of a continent affects its weather - larger continents have more severe weather) -human evolution was guided by changes in climate (although not directional or moving toward perfection because climate is always changing)
What types of tools are found in the Oldowan?
-core tools: multipurpose hammering, chopping, digging implements -flake tools: knives for butchering, processing plant materials, etc.
What adaptive shifts occurred with the origins of the genus Homo? What is the evidence for dietary change at this time?
-greater consumption of animal tissues, lger brains, stone tools, larger bodies & more efficient bipedalism, derived thermoregulatory systems -stone tools, cut-marked bones, dental reduction, brain expansion, tapeworms
What can you say about possible evolutionary relationships between the australopiths? What can you say about brain size, locomotion, habitat, diet, and social organization in the australopiths?
-habitual terrestrial bipeds, moving into savanna habitats, mostly frugivorous but possibly omnivorous (postcanine megadontia) -mulit-m, multi-f social groups. sexual dimorphism
plate tectonics and geographic distribution of primates
-oceans separated continents and thus organisms, allowing species diversity and divergent (and convergent) evolution -knowing how continents were distributed and when allows us to place and date primates' evolution and movement in relation to each other and the earth
New World Monkey evolution: what ideas have been proposed about how monkeys got to SA? What hypothesis is best supported, and by what evidence?
-rafting (SUPPORTED: fossil rodents appeared round the same time, v similar to those found in Africa round same time) -descended from NA primate (but no haplorrhine fossils in NA, requires voyage from NA to SA bc still unconnected) -crossed much earlier, when atlantic sea levels were lower in the oglio (but fayum primates w closest affinities much younger)
eocene (54 - 34 mya) -continental locales -climate -primates that arose/ radiated
-some contact bw europe & asia; asia & india; NA & Europe touching but then they moved farther apart -wetter and warmer, w tropical forests -primates with modern features appeared in all conts but australia, SA & antarctica - but mostly in the northern hem.
what evidence exists for plate tectonics?
-they look like they fit together -there are identical sedimentary formations on formerly joined coasts -there are extinct species with contiguous distributions across formerly joined coasts (ie, Mesosaurus)
Why might humans have an adolescent growth spurt? What ideas have been proposed to explain the long human post-reproductive life span (the existence of grandmothers)?
-to support mother: defers the caloric and energetic cost until the child can contribute to their own subsistence
holocene began
.01 mya
What are features that differentiate humans from the extant African apes? (5)
1. bipedalism 2. dentition & jaw musculature (thick enamel, parabolic dental arcade, reduced canines, larger molars) 3. larger brains 4. slow development / long juvenile period 5. variable material & symbolic culture, esp. spoken language
At what dates did early humans start colonizing cold environments?
1.4ish mya
pleistocene began
1.8 mya according to book, 2.5 mya according to Church
how old is the universe
13.8 bya
Laurasia & Gondwanaland broke up around _______ mya
130 (Cretaceous)
When do stone tools start to become abundant in the archeological record?
2.5 mya
Pangaea
200mya, all the continents were joined together in a single landmass and this was it
miocene began
23 mya
What is the earliest evidence for stone tools?
3.3 mya
ogliocene began
34 mya
how old is the earth
4.5 billion years old
pliocene began
5 mya according to book & churhc
eocene began
54 mya
paleocene began
65 mya
Dating method: Ar-Ar
Argon-Argon -K in sample is converted to an isotope before measured -more accurate dating of single rock crystals
Dating method: C-14
Carbon dating -ratio of C-12 to C-14 to N-14: when an animal dies, C-14 decays into N-14
What are the divisions of the Early Stone Age?
Early Stone Age, Oldowan, Achulean
Dating method: ESR
Electron-spin-resonance -apatite crystals (tooth enamel) -subjecting to a variable magnetic field to determine number of trapped electrons -works if density of high-energy particles flowing through site is known
Who is the best candidate for first haplorrhine in the fossil record? -also: where & when
Eosimias -SoChina -45-40 mya (beginning Ogliocene)
What species appears to be the earliest suspensory ape? -evidence?
Morotopithecus, 20 mya, Uganda apelike in bone structures: scapula, stiff lower back, femur "aspects"
plesiadapiforms fossil locations & when
NA - Montana, CO, NM, WY Paleocene epoch (65-54 mya)
Where do we find adapid and omomyid fossils, and when do they leave the fossil record?
North America, Asia, Europe, Africa leave the fossil record mid-Ogliocene (~30 mya, global cooling)
What makes the Fayum such an important site for the study of primate evolution? -describe Fayum during mid-late Eocene, early Ogliocene
Northern Africa (Egypt area) warm, wet, seasonal habitat - tropical forests extremely diverse primate community well-disposed to preserving organisms' remains
tertiary periods
PMOEP Pliocene Miocene Eocene paleocene
Dating method: K-Ar
Potassium - Argon. -date volcanic rocks found near fossil material, because any argon found in rock must be due to the decay of potassium
Sivapithecus & gigantopithecus -where & when -features a lil
Siva: -India & SE Asia, 13- 8 mya -looks like an orangutan giganto: -mainlaind asia, 9-.5mya -literally just f'ing giant
Dating method: TL
Thermoluminescence dating -number of trapped electrons which come from decay of radioactive material & cosmic rays -measuring amt of light given when heated to determine ^ -works if density of high-energy particles flowing through site is known
Dating method: U-series
Uranium-lead dating -zirconium crystals from igneous rocks -uranium decays into lead, so measure ratio of lead to uranium -esp in hominin sites in SA where no volcanic rocks present for K-Ar
How do hominoids differ from other catarrhine primates?
arboreal (suspensory locomotion), no tails, short, stiff lower back, long arms & fingers, mobile upper limbs
What species from the terminal Miocene or early Pliocene have been considered to be early hominins? -derived features? -other characteristics?
ard. ramidus, kaddaba; ororrin tugenensis; sahelanthropus tchadensis -partly arboreal, bipedalism, feminized canines, woodland/savanna omnivore
isotopes
atoms of a particular element that have a different number of neutrons in their nucleus than is normal
why are absolute dating techniques also called radiometric?
because they are determined by the radioactive decay of various elements
In what ways does human life history differ from that of chimpanzees?
both have long juvenile periods, but human juveniles are hella dependent; adolescent growth spurt; less time in interbirth period; we have post-reproductive life spans
how can we reconstruct ancient climates?
by extracting sediment from various levels of the ocean and comparing ratios of oxygen isotopes (O-16 and O-18). The concentration of O-18 increases when the world is cold; decreases when warm
Hominoids don't appear outside of Africa until after 17 mya - why is that?
climate changes pushed them out of Africa - into the drier, more seasonal, more open habitats
How does meat eating relate to brain size?
complex and cooperative foraging favored encephalization
early platyrrhine features (late ogliocene, SA) & who do they link to
dental forumula, post-orbital closure - link to parapithecids at Fayum
Based on the morphology of living gorillas, chimpanzees, and humans, what characteristics would we expect to see in the CLCA (chimpanzee/human last common ancestor)?
dimorphic canines, suspensory climber, brain size somewhere around 400-500 ccs, forest frugi- or omnivore
What is the oldest New World monkey fossil, and what is its age?
early platyrrhines, late oglio (~26mya)
to what grand order do primates belong?
euarchonta
to what supraorder to primates belong?
euarchontoglires
what does Churchill mean by derivative techniques?
faunal correlation & paleomag - using known dating to derive the date of other fossils
How might meat-eating be related to human life history?
favored adaptations that include larger brain sizes, which led to cooperative breeding
How does meat eating relate to food sharing?
favored adaptations that led to increased exposure to carnivores, which led to cooperative foraging
What innovations during the Acheulean may have helped hominins to expand into cold temperate zones?
fire, wooden spears,
What differences in the skeletons of chimps and humans are related to bipedal locomotion in humans?
flat, wide pelvis; femur slants down and inward;
What other features do we see in early euprimates?
grasping hands & feet, hind-limb dominant, shorter snout, larger brain
What, exactly, is meant by the terms "hominoid," "hominid," and "hominin?"
hominoid - superfamily (all apes) id- family (great apes- chimps, gorillas, orangutans) in- tribe (humans & immediate ancestors)
What do we mean by the "paradox of human reproduction?"
human babies are dependent for so long, but our interbirth period is super short even thought we expend more energy on birth and childcare than other species
how has climate changed over the course of the cenozoic?
it's gotten a hell of a lot colder and a hell of a lot drier
reminder to study slide 2 of lecture 14
know the primates' divergence dates
What were the characteristics of early H. erectus? How do the fossils from Dmanisi fit in?
large brain Dmanisi- smaller brain, smaller body size
K/T boundary
late mesozoic / beginning of the cenozoic, meteor struck & put lots of shit into the environment, creating a colder environment that dinosaurs couldn't adapt to: 90% died
Homo erectus is the oldest hominin that everyone feels certain was on the lineage to living humans, and it is the first hominin to appear to have the entire package of adaptive features that define the genus Homo. What species are important to understanding the evolutionary origins of H. erectus? What was the temporal span and characteristics of each species?
look at lecture 17, slide 10 on
When did hominoids first appear and radiate?
miocene (23-5 mya), Africa but radiated to Europe and Asia after 17 mya
What are the characteristics of the Acheulean? How does it differ from the Oldowan?
modified flakes that likely have specific purposes, (elaborated debitage & faconage)
should plesiadapiforms be considered primates?
no - while they posses some of the features of modern primates and while they are the ancestors of modern primates, they were not similar enough to be classified as primates. (arbitrary assessment anyway) a difference to highlight - lack of binocular vision
how does plesiadapiform carpolestes improve understanding of defining primate features?
nocturnal behavior favored good vision, hand-eye coordination, and grasping hands & feet (traits found in later primates)
If we were to ask you to place all of the australopiths on a temporal chart, with bars representing their time span, could you do it? What if I also asked you to add early Homo (through H. heidelbergensis)?
nope - just look at p 249 in the book for a lil
What species might make the best candidate for common ancestor of all of the living hominids?
not well known but pierolopithecus - 13 mya
Based on living species, which group has had a more successful radiation - apes or old world monkeys?
old world monkeys - only a few apes are left alive today
Who are the gracile australopiths and who are the robust australopiths?
paranthropus genus is robust - they've got hella big teeth/ powerful mandibles -later than gracile (2.5-1mya) -likely in response to changes in environment
What primates have been found at the Fayum? -characteristics? -relation to living primates
parapithecidae, propliopithecidae, ogliopithecidae (mosaic of primitive and derived traits) -dental formulas that show movement to modern characteristics -diurnal, arboreal
how do eocene primates relate to modern forms?
phylogenetic relationship unknown - still looking for the 'missing link' shared characteristics: grasping hands & feet, nails, hind limb-dominant - shorter snout & lg brain indicate moving towards modern primates
to whom are primates most closely related?
plesiadapiforms
What derived primate features differentiate Eocene euprimates from plesiadapiforms?
postorbital bar, forward-facing eyes, nails on most digits, hallux
what does euprimate mean?
primates of modern aspect
cenozoic periods
quaternary & tertiary
isotopes in radiometric dating v. isotopes used to reconstruct climate
radiometric dating - half-lives to determine age climate - ratio of types bc that's what's present in the ocean of the time using STABLE isotopes (don't decay)
quaternary periods
recent (holocene), pleistocene
absolute v. relative dating methods
relative - dating based on the pattern of polar magnetic reversals; dating based on the known ages of other layers of fossil/ sediment/ etc. absolute - dating based on radioactive decay of elements contained in / around fossil material
Dating method: Paleomag
relative dating using normal v. reversed magnetic epochs
In what ways were the proconsulids similar to living apes, and in what ways did they differ?
similar to apes in dentition & lack of tail different: size (smaller), pronograde posture, limb proportions, flexible lower back, arboreal
plesiadapiforms
small, shrewlike animal present in paleocene epoch from which modern primates evolved
Starting about 3 Ma, there appears to have been a divergence in adaptive strategies emerging among the hominins. What strategies were emerging, and what was driving it?
strategies: australopiths move toward omnivorous strategy, robust dopes move toward a more specialized diet (of low-quality or hard food) bc of shift to a more grasslands habitat
Quiz question (just for fun): presented with just the partial skull of the australopith child from Taung, Raymond Dart realized instantly that it was a bipedal animal - how?
the position of the foramen magnum is more like that of modern humans than that of apes - underneath the brain
What's up with the robust australopiths? Why is there a controversy about whether they belong in their own genus or not?
the skull musculature is just so different
Why are proconsulids sometimes referred to as "dental apes?"
they have the same dentition (Y-5)
How might stone tools be seen as a form of character displacement?
they were used to eat meat, which was not previously a part of the the hominid way
Why is it unlikely that the propliopithecids from the Fayum represent ancestors of New World monkeys?
they're much younger than the fossils dated in SA
stratigraphic superposition
unless something has disturbed the area, older specimen lie below younger (relative dating technique)
Dating method: Biostrat & faunal correlation
using info from known biological and faunal data in the area/ at relative depths to date the unknown
What is the evidence for bipedal locomotion in the australopiths?
valgus knee, bipedal pelvis, preserved footprints
plesiadapiforms characteristics
variable dentition, some terrestrial / arboreal / gliding, claws, grasping hands & feet (opposable thumb)
How is it that humans manage to reproduce faster than other apes?
we have a super short period of weaning
what has been the effect of climate change on evolution?
went from a gymnosperm to an angiosperm dominant (flowering plants) ecosystem as the result of the K/T boundary meteor & other climate changes - created new ecological niches for primates to fill (lil shrews, mostly - plesiadapiforms)
Laurasia
when Pangaea broke apart 150 mya, this was the northern half (North Am. & Eurasia minus India) - late Jurassic, early Cretaceous
Gondwanaland
when pangaea broke apart 150 mya, this was the southern half (everything but NA & Eurasia) - late Jurassic, early Cretaceous