Functional Morphology, Stable Isotopes, and Human Evolution: A Model of Consilience

Yeakel, Justin D.; Dominy, Nathaniel J.; Koch, Paul L.; Mangel, Marc

doi:10.1111/evo.12240

Cited by 18 publications

(16 citation statements)

References 87 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another category of small, hard food items include the corms and bulbs of various African plants (Dominy et al, ). Recent studies (Yeakel et al, ; Macho, ) suggest that such underground storage organs may have figured prominently in the diet of P. boisei , and the regular or fallback consumption of these foods is consistent with our hypothesis. However, it is worth bearing in mind that the mechanical properties of hard foods vary considerably and thus pose different challenges to the hominins consuming them.…”

Section: Discussionsupporting

confidence: 90%

The Feeding Biomechanics and Dietary Ecology ofParanthropus boisei

Smith

Benazzi

Ledogar

et al. 2014

The Anatomical Record

139

View full text Add to dashboard Cite

The African Plio-Pleistocene hominins known as australopiths evolved derived craniodental features frequently interpreted as adaptations for feeding on either hard, or compliant/tough foods. Among australopiths, Paranthropus boisei is the most robust form, exhibiting traits traditionally hypothesized to produce high bite forces efficiently and strengthen the face against feeding stresses. However, recent mechanical analyses imply that P. boisei may not have been an efficient producer of bite force and that robust morphology in primates is not necessarily strong. Here we use an engineering method, finite element analysis, to show that the facial skeleton of P. boisei is structurally strong, exhibits a strain pattern different from that in chimpanzees (Pan troglodytes) and Australopithecus africanus, and efficiently produces high bite force. It has been suggested that P. boisei consumed a diet of compliant/tough foods like grass blades and sedge pith. However, the blunt occlusal topography of this and other species suggests that australopiths are adapted to consume hard foods, perhaps including grass and sedge seeds. A consideration of evolutionary trends in morphology relating to feeding mechanics suggests that food processing behaviors in gracile australopiths evidently were disrupted by environmental change, perhaps contributing to the eventual evolution of Homo and Paranthropus.

show abstract

Section: Discussionsupporting

confidence: 90%

The Feeding Biomechanics and Dietary Ecology ofParanthropus boisei

Smith

Benazzi

Ledogar

et al. 2014

The Anatomical Record

139

View full text Add to dashboard Cite

show abstract

“…where Γ(·) is the gamma function [?, cf.]]Mangel:2006wa. Here, a i is the dispersion parameter, which is proportional to the mean encounter rate, and c measures the time between encounters [54,53,55]. Integrating across all possible values of ψ i , we obtain the Negative Binomial density with mean encounter rate a i /c and coefficient of variation 1/ √ a i [56].…”

Section: Deriving the Within-individual Isotopic Niche Widthmentioning

confidence: 99%

Exploring the Isotopic Niche: Isotopic Variance, Physiological Incorporation, and the Temporal Dynamics of Foraging

et al. 2016

Self Cite

View full text Add to dashboard Cite

Consumer foraging behaviors are dynamic, changing in response to prey availability, seasonality, competition, and even the consumer's physiological state. The isotopic composition of a consumer is a product of these factors as well as the isotopic "landscape" of its prey, i.e., the isotopic mixing space. Stable isotope mixing models are used to back-calculate the most likely proportional contribution of a set of prey to a consumer's diet based on their respective isotopic distributions, however they are disconnected from ecological process. Here we build a mechanistic framework that links the ecological and physiological processes of an individual consumer to the isotopic distribution that describes its diet, and ultimately to the isotopic composition of its own tissues, defined as its "isotopic niche." By coupling these processes, we systematically investigate under what conditions the isotopic niche of a consumer changes as a function of both the geometric properties of its mixing space and foraging strategies that may be static or dynamic over time. Results of our derivations reveal general insight into the conditions impacting isotopic niche width as a function of consumer specialization on prey, as well as the consumer's ability to transition between diets over time. We show analytically that moderate specialization on isotopically unique prey can serve to maximize a consumer's isotopic niche width, while temporally dynamic diets will tend to result in peak isotopic variance during dietary transitions. We demonstrate the relevance of our theoretical findings by examining a marine system composed of nine invertebrate species commonly consumed by sea otters. In general, our analytical framework highlights the complex interplay of mixing space geometry and consumer dietary behavior in driving expansion and contraction of the isotopic niche. Because this approach is established on ecological mechanism, it is well-suited for enhancing the ecological interpretation, and uncovering the root causes, of observed isotopic data.

show abstract

“…In contrast, grass leaves are not considered a viable hominin food by most because they are generally regarded as offering little nutritional value (low in protein and high in fiber) and having mechanical properties (particularly, measures of toughness) that are ill-suited for hominins lacking the occlusal relief and/or hypsodonty seen in leaf-eating primates or grazing herbivores (Yeakel et al, 2007;Lee-Thorp et al, 2012;Fontes-Villalba et al, 2013;Macho, 2014;Yeakel et al, 2014). However, it is noteworthy that gramnivory is observed in other omnivorous taxa exhibiting bunodonty such as black bears (Ursus arctos), which are known to eat 31 species of graminoids in Yellowstone National Park (Raia, 2004;Gunther et al, 2014).…”

mentioning

confidence: 99%

Grass leaves as potential hominin dietary resources

Paine

Koppa

Henry

et al. 2018

Journal of Human Evolution

View full text Add to dashboard Cite

Discussions about early hominin diets have generally excluded grass leaves as a staple food resource, despite their ubiquity in most early hominin habitats. In particular, stable carbon isotope studies have shown a prevalent C component in the diets of most taxa, and grass leaves are the single most abundant C resource in African savannas. Grass leaves are typically portrayed as having little nutritional value (e.g., low in protein and high in fiber) for hominins lacking specialized digestive systems. It has also been argued that they present mechanical challenges (i.e., high toughness) for hominins with bunodont dentition. Here, we compare the nutritional and mechanical properties of grass leaves with the plants growing alongside them in African savanna habitats. We also compare grass leaves to the leaves consumed by other hominoids and demonstrate that many, though by no means all, compare favorably with the nutritional and mechanical properties of known primate foods. Our data reveal that grass leaves exhibit tremendous variation and suggest that future reconstructions of hominin dietary ecology take a more nuanced approach when considering grass leaves as a potential hominin dietary resource.

show abstract

Functional Morphology, Stable Isotopes, and Human Evolution: A Model of Consilience

Cited by 18 publications

References 87 publications

The Feeding Biomechanics and Dietary Ecology ofParanthropus boisei

The Feeding Biomechanics and Dietary Ecology ofParanthropus boisei

Exploring the Isotopic Niche: Isotopic Variance, Physiological Incorporation, and the Temporal Dynamics of Foraging

Grass leaves as potential hominin dietary resources

Contact Info

Product

Resources

About