Anth 021 Exam 3 – Flashcards
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1. What are fossils? What types of information can they preserve?
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- body fossils- bones which have mineralized - trace fossils- foot prints/poo - molecular clocks- calibration to determine the rate and the date of each node thereafter in the tree
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2. How do absolute and relative dating methods differ?
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Relative - Establish the relation of ages between two or more objects. ex. 'This is younger than that' - stratigraphy -faunal succession - - No Actual Dates Absolute - Establish an absolute date. ex. 'This is 20 million years old' - tree ring dating -radiocarbon dating - K-Ar dating - - Age Range: Measurement Error
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3. Explain the Law of Superposition and the Law of Original Horizontality.
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- principle of original horizontality: ---- layers of strata are deposited horizontally or nearly horizontally. Thus, any deformations of strata must have occurred after the rock was deposited.Each time a new layer of sediment is deposited it is laid down horizontally on top of an older layer. - principle of superposition ----builds on the principle of original horizontality. The principle of superposition states that in an undeformed sequence of sedimentary rocks, each layer of rock is older than the one above it and younger than the one below it. Accordingly, the oldest rocks in a sequence are at the bottom and the youngest rocks are at the top.
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4. What are biostratigraphy and molecular dating? How does molecular dating work?
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Biostratigraphy- • Identifying evolutionary trends in reference taxon can provide relative ages for strata • Sometimes a species can be associated across different sites • If age of fossils known in one site age can be inferred if sharing taxa Molecular Clocks (dating)- • Compare DNA sequences to judge the evolutionary distance between groups • Estimate time since groups split from genetic distance • Rate of mutation in mtDNA or genomic DNA - Clock-‐like mutation rate per generation • Fossils = calibration to determine the rate and the date of each node thereafter in the tree
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5. How old is earth? Roughly how long did it take for multicellular life to evolve on earth?
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- Earth age- 4.6 billion years - life on earth - 3.5 billion years ago (1 billion years to occur)
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6. How does the tectonic drift impact world geography? What are the implications for primate evolution? Is the Atlantic Ocean presently getting bigger or smaller?
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- continental plates that move -Migration occurs in primate evolution -Atlantic Ocean is getting bigger
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7. Know the geologic epochs of the Cenozoic.
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Holocene: 10 kya - Development of agriculture Pleistocene: 2.6 mya - Evolution of genus Homo Pliocene: 5 mya - Adaptive radiation of bipedal hominids Miocene: 23 mya - Adaptive radiation of apes Oligocene: 34 mya - Adaptive radiation of anthropoids Eocene: 56 mya - Adaptive radiation of true primates and prosimians Paleocene: 66 mya - Origin of primates; Radiation of primate like mammals
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8. What types of ecological information can be deciphered from the geological record? How do we know?
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- Cooler weather results in increase of O(18) in seawater - Concentration of O(18) in the remains of mineralized microorganisms can indicate ambient temperature • C3 plants: Trees, brushes & shrubs (most plants) -Generates three - carbon compounds • C4 plants: Grasses - Generates four carbon compounds
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9. What are primates closest living mammalian relatives both living and extinct? What features to these animals share with true primates that might inform us of what the earliest primates were like? How do they differ which suggests they are not true primates?
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Now: -Tree shrews (Scandentia) are closely related to primates ----Most are arboreal and some are nocturnal - features that characterized early primates -Colugo (flying lemur- Dermoptera) is a close relative of primates Then: Plesiadapiforms - Protoprimates -primate-‐like mammals, Small size, Insectivorous Carpolestes - most 'primate-‐like' - Grasping digits, nail on first digit
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10. What are the general environmental characteristics of the Cenezoic geological epochs? What were the major primate or Plesiadapiform radiations for each epoch?
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Holocene: 10 kya -Development of agriculture Pleistocene: 2.6 mya - Evolution of genus Homo Pliocene: 5 mya - Adaptive radiation of bipedal hominids Miocene: 23 mya - Adaptive radiation of apes Oligocene: 34 mya - Adaptive radiation of anthropoids (Oligopithecids, Parapithecids, Propliopithecids, Propliopithecids) Eocene: 56 mya - Adaptive radiation of true primates and prosimians (Adapiforms- Adapis and Notharctus, Omomyiforms-Teilhardina, Archicebus ) Paleocene: 66 mya - Origin of primates; Radiation of primate like mammals (Plesiadapiforms - Protoprimates, Altiatlasius)
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11. Who were the Plesidapiforms? Where did the live and what features did they have? What do the tell us about the nature of the earliest primates?
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Plesiadapiforms - Protoprimates • Adaptive radiation of primate-‐like mammals found in Europe and North America • Small size - mouse, squirrel and cat sized forms • Very diverse and numerous • Specialized den//on • No postorbital bar • Lateral facing orbits • Small brain • Shorter digits with claws
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12. What were the earliest true primates like? Where were the found, when did they live, and what features did they have? Which living primates are adapiforms and omomyiforms most likely related to?
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-North America, Europe and Asia •Stereoscopic vision • Reduced diastema behind incisors (teeth close together) • Grasping hands with nails • Reduced snout size • Larger brain • Post-‐orbital bar • Two main groups: - Adapiforms- (Adapis, Notharctus lemur-‐like) -Omomyiforms- (Teilhardina- tarsier like)
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13. When did the lemurs radiation occur? What is known about their previous diversity? What may have led to the extinction of particular lemur species?
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• Genetic evidence suggests living lemur radiation dates to ~ 60 mya (Paleocene) -Hunted by humans and habitat destruction still a big problem in Madagascar • Poor African and Madagascar Paleocene and Eocene fossil record
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14. What is an evolutionary scenario? Which scenarios have been proposed to explain the initial evolution and radiation of primates?
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• Use variety of evidence (anatomy, ecology, paleontology) to understand the adaptive history of a species or group of species (An evolutionary story) Key Features: - Convergent orbits with orbital bar - Grasping hands and feet with nails - Generalized den//on - Larger brain 1) Arboreal Model 2) Visual Predation Model 3) Angiosperm Radiation Hypothesis
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15. Who were the first anthropoids? When did they arise and where? What features indicate they are true anthropoids?
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Eosimias - 42 mya, China • Short monkey like ankle • Arboreal, similar to some New World monkeys • Still very small, 200 g Oligocene (34-‐23mya) primate evolution in Africa, American and parts of East Asia
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16. What are the hypotheses for how New World monkeys got from the Old World to the New World? Which is better supported by the data and how?
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1) North American Origin • No evidence of strepsirhine to anthropoid transition in the Americas 2) Through Antarctica • Warmer in Eocene, but no fossil record 3) Migration from Africa • Requires a trans-‐Atlantic migration • Rare event, but given enough geologic /me possible • Currents are favorable and lower water level could have exposed islands
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17. When was the first hominoid radiation of hominoids and when did it occur? What are the important derived and ancestral characters associated with these earliest apes, such as Proconsul?
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The Miocene (23 - 5 mya)- Dental Some new features: • Larger brain • No tail • Longer limbs • Some increased forelimb mobility
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18. How widespread was the Miocene ape radiation?
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• The Miocene is the origin of the modern apes lineages "planet of the apes" • Numerous genera found throughout Miocene • Early Miocene has African radiation • Apes expand to Eurasia in Middle Miocene • African fossil record is generally sparse in Middle to Late Miocene
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19. What is the relative timing of the hominoid and cercopithecoid radiations?
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-Cooling of the Miocene • Loss of tropical and subtropical forests in Europe • Expanded grasslands in Africa, Europe and Central Asia • Apes lost in Europe and remain only in isolated areas in Africa and SE Asia • Diversify and radiate in the Late Miocene through the Pliocene and Pleistocene • Radiation into terrestrial and arboreal forms Apes have very low reproductive rates • Typically 5-7 year interbirth intervals • Monkeys have 2-3 year interbirth intervals
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20. What are the main ways in which humans and our ancestors differ from other apes and primates? Which of these occurred early in hominid evolution and which occurred later?
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1 - Big brains 2 - Bipedal locomotion (non-‐grasping foot ) 3 - Small canines (non-‐cutting canine)
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21. From head to toe, what are the major skeletal features associated with bipedalism? How do humans and apes differ in these features? Which early hominids show bipedal features?
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1- Narrow base of support 2- High center of mass 3- Hind limbs - shock absorbers & engine 4-Upright posture places head on top of spinal chord----Foramen magnum at bottom 5-"S" shaped Curvature of the Spine 6- Lumbar Lordosis- Backward curvature of spine is called a lordosis, Need longer back and lordosis to place trunk over pelvis and legs 7-Change in Pelvis Shape - Human pelvis is shorter & wider, Shorter iliac blade, Iliac blades flared to side, Shorter ischium 8-Lesser Gluteal Muscles- In humans they keep the pelvis from dipping toward the swinging leg with each step - Stabilization 9-Gluteus maximus: Stabilizes the trunk with each step in humans 10- Valgus Knee - Bicondylar Angle- Human thigh bone (femur) slants inward from hip joint to knee joint 11- No Grasping Feet 12- Arch of the Foot -Ardipithecines
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22. How does the dentition differ between hominids and apes? Which of these may reflect changes in diet and which might reflect a change in social structure? When did these features occur in the course of hominid evolution?
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- Uses of Canine/ Canine Reduction - Molar Cusps and Enamel Thickness -Human- • Rounder molar cusps, Crushing and resists, Thick enamel
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23. What are some of the behavioral and reproductive differences between humans and apes? What are some of the biological trends that humans show regarding their reproduction?
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• Live in multimale/multifemale societies • Strong tendency to pair bond • No canine dimorphism • Moderately larger males; deeper voice pitch; beards • Moderate testes: no sperm competition • Paternal investment in offspring • Unique female body composition • Concealed ovulation - paternity assurance? Males: No canine dimorphism - Low competition between males • Moderate size dimorphism - Low/moderate competition • Moderate sized testes - Copulate more frequently than typical single males, but do no engage in sperm competition • Male cooperation tends to be high Females: Unique body composition • No or extremely subtle ovulatory estrous - Little external signs of ovulation - Hidden from males - Little signs for changes in proceptivity - Hidden from self
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24. Which human-like features arose first during human evolution? How does our understanding now differ from those in the past? What has changed in our understanding of the human fossil record?
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Darwin- Intelligence-> Tool use -> Bipedalism ->Reduction of canines Sir Arthur Keith- bipedal first Grafton Elliot Smith- brain first Probably Bipedal and reduction on cainine then large brain then tool Sahelanthropus tchadensis- bipedal, small brain, smaller teeth, no tool Orrorin tugenensis- bipedal, smaller teeth
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25. What was the general history of the discovery of human fossils? Which paleontologists were the major players? What were a few of the major disputes concerning the significance of different fossils?
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Eugene Dubois - Pithecanthropus erectus Raymond Dart - Australopithecus africanus Louis and Mary Leakey - Australopithecus boisei disputes- which came first? Piltdown Dilemma
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26. Who were the earliest hominids? What evidence to we have that these fossils are hominids and not early chimpanzees?
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Ardipithecines- 1) Sahelanthropus tchadensis 2) Orrorin tugenensis 3) Ardipithecus kadaba 4) Ardipithecus ramidus Bipedalism smaller canines
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27. Who was Ardipithecus? What do we know about its locomotion, environments and behavior? What does Ardipithecus tell us about the last common ancestor between humans and chimpanzees?
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Ardi- Ardipithecus ramidus 1) A combination of early hominoid cautious climbing and derived and unique bipedal traits • Completely unique form of locomotion 2) Few suspensory and no knuckle walking features • Suggests these behaviors not part of hominids ancestral repertoire 3) Last common ancestor with humans and chimpanzees likely an cautious above branch climber 4) Suggests independent and parallel adaptation of extant apes for suspension and/or knuckle walking 1) Lineage dating back to near 7 mya 2) Canine reduction and bipedalism are earliest hominid traits - s:ll had small brains 3) Wide geographic range from Central to Eastern Africa 4) Lived in forested and woodland environments - not open grasslands 4) May be a common lineage
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28. Who were the australopithecines? What were their major characters with respect to dentition and locomotion? How did they differ from Ardipithecus?
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A) Obligate bipedalism B) Reduction of canine C) Enlargement of premolars and molars and chewing musculature differences: - Initial use of stone tools -increase in brain size Adri had only reduced K9, with a combo of arboreal features like grasping foot.
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29. What do we know about australopithecine locomotion? What type of evidence do we have? How was australopithecine locomotion similar to humans?
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- Obligate bipedalism -very human, maybe better - Wider pelvis and shorter legs of Au. afarensis produces greater bicondylar than even humans - Shorter flared pelvis, Short ischum for hamstring attachments - Lesser gluteals can stabilize the pelvis while walking and running - Legs intermediate between Ardi and humans - Getting longer - 5 - 6 Lumbar vertebrae - Similar to humans - Can produce lordosis - Laetoli Footprints • Big toe in line with rest of foot • Rounded heel • Arch of the foot • Fully bipedal
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30. What was the range of diversity of australopithecines? What were the major lineages? How did they differ? What types of environments were australopithecines found? How was their geographical distribution?
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- Radiation in 7 or more species - Ranged across African continent, Expanding habitats and territory - continent wide distribution - more open habitats, open woodlands, open grasslands -Invading new habitats - Australopithecus garhi - Australopithecus africanus - Australopithecus aethiopicus - Australopithecus sediba - Australopithecus boisei - Australopithecus robustus - Australopithecus afarensis
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31. Review primate taxonomy as discussed in lab section.
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32. What is the basic structure of a long bone?
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(arm and leg bones) have multiple parts The diaphysis is the shaft of the bone, which grows from the center out toward the ends of the bone The epiphyses are separate bone growth areas on either end of the bone The epiphyses eventually fuse to the diaphysis to form one solid bone.
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33. How has our increasing brain size affected our skeleton with respect to bipedalism?
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Obstetric Dilemma Humans have a problem with child birth that is not shared by other primates. Bipedalism narrows the pelvis, which reduces the size of the birth canal Increasing brain size makes the fetal skull larger These two trends come into conflict at the moment of birth
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34. What do the differences in limb lengths tell us about primate locomotion?
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Quadrupedal: Fore- and hindlimb lengths comparable Bipedal: Longer hindlimbs VCL: Longer hindlimbs Brachiation: Longer forelimbs
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Carbon14 radioisotope dating and how it differs from Potassium/Argon (K-Ar) dating methods. What is a half-life?
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Carbon14 radioisotope dating -only useful for measuring things that were formed in the relatively recent geologic past. (H/L of 5730) The most common ones: -Wood -Bones -Shells Potassium-Argon (K-Ar) method -that allows dating of materials that are beyond the limit of radiocarbon dating -volcanic ash -(H/L of 1.3 billion) half-life- The amount of time that it takes for half of the parent isotope to decay into daughter isotopes
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Aegyptopithecus-
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(ancestor to monkey and apes) • Oligocene anthropoid ~ 29 mya • Similarities to apes in dentition • Cautious above branch quadruped • Propliopithecid and earliest catarrhine (before split of apes and Old World monkeys • 2.1.2.3 dental formula; canine dimorphism • Larger 6-‐8 kg, cautious above branch quadruped • Smaller orbits with post-‐orbital closure • Ape-‐like molars with rounded cusps (Y-‐5 pattern)
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What is the significance of the Fayum and Aegyptopithecus?
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Fayum - of Egypt (37-‐29 mya) 1) Oligopithecids ---• Less than 1 kg ---•.1.2.3 catarhine dental formula ---• Larger olfactory system ---• Relatively small brain 2)Parapithecids •Canine dimorphism • 2.1.3.3 platyrrhine-‐like dental formula • Small size < 1 kg • Diurnal 3)Propliopithecids • Most derived Aegyptopithecus- (ancestor to monkey and apes) • Oligocene anthropoid ~ 29 mya • Similarities to apes in dentition • Cautious above branch quadruped•
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What were the characteristics of early apes found in Europe and Asia?
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-Proconsul (East Africa) - Dryopithecids (Europe) - Oreopithecus - Sivapithecus (Asia) -Gigantopithecus (Asia)
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Proconsul
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Dental characters link earlier Aegyptopithecus and a later apes Early Miocene of East Africa 22 -17 mya Four species recognized • Range from 17-50 kg • Molars with rounded cusps, Y-5 pattern • 2.1.2.3 dental formula • Large, dimorphic canines Some new features: • Larger brain • No tail • Longer limbs • Some increased forelimb mobility Some old (monkey-like) features: • Equal forelimb/hind limb lengths • Flexible spine • Deep chest -Cautious, above branch quadruped • Long back • Deep chest • Shorter fingers • Equal fore- and hind limbs
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Dryopithecids
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• First ape fossils appear after 17 mya - Tusk-like canines - Larger brains - Longer arms - More varied locomotion but not suspensory or knuckle-walking like modern apes
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Oreopithecus
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Late Miocene 9 - 7 mya • Swampy island habitat • Isolated from other apes Orangutan or gibbon like suspension • Short trunk and broad thorax • Very long forelimbs • High shoulder mobility • Full extension at the elbow joint Unique dental morphology • Unrelated to modern apes • Suspensory adaptations evolved in parallel
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Sivapithecus
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humerus like a baboon • Likely also an above branched quadruped similar to Proconsul • Some species are large and more terrestrial • Modern orang face with archaic ape skeleton - non suspensory
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Gigantopithecus
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• Up to 3 m or 10 feet tall & > 600 lbs • Likely an relative of the orangutan • Fossils recovered in China, India, Nepal and Vietnam • Mostly just jaws and teeth
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What are some of the features of early Old World monkeys?
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•Cercopithecoids begin to expand in number in the Late Miocene Victoriapithecus • Medium sized primate (7 kg) • Catarrhine dental formula 2.1.2.3 • Large dimorphic canine • Cercopithecoid-like bilophodont molars • Arboreal quadruped
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Intermembral Index:
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- Ratio of Arm Length / Leg Length 1 in Apes
