Exam 3 Review Sheet for Anthropology 105 PDF

**Exam 3 Review** **Anthropology 105** **Principles of Biological Anthropology** Exam 3 will take place during class in 6210 Sewell Social Sciences Monday November 11. The exam will be 50 minutes long and include only multiple-choice questions which you will answer using a Scantron answer sheet....

**Exam 3 Review** **Anthropology 105** **Principles of Biological Anthropology** Exam 3 will take place during class in 6210 Sewell Social Sciences Monday November 11. The exam will be 50 minutes long and include only multiple-choice questions which you will answer using a Scantron answer sheet. If you have extended time testing or other McBurney accommodations for testing, you need to sign up for a date/time on Canvas course page by clicking on Testing Center (RegisterBlast) to take the exam at the Testing and Evaluation Center. Use this review sheet to go over key concepts from Lectures 13-17 that will be covered in multiple choice questions on Exam 3. I have given this to you as a Word document so that you can use your notes to expand on it. The answers to these questions and concept definitions are on the lecture slides that are posted as pdf on Canvas, or were discussed by Professor Bryer during lecture. LECTURE 13: Primate social behavior - **Primate predation (other species hunt and eat primates): why is it important? What are counterstrategies to predation that primates use?** - Important because it affects the populations of other primates. - Vocalization (alarm calls for different animals), Increased group size (more eyes will see a predator), Dilution (larger group of animals, lowers your risk of getting killed), Deterrence (mobbing), Interspecific associations (can also be a form of dilution affect) - **What other animals hunt and eat primates?** - Snake, Eagle, Leopard, Crocodile, Lion. - Chimpanzees hunt monkeys - **What kinds of evidence do primatologists/biological anthropologists examine to study predation?** - They study tracks (made from a baboon's body after a leopard dragged it through the dirt.) - They study footprints (leopard's footprint next to the drag marks) - They study reminds (remains of a baboon after being killed and eaten by a predator) - **What are the benefits and costs of social grouping?** - Benefits: avoidance of predators, better access to food (defense of food and other groups can help find food) - Costs: more competition for food and mates, increase disease transmittion - **Be able to describe the simplified primate socioecological model.** - A diagram of a model of a society Description automatically generated with medium confidence - **Know the major type of social groupings in primates. Know at least one example of how some primate species are more complicated than these major types.** - Solitary/semi solitary - A lot of nocturnal - Strepsirrhines (lemurs lorises) - One male, multi female - Polygyny - gorillas - Multi female, multi male - Chimpanzees and Volvos - Macaques, baboons, capuchin monkeys, squirrel monkeys, colobines - Pair bonding - Gibbons, a few platyrrhine monkeys and strepsirrhines - **How do primatologists determine dominance rank in a primate social group?** - The outcome of contests - Body size - Strength - Experience - Willingness to fight - **What is primate dispersal and what are the benefits and costs of dispersal? Why does one sex tend to disperse in primates?** - - **What is an example of within group social behavior in primates? What is an example of between group social behavior in primates?** - Within - Affiliative behaviors (grooming) - Aggression (chasing, attacking) - Dominance rank - Between - Overlapping home ranges, inter group encounters where aggressive interactions don't occur. - Sometimes territorial boundary patrolling where they will attack other groups - **What do biologists mean by "reproductive strategies"?** - a set of traits (physical or behavioral) that solve a particular adaptive problems, in this case, finding mates and rearing young. - **What do female primate (and mammal) reproductive strategies tend to be limited by? What do male primate (and mammal) reproductive strategies tend to be limited by?** - Female reproductive success tends to be limited on access to food - Male reproductive success tends to be limited by access to mates - Limited window to mate (pregnancy) - Many males compete - High ranking females, produce the most births and have the infant survive more - **What is the difference between natural selection and sexual selection?** - Sexual selection favors traits that increase success in competition for mates - Male red deer use their antlers when they fight for females - Peacock tail enhances his attractiveness but hinders him for escaping for predators. - **Why is infanticide adaptive for male primates in one-male multi-female social systems?** - Infanticide: New males kill infants that are unrelated to them when they take over the group - Adaptive if - Probability of male siring the infant in question is low (he wouldn't want to kill his own blood) - Female can start reproducing sooner without presence of lactating infant - Infanticidal male has high probability of siring the next infant for that female - Risk of injury is low - **What are female primate counterstrategies to infanticide?** - Active defense of infants - Avoidance of new males - "friendships" with males for protection - Confusing paternity by mating with multiple males - Post-conception estrus (tricking) - Terminate pregannay when male takeover group occurs - **Why are muriquis surprising in their social and mating patterns for a multi-male multi-female social system primate?** - - Vocabulary to know: - Predation - Being eaten by predator - dilution effect - if there are more people in a group the chances that you would get killed is lower the bigger the group. - mobbing a predator - Deterrence. Crows mob an owl that is threating them. - chimpanzee - red colobus monkey - home range - where they live depending on the availability of food and how far it ranges and they seasonality of food - food availability - leaves are often more plentiful than fruit - seasonality in food availability - ripe fruit and young leaves are not always present - territoriality - Territorial animals (some primates) defend their home range aggressively and it does not overlap with any others. This is because they want to defend their mates and their resources. - pair bonding - Pairs - solitary/semi-solitary - Nocturnals - polyandry - Marmosets and tamarins - Cooperative breeding - One female breeds but more than one male may share a paternity of infants - a single female forms a stable pair bond with two males at the same time, is rare among mammals.  - Polygynandry - Multiple males, multiple females - polygyny - one male, multiple females - Skew in male reproductive success - Blue monkeys - multilevel societies - cooperative breeding - alloparental care - dominance interactions - threating chasing, attacking - dominance matrix -  - dominance rank - when dominance interactions have a consistent predictable outcome we can determine the dominance rank - dispersal - male philopatry - female philopatry - dominant - subordinate - dominance rank - affiliative social behavior - aggressive social behavior - intergroup encounters - between group social behavior - within group social behavior - mating system - reproductive strategy - a set of traits (physical or behavioral) that solve a particular adaptive problems, in this case, finding mates and rearing young. - reproductive success - reproductive skew - degree to which reproductive success is shared (low skew) or monopolized by one or few indivitdiuals - sexual selection - category of natural selection - intrasexual selection - enhance success in male-male competition - sperm competition - competitive process between spermatozoa of two or more different males to fertilize the same egg during sexual reproduction - sexual dimorphism - intersexual selection - make males more attractive to females (between the two sexes) estrus - sexual swelling, a signal that she is reproduction at that time, swelling after they have already conceived to trick males - muriqui - - Egalitarian - Platyrrhine in Brazil, largest monkey in south America - Multi-male multi-female groups - Polygynandrous (both sexes have multiple partners) - Male philopatry (males stay in the group their born in) - Mostly florivorous - Low sexual dimorphism - Interesting because: - Males rarely fight - Cannot calculate dominance ranks - Reproductive skew is very low (successes evenly distributed based of genetic analyses - Relatively large testes for body size, sperm competition LECTURE 14: Primate conservation - How does anthropogenic change alter wild primate diets and nutrition? - Change caused by humans - The effects of humans in and around primate habitats affect the foods and nutrition available to primated - Give an example of a nutritional, specifically macronutrient, reason that gorillas might crop raid/seek out agricultural crops - Theres more fiber and sugar in the agricultural crops - Give an example of a nutritional, specifically micronutrient, reason that gorillas might seek out *Eucalyptus* plantations. - The gorillas obtain up to two thirds of their sodium when consuming eucalyptus. Sodium is a micro-nutrient that\'s critically important for physiological processes, like muscle and nerve function and maintaining fluid levels in various parts of the body - How does climate change affect wild primate diet? What did researchers at Kibale National Park find when they compared the nutritional content of leaves of two tree species that red colobus monkeys eat in 1990 to those in 2010? - the leaf-dominant diet of many primates can put some species as risk because higher temperatures and lower rainfall will impact the amount and quality of browse - Because of the decrease in nutritional value there is a predicted 31% decline in the biomass of colobus monkeys - Two-thirds of all threatened primate species occur in just four countries. What are those four countries? - Brazil - Madagascar - Indonesia - Democratic Republic of Congo - What predisposes primate species to extinction risk? - Small population size / low population density - Small geographic range - Higher tropic levels (chain of extinction) - Complex social structures - Diurnally - Slow life histories - What threats do primates face? - Habitat destruction and fragmentation - Timber extraction - Agriculture - Mining - Hunting/Bushmeat trade - Pet trade - Disease - Of the living nonhuman great apes, which are facing the highest risk of extinction (i.e. which great apes have the lowest numbers in the wild)? - Bonobos - Why is it important to examine different species of gorillas, for example, rather than all gorillas together, when assessing extinction risk? - Because there is a high variance between the species of gorillas - West Lowland Gorillas had a higher pop than mountain gorillas - What agricultural industry is driving the habitat loss in orangutan habitats? - Oil Palm, Mosly in SE Asia - What other industries are driving habitat loss in primate habitats and how do these industries vary by region in how much habitat loss they cause? - Poaching - Soy - Neotropics - Cattle stock - High everywhere but SE Asia and especially Neotropics - Natural rubber - SE Asia - Industrial Hardwood - Neotropics - Review the case study in Kibale National Park where snares set for small mammals accidentally lead to injury in chimpanzees. How does this affect chimpanzee feeding and social behavior? - It does not affect feeding efficiency - When a chimp is caught in a snare, the damage may not only be a physical injury, but they will also lose their status in the group - In cases where local human communities rely on bushmeat for survival, the issue of bushmeat and primate conservation becomes more complicated. Why? - Because some communities rely on the bush meat and it could be seen as unethical to take away an important source of food from a group of people. - In Madagascar, bushmeat consumption is correlated to higher levels of hemoglobin in children under 12 - Removal of bushmeat from diet is expected(from a model) to lead to a 29% increase in anemia in preadolescents - How are mountain gorillas a good example of successful conservation over the last 20+ years? - Ecotourism - Cooperation -- Attention - With the help of conservation efforts the mountain gorillas have increased in population in recent years - Who needs to be involved if a primate conservation effort needs to succeed? Consider the mountain gorilla example and the muriqui example. - Scientists, the community, and government officials - Terms to be able to define: - Anthropogenic - humans - Anthropogenic change - Change caused by humans - Crop raiding - The action of or results of wild animals damaging standing crops by feeding on or trampling them - Climate change - A change in global or regional climate patterns - IUCN and classification of species status (vulnerable, endangered, critically endangered) - Species are classified by the IUCN Red List into nine groups, specified through criteria such as rate of decline, population size, area of geographic distribution, and degree of population and distribution fragmentation - Reevaluated every ten years - Habitation destruction - the elimination or alteration of the conditions necessary for animals and plants to survive - Habitat fragmentation - happens when parts of a habitat are destroyed, leaving behind smaller unconnected areas - Bushmeat trade - The trade and sale of wild animals for food, cause of extinction in animals - Palm oil - Island of Borneo (Malaysia, Indonesia, Brunei), deforestation for palm oil plantations ==\> destruction of orangutan habitat - Snares for catching animals - Traps that are put out to catch bush meat but can end up injuring other primates - Kibale Chimpanzee Project snare removal team - 1\) forest preservation and wildlife protection by reducing illegal activity in Kibale - 2\) community involvement - 3\) educational outreach. To work towards these goals, KSRP currently employs a Ugandan team of snare removal specialists - Ecotourism - the practice and business of recreational travel based on concern for the environment - Conservation - Protecting and preserving natural resources and the environment LECTURE 15: Primate origins - Has the Earth and placement of the continents changed over the last 300 million years? - Yes, because of the continental drift the earth has moved and separated from when it was once Pangea - Has Earth's climate changed over the past millions of years? - Yes there has been a gradual cooling and drying trend in last 20 million years - Cooling trend overall in last 65 million years - Warmer in early Eocene and early Miocene - Cooler and more variable in Pleistocene - How does long history of continental drift connect to long history of climate change? - Continental drift closed an oceanic gateway that once connected the Atlantic and Pacific Oceans, creating the Isthmus of Panama. The continental shift led to changes in ocean circulation and Earth\'s climate - How do scientists reconstruct changes in global temperature? - Taking the global temperature - Deep-sea cores - Oxygen isotopes - 16O lighter---evaporates into snow and rain - Trapped in glaciers and poles during cold periods - High 18O/16O ratio during cold periods - When dinosaurs went extinct, leaving a lot of open niches in the environment, what group of animals filled those niches and thrived? - mammals - How does the fossilization process work? - Burial is the key - Absorption of minerals and replacement of organic compounds - Hard materials fossilize more often (bone and ESPECIALLY teeth) - Soft tissues and behaviors rarely fossilize - How is the fossilization process biased in what we find in the fossil record? Why is the fossil record 'incomplete'? - Not everything fossilizes - Small animals are less likely to fossilize - Some habitats are less likely to create fossils - If a phylogeny is based on the fossil record, why does it tend to oversimplify relationships? - The majority of morphological features are lost to decay, only a small amount of anatomical features are created - How does carbon dating work? Why can't we date specimens that are millions of years old with carbon dating? - Isotopes - Same element, but different number of neutrons - Radioactively decays at a constant rate - The half-life (time it takes for half of radioactive material in the object to decay) of carbon-14 is 5,730 years - If half of the carbon-14 has decayed away, the fossil is 5,730 years old. - If 1/4 of it is present, then the fossil is 2times the half-life, or 11,460 years old - How does potassium-argon dating work? - Volcanic rocks - Fossils not directly dated - Can date fossils millions of years old based on dating of layers of volcanic rock around it - What features are you looking for as a paleoanthropologist to identify that a fossil is a primate? - Grasping hands and feet - Nails instead of claws - Forward-facing eyes encased in bone - Relatively large brain - Generalized teeth - 2-1-3-3 maximum formula - What are some morphological differences (cranial and postcranial) between plesiadapiforms and living strepsirrhines? - Plesiadapiforms had - no post orbital bar - A small brain - Diastema gap - A long narrow snout - Claws and no opposable toe - Strepsirrhines have a post orbital bar - A broader snout - A larger brain - And no diastema - The first true primates appeared in the Eocene epoch. What was the environment like then that might have been conducive to primates? - Continents shift more tropical forest habitats open up\ Earth warm and wet - Tropical forest spread into North America and Europe - Primates have evolved - Full suite of characters - Two types - Adapids (ancestors of lemurs) - Omomyids (ancestors of tarsiers) - What are the five main hypotheses about primate origins? - Visual predation hypotheses, - Leaping hypothesis - Generalized nocturnal hypothesis - Terminal branch hypothesis - Angiosperm hypothesis - The Eocene primate group the adapids are considered ancestors of what living primate group? - Lemurs - The Eocene primate group the omomyids are considered ancestors of what living primate group? - Tarsiers - Why is a specimen nicknamed "Ida" an unusual fossil of an adapid? - It was unusual because there was so much of the fossil remains found - Terms to be able to define: - Continental drift - the gradual movement of the continents across the earth\'s surface through geological time. - Pangaea - The name of the single landmass that broke apart 200 million years ago and gave rise to today\'s continents - Therapsids - an extinct group of reptiles from which mammals evolved warm-blooded, fur-covered reptiles - Early Triassic period - Mammal radiation - filling all the niches that dinosaurs left behind - Deep-sea cores - Cores drilled from the sea bed that provide the most coherent record of climate changes on a worldwide scale. - Oxygen isotopes - lighter oxygen is easier to evaporate, will be left in the water during episodes of high evaporation (due to high global temperature); help determine temperature history and salinity levels - Fossilization - when living material is replaced with mineral substances in the remains of an organism - Stratigraphy - the study of rock layers and the sequence of events they reflect - Principle of superposition - If a rock strata has not been disturbed the lowest stratum was formed before the strata above it - Carbon-14 Radioactive decay - Is 5,730 years - Carbon dating - a scientific method used to determine the age of an artifact - Potassium-argon dating - a method of dating rocks from the relative proportions of radioactive potassium-40 and its decay product, argon-40. - Plesiadapiforms - Paleocene organisms that may have been the first primates, originating from an adaptive radiation of mammals. - Paleocene - 65-55 mya. The earliest primates were here. extinction of dinosaurs, milder climate (tropical/subtropical forests) - Eocene - from 58 million to 40 million years ago; presence of modern mammals - Adapids - early lemur-like primates. Probably the group that gave rise to living strepsirrhines - Omomyids - Eocene euprimates that may be ancestral to tarsiers - Angiosperm hypothesis - basic primate traits evolved in conjunction with the emergence of angiosperms (flowering plants) - Visual predation hypothesis - primate traits like forward facing eyes evolved because of how that helps with catching insects to eat - Leaping hypothesis - Features evolved to help with leaping - Generalized nocturnal hypothesis - the earliest primates evolved their specific adaptations to live a generalized life of fruit, flower, and insect eating, but that they were nocturnal and only some branches of further primate evolution retained that nocturnal lifestyle. - Terminal branch hypothesis - vision allowed for primates to see the colors and size of blossoming fruit, while grasping hands gave them the advantage to eat it LECTURE 16: Primate origins & Hominin origins - In the late Eocene/early Oligocene, researchers have found the earliest anthropoids. Anthropoids are a name used to refer to monkeys and apes (so Central and South American monkeys + Asian and African monkeys + apes = anthropoids). - *Aegyptopithecus* *zeuxis* is an example of a species of early anthropoids. What features did this early anthropoid have? - 2-1-2-3 - Fruit eater - Sexually dimorphic - Arboreal quadruped - Diurnal - Relatively small brain - If you find a fossil primate, what can its teeth tell you about what the extinct primate ate? - The shape and size of teeth can tell you about the types of foods an animal ate - - What are the origins of Central and South American primates? How do researchers hypothesize that these monkeys migrated from Africa to South America? - Rafted Across the Atlantic to South America, the ancestors of modern South American monkeys such as the capuchin and woolly monkeys first came to the New World by floating across the Atlantic Ocean on mats of vegetation and earth - How and when do biological anthropologists think lemurs migrated from mainland Africa to the island of Madagascar? - lemurs arrived in Madagascar 40-50 million years ago, long after it became an island. It\'s thought they floated over from the African continent on rafts of vegetation - Why do we use the term "subfossil lemur" instead of "fossil lemur"? - Many lemur species have already gone extinct in the last 2000 years due to human activity are lemurs from Madagascar that are represented by recent (subfossil) remains dating from26,000 years ago to approximately 560 years ago - How many species of lemur have gone extinct in the past 2,000 years? What/who caused these extinctions? - At least 17 species of lemurs have gone extinct - Humans have caused these extinctions through habitat destruction and hunting - When and under what environmental conditions do the first apes evolve? - Miocene (23-5 Ma) - Warm and wet, became cool and dry over time - What are the morphological differences between monkeys and apes? - Apes have no tail - Forelimb suspension - Short, stiff lower back - Mobile joints - Long arms and fingers - How does *Proconsul* have both ape-like and monkey-like characteristics? - Apelike skull and teeth - Monkey like postcrania - Quadrupedal, nonsuspensory - Extinct *Sivapithecus* has similarities to what living great ape? - Orangutan (found in asia) - What's unusual about *Gigantopithecus*? (the hint is in the name) - They were giant and much larger than all great apes - What makes humans distinct from nonhuman apes? - We walk on two legs (bipedalism) - We have small canines and large molars with thick enamel - We have large brains for our body size - We have very slow life histories and a long juvenile period - We talk and have elaborate symbolic culture - What is a cranial feature of a biped? - The position of the foramen magnum - What is a spinal feature of a biped? - Lumbar lordosis - S-shaped curve in spine - Allows the head, neck, pelvis, and knees to be aligned. - What is a pelvic feature of a biped? - Bipeds have a short, stout pelvis and the iliac blades face to the side. - Why are abductor muscles key to bipedalism? - Join the femur to the wide flaring ilia - Stabilize the body when your weight is on one leg - What are features of knees and feet of a biped? - Knee - Bicondylar angle - Foot and ankle - Nongrasping big toe - Arches - What are four hypotheses for why bipedalism evolved? - Feeding adaptation (Arboreal bipedalism/Ground feeding) - Carrying and provisioning - Thermoregulation (Less solar radiation) - Energetics (Bipedalism saves energy) - Terms to be able to define: - Oligocene - The geological epoch 34 million to 24 million years ago during which definite anthropoids emerged - Anthropoid - apes that are closely related to humans - Fayum - A site southwest of Cairo, Egypt, where the world\'s best record of Oligocene primate fossils has been found - *Aegyptopithecus Zeuxis* - Member of the Propliopithecidae - Two premolars - Arboreal quadruped - Highly sexually dimorphic - Likely ancestral to extant cercopithecoids and hominoids - Rafting hypothesis - Late in the Eocene or very early in the Oligocene, the first anthropoids arose in Africa and reached South America by \"rafting\" over the water on drifting chunks of vegetation. - Subfossil lemur - Lemurs from Madagascar that are represented by recent remains dating from nearly 26,000 years ago to approximately 560 years ago. They include both extant and extinct species, although the term more frequently refers to the extinct giant lemurs - Miocene - 23 mya - 5.3 mya: Continued radiation of mammals and angiosperms; apelike ancestors of humans appear. - Miocene apes - -22 to 5 ma\ Proconsul, Sivapithecus, Dryopithecus, Ouranopithecus, Gigantopithecus\ -Africa, Asia, Europe\ -Y-5 molar pattern\ -Medium to large body, no tail - *Proconsul* - A genus of early Miocene proconsulids from Africa, ancestral to catarrhines.\ Africa\ Dated 27-17 Ma\ Frugivorous\ Forest environments\ Apelike skull and teeth\ Monkey like postcrania\ Quadrupedal ,nonsuspensory - *Sivapithecus* - A genus of Miocene sivapithecids, proposed as ancestral to orangutans. - *Gigantopithecus* - A genus of Miocene pongids from Asia; the largest primate that ever lived. - Mosaic - Hominin - Human and humanlike ancestors - Bipedalism - Obligate bipedalism - MUST do it; no other efficient choice(modern humans) - Habitual bipedalism - can do it efficiently and \"make a habit of it\" most of the time(recent human ancestors?) - Facultative bipedalism - can do it if they have to (chimps,gorillas; early hominins?) - Foramen magnum - Lumbar lordosis - The natural curve of the lower back (lumbar) area of the spine - Pelvis: iliac blade, ilium, ischium - Abductor muscles - Bicondylar angle - angle of the femur to allow for upright walking. Aligns knees closer to the line of center of gravity - Feeding adaptation hypothesis - bipedal movements might have evolved into regular habits because they were convenient for obtaining food and keeping balance - Carrying and provisioning hypothesis - humans began walking on two feet instead of four in order to free their hands to do other tasks - Thermoregulation hypothesis - standing upright = reduced exposure to solar radiation and regulation of body temperature - Energetics hypothesis - We evolved to bipedalism to conserve energy LECTURE 17: Hominin origins & early hominins - What are the hypotheses for why bipedalism evolved? - How did some researchers test the energetics hypothesis for the evolution of bipedalism? - What are characteristics that separate hominins from other apes? - What are the cranial and postcranial features of bipedalism? - Genetic evidence indicates that the last common ancestor of humans and chimpanzees lived sometime between 5--7 million years ago. We talked about several fossil species from this time period that are giving us insight into what this common ancestor may have looked like and what features first evolved in the earliest hominins. - What features of *Sahelanthropus tchadensis* are ape-like? What features of *Sahelanthropus tchadensis* are more like hominins/humans? Consider cranial and postcranial features. - Chad, Africa\ 6 - 7 million years old\ Hominin?\ Foramen magnum suggests bipedality\ Small canines\ Chimpanzee-sized brain\ Flat face; large browridge\ femur (thigh bone) is argued to be more human-like andindicates bipedalism - What features of *Orrorin tugenensis* are ape-like? What features of *Orrorin tugenensis* are more like hominins/humans? Consider cranial and postcranial features. - Kenya, Africa\ 6 million years old\ Mix of woodland and savanna\ Curved fingers suggest tree living\ Teeth chimpanzee-like\ Hominin?\ Femur suggests bipedality - What features of *Ardipithecus kadabba* are ape-like? What features of *Ardipithecus kadabba* are more like hominins/humans? - Ethiopia, Africa\ 5.8- 5.2 million years old\ Hominin?\ Canine sharpens against lower premolar\ Toe bone suggests bipedality - What features of *Ardipithecus ramidus* are ape-like? What features of *Ardipithecus ramidus* are more like hominins/humans? - Ethiopia, Africa\ 4.4 million years old\ Woodland habitat\ Hominin?\ Long fingers, long toes, body proportions suggest quadruped and climbing in trees, not an obligate biped\ Pelvis: lower part (ischium) like chimps and gorillas but top part (ilium)is more intermediate between nonhuman apes and hominins Small brain Small canines - If you were a paleoanthropologist who had just found fossil remains of *Ardipithecus ramidus'*s hand bones, would you think it was a fossil ape or a fossil hominin? - Consider the incisors, molars and canines found of *Ardipithecus ramidus.* For each tool type, are they more ape-like or more hominin/human like? - Incisors\ Smaller than frugivorous chimps Molars\ Thicker enamel than African apes; thinner than humans Canines\ Not sharpened\ Not dimorphic - In the range of 2 - 4 million years ago, hominins diversified into many different species. What are some key traits we see in hominin species in this time frame? - Small brains\ Skilled upright walking\ Retain tree-climbing ability\ Chimpanzee-sized with pronounced body size dimorphism\ Reduced canine dimorphism\ Large molars - Which came first in hominin evolution, a big brain or bipedalism? In other words, do any of the hominins we've discussed so far have big brains? - Bipedalism came first - Terms to be able to define: - Hominoid - group that includes all nonmonkey anthropoids - the living and extinct gibbons, orangutans, chimpanzees, gorillas, and humans - Non-honing canines - Small, worn canines\ No diastema - Honing complex - upper canine rubs against lower first premolar\--sharpening function - Diastema - a space between the canines and other teeth allowing the large projecting canines to fit within the jaw - Obligate bipedalism - Foramen magnum - Lumbar lordosis - Iliac blades / ilium - Bicondylar angle - Valgus knee - adducted femur, or a permanent knock-kneed-ness - *Sahelanthropus tchadensis* - *The earliest pre-australopithecine species found in central Africa with possible evidence of bipedalism.* - *Orrorin tugenensis* - *A preaustralopithecine species found in East Africa that displayed some of the earliest evidence of bipedalism.* - *Ardipithecus kadabba* - An early pre-australopithecine species from the late Miocene to the early Pliocene; shows evidence of a perihoning complex, a primitive trait intermediate between apes and modern humans - *Ardipithecus ramidus* ("Ardie") - Mosaic evolution - *a pattern of evolution in which the rate of evolution in one functional system varies from that in other systems* - Incisors - Teeth between the canines that are used for cutting. - Molars - Back teeth that grind food - Canines - - Canine dimorphism - difference between the sexes of a species in the size of the canine teeth