Talk:Facultative bipedalism/Archive 1

Proposed bibliography to add new information
These are sources I am going to use to add to the information on this page. If you have any suggestions, please let me know! Demes, Brigitte; O'Neill, Matthew (November 2012). "Ground reaction forces and center of mass mechanics of bipedal capuchin monkeys: Implications for the evolution of human bipedalism". American Journal of Physical Anthropology. 150 (1): 76–86. doi:10.1002/ajpa.22176.

This article discusses bipedalism in specifically capuchin monkeys and the evolution of bipedalism in humans.

Wunderlich, R. E.; Schaum, J. C. (April 2007). "Kinematics of bipedalism in Propithecus verreauxi". Journal of Zoology. 272 (2): 165–175. doi:10.1111/j.1469-7998.2006.00253.x.

This article covers bipedalism in specifically Verreaux’s Sifaka, as well as the similarities to other primate bipeds, and how bipedalism is related to energy conservation.

Aerts, P., Van Damme, R., D’Août, K., & Van Hooydonck, B. (2003). Bipedalism in lizards: whole-body modelling reveals a possible spandrel. Philosophical Transactions of the Royal Society B: Biological Sciences, 358(1437), 1525–1533. http://doi.org/10.1098/rstb.2003.1342 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1693243/

This article covers the mechanisms of lizard bipedalism and places the mechanisms in context of its evolution.

Lee, H.-J., Lee, Y.-N., Fiorillo, A. R., & Lü, J. (2018). Lizards ran bipedally 110 million years ago. Scientific Reports, 8(1), 2617. https://doi.org/10.1038/s41598-018-20809-z

This article primarily shows that lizards developed this behavior a long time ago, which will be a quick fact that will occupy no more than a sentence.

Hanna, J. B., Schmitt, D., Wright, K., Eshchar, Y., Visalberghi, E., & Fragaszy, D. (2015). Kinetics of bipedal locomotion during load carrying in capuchin monkeys. Journal of Human Evolution, 85, 149–156. https://doi.org/10.1016/j.jhevol.2015.05.006

This paper discusses the mechanisms of bipedalism related to load-carrying, which is of special significance for primates as load-carrying is related to the evolution of the behavior and thus, it’s important to mention the mechanisms of it.

Carvalho, S., Biro, D., Cunha, E., Hockings, K., McGrew, W. C., Richmond, B. G., & Matsuzawa, T. (2012). Chimpanzee carrying behaviour and the origins of human bipedality. Current Biology, 22(6), R180–R181. https://doi.org/10.1016/j.cub.2012.01.052

This article addresses the questions of why chimpanzees use facultative bipedalism which isn’t addressed very closely in other articles that get at the evolutionary basis for and mechanisms of bipedalism.

Hunt, K. (1996). The postural feeding hypothesis: an ecological model for the evolution of bipedalism. South African Journal of Science, 92 (2), 77-90. This paper suggest a combined terrestrial and arboreal postural feeding origin for hominid bipedalism- eating fruits from small open forest trees. He also touches on australopithecine morphology/anatomy and adaptation as a starting point for evolution.

Alexander, R. (2004). Bipedal animals, and their differences from humans. Journal of Anatomy, 204, 321-330.

This paper discusses how certain animals orient their bodies in order to walk and run bipedally, and how the patterns of force differ between species, especially compared to humans. It also talks about which species benefit the most from bipedalism, and who it is expensive for.

Fedak, M., Pinshow, B., & Schmidt-Nelsen, K. (1974). Energy Cost of Biped Running. American Journal of Physiology, 227(5), 1038-1044.

This paper looks at the energy cost of running of two and four legged animals, as well as the predicted cost of transport, looking an oxygen consumption during running at various speeds.

Alkunzle (talk) 12:51, 4 October 2018 (UTC)

Outline for redoing this page
A properly formatted copy of this can be found on my Sandbox.

Intro paragraph Definition - they have a pretty solid working definition in the previously established introduction. Make it more specific in terms of both contexts in which bipedalism is used and the high/low speed difference that it touches on, as well as mentioning the different types Overview of types of species (from what we have below - primates and lizards) Brief mention of different situation in which they perform facultative bipedalism (i.e. food gathering) Distinguish from obligate/habitual bipedalism in the fact that it is not done all the time Types of Bipedal Locomotion This is a very basic and simple overview that is currently lacking from the page. Having this will increase the clarity of the definition and provide context for the reader.

(Wunderlich & Schaum 2007)

●     Walking – evenly spaced gait

●     Running – has a period where both feet are off the ground

●     Skipping  - both feet are off the ground and then hit the ground right after each other, trailing foot changes each step

●     Galloping – similar to skipping, but the trailing foot stays the same in each step

Facultative Biped Species Obviously, naming the species that use facultative bipedalism and describing their behavior is the most substantial part of this page. We’ve separated it into primates and lizards because those were the two main categories that we identified through our research, and are mentioned on the current page. Having this level of detail about bipedalism in each of these species will greatly enhance the utility of the page.

Facultative Bipedalism in primates In which species bipedalism is found (homo - human, hylobates - gibbons, pan - chimpanzees and bonobos, pongo - orangutans, gorilla, propithecus - sifaka)

Lemurs -Propithecus bipedalism - Sifakas

Arboreal vertical clingers and leapers, will locomote bipedally on the ground Walking or bipedal gallop Comparisons to other primates Hip joint: humans have extended hip joint, pan and propithecus have flexed hip joint, Hylobates has most flexed hip joint Knee joint: propithecus is similar to other primates, though humans flex the knee joint less Propithecus and humans are the only ones to utilize the skipping/galloping type, pan and Hylobates mostly walk Sifaka have an anatomy that is specialized for vertical clinging and leaping but also makes them obligate bipeds on the ground to conserve energy. -Ring-tailed lemurs (lemur catta)

Can be arboreal and terrestrial, when terrestrial are quadrupedal 70% of the time and bipedal 18%, more than other other genus lemur When bipedal, they hopped or walked Monkeys -Capuchin monkey bipedalism

Arboreal quadrupeds, will locomote bipedally on the ground Spring-like walk, no running (with aerial phase) - the faster they go, the less they wobble Capuchins do not employ a pendulum-like gait. In humans, this allows recovery of energy through the interchange of kinetic and potential energy. Without this in capuchins, energy costs are high. Pendulum-like walking may be the distinction that led to human bipedalism One of the most successful facultative bipeds - frequent and skillful, particularly in regards to load carrying Describe the detailed kinetics of their motion -Baboons (papio)

Olive baboons- described as a quadrupedal primate, but bipedalism is observed occasionally and spontaneously in captivity and in the wild Immature baboons appear to be more bipedal than adults Bipedal postures and locomotion in infants, although infrequent, appear to distinguish them clearly from adults Go into more detail about the specific quantitative data Apes Apes in closed forest habitats are more bipedal than chimps and baboons, stationary or moving Terrestriality is not a spur to bipedal behavior -Gibbons (hylobates)

Anatomy that is specialized for vertical clinging and leaping but also makes them obligate bipeds on the ground to conserve energy. Low speed Vertical climbing develops similar hip and knee joint extensions to that used for bipedal locomotion Similar use of 3 primary back muscles to chimpanzees and humans -Chimpanzees

Excessive tilt and rotation compared to humans Exhibit bipedalism more often when carrying valuable/commodity resources Can carry more than twice as much when walking bipedally as opposed to quadrupedally Primarily used for food gathering/transporting purposes Among chimpanzees, as well as baboons, bipedalism has been linked to feeding - both on the ground and aloft when feeding from fruit trees; foraging in short trees with both feet on the ground allows for individuals to reach higher into the trees Posture feeding hypothesis -Australopithecus anatomy in relation to bipedalism

Pelvis and lower body morphology indicate bipedalism Also morphology that indicates less than bipedal conditions Australopithecines experienced high pelvic and femoral stresses - small diameter spine, wide hips, short legs require more energy per unit distance to operate -Other: Gorillas and orangutans are also facultative bipeds

Facultative bipedalism in lizards Bipedal running developed fairly early in lizard evolution, with fossils suggesting this behavior began 110 million years ago. Lots of debate over whether lizard bipedalism confers any advantages (faster, less energy consumption) In lizards, the full benefits of bipedal running have not yet been identified. Rather, it appears as if bipedal running is due to acceleration. When the hind limbs build enough power, a strike from the hind limb opens the lizard’s trunk angle and shifts its center of mass; this, in turn, increases front limb elevation In modeling, a very specific number of steps and rate of acceleration leads to the exact shift in the center of mass that allows the elevation of the front limbs; too fast and the center of mass moves too far back and the lizard falls over backward; too slow and the front limbs never elevate but real lizards adjust their movements (forelimbs, tail) to increase stretch of bipedal locomotion and are better at it than the model suggests Development due to simple acceleration/center of mass physics but does confer an advantage, so was exploited and the behavior evolved Passive engagement minimizes energy use to keep the front limbs on the ground Maybe makes maneuvering easier/better, helps increase speed → advantage but not a cause Doesn’t increase speed but does increase acceleration - acceleration thresholds at which the lizards begin running bipedally are lower than the Aerts model predicts → the lizards may be actively trying to run bipedally rather than passively going with it, so there may be some other advantage that we haven’t found yet Evolution of bipedalism Because a lot of the studies concerning the mechanics and such of bipedalism are framed in the context of how bipedalism evolved in humans, we think it is important to address the evolution of facultative bipedalism on this page. The evolution of behaviors, especially those that are related to anatomy and structure, is crucial to understanding what purposes they serve. The details provided in the section above give the necessary information to put this section in context of how bipedalism works mechanically.

-Origin of bipedalism in dinosaurs (Persons & Currie 2017)

Facultative bipedalism leading to obligate bipedalism in dinosaurs Using studies of lizards to reveal the conditions in which bipedalism arises Bipedalism as a method of increased speed through larger hind limb muscles -Origin in primates

Separate in humans, bonobos, and gibbons (Vereecke et al. 2005) Evolutionary explanation of development and/or selective pressure often linked to load-carrying - chimpanzees, bonobos, macaques, capuchins, baboons (Hanna et al. 2015): Either selective pressure or significant advantage; affects limb mechanics and anatomy as load carrying causes increased force on the lower limbs (Hanna et al. 2015); chimpanzees being able to carry more - in uncertain environments with potentially unavailable commodities, walking bipedally to carry more is advantageous (Carvalho et al., 2012) Various arboreal adaptations also likely made bipedalism advantageous (Preuschoft 2004) - specific types of a set of behaviors can illustrate parts of the evolutionary path Bipedalism possibly developed from vertical climbing and/or brachiation: brachiation changes arm structure/purpose to make quadrupedal walking difficult, causing a shift to bipedalism (like with gibbons) (Fleagle et al. 1981) Hip and thigh muscles involved in bipedal walking of facultative bipeds often resembles quadrupedal walking less than human walking, but when it doesn’t look like quadrupedalism, it looks like vertical climbing (Fleagle et al. 1981) Bipedalism more often resembles climbing than facultative bipedalism (Fleagle et al. 1981) Biomechanics contributes directly to an understanding of both morphology and fossil records (Hanna et al. 2015) -Origin in lizards

In lizards, may promote adaptive radiation (Clemente 2014)

Alkunzle (talk) 15:37, 16 October 2018 (UTC)

Peer Review
Suggestions/Overall Comments: - 1st paragraph 1st sentence--"often for only a limited period 'of time'" - 1st paragraph 4th sentence-- change "multiple different" to "different" - the information in the first intro paragraph could be written to be smoother in sentences, with less commas (i.e. "only occasionally becoming bipedal for a specific purpose"); the way it is written in the draft can come off as redundant - check the entire draft for grammar issues (commas, sentence structure) -typo in "Types of Facultative Bipedalism" - edit first sentence under the "Lemurs" section so that it is grammatically correct - same section; "Sifakas can locomote" instead of "locomoting" - same section; "quadrapedally" - first sentence of "Apes" section is run-on -same section; "and reduces the muscle..." - when mentioning Australopithecus, maybe have some introduction about what it is since it is not alive anymore (Maybe mention in Evolution section?) - first sentence under the "Lizards" section should be worded to be less confusing - overall the layout is present but there needs to be more elaboration on some topics that are introduced very briefly in one sentence, and then glossed over before moving onto the next topic.

Is everything relevant?: - not sure how relevant mentioning "kinetic and potential energy" is in the "Monkeys" section if it is not further elaborated on

Is the article neutral?: -article is neutral

Over-represented/Under-represented Viewpoints?: - there are several underrepresented sections

Do citations work?: - yes

Amtsai77 (talk) 05:28, 8 November 2018 (UTC)

Ian's Peer Review
Overall, the article is very detailed and contains several well explained examples of facultative bipedalism in multiple different species. There are a couple of grammar and organizational changes I would make to make the article flow a bit better. To begin, the hyphenated part of your third sentence of your opening paragraph can be incorporated into the sentence without the need for the hyphen. Additionally, the intro paragraph as a whole has a lot of longer sentences and varying your sentence length would make it easier to read and have a bit more flow to it. In the "Types of Bipedal Locomotion" paragraph, is there a wikipedia article on "skipping" that you can add? There is an article for all the other forms of bipedal locomotion and it would be nice to add if there is a wikipedia article on skipping. Another thing I would change is that I would try to find a picture of facultative bipedalism in something other than a primate species. You have three images of primates, but none of any other species and it would be a nice visualization to see what facultative bipedalism looks like outside of the common primate example. An additional comment is about the format of your last section, "Evolution of Bipedalism." This section has one subheading that makes it seem like the entire section is just about bipedalism in dinosaurs, but it seems that just the first paragraph is on dinosaurs. I would move the order of your paragraphs to have the subheading "Bipedalism in dinosaurs" (dinosaurs should be all lowercase) and the paragraph on dinosaur bipedalism last in the "Evolution of bipedalism" section to make things more clear. Again, your article is very good; I do not see anything that seems irrelevant to the topic the wikipedia article is on, the article is written from a neutral point of view, and all your citations work. I don't really see any underrepresented viewpoints in your article either. Again, great job!

Ian.holtz1 (talk) 15:26, 8 November 2018 (UTC)