BIOL 111 Announcements Final lab exam, Monday November 23, 6:30-7:30pm CORRECTION: Vertebrate hearts: amphibians + Flip-flop atria and ventricle(s) lungs body Clicker participation: 25 lectures + 2 (maybe 3) extra opportunities: 80% = 20 lectures (4 pts) 70% = 17 lectures (3 pts) 60% = 15 lectures (2 pts) 50% = 12 lectures (1 pt) Need 80% class participation in course evaluation to receive 3 rd clicker opportunity. 1 SA node vena cava body pulmonary artery RV RA LA aorta LV pulmonary vein lungs 2 BIOL 111 Organismal Biology Lecture 23 Mammal II: Primates, Hominid evolution, Mammalian nervous system 19 November 2009 1. Primates Mammals II lecture outline Characteristics Diversity Hominid evolution 2. Mammalian Nervous System Peripheral NS Central NS 3 4 Which statement is not TRUE regarding mammal evolution? 1. Synapsids were the dominant tetrapod group in the Permian. 2. True mammals evolved from therapsids about 220 mya (Triassic). 3. Marsupials & eutherians co-existed with dinosaurs. 4. The first eutherians were oviparous. 5. Monotremes (prototherians) are the extant mammal group that diverged from reptiles first. Synapsids were... 22% True mammals e... 29% Marsupials & e... 19% The first euth... 15% 15% Monotremes (pr... 5 Primates Arboreal, insectivorous eutherian ancestor Grasping limbs with opposable thumb* Forward-facing eyes Wider field of view Depth perception Big cerebrum Highly social Reduced brood size and extended parental care tarsier lemur chimpanzee 6 1
Primates Prosimians 235 species Two groups Prosimians lemurs lorises Anthropoids tarsiers monkeys apes humans Mostly arboreal & nocturnal Once found on all continents, but now just Africa & SE Asia. Lemurs on Madagascar have greatly radiated. crowned lemur Cenozoic 7 ring-tailed lemur slender loris 8 Anthropoids Tarsiers Small, arboreal, nocturnal, insectivores SE Asia Many endangered Anthropoids Tarsiers Among smallest of primates Very good jumpers Can rotate head 180 o 9 10 Anthropoids Monkeys split when SA & Africa still close New World Monkeys South & Central America all arboreal most have long prehensile tails relatively flat faces live in groups spider monkey pygmy marmoset Cenozoic 11 howler monkeys 12 2
Old World Monkeys (non-apes) Arboreal and grounddwelling No prehensile tail Mandrils, baboons, rhesus monkeys, macaques Japanese macaque proboscis monkey mandrill 13 Apes split from Old World Monkeys ~35 mya. Africa & Asia (non-human apes) no tail bigger brain Cenozoic 14 Apes Asia lesser apes Who is our closest living relative? = great apes = family Hominidae gibbon orangutan Africa 1. Monkey 2. Gorilla 3. Orangutan 4. Chimpanzee 5. Other 2% 15% 12% 67% 4% human gorilla chimpanzee 15 Monkey Gorilla Orangutan Chimpanzee Other 16 Chimpanzees Primate research at McGill lineage split ~ 6 mya 99% similarities in coding DNA highly intelligent: tool use (Goodall) learn symbols & numbers plan for future laughter bonobos 17 Prof Colin Chapman Depts: Anthropology, MSE, Biology Primate ecology & conservation Works in Kibale National Park, Uganda Courses: ANTH 311 (Primate behavior & ecology) ANTH 411 (Primate studies & conservation, in Africa) Website: http://www.arts.mcgill.ca/anthro/chapman_files/cweb/index. html 18 3
Hominids (Hominins) ~20 extinct species discovered Not a ladder to modern humans, rather a branched tree of extinctions Different groups co-existed Sahelanthropus tchadensis ~6.5 mya, Chad Common ancestor to chimps & humans or oldest hominid? Advantages of bipedalism? Less energetically costly Frees up forelimbs for other tasks Elevates head for better view of predators, prey Reduced canines More bipedal locomotion Increased brain size (later) 19 20 Hominid Phylogeny Australopithecus 21 Lucy Laetoli footprints, 3.5 mya, Tanzania Lucy discovered in 1974 by Johanson & Leakey Australopithecus afarensis 3.2 mya from Ethiopia Most complete hominid fossil at the time 1m height, small brain (chimp-sized), bipedal Evidence that bipedalism evolved before large brain size 22 Hominid Phylogeny Early Homo species still had relatively small brains but began using tools & capable of walking longer distances. Homo habilis handy man 2.5-1.5 mya first tool use 2 mya shorter jaw, bigger brain 23 Homo ergaster working man ancestor to modern humans 2-1.5 mya longer legs, shorter fingers suggesting walking not climbing, smaller teeth brain 2/3 rd size of modern humans reduced sexual dimorphism 24 4
Hominid Phylogeny Hominids left Africa approximately 1.6 mya. Homo erectus upright man 1.6 mya 200,000 yrs ago first hominid to leave Africa (Eurasia, Indonesia) fire & tool use small brains, thick skulls, same body size as modern humans 25 26 Hominid Phylogeny Brains reached modern size about 160,000 years ago. Homo neanderthalensis Neanderthals -- discovered in Neander Valley, Germany, 1856 -- 200,000-30,000 ya -- Europe & Asia only -- short, stalky but powerful build -- larger brain than H. sapiens? -- co-existed with H. sapiens (Cro-Magnons) -- gene flow between groups? 27 http://www.msnbc.msn.com/id/33721697/ns/technology_and_science-science/ 28 Modern humans evolved from H. ergaster ~200,000 yrs ago. Have Homo sapiens been alone for 30,000 years? Homo sapiens wise man evolved in Africa (Ethiopia) ~200,000 yrs ago arrived in North America ~20,000 more slender, lack heavy browridges of other hominids Cro-Magnon = European early modern humans ~30,000 ya cave paintings, carvings, antler spears, tools for woven clothing Altamira paintings, Spain 1. Yes 2. No 23% Yes 77% No 29 30 5
Hominid Phylogeny Another hominid species was discovered in Indonesia in 2004. Homo floresiensis Flores island, Indonesia existed to ~12,000 ya Much smaller than H. sapiens 31 Wiped out by a volcanic eruption 32 33 6
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