BIO 1M03 - Midterm 2 Questions With Verified Answers

The origin of mammals occurred in which era? - Answer Triassic Period (252 Ma- 201 Ma) What are some key events that occurred within the Triassic Period? (2 points) - Answer - Pangea supercontinent formed through continental drift. - Therapsida groups had evolved within vertebrates Therapsida groups had increased metabolic rate inferred through: ___________________ (3 points) - Answer - upright posture (relative to reptiles) - muscular diaphragm for enhanced breathing - breathing while eating (soft tissue secondary palate) Mammalia is a lineage within Therapsida which included which characteristics? (7 points) - Answer - cheek teeth w/multiple cusps - mobile muzzle w/lips and whiskers - scroll-like bones in nasal passages (to warm air) - small bodies - females nursed with milk - hair of fur 3 types of mammalian pregnancies - Answer - monotremata: lay eggs - marscipala: pouches - placentalia: fetus in uterus When did the origin of primates happen? - Answer Cretaceous - Paleogene (K-Pg) extinction (66 Ma) What happened during the Cretaceous - Paleogene Extinction? (2 pointa) - Answer - mammals survive meteorite impact event and fallout - undergo radiation (w/ increase in size) How did radiation impact primates? (6 points) - Answer - relatively large brain - forward facing eyes - mobile shoulder joints - opposable thumbs (toes) - nails rather than claws - flat cheek teeth, nipping incisors, enlarged canines Context of Primate Fossil Record (3 points) - Answer - Paleogene period (66 Ma - 23 Ma) - Pangea disassembling - Plesiadapiformes groups evolved Plesiadapiformes traits (4 points) - Answer - mobile elbow and ankle joint - long grasping fingers - opposable thumbs - non primate traits: relatively small brain, non-forward facing eyes, angled incisors, claws Aegyptopithecus zeuxis (4 points) - Answer - primate fossil record - Egypt (40-30 Ma) - primate traits - sagittal crest (large chewing force) Platyrrhines (flat noses, new world monkeys) (3 points) - Answer - sparse fossil record exists in South America dating to 36 Ma - oldest specimen (three teeth) resemble fossil teeth found in North America - How did they arrive at SA??? iguana typa beat Catarrhines (down noses, old world primates) (4 points) - Answer - Saudi Arabia Fossil (29 Ma) - characteristics common to Cercopithecidae (owp) + Hominoidea (apes) - lacking some derived features from each - affiliated closely w/ common ancestor Hominoidea (apes) (9 points) - Answer - Kenya/Uganda (20 Ma) - Genus: Proconsul - Relative common ape traits - large brains - broader noses - unspecialized cheek teeth - broad shoulders, long arms, short legs - wide, flat trunks, tailless - hang from/ stand on branches in trees, knuckle-walk, walk upright What happened to apes that leads to the diversity observed today? (2 points) - Answer - adaptive radiation - extinction events (climate change, cool & dry) Non human great ape and their respective primatologist (3 points) - Answer - Chimpanzees - Jane Goodall - Gorillas - Dian Fossey - Orangutans - Birute Galdikas Sahelanthropus tchadensis - Answer - 7-6 mya - single skull - brain small - browridge large - foramen magnum central - bipedal Ardipithecus ramidus - Answer - 4.4 mya - partial skeletons - brain small - canines large - foramen magnum central (bipedal) - flat face (unlike chimpanzees) - arms long and toes opposable; arboreal (live in trees) Australopithecus & Paranthropus - Answer - two genera containing 6 and 3 species - 4.4-2 Ma and 2.7-1 Ma - gracile & robust (thin and strong) Australopithecus afarensis - Answer - Lucy - 4-3 Ma - brain case small - arms long: brachiation & thought to have fallen to death Paranthropus boisei - Answer - 2.3-1.2 mya - Big jaw w/ big biting force - diet (tough plant material) - sagittal crest Homo habilis - Answer - 2.3 Ma - brain medium - teeth small - stone tools (unsophisticated) Homo erectus - Answer - 1.8 Ma - brain large - fire controlled; cooked food - stone tools (sophisticated) - migrated to Eurasia Homo neanderthalensis - Answer - 40-24 ka - brain large - forehead low - browridge large - powerful jaws - strong bodies - Europe and Asia - First tattoos and cave paintings Out of Africa Hypothesis - Answer The hypothesis that modern humans (Homo sapiens) evolved in Africa and spread to other continents, replacing other Homo species Evidence for Out-of-Africa Hypothesis (2 points) - Answer - Fossil: oldest specimen found in Morocco (315 ka) ancient, teeth large and derived, face flat - Molecular Evidence: genetic diversity greatest in Africa, evidence for interbreeding Bipedalism - Answer - the ability to walk upright on two legs - non- mutually exclusive hypothesis: thermoregulation tool use foraging migration - skeleton modifications foramen magnum - Answer - insertion point in skull - rear (quadrupedal) - central (bipedal) pelvis - Answer - chimps: long and flat - humans: bowl- shaped (balance) femur orientation - Answer - chimps: straight - humans frontal orientation, angled feet - Answer - chimps: reference - humans: large heel, foot arched, toes allow leveraging rather than grasping Tool use in non-human apes - Answer - Orangutans: poles to trap fish and twigs to get honey and termites - Gorillas: probe water depth w/ sticks and use poles for balance when in water - Chimps: twigs to extract honey, termites and ants - sharpened sticks to extract small prey - sponge-like mats to collect water Type 1 Olduwan - Answer - 2.6-1.7 Ma - Association with Homo habilis and Australopithecus garki - flakes and cores for sharpening & pounding Type 2 Acheulian - Answer - 1.6- 0.3 Ma - associated w/ Homo ergaster - hand axes for butchering Type 3 Mousterian - Answer - 0.3-0.4 - Homo neanderthalensis - hunting large game Homo sapiens tool use - Answer - weapons and refined tools (40- 10ka) - knives, chisels, drills, harpoons, spears, bows & arrows (cooperating and sharing behaviour) - stone, shell, bone, wood, antler, ivory (for fashioning artworks) paintings, jewelry and sculptures Hominina Foraging Strategies - Answer - Olduwan: exctractive foraging for tubes and roots and buthcering large prey obtained by hunting or scavenging - Acheulian: skinning, shearing meat from bone (large prey) - Mousterian: full- scale hunting Cooling and controlling fire - Answer - plant and meat materials are hard to chew and digest - cooking softens tough fibers - cooking kills potential pathogens and parasites Jaw musculature - Answer - genus Homo, jaw musculature reduced - muscles contain actin and myosin - gene MYH16 produces most myosin proteins - non human primates: intact gene &large powerful muscles - humans: mutant version (80% reduction in jaw musculature) Brain Case Ossification - Answer - primate cases: 8 separate cranial bones joined by fibrous, elastic sutures that ossify (become bony) during development - nonhuman apes: ossification complete in early childhood. Chimp brain 80% @ age 1 - humans: brain case grows until early adulthood 50% @ age 1 (full-size at 20) Brain Size - Answer - energy cost for maintaining a brain increases w/ its size - correlation between body mass & daily caloric intake among primates - gorilla brain small because it has no time to eat enough to support a larger brain Natural selection in Modern Humans (4 points) - Answer - Skin colour - Malaria resistance - Lactose persistance - Menopause Melanin - Answer - pigment that determines the color of the skin - produced by melanocytes (melanin producing cells within the epidermal layers) What skin colour did early Hominina and chimpanzees have? - Answer - fair skin colour