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fandomhigh2011-01-20 09:52 am
bootlessjane.livejournal.com) wrote in fandomhigh2011-01-20 09:52 am
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Primatology; Thursday, Fourth Period [ 01/20 ].
"And welcome back, class!" Jane greeted the room with her usual pomp brimming on the edge of excitement, which was likely to fall to pieces as soon as she got into lecturing again. "I hope you all enjoyed some of the odd weather we've been having; I know I've been finding it quite fascinating, and if any of you have any observations about it, I'd love to hear about them. But first, we'll discuss our primates, and today's topics in getting you better acquainted with this fascinating animal are anatomy, physiology, and morphology, oh my!"
"We'll be doing a few slide on the projector today," Jane continued, "so, Miss Norwood, if you would please get the lights. First, let us discuss primate skulls:
"Here in this image, you can see the skulls of four different primates: human, chimpanzee, orangutan, and macaque. Surely, you can easily see that, while they are clearly quite different from each other, there are also a great deal of similarities as well. All primates have forward-facing eyes on the front of the skull, as you can clearly see here."
Jane, now equipped with a long pointed, drifted the end of the stick in circles around the eyes of the skulls.
"Binocular vision allows accurate distance perception. There is a bony ridge above the eye sockets, seen here," again, the pointer drew the way. " This ridge is used to reinforce weaker bones in the face which are put under strain during chewing. Strepsirrhines have a postorbital bar, a bone which runs around the eye socket, to protect their eyes; in contrast, the higher primates, haplorrhines, have evolved fully enclosed sockets. If one looks closely, they can easily see the developments from lesser primates to the more fully formed human skull. One could also discuss how phrenology might be used to compare our primate cousins to ourselves, but that is a topic for another time, because there's much more to a primate than their heads. Still, it is important to note that the primate skull has a large domed cranium which is particularly prominent in anthropoids. The cranium protects the large brain, a distinguishing characteristic of primates. The endocranial volume is three times...three times!...greater in humans than in the greatest non-human primate.
"Of course," Jane added with a hearty chuckle, "it's not the size that matters, but rather how you use it. The primary evolutionary trend of primates has been the elaboration of the brain, in particular the neocortex, which is involved with sensory perception, generation of motor commands, spatial reasoning, conscious thought and, in humans, language. Most mammals will rely heavily on their sense of smell, but the arboreal life of primates give them a tactile, visually dominant sensory system, which gets the most use out of those big brains and is the basis for their increasingly complex social behaviours."
Jane clicked to the next slide
"Next up! Limbs and feet! Primates generally have five digits on each limb, with keratin nails on the end of each finger. Of course, there is the occasional anomoly of fewer or more digits, as there can be with humans as well. The bottom sides of the hands and feet have sensitive pads on the fingertips. Most have opposable thumbs, a characteristic primate feature; primates aren't the only ones to develop an opposable thumb, of course! Just look at the possum! Thumbs are wonderful things that we probably take quite for granted, that allow primates to use tools in ways that other animals cannot. In primates, the combination of opposing thumbs, short fingernails rather than claws, and long, inward-closing fingers is a relic of the ancestral practice of gripping branches, and has, in part, allowed some species to develop brachiation, swinging about by the arms from tree limb to tree limbnot to mention tree surfing, as a significant means of transportation. Prosimians have clawlike nails on the second toe of each foot, called toilet-claws, which they use for grooming.
"The primate collar bone is retained as prominent element of the pectoral girdle; this allows the shoulder joint broad mobility.Apes have more mobile shoulder joints and arms due to the dorsal position of the scapula, broad ribcages that are flatter front-to-back, and a shorter, less mobile spine compared to Old World monkeys, with lower vertebrae greatly reduced, resulting in tail loss in some species. Old World monkeys are unlike apes in that most have tails. The only primate family with prehensile tails are the New World Atelids, including the howler, spider and woolly monkeys."
Click, click, click, to show off each of those particular primates. Each click seemed to hold its own little burst of glee. And then she went back to the skulls.
"Primates show an evolutionary trend towards a reduced snout.Technically, Old World monkeys are distinguished from New World monkeys by the structure of the nose, and from apes by the arrangement of their teeth. In New World monkeys the nostrils face sideways; in Old World monkeys, they face downwards. There is a considerably varied dental pattern in primates and although some have lost most of their incisors, all retain at least one lower incisor.In most strepsirhines, the lower incisors and canines form a toothcomb, which is used in grooming and sometimes foraging, and the first lower premolar is shaped like a canine. Old World monkeys have eight premolars, compared with twelve in New World monkeys. The Old World species are divided into apes and monkeys depending on the number of cusps on their molars; apes have five, Old World monkeys have four, although humans may have 4 or 5. The main hominid molar cusp evolved in early primate history, while the cusp of the corresponding primitive lower molar was lost. Prosimians are distinguished by their immobilized upper lips, the moist tip of their nose and forward-facing lower front teeth.
"And now this is particularly interesting," Jane vowed as she kept babbling on. "The evolution of color vision in primates is unique among most eutherian mammals. While the remote vertebrate ancestors of the primates possessed three color vision, called trichromaticism, the nocturnal, warm-blooded, mammalian ancestors lost one of three cones in the retina during the Mesozoic period. Fish, reptiles and birds are therefore trichromatic or tetrachromatic while all mammals, with the exception of some primates and marsupials, are dichromats or monochromats. Nocturnal primates, such as the night monkeys and bush babies, are often monochromatic. Catarrhines are routinely trichromatic due to a gene duplication of the red-green opsin gene at the base of their lineage, 30 to 40 million years ago. Platyrrhines, on the other hand, are trichromatic in a few cases only. Specifically, individual females must be heterozygous for two alleles of the opsin gene located on the same locus of the X chromosome. Males, therefore, can only be dichromatic, while females can be either dichromatic or trichromatic. Color vision in strepsirrhines is not as well understood; however, research indicates a range of color vision similar to that found in platyrrhines. Fascinating, I know!
"But it does seem I've gotten quite into the specifics of the topic, far more than I had intetended, but you'll have to excuse me, I get quite carried away! I promise, this next part you should all find much more interesting, and that is simply that primates are sexually dimorphic, which means a phsyical difference in the male and female sexes."
Click!
"You can see here that the male Hamadryas baboons are grey, while the females are brown. You see a similar sexual dimorphism in birds, where the female will have a different plummage than the male. The difference will be quite greater in old world monkeys, which, hopefully by now, you've notice tend to be more similar to humans in that respect. Like humans, the dimorphism also exhibits itself in body mass, that males tend to be larger than females, but also in canine tooth size, fur colour as in the example, and even skin colour!
"Last but not least, primate species move by brachiation, bipedalism, leaping, arboreal and terrestrial quadrupedalism, climbing, knuckle-walking or by a combination of these methods. Several prosimians are primarily vertical clinger and leapers. These include many bushbabies, all indriids (i.e., sifakas, avahis and indris), sportive lemurs, and all tarsiers. Other prosimians are arboreal quadrupeds and climbers. Some are also terrestrial quadrupeds, while some are leapers. Most monkeys are both arboreal and terrestrial quadrupeds and climbers. Gibbons, muriquis and spider monkeys all use brachiation extensively. Woolly monkeys also sometimes brachiate. Orangutans use a similar form of locomotion called quadramanous climbing, in which they use their arms and legs to carry their heavy bodies through the trees. Chimpanzees and gorillas knuckle walk, and can move bipedally for short distances. Although numerous species, such as the Australopithecines and early hominids, have exhibited fully bipedal locomotion, humans are the only extant species with this trait. Still, I can't quite blame the fact that, sometimes, we might quite enjoy still hanging about and swinging on trees or so called 'monkey bars' for a bit of fun. "
"In fact, as a firm believer in a healthy mind and a healthy body...Lights, please, Mr. Calvin...let's all get up and take a little trip over to gymnasium, where I may have set up a bit of an obstacle course for us to get more in touch with the brachiation and bipedalism, leaping and climbing of our primate cousins! But before we head over there, let us open the floor up for any questions you may have about what we discussed, and I am going to pass around a copy of an image of various skeletons of different primates. Please study this image for next week, keeping an eye out for differences in the skeletal structures and we will discuss them next week. Any questions? If not, let's shake out those limbs and head out! Pity we haven't got prehensile tails ourselves!"
[[please wait for the ocd is up! ]]
"We'll be doing a few slide on the projector today," Jane continued, "so, Miss Norwood, if you would please get the lights. First, let us discuss primate skulls:
"Here in this image, you can see the skulls of four different primates: human, chimpanzee, orangutan, and macaque. Surely, you can easily see that, while they are clearly quite different from each other, there are also a great deal of similarities as well. All primates have forward-facing eyes on the front of the skull, as you can clearly see here."
Jane, now equipped with a long pointed, drifted the end of the stick in circles around the eyes of the skulls.
"Binocular vision allows accurate distance perception. There is a bony ridge above the eye sockets, seen here," again, the pointer drew the way. " This ridge is used to reinforce weaker bones in the face which are put under strain during chewing. Strepsirrhines have a postorbital bar, a bone which runs around the eye socket, to protect their eyes; in contrast, the higher primates, haplorrhines, have evolved fully enclosed sockets. If one looks closely, they can easily see the developments from lesser primates to the more fully formed human skull. One could also discuss how phrenology might be used to compare our primate cousins to ourselves, but that is a topic for another time, because there's much more to a primate than their heads. Still, it is important to note that the primate skull has a large domed cranium which is particularly prominent in anthropoids. The cranium protects the large brain, a distinguishing characteristic of primates. The endocranial volume is three times...three times!...greater in humans than in the greatest non-human primate.
"Of course," Jane added with a hearty chuckle, "it's not the size that matters, but rather how you use it. The primary evolutionary trend of primates has been the elaboration of the brain, in particular the neocortex, which is involved with sensory perception, generation of motor commands, spatial reasoning, conscious thought and, in humans, language. Most mammals will rely heavily on their sense of smell, but the arboreal life of primates give them a tactile, visually dominant sensory system, which gets the most use out of those big brains and is the basis for their increasingly complex social behaviours."
Jane clicked to the next slide
"Next up! Limbs and feet! Primates generally have five digits on each limb, with keratin nails on the end of each finger. Of course, there is the occasional anomoly of fewer or more digits, as there can be with humans as well. The bottom sides of the hands and feet have sensitive pads on the fingertips. Most have opposable thumbs, a characteristic primate feature; primates aren't the only ones to develop an opposable thumb, of course! Just look at the possum! Thumbs are wonderful things that we probably take quite for granted, that allow primates to use tools in ways that other animals cannot. In primates, the combination of opposing thumbs, short fingernails rather than claws, and long, inward-closing fingers is a relic of the ancestral practice of gripping branches, and has, in part, allowed some species to develop brachiation, swinging about by the arms from tree limb to tree limb
"The primate collar bone is retained as prominent element of the pectoral girdle; this allows the shoulder joint broad mobility.Apes have more mobile shoulder joints and arms due to the dorsal position of the scapula, broad ribcages that are flatter front-to-back, and a shorter, less mobile spine compared to Old World monkeys, with lower vertebrae greatly reduced, resulting in tail loss in some species. Old World monkeys are unlike apes in that most have tails. The only primate family with prehensile tails are the New World Atelids, including the howler, spider and woolly monkeys."
Click, click, click, to show off each of those particular primates. Each click seemed to hold its own little burst of glee. And then she went back to the skulls.
"Primates show an evolutionary trend towards a reduced snout.Technically, Old World monkeys are distinguished from New World monkeys by the structure of the nose, and from apes by the arrangement of their teeth. In New World monkeys the nostrils face sideways; in Old World monkeys, they face downwards. There is a considerably varied dental pattern in primates and although some have lost most of their incisors, all retain at least one lower incisor.In most strepsirhines, the lower incisors and canines form a toothcomb, which is used in grooming and sometimes foraging, and the first lower premolar is shaped like a canine. Old World monkeys have eight premolars, compared with twelve in New World monkeys. The Old World species are divided into apes and monkeys depending on the number of cusps on their molars; apes have five, Old World monkeys have four, although humans may have 4 or 5. The main hominid molar cusp evolved in early primate history, while the cusp of the corresponding primitive lower molar was lost. Prosimians are distinguished by their immobilized upper lips, the moist tip of their nose and forward-facing lower front teeth.
"And now this is particularly interesting," Jane vowed as she kept babbling on. "The evolution of color vision in primates is unique among most eutherian mammals. While the remote vertebrate ancestors of the primates possessed three color vision, called trichromaticism, the nocturnal, warm-blooded, mammalian ancestors lost one of three cones in the retina during the Mesozoic period. Fish, reptiles and birds are therefore trichromatic or tetrachromatic while all mammals, with the exception of some primates and marsupials, are dichromats or monochromats. Nocturnal primates, such as the night monkeys and bush babies, are often monochromatic. Catarrhines are routinely trichromatic due to a gene duplication of the red-green opsin gene at the base of their lineage, 30 to 40 million years ago. Platyrrhines, on the other hand, are trichromatic in a few cases only. Specifically, individual females must be heterozygous for two alleles of the opsin gene located on the same locus of the X chromosome. Males, therefore, can only be dichromatic, while females can be either dichromatic or trichromatic. Color vision in strepsirrhines is not as well understood; however, research indicates a range of color vision similar to that found in platyrrhines. Fascinating, I know!
"But it does seem I've gotten quite into the specifics of the topic, far more than I had intetended, but you'll have to excuse me, I get quite carried away! I promise, this next part you should all find much more interesting, and that is simply that primates are sexually dimorphic, which means a phsyical difference in the male and female sexes."
Click!
"You can see here that the male Hamadryas baboons are grey, while the females are brown. You see a similar sexual dimorphism in birds, where the female will have a different plummage than the male. The difference will be quite greater in old world monkeys, which, hopefully by now, you've notice tend to be more similar to humans in that respect. Like humans, the dimorphism also exhibits itself in body mass, that males tend to be larger than females, but also in canine tooth size, fur colour as in the example, and even skin colour!
"Last but not least, primate species move by brachiation, bipedalism, leaping, arboreal and terrestrial quadrupedalism, climbing, knuckle-walking or by a combination of these methods. Several prosimians are primarily vertical clinger and leapers. These include many bushbabies, all indriids (i.e., sifakas, avahis and indris), sportive lemurs, and all tarsiers. Other prosimians are arboreal quadrupeds and climbers. Some are also terrestrial quadrupeds, while some are leapers. Most monkeys are both arboreal and terrestrial quadrupeds and climbers. Gibbons, muriquis and spider monkeys all use brachiation extensively. Woolly monkeys also sometimes brachiate. Orangutans use a similar form of locomotion called quadramanous climbing, in which they use their arms and legs to carry their heavy bodies through the trees. Chimpanzees and gorillas knuckle walk, and can move bipedally for short distances. Although numerous species, such as the Australopithecines and early hominids, have exhibited fully bipedal locomotion, humans are the only extant species with this trait. Still, I can't quite blame the fact that, sometimes, we might quite enjoy still hanging about and swinging on trees or so called 'monkey bars' for a bit of fun. "
"In fact, as a firm believer in a healthy mind and a healthy body...Lights, please, Mr. Calvin...let's all get up and take a little trip over to gymnasium, where I may have set up a bit of an obstacle course for us to get more in touch with the brachiation and bipedalism, leaping and climbing of our primate cousins! But before we head over there, let us open the floor up for any questions you may have about what we discussed, and I am going to pass around a copy of an image of various skeletons of different primates. Please study this image for next week, keeping an eye out for differences in the skeletal structures and we will discuss them next week. Any questions? If not, let's shake out those limbs and head out! Pity we haven't got prehensile tails ourselves!"
[[
Sign In - Primatology, 01/20.
Re: Sign In - Primatology, 01/20.
Re: Sign In - Primatology, 01/20.
Re: Sign In - Primatology, 01/20.
Re: Sign In - Primatology, 01/20.
Re: Sign In - Primatology, 01/20.
Re: Sign In - Primatology, 01/20.
Listen to the Lecture - Primatology, 01/20.
Questions are welcome at any time, of course, particularly at the end.
To the Gymnasium! - Primatology, 01/20.
"Remember," Jane said, rolling up her sleeves as well, because she believed the best way to encourage them was to lead by example, "to keep in mind the movements of primates as we swing about. Keep in mind how useful your thumbs are and the way our joints are put together to promote this sort of movement. But be careful! There's mats down everywhere in case you far. We wouldn't want to smash up these big skulls of ours!"
Talk to Jane - Primatology, 01/20.
OOC - Primatology, 01/20.
I, however, have absolutely NO EXCUSE for the length of this lecture, except that I am clearly batshit.