Behavioral ecological implications of early hominid body size

1994 ◽  
Vol 27 (1-3) ◽  
pp. 77-87 ◽  
Author(s):  
Henry M. McHenry
Keyword(s):  
Body Size ◽  
Early Hominid ◽  
Ecological Implications

The Ecological Implications of Body Size.

1985 ◽  
Vol 22 (1) ◽  
pp. 291 ◽  
Author(s):  
N. Bonner ◽  
R. H. Peters
Keyword(s):  
Body Size ◽  
Ecological Implications

Tooth size and shape and their relevance to studies of hominid evolution

1981 ◽  
Vol 292 (1057) ◽  
pp. 65-76 ◽  
Keyword(s):  
Body Size ◽  
Hominid Evolution ◽  
Tooth Size ◽  
Taxonomic Significance ◽  
Early Hominid ◽  
Australopithecus Africanus ◽  
Preliminary Results ◽  
Rate Of Increase ◽  
Crown Shape ◽  
Morphological Differences

Teeth have the potential to provide evidence about both the patterns of diversity of fossil hominids and the functional adaptations of early hominid taxa. Comparative studies of dental function and the direct examination of wear patterns in fossil teeth are now providing data for testing hypotheses that major differences in dietary adaptations underlie lineage diversity in the early hominids. However, this review focuses on the contributions that dental evidence can make to hominid systematic studies. Attention is drawn to the value of tooth enamel as a morphological marker and the major contribution that teeth make to the hominid fossil sample. Systematic analysis of hominid remains must start with the identification of patterns of morphological variation. Only then can the taxonomic significance of the morphological differences be assessed and attempts made to link designated taxa in a phylogenetic scheme. The preliminary results of a detailed metrical survey of early hominid premolar and molar teeth are presented. As part of this study cusp areas of first mandibular molars were measured by planimetry. Analysis of these data, without any prior assumptions about taxonomic groups, has demonstrated that the major axis of variation separates the pooled sample into morphological subgroups. These methods provide a systematic and rigorous way of identifying patterns of tooth crown morphology and will allow a more objective assessment of the affinities of individual specimens. Fossil taxa are described in terms of both absolute and relative tooth size. If canine base area and molar crown area are considered there is considerable overlap between Australopithecus africanus and Australopithecus ( paranthropus) robustus whereas there is little or no overlap between the ranges of Australopithecus africanus and Australopithecus (Parnthopus) boisei . Differences in relative tooth size among fossil taxa are taken as an example of how to attack the problem of assessing the taxonomic significance of morphological differences. Analogues from modern primates are used to derive tooth-body size relations for three relative growth models. The results suggest that increases in body size are usually accompanied by a more rapid rate of increase in canine size than in molar size. This suggests that the relatively smaller canines of the ‘robust’ australopithecines are not the result of simple scaling, but represent the result of selection against an allometric trend. Preliminary results of a survey of the subocclusal morphology of fossil teeth are presented to indicate the potential of radiographic studies and to demonstrate that changes in root morphology can be correlated with crown shape and relative size.

Size matters: systematic and ecological implications of allometry in the responses of chironomid midge morphological ratios to experimental temperature manipulations

2005 ◽  
Vol 83 (4) ◽  
pp. 553-568 ◽  
Author(s):  
Brendan G McKie ◽  
Peter S Cranston
Keyword(s):  
Body Size ◽  
Phylogenetic Reconstruction ◽  
Size Variation ◽  
Adaptive Significance ◽  
Adult Size ◽  
Allometric Relationships ◽  
Terrestrial Environment ◽  
Environmental Regimes ◽  
Wide Range ◽  
Ecological Implications

Separated populations of wide-ranging ectothermic species may be subjected to differing ambient environmental regimes, with consequences for adult size and related allometric characteristics. We investigated effects of environmentally induced size variation in freshwater Australian Chironomidae (Diptera) on several morphometric ratios used to account for such variation in taxonomic classification. Echinocladius martini Cranston, 2000 (Orthocladiinae) and Australopelopia prionoptera Cranston, 2000 (Tanypodinae) larvae were sampled from tropical and temperate populations separated by approximately 1800 km, and reared to adult at temperatures representing the continent-wide range encountered by these species. Additionally, adults were sampled regularly from a field population to assess seasonal variation. Body size was related inversely to rearing temperature for both species. Nonlinear (allometric) relationships were observed consistently between body size and ratios pertaining to the antennae (AR, the ratio of the terminal to subapical flagellomeres) and legs (BV, the ratio of proximal segments to distal tarsomeres), demonstrating that these ratios inadequately factor out within-species, size-related divergence. Responses of other ratios varied erratically with sex, species, and population. We advocate cautious use of these ratios in taxonomy and phylogenetic reconstruction. We discuss possible adaptive significance of allometry in the male antennae related to the "tuning" of sound-sensitive structures to the expected terrestrial environment encountered at emergence.

scholarly journals Body size and flight distance in stingless bees (Hymenoptera: Meliponini): inference of flight range and possible ecological implications

2004 ◽  
Vol 64 (3b) ◽  
pp. 563-568 ◽  
Author(s):  
E. D. Araújo ◽  
M. Costa ◽  
J. Chaud-Netto ◽  
H. G. Fowler
Keyword(s):  
Body Size ◽  
Stingless Bees ◽  
Spatial Dynamics ◽  
Principal Component ◽  
Flight Distance ◽  
Forest Fragments ◽  
Future Studies ◽  
Flight Range ◽  
Ecological Implications ◽  
Highly Correlated

We examined the spatial implications of maximum flight distance for several species of stingless bees. Data suggested that maximum flight distance in Meliponini is a function of body size, especially generalized wing size, which can be estimated through principal component analysis. For six species of stingless bees, flight distances and generalized wing sizes were highly correlated (r = 0.938). This indicates that species of Meliponini occupy an effectively larger area as body size increases, which has important implications in the spatial dynamics of local populations restricted to forest fragments. We also used the fitted linear regression model to estimate the maximum flight distance for 12 other species of Meliponini. The results of this research may provide insights for future studies of biological conservation.

Summer food habits of female new river crayfish (Cambarus chasmodactylus) in Anthony Creek, West Virginia

2015 ◽  
Vol 21 (1) ◽  
pp. 95-101
Author(s):  
Raquel A. Fagundo ◽  
Zachary J. Loughman
Keyword(s):  
Body Size ◽  
West Virginia ◽  
Food Habits ◽  
Linear Models ◽  
Late Summer ◽  
Reproductive State ◽  
Organic Detritus ◽  
Central Appalachians ◽  
Ecological Implications ◽  
Food Consumed

Abstract Cambarus chasmodactylus is restricted to the New River drainage of the Central Appalachians. Female crayfish display cyclic reproductive states, but the ecological implications of this cycle have yet to be assessed. Female C. chasmodactylus were collected from Anthony Creek, West Virginia during the summer months to investigate food habits. Stomach content frequencies were obtained for four broad categories. Food items were identified to the lowest taxonomic level applicable. Feeding spectra were used to assess the importance of prey items. Generalized linear models were used to assess the effects of season, body size, and reproductive state on broad food categories, amount of food consumed, and the frequency of the most abundant prey item. The most food was consumed during June and the least in August. Organic detritus was consumed most frequently and reached its highest frequency in late summer. Animal matter was consumed more frequently by larger animals. Snails were the most predominate animal ingested, showing lower frequencies in June and September in comparison to August and October. Results indicate New River crayfish are feeding generalists and food habits changed with season. There is indication that body size and reproductive state may have a direct or indirect link to food habits.

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