|
No. |
Theory & first Mention |
Location |
Strong [i] Selection ? |
Intermediate steps easy &
advantageous?[ii] |
Applies to Both Sexes? |
Explains why chimps not bipedal?[iii] |
Explains Australopith anomalies[iv] |
Observed in Chimpanzees[v] |
Depends on[vi] |
Contradicts[vii] |
Popularity in Texts[viii] |
|
1 |
Terrestrial |
Some |
Some |
Mainly
Male |
No |
No |
Yes |
|
|
7 |
|
|
2 |
Terrestrial |
No |
No |
Yes |
No |
No |
Yes |
|
|
6 |
|
|
3 |
Savannah |
Some |
No |
Yes |
Yes |
No |
Yes |
|
|
5 |
|
|
4 |
Coastal
Areas |
Some |
Yes |
Yes |
Yes |
Yes |
No |
|
|
1 |
|
|
5 |
Terrestrial |
Some |
Yes |
Only
male |
No |
Perhaps |
Yes |
|
|
4 |
|
|
6 |
Woodland |
Some |
Yes |
Yes |
No |
No |
Yes |
|
13 |
5 |
|
|
7 |
Woodland |
No |
Yes |
Yes |
No |
Perhaps |
Yes |
|
13 |
2 |
|
|
8 |
|
Some |
No |
Yes |
No |
No |
No |
|
|
6 |
|
|
9 |
9.
Infant
dependency on Mother (Tanner 1981) |
|
|
No |
Only female |
Yes |
No |
No |
|
|
2 |
|
10 |
10.
Reproductive
Strategy & Provisioning (Lovejoy 1981) |
Terrestrial |
No |
No |
|
No |
No |
No |
|
|
4 |
|
11 |
11.
Energetically
Efficient Meat Scavenging (Shipman 1984) |
Savannah |
Some |
No |
|
Yes |
No |
No |
9 |
|
2 |
|
12 |
12.
Long-distance
Migration (Sinclair 1986) |
Mosaic/Patchy Woodland |
Some |
No |
Yes |
No |
No |
No |
9 |
|
1 |
|
13 |
13.
Thermoregulation
(Wheeler 1984) |
|
Some |
Some |
Yes |
Yes |
No |
No |
|
6
8 15 16 |
|
|
14 |
Mosaic/Patchy Woodland |
Some |
No |
Yes |
Yes |
No |
No |
9 |
|
0 |
|
|
15 |
15.
Aquarboreal wading (Verhaegen 1997) |
Flooded mangrove forest |
Yes |
Yes |
Yes |
Yes |
Yes |
No |
|
13 |
|
|
16 |
16.
River
Wading (Kuliukas 1997[ix]) |
East
African Rivers and associated Gallery Forests |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
|
13 |
0 |
[i] ‘Strong’ selection in a ‘selfish’ individual sense. If a pre-pubescent individual was maladapted to do this, how likely would he/she perish. Wading is clearly the strongest in this sense.
[ii] Does the proposed theory include advantages at every step between a knuckle-walking ancestor and full human bipedalism?
[iii] The theory should also propose why chimpanzees did not become bipedal.
[iv] By ‘anomalies’ we mean those australopith features that do not seem to fit in with fully human bipedalism.
[v] Corresponding behaviour observed in chimpanzees (p. troglodytes or p. paniscus)
[vi] Some theories build on from others and depend on them
[vii] Most of these theories are complementary in as much as they could all be factors in the evolution of bipedalism. Some however do seem to be contradictory and mutually exclusive.
[viii] ‘Popularity’ here is rated in terms of how many ‘standard’ university text books mention the theory. Books used were… “How Humans Evolved” (Boyd & Silk 2000); “Cambridge Encyclopaedia of Human Evolution” (Eds Jones, Martin & Pilbeam 1996); “Primate Adaptation & Evolution” (Fleagle 1999); “Understanding Human Evolution” (Poirier & McKee 1999); “The Human Career” Klein 1999; “Reconstructing Human Origins” (Conroy 1997); “Principles of Human Evolution” (Lewin 1998); “The Past in Perspective” (Leder, 1996)
[ix] I have not seen any published material promoting this as a mechanism for the origin of bipedalism. I first posted it to the Paleoanthropology newsgroup in 1997.