BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing...
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Transcript of BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing...
BIOLOGYCONCEPTS & CONNECTIONS
Fourth Edition
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
From PowerPoint® Lectures for Biology: Concepts & Connections
CHAPTER 19Human Evolution
Modules 19.3 – 19.10
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Humans and apes diverged 5 to 7 million years ago
– (less than 18 hours ago on our year-time scale)
– The first hominid appeared about 6 million years ago
– There are two branches: Australopithecines (now extinct) and Homo (us)
– Hominids are species on the human branch of the evolutionary tree
HOMINID EVOLUTION
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
5 features of human evolution
• Increased brain size
• Shorter jaws, flatter faces, and pronounced chins
• Bipedal posture (walking upright on two legs)
• Reduced size difference between the sexes
• Family structure: longer infant care, monogamy
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 19.3
Mill
ions
of y
ears
ago
Australopithecusanamensis
Ardipithecusramidus
Ardipithecusramidus kadabba
Orrorin tugenesis
Australopithecusafarensis
Australopithecusafricanus
Australopithecusrobustus
Australopithecusboisei
Homoergaster
Homohabilis
Homoerectus
Homoneanderthalensis
Homosapiens
?
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• 3.5 mya, we evolved upright posture and bipedal movement
– Mary Leakey found fossil footprints to confirm this
– This is the first and most important step in early human evolution
19.4 Upright posture
Figure 19.4
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Lucy
• Lucy is a 3 myo skeleton found in Africa
• She was an Australopithecus aferensis
• She was fully grown and 3 feet tall with a head the size of a softball
• She is one of our early ancestors
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Homo habilis, an early African hominid, coexisted with some of the australopithecines
– They had larger brains and made simple tools
– They evolved into the more advanced Homo erectus
• Homo erectus evolved into Homo sapiens, who left Africa and spread around the world.
19.5 Homo and the evolution of larger brains
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• One of the regional descendents of H. erectus was the stocky and muscular Neanderthals
– They lived throughout Europe from about 200,000 to 40,000 years ago
19.6 When and where did modern humans arise?
Figure 19.6
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Based on DNA and fossil evidence, scientists now know that all humans originally evolved in Africa
– This group arose around 100,000 years ago
– They migrated out of Africa
– They replaced regional populations of archaic peoples (including Neanderthals)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Major milestones in the evolution of Homo sapiens are the evolution of
– Bipedal posture, straight spine (due to changes in our feet and backbone)
– a large brain
– a prolonged period of parental care
OUR CULTURAL HISTORY AND ITS CONSEQUENCES
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Development of Culture
• 3 stages:
– Scavenging-gathering-hunting
– Agriculture
– Machine Age
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• The first humans survived by scavenging, gathering, and hunting
– Early scavengers and hunters may have killed off saber-toothed cats and woolly mammoths
19.8 Scavenging-gathering-hunting
Figure 19.8
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Agriculture arose about 10,000-15,000 years ago
– People settled down and began growing food and domesticating animals in Iraq/Iran/Saudi Arabia
– Early farmers in the Fertile Crescent allowed their land to be overgrazed and depleted the soil: now it’s a desert
19.9 Agriculture was a second major stage of culture
Figure 19.9
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• The Industrial Revolution began in the 1700s
• Industrialization brought a change from hand production to energy-intensive, large-scale machine production
19.10 The machine age is the third major stage of culture
Figure 19.10
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Mechanized farming and improved medicine have led to the accelerated growth of the human population
• Our impact on the environment has also accelerated
– We are changing the world so quickly that many species cannot adapt
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
So, did we come from monkeys?
• No, we share a common ancestor with monkeys
• We are related to monkeys
• We share DNA, physical and social characteristics with them
• But we are more closely related to apes