Human Evolution

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Human Evolution
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Human Evolution I. What are humans related to?
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Human Evolution I. What are humans related to?
- Morphologically similar to apes
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Human Evolution I. What are humans related to?
- Morphologically similar to apes - hands,
binocular vision (Primates)
No tail
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Human Evolution I. What are humans related to?
Apes
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Human Evolution I. What are humans related to?
Apes II. How do we differ?
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Human Evolution I. What are humans related to?
Apes II. How do we differ? - Behaviorally (walk
erect)
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Human Evolution I. What are humans related to?
Apes II. How do we differ? - Behaviorally
(walk erect) - Behaviorally (intelligence and
learning)
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Human Evolution I. What are humans related to?
Apes II. How do we differ? - Behaviorally (walk
erect) - Behaviorally (intelligence and
learning) - Morphologically, humans have -
larger head/body ratio
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Human Evolution I. What are humans related to?
Apes II. How do we differ? - Behaviorally (walk
erect) - Behaviorally (intelligence and
learning) - Morphologically, humans have -
larger head/body ratio - smaller jaw/head ratio
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Human Evolution I. What are humans related to?
Apes II. How do we differ? - Behaviorally (walk
erect) - Behaviorally (intelligence and
learning) - Morphologically, humans have -
larger head/body ratio - smaller jaw/head
ratio - shorter arms/body ratio
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Human Evolution I. What are humans related to?
Apes II. How do we differ? - Behaviorally (walk
erect) - Behaviorally (intelligence and
learning) - Morphologically, humans have -
larger head/body ratio - smaller jaw/head
ratio - shorter arms/body ratio - less hair
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Human Evolution I. What are humans related to?
Apes II. How do we differ? - Morphologically Hum
an Chimp Gorilla Orangutan Gibbon
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Human Evolution I. What are humans related to?
Apes II. How do we differ? - Genetically Big
Surprize! Human Chimp Gorilla Orangutan
Gibbon
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Human Evolution I. What are humans related to?
Apes II. How do we differ? - Genetically Big
Surprize! Human Chimp Gorilla Orangutan
Gibbon
lt 1 difference in gene sequence
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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? Can
this 1 difference account for the dramatic
behavioral and morphological differences we
see? Yes, some genes have big effects. These are
regulatory genes, acting during development. They
influence the expression of lots of other genes
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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? Can
this 1 difference account for the dramatic
behavioral and morphological differences we
see? Yes, some genes have big effects. These are
regulatory genes, acting during development. They
influence the expression of lots of other genes
- Can we test this hypothesis? Do the differences
correlate with developmental effects?
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• Yes. All differences correlate with
  developmental differences between juvenile
  primates and adults
• Juveniles Adults
• Larger Head/body ratio smaller
• Smaller jaw/head ratio larger
• Shorter limb/body ratio longer
• Less hair more hair
• Better learning poorer learning

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• Yes. All differences correlate with
  developmental differences between juvenile
  primates and adults
• Juveniles Adults
• Larger Head/body ratio smaller
• Smaller jaw/head ratio larger
• Shorter limb/body ratio longer
• Less hair more hair
• Better learning poorer learning
• Human-like Ape-like

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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? Can
this 1 difference account for the dramatic
behavioral and morphological differences we
see? Yes, if the small change is in
developmental genes, they can have BIG
effectshumans might be a type of ape that
didnt grow up The ways we differ supports this
hypothesis
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Yes, if the small change is in developmental
genes, they can have BIG effectshumans might be
a type of ape that didnt grow up
Small changes in development, especially if they
occur early in development, can result in big
effects.
Human
Chimp
Primate developmental trajectory
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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? IV.
Are there common ancestors?
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Molecular clock analyses
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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? IV.
Are there common ancestors? Yes. Just where
evolution predicts they should be (After other
monkeys and apes, before humans and existing
apes).
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Science, Nov 19, 2004
Pierolapithecus catalaunicus
12-13 mya oldest ape
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V. Are there common ancestors? - Fossil and
genetic analysis independently predicted a common
ancestor between humans and chimps lived 5-8
million years ago.
Chimpanzee
Human
Homo sapiens
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V. Are there common ancestors? - Fossil and
genetic analysis independently predicted a common
ancestor between humans and chimps lived 5-8
million years ago.
Chimpanzee
Human
Homo sapiens
Sahelanthropus tchadensis discovered in Chad in
2001. Dates to 6-7 mya. Only a skull. Is it on
the human line? Is it bipedal? Probably not
(foramen magnum). Primitive traits, as a common
ancestor might have.
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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? IV.
Are there common ancestors? V. Are there
intermediate links to modern humans?
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V. Are there intermediate links to modern
humans? - yes, and in a nearly continuous
sequence.
Chimpanzee
Australopithecus afarensis
Australopithecus africanus
Homo habilis
Human
Homo sapiens
Homo erectus
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V. Are there intermediate links to modern
humans? - with a divergence of two types of
hominids around 2 mya
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V. Are there intermediate links to modern
humans? - with a divergence of two types of
hominids around 2 mya
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V. Are there intermediate links to modern
humans? - with a divergence of two types of
hominids around 2 mya
slender species
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V. Are there intermediate links to modern
humans? - with a divergence of two types of
hominids around 2 mya
slender species
robust species
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V. Are there intermediate links to modern
humans? - with a divergence of two types of
hominids around 2 mya
Primitive species, with their bipedality
disputed. Are they on the human line? The chimp
line? Ancestral to both? Cant tell they are
so INTERMEDIATE.
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Morphological cladogram
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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? IV.
Are there common ancestors? V. Are there
intermediate links to modern humans? VI. When did
these changes evolve?
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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? IV.
Are there common ancestors? V. Are there
intermediate links to modern humans? VI. When did
these changes evolve? - The distinguishing
traits of Hominids are erect gait and large
brain.
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And, as weve discussed, Australopithecus
afarensis walked erect.
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And, as weve discussed, Australopithecus
afarensis walked erect.
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• A. Afarensis prints at Laetoli, approximately
  3.56 myr, were made by an obligate biped
• - heel strike.
• - Lateral transmission of force from the heel to
  the base of the lateral metatarsal.
• - A well-developed medial longitudinal arch.

- Adducted big toe, in front of the ball of the
foot and parallel to the other digits. - A deep
impression for the big toe commensurate with
toe-off.
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- A tibia from A. anamensis found in 1994 is
oldest direct evidence of bipedality (4.1 mya)
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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? IV.
Are there common ancestors? V. Are there
intermediate links to modern humans? VI. When did
these changes evolve? - The distinguishing
traits of Hominids are erect gait and large
brain. - Erect gait came first
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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? IV.
Are there common ancestors? V. Are there
intermediate links to modern humans? VI. When did
these changes evolve? - The distinguishing
traits of Hominids are erect gait and large
brain. - Erect gait came first - Brain size
increase was later, particularly with Homo
habilis and H. erectus..
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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? IV.
Are there common ancestors? V. Are there
intermediate links to modern humans? VI. When did
these changes evolve? VII. Why did these changes
occur?
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VII. Why did these changes occur? - Walking
Erect Adaptive in the expanding dry grasslands.
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VII. Why did these changes occur? - Walking
Erect Adaptive in the expanding dry grasslands.
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VII. Why did these changes occur? - Increased
Brain Size - walking erect frees the hands
for activity - With tools use (seen in Homo
habilis), animals could be killed. This
increases protein in diet, needed for growth
(particularly the brain).
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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? IV.
Are there common ancestors? V. Are there
intermediate links to modern humans? VI. When did
these changes evolve? VII. Why did these changes
occur? VIII. And what of our species?
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VIII. And what of our species? - From Africa
200,000 years ago (earliest fossils, genetic
variability, etc.)
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VIII. And what of our species? - From Africa
200,000 years ago (earliest fossils, genetic
variability, etc.) - Bands of hunter gatherers
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VIII. And what of our species? - From Africa
200,000 years ago (earliest fossils, genetic
variability, etc.) - Bands of hunter gatherers
- Cave Art about 30,000 years ago
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VIII. And what of our species? - From Africa
200,000 years ago (earliest fossils, genetic
variability, etc.) - Bands of hunter gatherers
- Cave Art about 30,000 years ago - 14,000 years
ago, bands settled in different areas of the
globe and began to grow local crops. First
Agricultural Revolution.
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HUMAN PREHISTORY Where did humans come from?
agriculture
to chimps
burial
tools
art
1.75 mya
0.2 mya
5.0 mya
75,000
14,000
99.6 before art
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Human Evolution I. What are humans related to?
Apes II. How do we differ? III. Resolution? IV.
Are there common ancestors? V. Are there
intermediate links to modern humans? VI. When did
these changes evolve? VII. Why did these changes
occur? VIII. And what of our species? IX.
Evolutionary patterns and new stuff!
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IX. Evolutionary patterns and new stuff! -
Hominids provide all the classical patterns of
evolution seen in the rest of life
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IX. Evolutionary patterns and new stuff! -
Hominids provide all the classical patterns of
evolution seen in the rest of life - common
ancestry from primitive forms
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IX. Evolutionary patterns and new stuff! -
Hominids provide all the classical patterns of
evolution seen in the rest of life - common
ancestry from primitive forms - new innovation
in new environment (bipedality as climate
changed)
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IX. Evolutionary patterns and new stuff! -
Hominids provide all the classical patterns of
evolution seen in the rest of life - common
ancestry from primitive forms - new innovation
in new environment (bipedality as climate
changed) - radiation of species with this trait
(bipedalism)
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IX. Evolutionary patterns and new stuff! -
Hominids provide all the classical patterns of
evolution seen in the rest of life - common
ancestry from primitive forms - new innovation
in new environment (bipedality as climate
changed) - radiation of species with this trait
(bipedalism) - competitive contraction and a
winner (H. sapiens)
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IX. Evolutionary patterns and new stuff! -
Hominids provide all the classical patterns of
evolution seen in the rest of life - New
Stuff!
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Nature Oct 28, 2004
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- And there are new surprizes all the time
Homo floresiensis Nature, Oct. 28, 2004
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IX. Evolutionary patterns and new stuff! -
Hominids provide all the classical patterns of
evolution seen in the rest of life - New
Stuff! Island species are often either dwarf
species or giant species
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IX. Evolutionary patterns and new stuff! -
Hominids provide all the classical patterns of
evolution seen in the rest of life - New
Stuff! Island species are often either dwarf
species or giant species - dwarf because
resources might be limiting
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IX. Evolutionary patterns and new stuff! -
Hominids provide all the classical patterns of
evolution seen in the rest of life - New
Stuff! Island species are often either dwarf
species or giant species - dwarf because
resources might be limiting - giant if niches
are open
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IX. Evolutionary patterns and new stuff! -
Hominids provide all the classical patterns of
evolution seen in the rest of life - New
Stuff! - Conclusion Rather than lacking
evidence, the history of humans provides one of
the BEST examples in support of evolution by
common descent.