mgmtright.blogg.se

• Gorilla skull vrs african skull series#

Click on the animation below for a 360° view of the 3D morphospace shown in Figure 1a.Ī) The first three principal axes (PA 1–3) of catarrhine cranial shape variation define a morphospace within which humans ( Homo), apes (other hominoids), and Old World monkeys (colobines and cercopithecines) occupy separate, nonoverlapping regions. For this reason, the morphological patterns that these axes summarize often mirror the classical evolutionary "trends" described by early primatologists (e.g., Fleagle et al., 2010). Major axes of primate cranial variation often reflect reorganizations of cranial structure that define important evolutionary events such as the strepsirrhine-haplorhine divergence or the origin of modern apes.

Since the advent of multivariate morphometric analysis, cranial diversity is more commonly conceptualized as a multidimensional " morphospace" (Figure 1), within which species can be mapped relative to axes of morphological variation corresponding to features such as endocranial volume and facial length. Over time, changes in systematic philosophies and advances in analytical methods have reshaped our thinking about primate diversity. These tendencies or trends delineated a morphological continuum extending from small-brained, snouty "lower primates" ( prosimians) through more "advanced" anthropoids (monkeys and apes) and culminating with large-brained, small-faced Homo sapiens.

Gorilla skull vrs african skull series#

Historically, primate cranial variation was conceptualized in terms of a series of progressive evolutionary "tendencies" such as enlargement of the brain, decreased reliance on olfaction, increased visual acuity, reduction of the jaws and dentition, and assumption of more orthograde (upright) head postures (e.g., Le Gros Clark, 1959 Biegert, 1963). Over the course of primate evolution, natural selection within different primate radiations has produced alternative morphological compromises among these potentially conflicting functional and structural demands, resulting in a diversity of primate cranial forms (Biegert, 1963). In addition to these functional demands, primate cranial form is subject to developmental and architectural constraints arising from shared processes of mammalian cranial growth and biomechanical properties of bone and related tissues (Lieberman et al., 2000). The primate cranium is a complex and highly integrated structure that serves numerous vital functions including respiration and olfaction, food acquisition and mastication, vocal and visual communication, and protection of the brain and its appendages (principally the eyes) (Lieberman et al., 2008).