EXAM: FINAL Thursday, 13 Dec 2007, 2:00 4:00pm
Review Questions for Exam #3 (the FINAL) The FINAL exam will be mixed format and non-cumulative. You are responsible for both lecture and material from the text (see below). Also take advantage of your lab manual and online resources such as http://www.wwnorton.com/web/evolve Readings: Boyd and Silk (2006) How Humans Evolved, 4th Edition. Please focus on: Ch. 10: 242-255 (Box 10.3, p262-263); Ch. 11: p269-297; Ch. 12: p304-314; Ch. 13: p327-332, p337353, p358-360; Ch. 14: p362-364, p376-388; Ch. 15: ALL; Ch. 16: p431-440, p445-455; Ch. 17: p457472 Annual Editions in Physical Anthropology 07/08: Articles 35-38, 43-44.
Why might geology and climate change been important factors in relation to primate (and human) evolution? The position of the continents plays an important role in the evolution of species and continental drift is one of the engines of climate change. Since the environment is constantly changing, evolution does not follow a straight distinct path. What is continental drift / plate tectonics? Continental drift is the movement of the continents. The enormous relatively light plates of rock that make up the continents slowly drift around the globe, floating on the denser rock that forms the floor of the deep ocean. What are some examples of absolute and relative dating methodologies? What is the general basis for each of these techniques (e.g. radioactive decay, stratigraphy, faunal correlation)? Radioactive decay (potassium-argon dating): when molten rock emerges from a volcano, the argon gas is boiled out of the rock. Any argon present in the rock therefore is from the decay of potassium that occurs at a known and constant rate and therefore, the ratio of potassium to argon can be used to date volcanic rock. This dated layer is then used to estimate the age of fossils found in lower geological layers. Carbon-14 dating: When an animal or plant dies, carbon-14 decays into the carbon-12 isotope at a constant rate. Fossils can be dated by measuring the ratio of these two isotopes. Thermoluminescence dating: This is based on an effect of high-energy nuclear particles traveling through rock. Electron-spin-resonance dating: This is used to determine the age of apatite crystals, an inorganic component of tooth enamel, based on the presence of trapped electrons. Paleomagnetism: refers to the study of the record of the Earth's magnetic field preserved in various magnetic minerals through time What are plesiadipiformes? Describe some of their characteristics, as well as "when" and "where" they occur in the fossil record. Are they (or are they not) good candidates for primate ancestors? Plesiadipiformes are a group of fossil animals found in what is now Montana, Colorado, New Mexico, and Wyoming dating from the Paleocene epoch, 65-54 mya. They varied from tiny, shrewsized creatures to animals as big as a marmot. They were solitary quadrapedals with a welldeveloped sense of smell, had variable teeth suggesting a wide range of dietary specializations, did not have binocular vision and most had claws on their hands and feet. They possess some but not all of the traits within the primate order so the decision of how to classify these creatures depends on the arbitrary assessment of how similar they are to other primates.
FINAL EXAM: Thursday, 13 Dec 2007, 2:00 4:00pm
Where do adapiformes and omomyids fit into primate evolution (i.e. How old are they. where are they found, and what are their characteristics)? These are found in the Eocene epoch 54-34 mya. Omomyids had huge eye orbits (nocturnal) like tarsiers, omnivorous, and elongated calcaneus bones in their feet possibly allowing them to leap from tree branches. Adapids were larger with longer snouts, omnivorous, and smaller eye orbits (diurnal). Unsure of how these fossil primates are related to modern prosimians. What is known about the evolutionary history of New World Primates? Specifically, where might they come from? The earliest NWM fossils come from the late-Oligocene site in Bolivia, had three premolars and were frugivores, and were about the size of owl monkeys. Some think that these primates originated from Africa but it is unclear how they got to South America since the two continents were separated by about 2,000 miles of ocean. Others believe they could have come from North America however no anthropoid fossils have been found there. Know the relationship between epochs and the fossil primates that are most abundant in the that period (e.g. Miocene = age of apes) Paloecene: 65-54 mya Plesiadapids Eocene: 54-34 mya Adapids & Omomyids Oligocene: 34-23 mya Anthropoids Miocene: 23-5 mya Hominoids (Apes) Pliocene: 5-1.7 mya Hominids (monkeys) Pleistocene: 1.7 mya - Hominins What are some human-like ("derived") and pongid-like ("ancestral") traits used for analyzing fossil specimens? (Hint: think cranial characteristics) Human-like: wide parabolic dental arcade, thick enamel, reduced incisors, larger molars in relation to other teeth, larger brain relative to body size, reduced subnasal prognathism, foramen magnum under skull Pongid-like: pronounced subnasal prognathism, diastema present (tooth gap in lower jaw for upper canine), parralel (U) dental arcade, pronounced canine dimorphism, pneumatized basicranium, receding chin What are the locations, estimate ages, and 3 diagnostic traits for Australopithecus, Paranthropus and related species (e.g. Ardipithecus, Kenyanthropus, Ororrin & Sahelanthropus)? Ardipithecus (Middle Awash Basin, Ethiopia, 5.8-4.4 mya): foramen magnum under skull, small incisor-like canines, small molars, thin tooth enamel, pneumatized basicranium Ororrin (Tugen Hills, Kenya, 6.0 mya): ape-like teeth, thick tooth enamel, climbing and bipedal adaptations Sahelanthropus (Toros-Menalla, Chad, 7.0-6.0 mya): relatively flat face, massive brow ridge, foramen magnum under the skull, small braincase A. Anamensis (Kanapoi, Kenya, 4.2-3.8 mya): large molars with thick enamel, U-shaped dental arcade, receding chin A. Afarensis (Hadar, Ethiopia, 4.0-3.0 mya): small endocranial volume, pneumatized basicranium, subnasal prognathism, V-shaped dental arcade, modest diastema A. Africanus (South Africa, 3.0-2.2 mya): fewer air pockets in skull, short face, reduced subnasal prognathism, large molars, fast maturation A. Garhi (Awash Valley, Ethiopia, 2.5 mya): sagittal crest, subnasal prognathism, broad canine, large molars, small brain, elongated femur
FINAL EXAM: Thursday, 13 Dec 2007, 2:00 4:00pm
A. Habilis/Rudolfensis (East Turkana, Kenya, 2.4-1.6 mya): large brain with robust skulls & teeth, small brains with gracile skulls and teeth, associated with tools P. Aethiopicus (West Turkana, Kenya, 2.5 mya): massive chewing apparatus, sagittal crest P. Robustus (Swartkrans, S. Africa, 1.8-1.0 mya): small brain, bipedal, massive chewing apparatus, meat in diet? P. Boisei (Olduvai Gorge, Tanzania, 2.2-1.3 mya): hyperrobust paranthropine, larger body, larger molars, skull specialized for chewing K. Platyops (West Turkana, Kenya, 3.5-3.2 mya): small chimp-like ear hole, small braincase, thick enamel, small molars, broad flat face Why might have bipedalism evolved? What are some hypotheses and which are supported with the available evidence? Bipedal locomotion is an efficient form of locomotion over long distances Erect postures allow hominids to keep cool because there is less surface area to absorb direct sunlight and there is more wind at a taller height Leaves the hands free to carry things Bipedal posture allows efficient harvesting of fruit from small trees What are the ages, locations and characteristics of fossil stone tool industries? Oldowan Tool Industry (Mode I): 2.5-1.5 mya, simple cores and flakes, "choppers, hammers, &scrapers" Acheulean Tool Industry (Mode II): 1.6 mya, bifaces (hand ax, cleaver, pick) Levallois Technique (Mode III): 300 kya, prepare a core with one convex surface, make a striking platform at one end, knock off flake by hitting the platform; Mousterian Industry for Neanderthals Upper Paleolithic (Mode IV): 45 kya, blade tools, many distinct standardized tool types What are the difficulties in identifying the most likely toolmaker (and tool-user) among fossil species? There are a large number of species in East Africa between 2.5 and 1.7 mya so it isn't clear who used the tools. It could be possible that the earliest tools were made by species that don't appear until later in the fossil record because stone tools are more durable than bones. What are some proposed uses of Oldowan (Mode I) and Acheulean (Mode II) tools? Oldowan tools could have been used for butchering large animals, chopping down small trees, digging in termite mounds, and process carcasses. Acheulean tools were used for butchering large animals, digging up tubers, burrowing animals, and water, stripping bark from trees to get at the nutritious cambium layer underneath, hurling at prey animals, and dispensing flake tools What are the characteristics of the early Pleistocene hominids (Homo ergaster/erectus)? H. Ergaster (East & S. Africa, 1.8-0.6 mya): 1st "migrant", associated with Mode II tools, larger braincase, occipital torus, receding forehead, no chin, less prognathic face, higher skull, smaller jaws and teeth, larger brain than earlier hominins H. Erectus (Java & China, 1.8 mya 30 kya): thicker skull, pronounced browridges, sloped sides of skull, pronounced occipital torus, sagittal keel, associated with Mode I tools only What are the characteristics of the middle-Pleistocene hominids (Homo heidelbergensis)? (250-50 kya) They had larger brains in relation to body size than H. ergaster. Their skulls had more vertical sides, higher foreheads, and a more rounded back all more similar to modern humans.
FINAL EXAM: Thursday, 13 Dec 2007, 2:00 4:00pm
However, they also had thick cranial bones, a large prognathic face, no chin, and large browridges. Their bodies very were robust, more so than modern humans. What are Neandertal characteristics? Be sure to know age ranges and localities. (W. Eurasia, 127-30 kya) Their faces bulge out in the middle, they have double-arched browridges, and the backs of their skull is rounded (rounded basicrania). They have large brains, small back teeth and large heavily worn front teeth, and robust heavily muscled bodies. Where does "Flores Man" (Homo floresiensis) fit into our understanding of human evolution? "Flores Man" shows us that human lineage is subject to the same kinds of evolutionary forces as other creatures are because the island it was found on have always been isolated from Asia and Australia. What are two hypotheses for the origins of modern humans? For each, give assumptions, predictions, dispersal scenarios, and assess the genetic and morphological evidence. Multi-regional continuity gradual evolution in all regions, anatomically modern humans arise throughout the world at about the same time, regional morphological differences are old. Not supported by genetic evidence but supported by similarities in skeletal features between some fossils and more recent populations in the same area Replacement Model gradual evolution in Africa only, outside of Africa dramatic shifts 100kya, differential timing in first appearance of anatomically modern humans. The oldest fossils of anatomically modern humans occur in Africa. African populations show the most genetic variability today which is possible evidence that the population explosion began in Africa. What are some general conclusions that can be made about human evolution in terms of the last common ancestor (with chimpanzees) and both the major anatomical and behavioral transitions? Modern humans have a smaller face with a protruding chin and smaller teeth, a rounded skull with high foreheads, rounded basicranium, and reduced browridges, and a less robust postcranial skeleton with longer limbs and thinner walled bones. Modern humans did not use their teeth as tools as earlier ancestors had and relied less on body strength and more on elaborate tools and other technological innovations to do their work. What are some sources of variation between and among populations? Between Mutation (selection-mutation balance), selection (balanced polymorphism), disequilibrium Among Local adaptation, genetic drift (founder effect), migration & population growth What are selection-mutation balance, balanced polymorphisms and disequilibrium? Give an example for each. Selection-mutation balance: an equilibrium that occurs when the rate at which selection removes a deleterious gene is balanced by the rate at which the mutation introduces that gene. The frequency of genes at selection-mutation balance is typically low Balanced polymorphism: a steady state in which both alleles persist in the population because the heterozygote have a higher fitness than either homozygous has (as is the case with carries of sickle-cell allele) Disequilibrium variation could exist because environments have recently changed and genes that were previously beneficial have not yet been eliminated
FINAL EXAM: Thursday, 13 Dec 2007, 2:00 4:00pm
What is Allen's rule? What is Bergman's rule? Allen's Rule: limb proportions are shorter in colder climates Bergman's Rule: with increasing size, surface area to volume decreases Contrast adaptation with acclimatization. Adaptation: traits with a genetic basis and formed through selection (long-term) Acclimatization: physiological response within an individual (short-term); an example is high altitude stress: difficult ventilation, respiratory alkalosis, circulation problems, increase in red cell volume Define and give examples of concordant and discordant variation. Concordant variation has to do with monozygotic twins (identical) that begin life when the embryo divides into two genetically identical individuals. If the variation is genetic only, then monozygotic twins will be more alike each other then dizygotic twins (fraternal) that only share half of the same DNA. Discordant variation has to do with the idea of environmental covariation. If most of the variation is due to the environment then identical twins will be no more alike than fraternal twins. How are geographic variation and race related? Dark skin might have evolved to protect against the breakdown of folate. Skin color is a balance of vitamin D production and folate loss. Recent migrations produce disequilibrium. With regards to race, there is no single natural classification. Racial classification explains little genetic variation and does not represent natural biological categories. Genetic and morphological similarity is associated with geographic proximity. Understand why evolution is relevant to human behavior. Phenotypic traits reflect interactions between genes and the environment. Every trait results from the interaction of a genetic program with the environment Natural selection can shape developmental processes so that organisms develop different adaptive behaviors in different environments. Evolved mechanisms cause humans to share universal characteristics such as inbreeding avoidance and the capacity for language What do we know about the origins and evolution of language? Consider the following: ape studies, comparative neuroanatomy, morphological correlates (e.g. thoracic vertebrae, hyoid, hypoglossal canal), adaptive explanations, arguments for early vs. late origin, and the FOXP2 gene. Ape studies: Koko the gorilla has learned basic sign language; Kanzi the bonobo uses lexigrams to communicate. Apes show linguistic abilities similar to young children but their difficulties suggest language could be a derived trait. Comparative neuroanatomy: increase in volume of posterior parietal cortex (Wenicke's area) that is associated with language comprehension and a reorganization of the frontal lobe (Broca's area) which is associated with the production of language Morphological correlates: larynx, thoracic vertebrae and hyoid are located below the jaw in humans as opposed to behind the jaw in apes. We have a wider hypoglossal canal compared to other apes Adaptive explanations: organizing hunts, sharing food, passing on tool-making skills, caring for and training young, the list goes on Early origin (2.0 mya): brain size, brain asymmetry, complexity of language Late origin (100-40 kya): thoracic vertebral canal, hyoid bone, tools & art
FINAL EXAM: Thursday, 13 Dec 2007, 2:00 4:00pm
FOXP2 gene: it codes for a transcription factor, facilitates transcription from DNA to RNA, and has the potential to affect many genes. There have been two mutations in this gene since human lineage Be familiar with explanations for sexual aversions in modern humans; i.e. Why do humans exhibit universal inbreeding avoidance? Offspring of related parents have lower fitness than those of unrelated parents. Matings between close relatives are very rare among nonhuman primates because they have a strong inhibition against mating with close kin. Adults are not sexually attracted to the people with whom they grew up (evidence from Kibbutz age-mates studies and negative third-party attitudes towards incest). How are social facilitation, observational learning, ratcheting related to social transmission and the evolution of culture? Social facilitation occurs when the activity of one animal indirectly increases the chance that other animals will learn the behavior on their own. This explains the evolution of tool use but it can only preserve variation in behavior that organisms can learn on their own. Observational learning occurs when a "nave" animal learns how to perform an action by watching the behavior of the experienced, skilled animals. This allows cumulative cultural change. Ratcheting: cumulative change; this allows us to trace the evolution of certain technological innovations over time Culture is information acquired through some form of social learning and is adaptive How do humans compare to non-human primates in their sexual characteristics and mating patterns? Body size dimorphism, relative testis size, relative penis length, and female morphology are all similar. Mild polygyny, serial monogamy, pair-bonding with extra pair copulations, fraternal polyandry, culture-dependent How does evolutionary biology predict human mate choice (for both men and women)? And what are some social consequences of mate preferences in humans? Men prefer younger mates because male success depends largely on the fertility of their mate. Both men and women care most about the personality of their mates. There is a difference between men and women in mate preference based predicted by parental investment. Women value stable and exclusive pair bonds since they invest 9 months on pregnancy and more time to raise a child while men try to maximize partners. Men often seek women who are younger than they are which is based on reproductive potential. Women on the other hand are less concerned about the age of their mate and more so about their mate's ability to provide resources for them and the offspring. Culture predicts people's mate preferences better than gender does. Men and women from the same culture are more like one another than men or women from another culture. Marriage patterns are different in different cultures such as the polygyny exhibited in Kipsigis women and the polyandry exhibited in Nyinba What has been the role of biological anthropology in our understanding of the origins and evolution of modern humans and our behavior?
We use a comparative & inter-disciplinary approach, evolutionary mechanisms, primate behavioral ecology, the fossil record, and modern variation and adaptation to understand what we can Who are we? One variable & dispersed population, highly encephalized (having to do with the brain), bipedal hominins, dependant on culture Where from? Environmental change, geology & climate, competition/mutations