Interpreting the posture and locomotion of Australopithecus afarensis: where do we stand?
Interpreting the posture and locomotion of Australopithecus afarensis: where do we stand?
复制标题
解读南方古猿阿法种的姿势和运动：我们站在哪里？
DOI：
10.1002/ajpa.10185
复制
发表时间：
2002
影响因子：
2.8
通讯作者：
C. Ward
中科院分区：
文献类型：
--
作者：
C. Ward
重建向两足动物的转变是理解早期原始人进化的关键。因为它是最广为人知的早期原始人物种，所以阿法南古猿形成了解释所有早期原始人运动的基线。虽然大多数研究人员都同意阿法罗松树个体是习惯性的两足动物，但他们对树生环境对它们的重要性意见不一。产生分歧的主要原因有两个。首先，对于如何解释原始字符，存在着不同的观点。原始性状可以通过稳定选择、多效性或其他个体发育机制来保留。或者，他们可能正在被削减，或者他们可能只是选择性地保持中立。其次，研究人员对这些化石提出了截然不同的问题。一些人感兴趣的是重建塑造阿法尔黑杨的选择历史，而另一些人则对重建阿法尔黑曲霉的行为感兴趣。通过明确地勾勒出我们是否有兴趣重建选择性的历史或行为，我们可以开发可测试的假说来管理我们对化石的研究。要推断形成一个分类单元的选择历史，我们必须首先考虑字符的极性。增强特定功能的衍生特征，在现有的同源物中被发现与该功能相关，并且表观遗传学敏感数据表明实际上用于该功能，可被解释为适应。解释原始特征保留的零假设是选择性中性，或非顺应性。要反驳这一点，需要表现出积极的稳定或负面选择(失望)。当原始性状与一个具有明显适应性价值的派生函数相妥协时，可以推断稳定选择。长期停滞、持续使用某一特定功能的性状，或该性状的变异性没有变化，这些都是可以支持原始性状适应假说的证据，但仍不能证明无效假说是错误的。失望，或负选择，应该导致一个性状的减少或丢失。为了推断化石物种的行为，我们必须首先确定它的适应性，用这一点来对它的行为做出假设，并使用由个人活动模式修改的表观遗传敏感特征来测试这些假设。当使用这个框架评估阿法尔原始人的数据时，很明显，这些原始人经历了习惯性两足动物的选择，但解释原始类人猿特征保留的非适应零假设目前还不能被证伪。南方古猿颅后形态的明显停滞是目前保持其原始特征的稳定选择的最有力证据。个体发育过程中受个体行为影响的特征的证据表明，阿法罗非鱼个体习惯于两足行走，但到目前为止，关于树栖行为的证据并不确凿。通过明确我们正在提出的关于早期人类化石的问题，提炼我们关于性格极性的知识，并阐明影响形态的因素，我们将能够在理解阿法尔人和所有早期人的姿势和运动方面取得进展。
Reconstructing the transition to bipedality is key to understanding early hominin evolution. Because it is the best-known early hominin species, Australopithecus afarensis forms a baseline for interpreting locomotion in all early hominins. While most researchers agree that A. afarensis individuals were habitual bipeds, they disagree over the importance of arboreality for them. There are two main reasons for the disagreement. First, there are divergent perspectives on how to interpret primitive characters. Primitive traits may be retained by stabilizing selection, pleiotropy, or other ontogenetic mechanisms. Alternately, they could be in the process of being reduced, or they simply could be selectively neutral. Second, researchers are asking fundamentally different questions about the fossils. Some are interested in reconstructing the history of selection that shaped A. afarensis, while others are interested in reconstructing A. afarensis behavior. By explicitly outlining whether we are interested in reconstructing selective history or behavior, we can develop testable hypotheses to govern our investigations of the fossils. To infer the selective history that shaped a taxon, we must first consider character polarity. Derived traits that enhance a particular function, are found to be associated with that function in extant homologs, and that epigenetically sensitive data indicate were actually being used for that function, can be interpreted as adaptations. The null hypothesis to explain the retention of primitive traits is that of selective neutrality, or nonaptation. Disproving this requires demonstration of active stabilizing or negative selection (disaptation). Stabilizing selection can be inferred when primitive traits compromise a derived function clearly of adaptive value. Prolonged stasis, continued use of the trait for a particular function, or no change in variability in the trait are evidence that can support a hypothesis of adaptation for primitive traits, but still do not falsify the null hypothesis. Disaptation, or negative selection, should result in a trait being reduced or lost. To infer the behaviors of a fossil species, we must first determine its adaptations, use this to make hypotheses about its behavior, and test these hypotheses using epigenetically sensitive traits that are modified by an individual's activity pattern. When the A. afarensis data are evaluated using this framework, it is clear that these hominins had undergone selection for habitual bipedality, but the null hypothesis of nonaptation to explain the retention of primitive, ape-like characters cannot be falsified at present. The apparent stasis in Australopithecus postcranial form is currently the strongest evidence for stabilizing selection maintaining its primitive features. Evidence from features affected by individual behaviors during ontogeny shows that A. afarensis individuals were habitually traveling bipedally, but evidence presented for arboreal behavior so far is not conclusive. By clearly identifying the questions we are asking about early hominin fossils, refining our knowledge about character polarities, and elucidating the factors influencing morphology, we will be able to progress in our understanding of the posture and locomotion of A. afarensis and all early hominins.
现代哺乳动物牙齿微磨损和饮食的综述。
DOI：
--
发表时间：
1988
期刊：
Scanning microscopy
影响因子：
--
作者：
Teaford,MF
通讯作者：
Teaford,MF