BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Neil A. Campbell Jane B. Reece Lawrence

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


• 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


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


Figure 19.3

Mill

ions

of y

ears

ago

Australopithecusanamensis

Ardipithecusramidus

Ardipithecusramidus kadabba

Orrorin tugenesis

Australopithecusafarensis

Australopithecusafricanus

Australopithecusrobustus

Australopithecusboisei

Homoergaster

Homohabilis

Homoerectus

Homoneanderthalensis

Homosapiens

?


• 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


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


• 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


• 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


• 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)


• 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


Development of Culture

• 3 stages:

– Scavenging-gathering-hunting

– Agriculture

– Machine Age


• 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


• 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


• 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


• 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


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

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BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Neil A. Campbell Jane B. Reece Lawrence