Download lecture 14

Jeanne Sept
10/22/04
Looking
for a
Missing
Link
chimps
human
genetics
anatomy
behavior
ecology
genetics
anatomy
behavior
ecology
Scientific
American
Pp 4-19
?
Ramapithecus !
chimps
human
Interpretive tools:
Evolutionary baggage:
Principles of biology,
ecology & culture
Unpack ourselves
to understand our past
?
Biped = first
hominid ?!
15-8 mya
Traditional classification
gorilla
chimp
bonobo
human
Traits of Last Common Ancestor?
Broad shoulders
Broad shoulders
Broad shoulders
No tail
No tail
No tail
hairy
hairy
No tail
hairy
Large canine
Large canine
less hairy
Small canine
Brain 300-500cc
Brain 1300-1500cc
Large canine
large canine
Brain 300-500cc
Brain 300-500cc Brain 300-500cc
Brachiator
Crushing molars
Large molars
Tools ?
Knuckle walk
Cuspy molars
Large molars
No tools
Broad shoulders
hairy
Knuckle walk
Knuckle walk
& biped
Cuspy molars
small molars
Cuspy molars
small molars
Tool user
Tools ?
Broad shoulders
No tail
biped
Crushing molars
small molars
Tool user
Groups?
A105 Lecture
1
Jeanne Sept
10/22/04
Genetic distance
Genotype!
DNA-DNA hybridization
Phenotype problematic =
ambiguous evidence of
inheritance
– E.g. convergent traits
Genetic relationship:
Bonobo
Molecular systematics
– Family trees based on genetic
comparisons
- Protein comparisons
- DNA-DNA hybridization
- Heating temperature for hybrid
strands of DNA is proportional
to % genetic base mismatches
- Chromosome sequencing
- Mitochondrial DNA sequencing
Bonobo
-
Chimp
0.7%
Gorilla
2.3 %
2.3 %
Orangutan
3.6 %
3.6 %
Genetic distance
gorillas
orangutans
0.7%
2.3%
Gorilla
Orangutan
3.6 %
-
Genetic distance
Bonobo
chimps
Chimp
Chimp
Gorilla
Bonobo
-
Chimp
0.7%
Gorilla
2.3 %
2.3 %
Orangutan
3.6 %
3.6 %
3.6 %
1.6 %
1.6 %
2.3 %
Orangutan
-
3.6%
Human
Genetic distance
chimps
humans
gorillas
Trees based on MtDNA
orangutans
0.7%
1.6%
2.3%
3.6%
A105 Lecture
2
Jeanne Sept
10/22/04
Genotype & Phenotype
Molecular systematics
– Human genome project
– Chimp genome project
- Individual differences in genes may code
for critical Amino Acid differences, coding
for different proteins
- E.g. immune system genes
- E.g. early brain development
- Smell, hearing
- Long bone growth
- Hairiness
- Digestion
DNA prediction:
How old should “Missing
Link” between chimps
and humans be?
4.8%
____
1.6%
22 million years
=
______________
X million years
7.33 mya
7.2%
____
1.6%
Calibrating DNA splits
chimps
gorillas
orangutans
gibbons
OW
monkeys
0.7%
1.6%
2.3%
When?
3.6%
4.8%
7.2%
Proconsul
How old
is
missing
link?
~ 22 mya
Calibrating DNA splits
chimps
human
gorillas
orangutans
gibbons
OW
monkeys
0.7%
1.6%
5-7 mya
2.3%
3.6%
22 million years
=
human
______________
X million years
4.89 mya
Proconsul
4.8%
~ 22 mya
Ramapithecus !
7.2%
DNA mismatch?
chimps
human
gorillas
orangutans
gibbons
OW
monkeys
Ramapithecus
5-7 mya
Biped = first hominid
?!
15-8 mya
A105 Lecture
~ 10 mya ?
Proconsul
~ 22 mya
3
Jeanne Sept
10/22/04
Ramapithecus
First hominid?
– Older than expected
Sivapithecus
A big ape!
What to do?
– Find more fossils!
Sivapithecus
Ancestor of Orangutan
2 Siwaliks hominids?
Ramapithecus
Sivapithecus
Big
Big canine
Small
Small canine
One ape species!
DNA = branching pattern
human
chimps gorillas
orangutans
gibbons
OW
monkeys
5-7 mya
Sivapithecus
~ 10 mya
Proconsul
~ 22 mya
Sexual dimorphism
A105 Lecture
4
Jeanne Sept
10/22/04
a “missing link” ?
chimps
human
Search for missing link:
When ?
– Probably 5-7 million years ago
-
Based on DNA + fossils
Where?
– Africa
-
Based on DNA + comparative anatomy
?
Feet first?
small-brained biped
Walking the Walk :
interpreting fossils
Chimps on 2 legs
Comparative anatomy
Bio-mechanics
Fossils
A105 Lecture
Living
species
Living
species
5
Jeanne Sept
10/22/04
Danger of Collapse
Bipedal challenge
How to keep your
balance on one foot?
– Avoid collapse to
unsupported side
Unstable !
Hip muscles
Muscle contracts
Leg swings back
A105 Lecture
Leg swings out
6
Jeanne Sept
10/22/04
Bipedal challenge
How to keep your
balance on one foot?
– Avoid collapse to
unsupported side
A105 Lecture
7