Pilbeam D, Gould S J
Science. 1974 Dec 6;186(4167):892-901. doi: 10.1126/science.186.4167.892.
Our general conclusion is simply stated: many lineages display phyletic size increase; allometric changes almost always accompany increase in body size. We cannot judge adaptation until we separate such changes into those required by increasing size and those serving as special adaptations to changing environments. In our view, the three australopithecines are, in a number of features, scaled variants of the "same" animal. In these characters, A. africanus is no more "advanced" than the larger, more robust forms. The one early hominid to show a significant departure from this adaptive pattern toward later hominids-cranially, dentally, and postcranially-is H. habilis from East Africa. The australopithecines, one of which was probably a precursor of the Homolineage, were apparently a successful group of basically vegetarian hominids, more advanced behaviorally than apes (87), but not hunter-gatherers. The fossil hominids of Africa fall into two major groupings. One probable lineage, the australopithecines, apparently became extinct without issue; the other evolved to modern man. Both groups displayed steady increase in body size. We consider quantitatively two key characters of the hominid skull: cranial capacity and cheek tooth size. The variables are allometrically related to body size in both lineages. In australopithecines, the manner of relative growth neatly meets the predictions for functional equivalence over a wide range of sizes (negative allometry of cranial capacity with a slope against body weight of 0.2 to 0.4 and positive allometry of postcanine area with a slope near 0.75). In the A. africanus to H. sapiens lineage, cranial capacity increases with positive allometry (slope 1.73) while cheek teeth decrease absolutely (slope - 0.725). Clearly, these are special adaptations unrelated to the physical requirements of increasing body size. We examined qualitatively other features, which also seem to vary allometrically. Of course, many characters should be studied quantitatively, but we think that the scheme outlined here should be treated as the null hypothesis to be disproved.
许多谱系显示出系统发育的体型增大；异速生长变化几乎总是伴随着体型的增加。在我们将这些变化区分为因体型增大而产生的变化和作为对不断变化的环境的特殊适应的变化之前，我们无法判断适应性。我们认为，三种南方古猿在许多特征上是“同一”动物的缩放变体。在这些特征方面，非洲南方古猿并不比体型更大、更强壮的形态更“先进”。从颅骨、牙齿和颅后部位来看，最早表现出与这种适应模式有显著差异、朝着后来人类方向发展的早期人类是来自东非的能人。南方古猿可能是人类谱系的前身之一，显然是一群成功的基本素食的人类，在行为上比猿类更先进（87），但不是狩猎采集者。非洲的化石人类分为两大组。一个可能的谱系，即南方古猿，显然毫无后继地灭绝了；另一个则进化成了现代人。两组都显示出体型的稳步增加。我们定量研究了人类头骨的两个关键特征：脑容量和颊齿大小。在这两个谱系中，这些变量与体型呈异速生长关系。在南方古猿中，相对生长方式在很大范围内的体型上都恰好符合功能等效性的预测（脑容量的负异速生长，相对于体重的斜率为0.2至0.4，犬齿后区域的正异速生长，斜率接近0.75）。在从非洲南方古猿到智人的谱系中，脑容量以正异速生长增加（斜率为1.73），而颊齿绝对减小（斜率为 - 0.725）。显然，这些是与体型增大的生理需求无关的特殊适应。我们定性地研究了其他似乎也呈异速生长变化的特征。当然，许多特征应该进行定量研究，但我们认为这里概述的方案应被视为有待推翻的零假设。
