Bio 100 - Study Guide 19 Human Evolution The Primate Lineage
Human Evolution The Primate Lineage 1. Basic primate traits.humans 2. Primate phylogenetic tree 3. Species of Homo 4. Milestones of human evolution 5. Punctuated equilibrium human evolution
Table of Mammal Characteristics Thermoregulation Nutritional Efficiency Locomotion and Posture Trait This means they can They have Multiple, Developed Life Stages Behavioral Flexibility Maintain and change body temperature Eat and digest a lot to keep themselves going Move in many different ways Spread growth and development over a longer period Change behavior to cope with changes in the environment Hair to insulate, sweat glands to cool off, and are warmblooded so unlike reptiles, they don t have to be in a sunny spot to stay warm A hard palate that divides chewing and breathing apparatus so they can eat and breathe at the same time, two sets of teeth over the lifetime and several different kinds of teeth for different functions A variety of options when traveling through the environment and seeking food Four main stages: In Utero Infancy Juvenile Adult Humans add Childhood between Infancy and Juvenile A better chance of using resources, surviving and reproducing due to larger brains
Distinguishing characteristics of primates include: Forward-facing eyes for binocular vision (allowing depth perception) Increased reliance on vision: reduced noses, snouts (smaller, flattened), loss of vibrissae (whiskers), and relatively small, hairless ears Color vision
Opposable thumbs for power grip (holding on) and precision grip (picking up small objects) Grasping fingers aid in power grip Flattened nails for fingertip protection, development of very sensitive tactile pads on digits
Progressive expansion and elaboration of the brain, especially of the cerebral cortex http://www.serpentfd.org/section2hominidevolution.html
Primitive limb structure, one upper limb bone, two lower limb bones, many mammalian orders have lost various bones, especially fusing of the two lower limb bones http://www.exploringnature.org/db/detail.php?dbid=24&detid=34
Generalist teeth for an opportunistic, omnivorous diet; loss of some primitive mammalian dentition, humans have lost two premolars Eruption time averages have been calculated among the general population (US). They are average values, so the variation can range ±6 months Average "eruption" time Teeth (in months after birth) 1) Lower central incisor 2) Upper central incisor 3) Upper lateral incisor 4) Lower lateral incisor 8 months 10 months 11 months 13 months 5) Lower first molar 16 months 6) Upper first molar 16 months 7) Upper canine 19 months 8) Lower canine 20 months 9) Lower second molar 10) Upper second molar 27 months 29 months
Greater facial mobility and vocal repertoire Progressive and increasingly efficient development of gestational processes Prolongation of postnatal life periods Reduced litter size usually just one (allowing mobility with clinging young and more individual attention to young) Most primates have one pair of mammae in the chest Complicated social organization
Living Primates There are three main groups of living primates: Lemurs, lorises, and pottos Tarsiers Anthropoids (monkeys and apes)
Millions of years ago Lemurs, lorises, and pottos Tarsiers New World monkeys Old World monkeys Gibbons Orangutans Gorillas Chimpanzees Humans LE 34-38 Anthropoids 0 10 20 30 40 50 60 Ancestral primate
Sifaka, a type of Lemur
LE 34-39 New World monkeys, such as spider monkeys (shown here), squirrel monkeys, and capuchins, have a prehensile tail and nostrils that open to the sides. Old World monkeys lack a prehensile tail, and their nostrils open downward. This group includes macaques (shown here), mandrills, baboons, and rhesus monkeys.
LE 34-40a Gibbons, such as this Muller s gibbon, are found only in southeastern Asia. Their very long arms and fingers are adaptations for brachiation.
LE 34-40b Orangutans are shy, solitary apes that live in the rain forests of Sumatra and Borneo. They spend most of their time in trees; note the foot adapted for grasping and the opposable thumb.
LE 34-40d Chimpanzees live in tropical Africa. They feed and sleep in trees but also spend a great deal of time on the ground. Chimpanzees are intelligent, communicative, and social.
LE 34-40c Gorillas are the largest apes: some males are almost 2 m tall and weigh about 200 kg. Found only in Africa, these herbivores usually live in groups of up to about 20 individuals.
LE 34-40e Bonobos are closely related to chimpanzees but are smaller. They survive today only in the African nation of Congo.
Anthropoid Hominoid Hominid (pl. Hominin)
Hominids originated in Africa about 6 7 million years ago Early hominids had a small brain but probably walked upright, exhibiting mosaic evolution
The fossil record has 20 species of extinct hominids Two common misconceptions about early hominids: Thinking of them as chimpanzees Imagining human evolution as a ladder leading directly to Homo sapiens
Millions of years ago LE 34-41 0 0.5 Paranthropus boisei Paranthropus robustus Homo ergaster? Homo neanderthalensis Homo sapiens 1.0 1.5 Australopithecus africanus 2.0 2.5 3.0 3.5 4.0 Australopithecus anamensis Kenyanthropus platyops Australopithecus garhi Homo rudolfensis Homo habilis Homo erectus 4.5 5.0 Ardipithecus ramidus Australopithecus afarensis 5.5 6.0 Orrorin tugenensis 6.5 7.0 Sahelanthropus tchadensis
1 HOMO HABILIS ~ NICKNAME: Handyman LIVED: 2.4 to 1.6 million years ago HABITAT: Tropical Africa DIET: Omnivorous nuts, seeds, tubers, fruits, some meat 2 HOMO SAPIEN ~ NICKNAME: Human LIVED: 200,000 years ago to present HABITAT: All DIET: Omnivorous - meat, vegetables, tubers, nuts, pizza, sushi 3 HOMO FLORESIENSIS ~ NICKNAME: Hobbit LIVED: 95,000 to 13,000 years ago HABITAT: Flores, Indonesia (tropical) DIET: Omnivorous - meat included pygmy stegodon, giant rat 4 HOMO ERECTUS ~ NICKNAME: Erectus LIVED: 1.8 million years to 100,000 years ago HABITAT: Tropical to temperate - Africa, Asia, Europe DIET: Omnivorous - meat, tubers, fruits, nuts 5 PARANTHROPUS BOISEI ~ NICKNAME: Nutcracker man LIVED: 2.3 to 1.4 million years ago HABITAT: Tropical Africa DIET: Omnivorous - nuts, seeds, leaves, tubers, fruits, maybe some meat 6 HOMO HEIDELBERGENSIS ~ NICKNAME: Goliath LIVED: 700,000 to 300,000 years ago HABITAT: Temperate and tropical, Africa and Europe DIET: Omnivorous - meat, vegetables, tubers, nuts 7 HOMO NEANDERTHALENSIS ~ NICKNAME: Neanderthal LIVED: 250,000 to 30,000 years ago HABITAT: Europe and Western Asia DIET: Relied heavily on meat, such as bison, deer and musk ox http://rst.gsfc.nasa.gov/sect20/a12c.html
http://rst.gsfc.nasa.gov/sect20/a12c.html
LE 34-42b Upright posture evolved before a Large Brain The Laetoli footprints, more than 3.5 million years old, confirm that upright posture evolved quite early in hominid history.
Larger Brains Mark the Evolution of Homo http://brainmind.com/lefthemisphere.html
Derived Characters of Hominids A number of characters distinguish humans from other hominoids: Upright posture and bipedal locomotion Larger brains Language capabilities Symbolic thought The manufacture and use of complex tools Shortened jaw
Climate played a role in the evolution and migration of hominids. Warm periods, and especially ice ages, were prime factors. http://rst.gsfc.nasa.gov/sect20/a12c.html
Australopiths Australopiths are a paraphyletic assemblage of hominids living between 4 and 2 million years ago Some species walked fully erect and had human-like hands and teeth
LE 34-42a Lucy, a 3.24-million-year-old skeleton, represents the hominid species Australopithecus afarensis.
LE 34-42c An artist s reconstruction of what A. afarensis may have looked like.
Early Homo The earliest fossils placed in our genus Homo are those of Homo habilis, ranging in age from about 2.4 to 1.6 million years Stone tools have been found with H. habilis, giving this species its name, which means handy man
Homo ergaster was the first fully bipedal, large-brained hominid The species existed between 1.9 and 1.6 million years ago
Homo erectus originated in Africa about 1.8 million years ago It was the first hominid to leave Africa
Neanderthals Neanderthals, Homo neanderthalensis, lived in Europe and the Near East from 200,000 to 30,000 years ago They were large, thick-browed hominids Neanderthals became extinct a few thousand years after the arrival of Homo sapiens in Europe
Homo sapiens Homo sapiens appeared in Africa at least 160,000 years ago
The oldest fossils of Homo sapiens outside Africa date back about 70,000 years ago http://creationwiki.org/human_migration
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