David Sadava H. Craig Heller Gordon H. Orians William K. Purves David M. Hillis Biologia.blu B

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David Sadava H. Craig Heller Gordon H. Orians
William K. Purves David M. Hillis
Biologia.bluB Le basi molecolari della vita
e dellevoluzioneThe Evolution of the Human
Species
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The Evolution of the Human Species

• Who were the first humans?
• When and where did they live?
• What makes us human?

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The Evolution of the Human Species - Who were the
first humans?
Human appearance on Earth
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The Evolution of the Human Species - Who were the
first humans?
Human taxonomy
Domain Eukaryota
Kingdom Animalia
Phylum Chordata
Subphylum Vertebrata
Class Mammalia
Order Primates
Superfamily Hominoidea
Family Hominidae
Genus Homo
Species Homo sapiens
Subspecies Homo sapiens sapiens
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The Evolution of the Human Species - Who were the
first humans?
Primate evolutionary trends

• Digit mobility (grasping and opposability)
• Optical shift
• Bipedalims
• Relative size of the cerebral cortex
• Parental care

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The Evolution of the Human Species - Who were the
first humans?
Close relatives
Human species and anthropomorphic apes (gorilla,
gibbon, orangutan, chimpanzee) belong to the
superfamily of the Hominoidea, primates without
tails.
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The Evolution of the Human Species - What makes
us humans?
Hominidae characteristics
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The Evolution of the Human Species - Where did
the first humans live?
A common ancestor
Different climates in the two areas of the
Eastern African Rift Valley are thought to have
caused the evolutionary divergence between
Hominidae and anthropomorphic apes.pes
Atlantic ocean
Indian ocean
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The Evolution of the Human Species - Who were the
first humans?
Early hominid characteristics

• Bipedalism
• Brain size grew larger (genus Homo)
• Reduction of sexual dimorphism (Homo erectus)

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The Evolution of the Human Species - When did the
first humans live?
Species Date (thousand years) Body weight (kg) Mean cranial capacity (cm3) Cephalic index
Homo s. sapiens To present 58 1349 5.3
Homo sapiens 35-10 65 1492 5.4
Homo neandertaliensis 75-35 76 1498 4.8
Late Homo erectus 600-400 68 1090 3.8
Early Homo erectus 1800-600 60 885 3.4
Homo habilis 2400-1600 42 631 3.3
Australopithecus africanus 3000-2300 36 470 2.7
Australopithecus afarensis 4000-2800 37 420 2.4
Chimpanzee To present 45 395 2.0
Gorilla To present 105 505 1.7

• ratio of the maximum width of the head
  multiplied by 100 divided by its maximum length
• The first members of the genus Homo appeared
  around 2.5 million years in Africa.

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The Evolution of the Human Species - Who were the
first humans?
Turkana Boy (Homo erectus)
Homo erectus is generally considered to have been
the first species to have expanded beyond Africa,
and related fossils are spread over two
continents. A nearly complete 1.6-million-year-old
skeleton, found near Lake Turkana, Kenya,
belonged to an eight-year-old boy.
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The Evolution of the Human Species - Who were the
first humans?
Professor Svante Pääbo holding the skull of a
Homo neandertaliensis
An international consortium of researchers has
sequenced the genome of our closest relative, the
Neandertal. Results indicate that Neandertals
are slightly more closely related to modern
humans outside Africa. The team also identified
several genomic regions that appear to have
played an important role during human
evolution. (Science on May 7, 2010)
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The Evolution of the Human Species - What makes
us humans?
Two possible models
Out-of-Africa model
Multiregional model
Europe Africa Asia
Europe Africa Asia
Interbreeding between people living in Europe,
Asia, and Africa (gene flow)
(present)
Homo sapiens evolved from Homo erectus in Africa
0.5 million years ago
Modern humans evolved more or less simultaneously
in all major regions of the Old World from local
archaic humans.
Humans with modern traits left Africa from 50,000
to 60,000 years ago to settle the world
(1.8 million years ago)
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The Evolution of the Human Species - What makes
us humans?
Cultural evolution

• Worked stone tools
• Evolution of language
• Cave art, burials
• Domestic animals
• and agriculture

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