Hominoid energetics: could load carriage have driven the early adoption of bipedal locomotion in human evolution?

类人猿能量学：负载运输是否会推动人类进化中双足运动的早期采用？

• 批准号: NE/C520463/1
• 负责人: William Sellers
• 金额: $ 7.5万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FC520463%2F1
• 关键词: Hominoid; energetics; could; load; carriage

Habitual walking on two legs (bipedalism) is one of the unique features that distinguishes humans and their immediate fossil ancestors from the chimpanzees, gorillas and all other non-human primates. The evidence from fossil hominid leg bones and preserved trails of footprints shows that this change to bipedal walking happened very soon after the human evolutionary lineage diverged from the African apes, which suggests that bipedalism may have been an important catalyst for some of the other traits that define the human condition. The importance of bipedal locomotion is highlighted by the large number of theories that have been proposed to explain why walking on two legs is preferable to walking on all fours. Many of these theories argue that by using only your legs for walking you are able to free up your arms for some other purpose, and it is often suggested that this other purpose involves manipulating or carrying something - whether it is food, infants, tools or weapons. This is supported by the fact that when chimpanzees are observed walking upright t is often when they are carrying items of food. However carrying unlike walking is an activity that leaves no direct trace in the fossil record. One of the few ways of testing such theories relating to the advantages and disadvantages of behaviours in long extinct animals is to create computer simulations. These simulations allow us to estimate the actual numerical values of the benefits of behavioural change in terms of energy (and hence food) saved. If such a change has a disproportionately large net benefit then we have some evidence to support our hypothesis, however if the effect is small then this would suggest that we need to look elsewhere. The caveat here is that we must be very careful that our simulation of a particular behaviour is good enough otherwise we would be unwise to trust its predictions. The goal of this project is to produce a computer simulation of carrying behaviour in early human and human-like fossils and to use it to estimate the ease with which one of these animals could carry particular objects any given distance. To achieve this we are proposing to modify our existing computerised walking simulator (which is accurate to within 5-15%) so that it can simulate walking whilst carrying a variety of objects. We then propose to adjust the model so that its predictions match the carrying capabilities of human and non-human subjects that we intend to measure experimentally. Finally we aim to scale the model to represent the body shape of the fossil forms which will allow us to estimate the energy cost of carrying in these fossils. We will then be able to see whether our values affect the conclusions of previous work that has used alternative methods to estimate carrying cost. Our walking simulation is at the cutting edge of computer science. It uses an advanced physics engine similar to those used in the latest video games to rapidly calculate the movements of the skeleton depending on the forces generated by the muscles. The muscle forces themselves are chosen using an artificial intelligence technique (the so called genetic algorithm) that lets us tailor these forces to maximise some underlying quantity - in our case the energetic efficiency of carrying. This combination means that our simulations do not simply copy the movements seen in modern humans but are able to generate their own unique sets of movements from scratch which provides a much better estimate of the actual capabilities of fossil animals. For validation we will use the full range of modern biomechanical analysis techniques on our human subjects and for our non-human subjects we intend to use a combination of RADAR and thermal imaging to measure heart and breath rate. These values are known to be related to actual metabolic cost and because they can be measured remotely they are ideal for use with endangered animals such as great apes.

习惯用两条腿走路（两足行走）是将人类及其直接化石祖先与黑猩猩，大猩猩和所有其他非人类灵长类动物区分开来的独特特征之一。来自原始人类腿骨化石和保存下来的脚印痕迹的证据表明，这种向两足行走的转变发生在人类进化谱系从非洲猿类分化之后不久，这表明两足行走可能是定义人类状况的其他一些特征的重要催化剂。两足行走的重要性被大量的理论所强调，这些理论被提出来解释为什么用两条腿走路比用四肢走路更好。这些理论中的许多理论认为，通过只用你的腿走路，你可以腾出你的手臂用于其他目的，而且通常认为，这个其他目的涉及操纵或携带东西-无论是食物，婴儿，工具还是武器。这一点得到了以下事实的支持：当观察到黑猩猩直立行走时，通常是在它们携带食物的时候。然而，搬运与行走不同，搬运是一种在化石记录中没有留下直接痕迹的活动。要检验这类与灭绝已久的动物行为的利弊有关的理论，为数不多的方法之一就是创建计算机模拟。这些模拟使我们能够估计行为改变在节省能源（以及食物）方面的实际数值。如果这样的变化有一个不成比例的大净效益，那么我们有一些证据来支持我们的假设，但是，如果影响很小，那么这将表明我们需要寻找其他地方。这里需要说明的是，我们必须非常小心，我们对特定行为的模拟足够好，否则我们相信它的预测是不明智的。该项目的目标是对早期人类和类人化石的搬运行为进行计算机模拟，并利用它来估计这些动物中的一种在任何给定距离搬运特定物体的难易程度。为了实现这一目标，我们建议修改我们现有的计算机化步行模拟器（精确度在5-15%之间），以便它可以模拟步行，同时携带各种物体。然后，我们建议调整模型，使其预测相匹配的承载能力的人类和非人类受试者，我们打算测量实验。最后，我们的目标是缩放模型，以代表化石形式的身体形状，这将使我们能够估计携带这些化石的能源成本。然后，我们将能够看到我们的价值观是否会影响以前的工作，使用替代方法来估计持有成本的结论。我们的行走模拟处于计算机科学的前沿。它使用了一个先进的物理引擎，类似于最新的视频游戏中使用的引擎，根据肌肉产生的力量快速计算骨骼的运动。肌肉力量本身是使用人工智能技术（所谓的遗传算法）来选择的，该技术可以让我们定制这些力量，以最大限度地提高一些潜在的数量-在我们的情况下，携带的能量效率。这种组合意味着我们的模拟并不是简单地复制现代人类的运动，而是能够从头开始生成自己独特的运动集合，这为化石动物的实际能力提供了更好的估计。为了验证，我们将在我们的人类受试者上使用全方位的现代生物力学分析技术，对于我们的非人类受试者，我们打算使用雷达和热成像的组合来测量心率和呼吸率。这些值与实际代谢成本有关，因为它们可以远程测量，所以它们非常适合用于濒危动物，如类人猿。

项目成果

Exploring diagonal gait using a forward dynamic three-dimensional chimpanzee simulation.

使用前向动态三维黑猩猩模拟探索对角步态。

• DOI: 10.1159/000351562
• 发表时间: 2013
• 期刊: Folia primatologica; international journal of primatology
• 作者: Sellers WI