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24 Cards in this Set
- Front
- Back
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Mammals |
The amniote lineage More than 5300 species |
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Derived characteristics of Mammals |
1. Nourish young with milk (a balance diet of fats, sugars, proteins, minerals and vitamins) 2. Hair And fat layer under skin: insulation to protect against cold or hot and conserves water 3. Kidney: conserves water when removing waste 4. 4 chambered heart: respiratory and circulation system help metabolism 5. Larger brain to learn skills 6. Long duration of parental care to learn survival 7. Jaws and teeth vary for chewing different kinds of food |
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Synapsids |
Group mammals belong to Early ones lacked hair, had sprawling gait and laid eggs |
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Early evolution of mammals |
Distinctive feature of synapsids: single temporal fenestra (a hole behind the eye socket on each side) which humans retain Jaw muscle passes thru the temporal fenestra and anchor your temple..these changes took 100 million years Also 2 of the bones that made up the jaw (quadrate and articular) were inc in middle ear |
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The first mammals arose during the... |
Jurassic period By the Cretaceous period, 3 lineages existed: monotremes, marsupials, and eutherians |
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Monotremes |
Found only in Australia and New Guinea One species of platypus and 4 of spiny anteaters Lay eggs Have hair and produce milk but lack nipples (scerete milk thru glands on belly) |
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Marsupials |
Opossums, kangaroos, and koalas Share derived characteristics with eutherians (higher metabolic rates, nipples, and give birth) You do are born early and usually in a pouch (called a marsupium). Some open in the rear
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Eutherians (placental mammals) |
More complex placentas then marsupials Longer pregnancy |
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Derived characteristics of primates |
Lemurs, tarsiers, monkeys, and apes Hands and feet for grasping Digits have flat nails instead of claws Large brain Short jaws, flat face with forward facing eyes Tree dwellers, big toe separate (except in humans) for grasping Opposable thumbs for grip. Humans have distinctive bone structure for more precise manipulation |
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Living primates |
3 main groups: 1. lemurs, lorises, and bush babies 2. Tarsiers (more closely realated to anthropoids than first group due to time) 3. Anthropoids (monkeys and apes) |
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Anthropoids |
2 groups: 1. Monkeys: new and old world 2. Apes: hylobates (gibbons), Pongo (orangutans), Gorilla, Pan(chimpanzees and bonobos), and Homo (humans) Diverged from old world monkeys 25-30 million years ago Long arms, short legs, no tail Apes have largest brain |
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Homo Sapians |
200,000 years old on a planet that’s 3.5 billion years old |
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Derived characteristics of humans |
Stand upright Bipedal (walk on 2 legs) Larger brain Reduced jawbones and jaw muscle Shorter digestive tract Only 1% of genome is different (differ in 19 regulatory genes) |
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The earlier hominins |
Paleoanthropology (study of human origin) found 20 extinct species (hominins) closely related to humans rather than chimps Sachelanthropus: earliest hominins shared record canine teeth and flat faces, upright (hole, foremen magnum, is underneath skull rather than further back) While showing signs of bipedalism, their brains stayed small Small in height with large teeth (1.2 m) |
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2 misconceptions of hominins |
1. As chimps or revolved from chimps. Diverged and acquired their characteristics form common ancestor shared with humans 2. Not a ladder of evolution. At times several hominins species existed at the same time. Differed in skull shape, body size, and diet. All but one became extinct. More like only surviving member of branched evolutionary tree |
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Australopiths |
Groups where hominins diversity expanded btw 2 and 4 million years ago A. Africanus: in South Africa walked fully erect, human like hands and teeth. Brain was only about 1/3 size of human brain A. Afarensis: Found Lucy who was 1 m tall, existed at least 1 million years. Brain size of softball, long lower jaws, bipedal, long arms |
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Another lineage of australopiths |
Hominins included species paranthropus boisei (hard skulls and large teeth) Gracile: slender light feeding for softer foods |
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Bipedalism |
Grasslands developed requiring more walking Natural selection for more efficient ground travel Takes more energy for chimps to walk More complex than theory above..all different evolving in species and live in different environments |
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Tool use |
Possibly originated before larger brains Some used stone tools to cut animals Chimps and orangutan use sticks and rocks to get food and leaves for shoes. No evidence of tool may be due to difficulty of finding tools (ie rock that was used to saw or hammer) |
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Early Homo |
Homo habilis-earliest species in our genus. Had shorter jaw and larger brain. Sharp stone tools have been found with fossils (range from 2.4-1.6 million years) Homo ergaster: (1.9-1.5 million) larger brain than habilis. As well as long legs for walking. Weight btw genders declined suggest more pair bonding. Small teeth. Better tools. Homo erectus: first to travel. Extinct btw 200,000 and 70,000 years ago |
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Neanderthals |
Became extinct btw 28,000-40,000 years ago Had larger brain than humans, buried their dead, and made hunting tools from stone and wood Share a common ancestor with humans Some gene flow btw the 2 species (DNA found in jaw bone had Neanderthal DNA..persons great great great grandparent was Neanderthal |
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Homo sapiens |
Originated in Africa. Oldest fossils are 195,000-160,000 years old. Middle East-115,000 years old. New world-15,000 years old Less pronounced brow and were more slender Homo naledi: small brain, hands for fine motor skills, bipedal |
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Homo floresiensis |
Controversy over whether they were more like an older ancestor |
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Cognition |
77,000 year old art of geometric markings 30,000 years ago, cave paintings were produced |
