ANTH102 Final Exam Review Slides F24 PDF

Final Exam Review ANTH102 Professor Evans Fall 2024 FINAL EXAM: December 19, 2024 8:30AM-10:30AM (note: different than our usual class time) Don’t forget to study the concepts, taxa, and sites on the...

Final Exam Review ANTH102 Professor Evans Fall 2024 FINAL EXAM: December 19, 2024 8:30AM-10:30AM (note: different than our usual class time) Don’t forget to study the concepts, taxa, and sites on the review sheet too. Good luck!   Final Exam Review 1. How can geological studies provide us with a record of past life?  Geologic Geologic Time Timescale  Geologic Timescale An appreciation of the history of life relies on an understanding of the deep time involved Helps us to reconstruct and interpret evolutionary changes Without a chronological sequence, fossil record would be scientifically useless Able to record the major changes and events in evolution  Dating Methods Answer questions about when past organisms were alive Understand habitats of past plants and animals (which can also help us to understand the effects of habitat changes which may occur in the future, e.g. climate change) Relative and absolute dating –> greater understanding of evolutionary record and sequence of events Relative – e.g. stratigraphic correlation, chemical dating, biostratigraphic dating, cultural dating Absolute – e.g. tree rings, radiometric dating (e.g. K-Ar)  Radiometric Dating Form of absolute dating to determine age of rocks/minerals which have radioactive isotopes Isotopes = different forms of the same chemical element Some chemical elements are unstable, meaning that they change from one isotope to another isotope or another element Isotopes change into other isotopes/elements via a process called radioactive decay Decay rate (rate at which one isotope turns into another isotope/element) often happens at a fairly constant rate By knowing the decay rate and measuring the amount of different isotopes or elements in a sample of rock/minerals, it is possible to determine the age of the specimen (because you can determine how much time would have had to pass for there to be that much of each isotope or element) Example: Potassium-Argon (K-Ar) dating – particularly useful because volcanic rock is prevalent across the world When a volcano erupts, the heat is so extreme that it drives off all argon gas in the rock After the rock cools, the solid potassium (K) that’s in the rock sealed by lava then begins to decay to argon (Ar) gas) and the gas accumulates, trapped within the rock’s crystalline structure. To date the volcanic rock, you measure the amount of argon (Ar) gas and the amount of potassium (K) in the rock The more argon (Ar), the older the rock Law of Niels Stenson: Law of Superposition Superposi tion = the lower the stratum (layer of rock), the older its age Oldest rock layers are at the bottom; youngest rock layers are at the top Strata (layers of rock) represent various periods of deposition Each stratum contains a unique collection of fossils representing extinct life forms Earliest life forms are going be found in the oldest rock Younger and younger rock will contain appearances of newer life forms Possible to reconstruct: Ancient environments Extinct taxa Timing of major evolutionary events Speed of evolution Environmental pressures that operated on a species  Final Exam Review 2. What is the significance of the primate fossils found in the Fayum, Egypt? Who is Apidium thought to be the common ancestor of and what is this supported by? What about Aegyptopithecus? Many primate fossils from the early Oligocene (~34 Ma) have been found in the Fayum Depression, Egypt For over a century, fossil Early Anthropoids: 33- primates, 37 Ma particularly early fossil anthropoids have been known from the Fayum What the Fayum looks Fayum particularly known for its diversificati on of anthropoids (monkeys & apes) Provides many insights into the initial radiation and diversification What the of higher Fayum primates looked like 33-37 Ma  Apidium Fayum, Egypt Good sample of early anthropoid fossils (by 37 Ma). Catopithecus, Aegyptopithecus both have dental formula of 2.1.2.3 Apidium has dental formula of 2.1.3.3 Have relatives of living Platyrrhines and Catarrhines in  Apidium Dental formula 2.1.3.3 (same as modern platyrrhine dental formula) Possible ancestor of New World monkeys (platyrrhines) Aegyptopith ecus Dental formula 2.1.2.3 (same as modern catarrhine dental formula) Possible common ancestor of  Final Exam Review 3. Which features of humans link us back to other life on Earth? Features of the human body that reflect our descent from many organisms that appeared earlier in time DNA and RNA found in all living organisms Features of the human body that reflect our descent from many organisms that appeared earlier in time Multicellularity of invertebrates in ancient oceans Features of the Tetrapod ancestry human body that reflect our descent from many organisms that appeared earlier in time Tetrapods developed from a branch of lobe-finned fish living in the early to middle Devonian period  Final Exam Review 4. How was mammal evolution affected by the presence and then the extinction of the dinosaurs?  Mesozoic Era: Age of Reptiles 65 to 245 mya Dinosaurs rule world Egg-laying mammals evolve from synapsid reptiles Marsupial and Placental mammals evolve Birds evolve from dinosaurs First Angiosperm (flowering) plants Competition with Dinosaurs Restricts Mammals to a Few Niches As a result of this competition with the dinosaurs, the earliest mammals tend to be small, insectivorous or carnivorous  Cenozoic Era: Age of Mammals 65 Ma – Today Begins with major adaptive radiation of mammals and birds (extinction of the dinosaurs opened up a lot of previously unavailable ecological niches) Plesiadapiformes: ca. 63 Ma 1st definitive primates: Strepsirrhine fossils ca. 58 1st definitive Haplorrhine fossils ca. 40 Ma First hominins: 5-7 Ma  Final Exam Review 5. What are the proposed theories of primate evolution? What are the problems with each?  Why Did Primates Emerge?  Theories of primate evolution – Arboreal hypothesis Smith and Jones Moving from the ground to the trees caused selective pressures that resulted in the ancestral primate. Primate traits such as grasping hands and binocular vision were adaptations to life in the trees. Problem with arboreal hypothesis: other arboreal animals (e.g. squirrels), do NOT require these specializations Arboreal pressures alone not enough to explain primate origins  Why Did Primates Emerge?  Theories of primate evolution – Visual predation hypothesis Challenges arboreal notion: many mammals are arboreal without having evolved primate traits. Matt Cartmill proposed that primate traits evolved in response to preying on insects and other small creatures. Suggests that elaborate visual system helps them to hunt insects. – Predicts that the earliest euprimates should be nocturnal and insectivorous Why Did Primates Emerge?  Theories of primate evolution – Visual predation hypothesis The exploitation of small prey resulted in the primate suite of adaptations (e.g. grasping hands, stereoscopic vision) However, this visual predation hypothesis does not explain fruit-eating primates (most primates are not insectivorous!)  Why Did Primates Emerge?  Theories of primate evolution – Angiosperm radiation hypothesis Randall Sussman proposed that primate traits were a response to the development of fruit-bearing angiosperm plants. Grasping hands and feet evolved for feeding on fruits at the ends of branches This theory was in response to the nocturnal visual predation theory (logic is that most primates are frugivorous, NOT insectivorous so it is more likely that primates evolved to access flowers/fruits in terminal branches rather than to hunt insects) Proposed that excellent stereoscopic vision & grasping hands were essential for the foraging of flowering plants, which arose during the same geologic period in which early primates emerged Predicts that the earliest primates should be mainly frugivorous and primate origins coincide with the Problem with angiosperm radiation hypothesis: doesn’t really explain the elaborate visual adaptations primates – e.g., you don’t need all that fancy visual equipment to  Probably a combination of theories Many people think primate adaptations evolved due to visual predation + angiosperm radiation Primate traits evolved in a mosaic fashion Earliest primates ventured out into the terminal branches to feed on fruits/flowers (grasping hands and feet evolve) THEN… Visual predation of insects puts pressure for the elaborate visual system to evolve (stereoscopic, convergent vision evolves)  Final Exam Review 6. How do the crania and postcrania of the Miocene apes compare to monkeys? What about with living apes? Craniodent al traits of Miocene apes look more like modern apes e.g., bigger overall brain size compared to OWMs Skulls and teeth are apelike in appearance; rest of skeleton (postcranial skeleton) is monkeylike. Miocene Great Ape Living Ape Today Our Origins, 2th Edition Copyright © 2011 W.W. Norton & Company  Final Exam Review 7. Did climatic change over the course of the Miocene favor apes or monkeys? How so? Reversal of Fortune, Apes versus Monkeys Climatic change favored monkeys over apes over the course of the Miocene  Reversal of Fortune: Apes vs. Monkeys Climatic change favored monkeys over apes over the course of the Miocene (23 - 5 million years ago) Environments got cooler, drier, more seasonal Monkeys were favored as they efficiently consume a broader range of foods than apes, including foods more commonly found in drier environments (eat fruit, but also consume leaves, seeds, grass, etc.) Apes largely remained in woodlands and forests, consumed fruit; modern apes are the descendants of these survivors  Final Exam Review 8. What are the characteristics used to define hominins?  Order Primates Suborder Haplorhini Infraorder Catarrhine Superfamily Hominoidea Family Hylobatidae Pongidae Homininae 1. Bipedal – gibbons chimpanzee habitually walk on bonobo two legs gorilla 2. Canine reduction orangutan Homo Paranthropus Australopithecus Ardipithecus (?) Extinct Orrorin (?) Found in Africa only Sahelanthropus (?)  Final Exam Review 9. What skeletal features are indicative of bipedalism? What skeletal features are indicative of climbing around in trees?  The two arches of the foot 1) Front to back 2) Side to side Differs from quadrupedal apes who have flat feet (reflecting an  The hallux (big toe) Shorter and bulkier and non-divergent/non-opposable/adducted in humans Pan G. gorilla G. beringei Homo Derived features indicative of bipedalism 1. Foramen magnum underneath skull/anteriorly positioned (to balance head on vertebral column) 2. S-shaped spine 3. Short, broad pelvis 4. Femur is angled towards midline (valgus knee), maintains balance over one foot 5. Femur and tibia joints enlarged for weight transmission 6. Relatively long legs 7. Non-opposable big toe, arches in foot Ardipithecus ramidus features Head balanced on vertebral column (more derived trait) Pan-sized brain (more ancestral trait) No canine-honing complex (more derived trait) Less projecting face than Pan (more derived trait) Small cheek teeth like Pan (more ancestral trait) Ardipithecus ramidus features Body size dimorphism low (more derived trait) Arms not elongated as much as a living ape (more derived trait) Femora angle towards midline (more derived trait) Hands with long fingers (more ancestral trait), hand & wrist lack knucklewalking features (more derived trait) Short, broad pelvis (more derived trait)  Ardipithecus ramidus More omnivorous than Pan (which relies on fruit) Above branch crawling in trees Primitive form of bipedalism on ground. Pelvic balancing not well- developed, big toe for grasping branches, but stiff midfoot used as a lever when walking bipedally on ground. Ardi = part time biped/part time quadruped  Ancestral traits Australopithecus afarensis (Lucy’s species) shares with living apes Brain only a little larger than Pan: 400-500 cubic centimeters (cc) Projecting face, dental arcade shape ape-like, U-shaped Has diastema Canines larger More sexually dimorphic than humans Limb proportions intermediate between chimpanzees and humans (long arms, long legs) Long, curved fingers and toes  Features in A. afarensis indicative of bipedalism Forwardly placed, downwardly-directed foramen magnum Basically human arch structure in the foot with non-opposable big toe (hallux) Valgus knee at carrying angle (helps to center body over one leg while the other is in motion) Pelvis with short, broad iliac blade  Final Exam Review 10. What kind of habitat change occurred during the Pliocene (more specifically, from 3-2 Ma)? How did this affect human evolution? Habitat at 3 Ma  Habitat by 2.5 Ma During the Pliocene, the climate became cooler, drier, and more seasonal, similar to modern climates. Global cooling may have spurred on the disappearance of forests and the spread of grasslands and savannas. With this environmental shift, moreClimate has become cooler during the Cenozoic Climate has become more variable over the last 5 Ma  At 2.5-2.8 Million Years Ago Gracile australopithecines disappear from East Africa Early Homo and robust australopithecines (Paranthropus) appear 1st archeological sites Frequently related to late Pliocene environmental change  Final Exam Review 11. How did the “robust” australopithecines (Paranthropus) compare to the “gracile” australopithecines (Australopithecus)?  Paranthropus robustus, South Africa Robust cranial traits of large teeth, large face, well- developed sagittal crest, Differences in dental wear between gracile and robust australopiths indicates that the robust australopiths were eating foods which required heavier chewing than Robust Australopithecines (Paranthropus): CHEWING1.4MACHINES! – 2.7 Ma, East and South Africa Brain a bit larger than A. afarensis, ca. 410-520 cc Body size, degree of sexual dimorphism like Australopithecus species U-shaped dental arcade Relied at least seasonally on more difficult to chew foods than graciles: Giant jaws Premolars and molars enormous  Final Exam Review 12. How do the dental trends within the australopithecines (Australopithecus, Paranthropus) differ from the dental trends within the genus Homo (from Homo habilis to modern humans)? What might explain this?  ca. 2.8 MYA earliest Homo appears Genus: HOMO -brain larger than that of chimpanzee, Australopithecus - narrow molars, premolars, enamel thinner than in Paranthropus  Homo habilis cranial capacity: 500-650 cc Showed the first substantial increase in brain size in hominins! Larger brain, as well as a reduced chewing complex  Early Homo had smaller cheek teeth, and larger incisors than Paranthropus boisei Paranthropus boisei Homo habilis, OH 65  Final Exam Review 13. What are the proposed explanations for the shift from quadrupedalism to bipedalism? Which is most likely?  Explanations for Bipedality It’s handy It’s cool It’s efficient  It’s Handy Bipedalism frees up the hands for: feeding food transport tool use and transport It’s Cool Bipedalism lessens heat stress in direct If sunlight you’re walking bipedally, you are going to decrease the surface area of your body that is exposed to the sun (less of your body is faced toward the sun – the top of your head when walking bipedally vs. your whole back when walking quadrupedally)  Sockol MD, Raichlen DA, Pontzer H (2007) Chimpanzee locomotor energetics and the origin of human bipedalism. Proceeding of the National Academy of Science 134: 12265–12269. Human bipedalism is much more energetically efficient than chimpanzee knucklewalking Chimpanzees ON AVERAGE expend same Most amount of energy knucklewalking and walking likely bipedally, AND… Variation in energetic efficiency among explanati individual chimpanzees walking bipedally; in on! individuals with longer strides bipedalism was more efficient than knucklewalking Origins of Bipedalism Emergence of bipedalism has been related to the ecological context of early hominins, including the switch from a forested environment to a more open, forest/savannah or savannah environment  Final Exam Review 14. Know the timeline of Homo erectus. When did it first appear? Where? How long did it last in these places? What happened to it?  Early Homo erectus appears in Africa by 1.9 Ma, disperses out of Africa by ca. 1.8 Ma Among the earliest & most spectacular of the erectus fossils is an 80% complete juvenile skeleton “Nariokotome Boy”/”Turkana Boy” (seen here)  Homo erectus skeleton WT 15000, 1.5 Ma  Following Homo erectus, more advanced hominins appeared in the Old World, first in Africa and Europe, and later in Asia. This new form is often called Homo heidelbergensis. Important: Homo erectus was the first hominin species to move out of Africa and into Asia and  Homo erectus lasted longer in China Disappears from Africa & Europe ca. 800 Ky Found in China until ca. 200 Ky Homo heidelbergensis or a comparably derived hominin found in China after 200 Ky Replacement of Homo erectus by Homo heidelbergensis? Or did the two species co- exist in places?  Final Exam Review 15. What kind of mating system did Homo erectus have? How can we infer this? (about other taxa as well) Australopithecine Social Systems High levels of sexual Homo dimorphism in Australopithecus suggestive of strong intrasexual selection— Multimale, multifemale Inferring mating systems from extinct hominins High levels of sexual dimorphism – lots of intrasexual selection (lots of competition between males for females) Circumstances likely to foster a situation in which males need to compete a lot?  Multimale, multifemale groups Sexual dimorphism reached modern human levels (i.e., low levels of sexual dimorphism) around the time of Homo erectus 0.5-2 million years ago – may suggest that human ancestors began the transition to monogamy around this time  Final Exam Review 16. In what ways do anatomically modern humans (Homo sapiens) differ from other hominins? What characteristics gave them an edge over earlier human forms (e.g. Neanderthals)? The Modern Human Skull AMH=anatomically modern human Brain size avg 1340 cc Short, high braincase Sides of braincase roughly parallel Short face tucked underneath frontal lobes of brain Mandible with chin (inverted T) Aurignacian: 32-43 KY Earliest European Upper Paleolithic culture (Blade, burin and bone technology) Aurignacian tool industry characterized by worked bone or antler points Flint tools have fine blades that have been struck from prepared cores rather than using crude flakes Involves high levels of sophistication and self-awareness The Ultimate Success of Homo sapiens May be related to COGNITIVE CHANGES (how we perceive and think about the world around us): Changes in our brain structure? Development of sophisticated, symbolic language? Cumulative cultural change? anderthals apparently had the “capacity” for some componen of the Upper Paleolithic way of life Likely that Neanderthals were quite sophisticated and were able to participate in similar cultures as modern Homo Culture as Adaptation: Cumulative Cultural Change Human culture is cumulative; technology, beliefs, art, etc. are results of many generations of cultural change. Cultural change much slower in earlier  Final Exam Review 17. What do analyses of mtDNA (mitochondrial DNA) and nDNA (nuclear DNA) of Neanderthals and modern humans reveal? Nuclear DNA, mitochondrial DNA and cranial shape all exhibit greatest diversity within Africa. This is consistent with the modern human genome originating in Africa. Neanderthal mtDNA largely outside range of variation of modern human mtDNA; 300-400 Ky period of isolation/divergence? Suggests that Neanderthals are not ancestral to modern humans Neanderthal nuclear DNA also suggests period of isolation from Homo sapiens, and provides evidence for gene flow (interbreeding) between Neanderthals and non-African Homo sapiens populations CONSENSUS: Neanderthals not ancestral to Homo sapiens, but probably interbred with them. Homo sapiens probably interbred with archaic humans in Asia and Africa as well, so that 3-5% of the modern human genome came from other forms of human *****Homo sapiens evolved in Africa, but occasionally interbred with archaic forms of humans (like Neanderthals and Denisovans) when they encountered them  Final Exam Review 18.Which is the most plausible model proposed to explain modern human origins? Most reasonable model: Replacement with some hybridization AMH evolve in Africa 100-200 Ky Consistent with genetic evidence & fossil evidence Traits such as jewelry production, pigment processing, etc. occur first in Africa, suggesting that the AMH had the capacity for modern behavior prior to 50 Ky—(no major mutation at 50 Ky—NO “HUMAN REVOLUTION”) Homo sapiens spreads across Europe and Asia by 25 Ky, with some interbreeding with archaic forms of human Contribution of archaic human populations to the modern human gene pool varied, but it seems likely that archaic forms of human in Europe (Homo neanderthalensis), Asia (Homo heidelbergensis?, Homo erectus?, Denisovan?), and Africa interbred with modern humans and contributed to the Homo sapiens gene pool.  Final Exam Review 19. What were the effects of the agricultural evolution?  Agriculture: An Adaptive Tradeoff Population has increased from 2 million to 6 billion in the last 10,000 years (more food being produced to support population growth) Competition for resources strains the global environment (e.g. organized warfare, increased interpersonal violence) Environmental Degradation Cultural and technological changes have had negative effects. Cooking with pottery softens food, so that you do not need to chew as much Reduced stresses on humans’ chewing muscles This reduced stress, like that on any muscle, also reduced the underlying bone We have much smaller jaws because our  Dental Crowding & Malocclusion  Face and jaws in H. sapiens have gotten smaller over time  Masticatory-functional hypothesis: changes in skull form are a response to decreased demands on the chewing muscles.  Because teeth have reduced more slowly in size than the bones of the face, dental crowding has occurred  Changes in the human skull : Shorter, more globular, smaller face, less room for teeth These changes represent a response to decreased demands on the chewing muscles as people shifted from eating hard-textured wild foods to eating soft-textured  Human skeletons have become less “robust” over time  Agriculture’s Changes to Workload/Activity  Changes in workload and activity have also affected human physical appearance.  Bone responds to stresses on it over the course of a lifetime.  How hard someone works affects the skeleton.  The general evolutionary Hunter-gatherers had larger cross-sections of both femora trend in humans is to a and humeri (indicating greater bone strength) when smaller, more gracile compared to agriculturalists  How Did Agriculture Affect Human Biological Change?  Health and the Agricultural Revolution often led to a less nutritious diet (reliance on a few crops, less meat) – The Consequences of Declining Nutrition: Tooth Decay Dental caries, or cavities, increased after certain plants (corn) were introduced.  How Did Agriculture Affect Human Biological Change?  Health and the Agricultural Revolution – Population Crowding and Infectious Disease Increased population size and density caused the spread of more infectious illnesses; diet was also affected. Bones can reveal the presence of infectious illnesses even after hundreds of years.  If It Is So Bad For You, Why Farm?  Agricultural practices increased human fertility.  More calories per land unit and more food resources for population increases  Final Exam Review 20. How are infectious diseases spread? What are their impacts (past, present, and future)?  Infectious Disease Caused by invading organisms such as bacteria, viruses, or fungi. Can exert enormous selective pressure Influence the frequency of alleles that affect the immune response Epidemic: New cases of a disease spread rapidly through the population  Impact of Infectious Disease Since the 1940s - antibiotics have reduced the mortality rate. Late 1960s - surgeon general prematurely declared the war against infectious disease won Between 1980 and 1992 - deaths by infectious disease increased by 58% (possibly due to overuse of antibiotics)  Environmental factors may increase the impact of infectious disease Global warming—tropical diseases may spread Population Movement Overcrowding/unsanitary conditions Overuse of Antibiotics Infectious disease may prove to be a huge challenge in the future