Dear Students!
Our next speaker will be
Algis Kuliukas who will talk about the Waterside Hypothesis (former
Aquatic Ape Hypothesis).
This is the paper you need to read:
Algis V. Kuliukas: A Wading Component in the Origin of Hominin Bipedalism
If you are interested in other arguments besides
Bipedalism, I can send you an e-book which is quite resent (2012) and
covers most of the arguments!
All in all, I really liked this article. It was extremely well organized and easy to follow.
ReplyDeleteEvidence that Chimps go in water still seems a little weak to me. The force to get them in the water is the food brought to them. While this shows that they can wade in water, I’m not sure it answers the question of what evolutionarily could have forced them into the water. Were there aquatic plants that they were driven to eat for some reason?
Further, while the study on bonobos did have some results, I’m not sure if it’s too conclusive, and I would like to know if it has been replicated. Sure, it shows that they can do it, but once again, the time spent in water was very little (not sure how much would be needed to push selection), and it’s not clear if there would be any natural food in the water to attract them, or a need/desire for them to go towards that food even if it existed.
I also find the wading hypothesis to be interesting from the notion of scaffolding. Intuitively, it seems plausible for water to act as a physical scaffold for upward, bipedal posture. Even if standing upright is more difficult in water than on land, the water itself would seem, at least to my mind, a good scaffold that would aid early ancestors/apes in initially standing on two legs. (This seems to be supported in terms of walking, but I think the claim that it aided standing would also help the claim.) Perhaps I’m wrong on this assumption, however.
I really enjoyed this article.
ReplyDeleteI think I share the same hesitation that Brad voiced. There must have been something mighty tasty in that water.
Are there any other traits specific to humans and not to other primates whose development is also supported by the waterside hypothesis?
I found this article pretty compelling. It's interesting to me how some hypotheses seem to fall out of fashion or go unnoticed for reasons that have nothing to do with their merit. I'd also like to echo Brad's appreciation of the clarity and organization of the paper. Though I find the author's assertion that wading has been overlooked as an explanatory model for the development of bipedalism in Hominids very compelling, I worry that this might have more to do with the quality of writing than the quality of the argument. I am especially curious about the reception of the evaluative/comparative model he puts forward. As he says, his own subjective opinion enters into the chosen points of comparison, the simple way they are applied, and the evaluation of the studies he carries out (Here, I mean the way he assigns point values to each theory regarding how well it satisfies the conditions he puts forward, i.e. the darwinian subgroup, ecological subgroup, etc.) So I'm curious if anyone else has undertaken a similar meta-study and come up with different results. It seems to me that such an evaluation should at least be carried out by a number of researchers (even if they are working in concert) so as to move towards something more resembling a consensus before we take the results as anything more than suggestive.
ReplyDeleteIn this study, they have looked over the models assuming the origin of bipedalims. They propose a frame work model. Actually I was not able to fully figure out how it assessed the models. And lastly she contains two empirical evidences supporting a wading model. To me, it was not so much worthy to debate upon what models is wrong or true. Because all of theories appear to be reasonable, so they all might contribute to bipedalism under natural selectiveness.
ReplyDeleteIt was interesting to read all possible scenarios to suggest factors that might have driven the evolution of hominin bipedalism. And I agree that the paper was well organized. Yet, I still am doubtful about the reasons suggested to explain human bipedal origins. Here is the reason why I still am not fully persuaded. From the anatomical perspective, human adult have an increased risk for aspiration, which mainly due to upright position. Many scenarios and hypotheses of human bipedal origins seem to address that there should be some benefits of being bipedal. However, it is hard to think for me that there is any other good reason to risk one's own life.
ReplyDeleteThe target article offers a clear overview of various models that have been proposed for explaining the evolution of human bipedality, as well as offering evidence in support of the waterside wading hypothesis. I have two questions, one in regards to the content and another about general scientific pedagogy.
ReplyDeleteFor the content point, the author notes that the meta-analysis of available models and the SIMPLE ranking is based on a non-weighted set of criteria. In light of the epistemological problem concerning the formulation of acceptable (i.e. falsifiable or testable) hypotheses in the literature, would weighting the ranking system help formulate stronger hypotheses from an epistemological perspective or will they remain no more or less fit to solve this issue? For the pedagogical point, is it a common occurrence to find similar discrepancies in other areas between the research on certain hypotheses and their explanation in introductory textbooks or no?
The wading hypothesis seems to explain more than other models about why we are bipedal. For the explanation of being hairless in humans, I wonder why humans’ head has hair but our shoulders do not have much hair? When we become bipedal, our head and shoulders get sunburn easily, but the process of becoming bipedal did not keep the hair on our shoulders unless we used to be in deep water often or already started to wear clothes.
ReplyDeleteI commend Kuliukas for attempting to create a scientific way to study bipedialism in chimpanzees but I do have to agree with the earlier posts that evidence of bipedalism in primates seems somewhat unsubstantiated. The situation in which apes were systematically observed makes me wonder what other factors of captivity influence this behavior? For instance the observation at Conkouati reserve lagoon (p.16), these chimps were put on this island with low vegetation which created a situation that they may not normally encounter. Is this really a natural occurrence in that respect? However, how do you conduct a study to support or refute the wading hypothesis and control for confounds? I found this article very interesting and easy to follow. There seems like there is more strength in this notion that the other models. The wading hypothesis is definitely a theory in need of more exploration especially in light of its rejection being so based on claims that do not reflect a scientific cause for its lack of reception.
ReplyDeleteIt seems like the aquatic ape hypothesis has gotten pretty short shrift in the evolutionary discourse. This article makes a pretty compelling case for why it should be taken more seriously, and I, for one, am sold. I guess I can't quite understand why everyone in the field isn't taking the multifactorial approach.
ReplyDeleteFolks have done a somewhat decent job in doing away with teleological hypotheses (they still remain implicit in many of them, but at least there's a conscious effort to avoid teleology in evolution), but it still seems like there's something like a commitment to First Cause here. Shouldn't we just just admit that within the landscape of causal factors in the genesis and perpetuation of the bipedal stance, being near water has played a substantial, but hardly exclusive role?