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1.
The "squeeze" form of power grip is investigated for the purposes of clarifying the hand posture and activities associated with the grip, assessing the potential in chimpanzees for using the grip, and identifying morphological correlates of an effective power grip that may be recognized in fossil hominid species. Our approaches include: (1) the analysis of the human grip, focusing on both the hand posture involved and hand movements associated with use of the grip in hammering; (2) the analysis of similar chimpanzee grips and associated movements; (3) comparative functional analysis of regions in the hand exploited and stressed by the grip and its associated movements in humans; and (4) a review of the literature on the power grip and its morphological correlates. Results of the study indicate that humans use a squeeze form of power grip effectively to wield cylindrical tools forcefully as extensions of the forearm. Several morphological features occur in high frequency among humans which facilitate the grip and are consistent with the large internal and external forces associated with it in hammering and in other tool-using activities. Chimpanzee hand postures resembling this form of human power grip are not fully comparable and lack some of these morphological correlates that facilitate its use. The hand of Australopithecus afarensis does not appear to have been stressed by use of the grip, but there is some evidence for this type of stress in the metacarpals from Sterkfontein Member 4. Hands from Olduvai and Swartkrans do not provide sufficient evidence for assessment of power grip capabilities. 相似文献
2.
Damiano Marchi Daniel J. Proctor Emma Huston Christina L. Nicholas Florian Fischer 《Comptes Rendus Palevol》2017,16(5-6):645-654
This study quantifies the metacarpal 1 (MC 1) proximal articular surface using three-dimensional morphometrics in extant hominids and fossil hominins (SK 84, cf. Paranthropus robustus/Homo erectus and StW 418, Australopithecus africanus) to understand which characteristics of the proximal metacarpal 1 are potentially correlated with human manipulative abilities and if they can be used in a paleoanthropological setting. A principal components (PC) analysis was used to compare MC 1 proximal articular surface shape and ANOVA and Tukey's HSD post-hoc tests were conducted to determine differences among groups. Homo is significantly different from nonhuman hominids having a less radioulnarly and dorsovolarly curved articular surface. All nonhuman hominids have more curved articular surface with Gorilla showing the most curved joint. Moreover, this study highlights the presence of a radially extended surface in Homo that may be related to the greater thumb abduction in human manipulation activities. Both fossils analyzed show a great ape-like MC 1 proximal articular surface which, associated with recent trabecular and archaeological evidence, may indicate that the ability to make/use stone tools preceded the morphological adaptations associated today with such behavior. 相似文献
3.
Karen Steudel 《American journal of physical anthropology》1982,59(4):431-441
Seven measurements were taken on the postcranial skeleton of 249 specimens representing ten species of catarrhine primates and tested to determine their relationship with size. Size was measured as skeletal weight on each individual. It was found that the interspecific line based on the entire sample was in some cases determined not only by morphological adjustments for size variation but also by changes in locomotor adaptations of differently sized species within the sample. It is suggested that it is consequently preferable to study allometric relationships within a species or within a group of species that differ in size but are similar in their mode of locomotion. The allometric analysis reveals some interesting patterns within the data. Limb lengths scaled with either negative allometry or isometry over the entire sample. Within the species groups isometry was the rule except for pongid femurs, which showed negative scaling. Humerus length scaled at the same rate in pongids as in cercopithecoids but had a slightly higher intercept value. While colobines and cercopithecines scaled at similar rates for all seven dimensions, the colobine line was shifted to a position above that for cercopithecines in every case. It is suggested that this is a result of adaptation for leaping in the former group. Other implications of the allometric results are discussed. 相似文献
4.
Alexandra Zieritz Antonio G. Checa David C. Aldridge Elizabeth M. Harper 《Journal of Zoological Systematics and Evolutionary Research》2011,49(1):6-15
Microprojections of unionoid shells are virtually unstudied but could be important characters for resolving questions on the phylogeny and ecology of these bivalves. By investigating 26 unionoid and three species of their closest living relatives, the Trigonioida, using scanning electron microscopy, we identified three types of periostracal microprojections. (1) Microridges were present only in one species from each of the two unionoid families Mycetopodidae (Anodontites trapesialis) and Iridinidae (Chambardia bourguignati) and may represent a synapomorphy for the mycetopodid‐iridinid clade. In A. trapesialis, microridges were additionally equipped with (2)ensp;flag‐like projections (microfringes), possibly a synapomorphic character for the Mycetopodidae. Examination of partially bleached specimens indicated that both microridges and microfringes are predominantly or purely organic. In contrast, previously undescribed (3) spicule‐like spikes represent calcifications within the periostracum. These were found in 20 of the 29 species and four of the six unionoid families. Spikes were particularly large and abundant in umbonal (juvenile) shell regions and species characteristic of fast‐flowing habitats. These structures may thus serve in protecting the periostracum and shell underneath, and/or stabilizing life position by increasing shell friction. Microfringes and microridges, on the other hand, possibly aid in the orientation of the mussel within the sediment. 相似文献
5.
We describe the kinematics and performance of the natural jump in the weevil Orchestes fagi (Fabricius, 1801) (Coleoptera: Curculionidae) and its jumping apparatus with underlying anatomy and functional morphology. In weevils, jumping is performed by the hind legs and involves the extension of the hind tibia. The principal structural elements of the jumping apparatus are (1) the femoro-tibial joint, (2) the metafemoral extensor tendon, (3) the extensor ligament, (4) the flexor ligament, (5) the tibial flexor sclerite and (6) the extensor and flexor muscles. The kinematic parameters of the jump (from minimum to maximum) are 530–1965 m s?2 (acceleration), 0.7–2.0 m s?1 (velocity), 1.5–3.0 ms (time to take-off), 0.3–4.4 μJ (kinetic energy) and 54–200 (g-force). The specific joint power as calculated for the femoro-tibial joint during the jumping movement is 0.97 W g?1. The full extension of the hind tibia during the jump was reached within up to 1.8–2.5 ms. The kinematic parameters, the specific joint power and the time for the full extension of the hind tibia suggest that the jump is performed via a catapult mechanism with an input of elastic strain energy. A resilin-bearing elastic extensor ligament that connects the extensor tendon and the tibial base is considered to be the structure that accumulates the elastic strain energy for the jump. According to our functional model, the extensor ligament is loaded by the contraction of the extensor muscle, while the co-contraction of the antagonistic extensor and flexor muscles prevents the early extension of the tibia. This is attributable to the leverage factors of the femoro-tibial joint providing a mechanical advantage for the flexor muscles over the extensor muscles in the fully flexed position. The release of the accumulated energy is performed by the rapid relaxation of the flexor muscles resulting in the fast extension of the hind tibia propelling the body into air. 相似文献
6.
Species of Hexarthra and Polyarthra are freshwater rotifers with well-known escape behaviors that result from interactions with planktonic predators. Both rotifers bear a suite of mobile appendages that function in evasive maneuvers and saltatory jumps through the water column, but the anatomical and functional bases of these actions are poorly understood. Here, we use a combination of phalloidin staining, confocal laser scanning microscopy, and video analysis to describe the morphology of the somatic muscles that supply the mobile appendages in order to understand how they function in escape behavior. Results show that species of Hexarthra, which bear six radially distributed limbs, possess a highly complex trunk musculature that supplies the inside of each limb with its own abductor and adductor muscles, i.e., a direct muscle supply. The singular dorsal and ventral limbs each receive a pair of large abductor and adductor muscles (four muscles total per limb), while the paired dorsolateral and ventrolateral limbs each receives three muscles (two abductors, one adductor per limb). Contraction of the abductor muscles creates a power stroke in the form of an anterior sweep of the limbs, which leads to a three-dimensional tumbling of the rotifer through the water column. Alternatively, species of Polyarthra possess 12 blade-like appendages that are arranged into four equal bundles; each bundle receives an indirect muscle supply that attaches to the shoulder of the paddles. A single longitudinal paddle muscle supplies each dorsolateral bundle, while a pair of longitudinal paddle muscles supplies each ventrolateral bundle. Contraction of these muscles, whether singly or in concert, functions to abduct the paddles in a power stroke, leading to rotation of the body and movement of the rotifer. The recovery stroke is hypothesized to be a multi-step process that begins with reorientation of the appendages prior to adduction, followed by contraction of various muscles to antagonize the paddle muscles. In total, these observations reveal novel complexities in the rotifer muscular system that aids our understanding of the biophysics of predator avoidance in appendage-bearing rotifers. 相似文献
7.
The scapula of the ecomorphologically diverse South American caviomorph rodents was studied through geometric morphometric techniques, using landmarks and semilandmarks to capture the shape of this complex morphological structure. Representatives of 33 species from all caviomorph superfamilies, as well as Hystrix cristata for comparisons, were analyzed. Marked differences in scapular shape were found among the major caviomorph lineages analyzed, particularly in the shape and length of the scapular spine and development of the great scapular notch. Shape differences were not influenced by body size, and only partially influenced by locomotor mode. Thus, at this scale of analysis, phylogenetic history seems to be the strongest factor influencing scapular shape. The scapular shape of erethizontids, chinchillids and Cuniculus paca could represent the less specialized state with respect to the highly differentiated scapula of octodontoids and most cavioids. In this sense, the characteristic scapular morphologies of octodontoids and cavioids could reflect particular functional capabilities and constraints associated with the evolution of prevalent locomotor modes within each lineage. 相似文献
8.
We assessed the influence of a variety of aspects of locomotion and ecology including gait and locomotor types, maximal running speed, home range, and body size on postcranial shape variation in small to medium-sized mammals, employing geometric morphometric analysis and phylogenetic comparative methods. The four views analyzed, i.e., dorsal view of the penultimate lumbar vertebra, lateral view of the pelvis, posterior view of the proximal femur and proximal view of the tibia, showed clear phylogenetic signal and interesting patterns of association with movement. Variation in home range size was related to some tibia shape changes, while speed was associated with lumbar vertebra, pelvis and tibia shape changes. Femur shape was not related to any locomotor variables. In both locomotor type and high-speed gait analyses, locomotor groups were distinguished in both pelvis and tibia shape analyses. These results suggest that adaptations to both typical and high-speed gaits could explain a considerable portion of the shape of those elements. In addition, lumbar vertebra and tibia showed non-significant relationships with body mass, which suggests that they might be used in morpho-functional analyses and locomotor inferences on fossil taxa, with little or no bias for body size. Lastly, we observed morpho-functional convergences among several mammalian taxa and detected some taxa that achieve similar locomotor features following different morphological paths. 相似文献
9.
10.
目的:探讨A和B两神教学方法在护理专业人体形态学教学中的应用及比较.方法:通过应用A和B两种教学法,对全日制护理学专科2010-2班和护理学专科2011-2班的人体形态学期末考试平均成绩和及格率进行比较和分析.结果:采用A教学法的护理学专科2011-2班的最高分为88分,最低分为42,平均成绩为75.45分,标准差为10.34.采用B教学法的护理学专科2010-2班的最高分为84分,最低分为36,平均成绩为64.34分,标准差为11.65.对护理学专科2011-2班和2010-2班的平均成绩进行F检验,F=1.12<1.50,故P>0.10,方差齐,敌可用方差相等情形的两样本t检验,t=5.36>2.66,故P<0.01,两组平均成绩之间差异有统计学意义;采用A教学法的护理学专科2011-2班的及格率为81.54%,采用B教学法的护理学专科2010-2班的及格率为65.15%.对于以上两个班及格率进行卡方检验,x=4.49>3.84,故P<0.05,两组及格率之间差异有统计学意义.以上结果说明采用A教学法的护理学专科2011-2班的平均成绩和及格率明显高于采用B教学法的护理学专科2010-2班.结论:在人体形态学教学中,A教学法跟B教学法比具有明显的优势,同时A教学法自身也有不足之处. 相似文献
11.
Energetics in Homo erectus and other early hominins: the consequences of increased lower-limb length
Steudel-Numbers KL 《Journal of human evolution》2006,51(5):445-453
Previous studies of daily energy expenditure (DEE) in hominin fossils have estimated locomotor costs using a formula that was based on six species, all 18 kg or less in mass, including no primates, and that has a number of other problems when applied in an ecological context. It is well established that the energetic cost of human walking is lower than that of representative mammals, particularly for individuals with long lower limbs. The current study reevaluates the daily energy expenditures of a variety of hominin species using more appropriate approaches to estimating locomotor costs. To estimate DEE for primates, I relied on published data on body mass, day range, and the percentage of time spent in various activities. Based on those data, I calculated a value for nonlocomotor DEE. I then used a variant of a method that I have suggested elsewhere to calculate the daily cost due to locomotion (DEEL) and summed the two to calculate total DEE. The more up-to-date methods for calculating the cost of travel result in lower estimates of this aspect of the energy budget than seen in previous studies. Values obtained here for DEE in various representatives of Australopithecus are lower than reported previously by around 200 kcal/day. Taking into account the greater economy of human walking, particularly the effect of the longer lower limbs found in many later Homo species, also results in lowered estimates of DEE. Elongation of the lower limbs in H. erectus reduced relative travel costs nearly 50% in comparison to A.L. 288-1 (A. afarensis). The present method for calculating DEE indicates that female H. erectus DEE was 84% greater than that of female Australopithecus; this disparity is even larger than that suggested by previous workers. 相似文献
12.
Terrestrial legged locomotion requires repeated support forces to redirect the body's vertical velocity component from down to up. We assume that the redirection is accomplished by impulsive leg forces that cause small-angle glancing collisions of a point-mass model of the animal. We estimate the energetic costs of these collisions by assuming a metabolic cost proportional to positive muscle work involved in generating the impulses. The cost of bipedal running estimated from this collisional model becomes less than that of walking at a Froude number (v2/gl) of about 0.7. Two strategies to reduce locomotion costs associated with the motion redirection are: (1) having legs simulate purely elastic springs, as is observed in human running; and (2) sequencing the leg forces during the redirection phase; examples of this sequencing are the ba-da-dump pattern of a horse gallop and having push-off followed by heel-strike in human walking. 相似文献
13.
Variability profiles measured over a set of aligned sequences can be used to estimate evolutionary freedom to vary. Differences
in variability profiles between clades can be used to identify shifts in function at the molecular level. We demonstrate such
a shift between the alpha and beta subunits of hemoglobin. We also show that the variability profiles for myoglobin are different
between whales and primates and speculate that the differences between the two clades may reflect a shift associated with
the novel oxygen storage demands in the lineage leading to whales. We discuss the relationship between sequence variability
and ``evolutionary opportunity' and explore the utility of Maynard Smith's multidimensional evolutionary opportunity space
metaphor for exploring functional constraints, genetic redundancy, and the context dependency of the genotype-phenotype map.
This work has implications for quantitatively defining and comparing protein function. Supplementary data is available from
bioinfo.mbb.yale.edu/align.
Received: 16 September 1999 / Accepted: 19 May 2000 相似文献
14.
Marco Antônio Batalha Igor Aurélio SilvaMarcus Vinicius Cianciaruso Helena FrançaGustavo Henrique de Carvalho 《Flora》2011,206(11):949-956
Soil, drought, and fire are abiotic factors that may act as environmental filters in the cerrado, the Brazilian savanna. We used a framework to analyze environmental filtering in geographic and phylogenetic context, sampling woody species in one of the largest cerrado reserves. In 100 quadrats, we measured 10 functional traits on each woody individual. We also measured several soil variables, altitude and slope as a rough surrogate of water availability, interval between fires, and time since last fire. Almost all environmental variables were spatially auto-correlated. We found an overall trait clustering, but not an overall phylogenetic clustering. Nevertheless, we found a phylogenetic signal for some traits. Linking phylogeny, traits, environment, and space, we were able to detect a major dichotomy between two geomorphological units. The flat tableland was positively related with altitude, fire frequency, and nutrient-richer soil. Environmental filtering caused by water availability and fire lead to trait clustering, with smaller shrubs and trees that presented thicker barks, denser woods, sclerophyllous leaves, highlighted by the prevalance of Myrtaceae. The other geomorphological unit, hilly terrain, was positively related with slope, low fire frequency, and nutrient-poorer soil. Environmental filtering was caused especially by nutrient-poor soil that lead to trait clustering, assembling taller trees, with thinner barks, lighter woods, and compound, large, tender, nutrient-richer leaves, distributed across many lineages, including Fabaceae. Hence, the high environmental variability in space with different environmental filters assembled different combination of plant traits and lineages, increasing the overall diversity in cerrado. 相似文献
15.
Morphological and functional development of characters from pelagic larval to benthic juvenile periods in the yellowfin goby, Acanthogobius flavimanus, were examined on the basis of 275 specimens (9.4–25.9mm in standard length) collected in shallow water in the Tama River estuary, central Japan. Judging from the development of osteological features, late pelagic juveniles possessed fully developed swimming and feeding abilities. Rapid changes in various characters, including the formation of a loop-shaped gut, increases in condition factor and teeth number, broader upper-field view capability, and extended scaly area and pigmentation development, occurred during the transition from late pelagic to early benthic periods. Most of the changes were associated with structural and functional aspects enabling more efficient use of benthic resources or the avoidance of predators in the benthic habitat. 相似文献
16.
We studied Polylepis forests along an elevational transect between 3,650 and 4,050 m a.s.l. at the treeline of the moist eastern cordillera in
Bolivia to examine changes in above- and below-ground stand structure, leaf and root morphology, and regeneration in relation
to stand microclimate. Field measurements and model predictions indicated relatively cold growth conditions of the Polylepis forests. Tree height, stem diameter, and basal area of the stands decreased markedly while stem density increased with elevation.
Leaf morphology differed between the two occurring Polylepis species, and trees at the treeline had smaller leaves with higher specific leaf area. In contrast, fine root biomass increased
from 37 g m−2 at the lowermost stand to 234 g m−2 at the treeline. Trees of the uppermost stand had higher specific root surface area and a much higher number of root tips
per unit dry mass. Thus, root surface area and total number of root tips per unit ground area increased conspicuously from
the lowermost stand to the treeline. Density of young growth inside the forest increased towards the treeline, while density
in the open grassland decreased with elevation. Young growth originated from sexual reproduction at the lower forest but was
comprised exclusively of root suckers at the treeline stand. We conclude that both the marked change in carbon allocation
towards the root system, as well as the changes in root morphology with elevation indicate an adaptation to reduced nutrient
supply under cold conditions of these Polylepis stands at the treeline in E Bolivia.
相似文献
Dietrich HertelEmail: |
17.
J. T. Watson R. E. Ritzmann 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,182(1):23-33
We have combined kinematic and electromyogram (EMG) analysis of running Blaberus discoidalis to examine how middle and hind leg kinematics vary with running speed and how the fast depressor coxa (Df) and fast extensor tibia (FETi) motor neurons affect kinematic parameters. In the range 2.5–10 Hz, B. discoidalis increases step frequency by altering the joint velocity and by reducing the time required for the transition from flexion to extension. For both Df and FETi the timing of recruitment coincides with the maximal frequency seen for the respective slow motor neurons. Df is first recruited at the beginning of coxa-femur (CF) extension. FETi is recruited in the latter half of femur-tibia (FT) extension during stance. Single muscle potentials produced by these fast motor neurons do not have pronounced effects on joint angular velocity during running. The transition from CF flexion to extension was abbreviated in those cycles with a Df potential occurring during the transition. One effect of Df activity during running may be to phase shift the beginning of joint extension so that the transition is sharpened. FETi is associated with greater FT extension at higher running speeds and may be necessary to overcome high joint torques at extended FT joint angles. Accepted: 24 May 1997 相似文献
18.
Activation of phospholipase D by 8-Br-cAMP occurs through novel pathway involving Src, Ras, and ERK in human endometrial stromal cells 总被引:2,自引:0,他引:2
We investigated the mechanism of 8-Br-cAMP-mediated phospholipase D (PLD) activation using a primary cell culture system of human endometrial stromal cells (ES cells). PLD activity was increased by the treatment of ES cells with 8-Br-cAMP, maximally at 5 min. To determine whether the effects of 8-Br-cAMP on PLD occurred as a consequence of PKC activation, ES cells were preincubated for 15 min with RO320432 (1 microM) and GF109203X (1 microM), the PKC inhibitors, or they were pretreated for 24h with phorbol myristate acetate (100 nM) to downregulate PKC. However, these treatments had no effects on PLD activation induced by 8-Br-cAMP. Furthermore, 8-Br-cAMP had no effects on the subcellular distribution of PKC alpha and PKC betaI, confirming no involvement of PKC. 8-Br-cAMP activated ERK1/2, maximally at 5 min, and PD98059 (MEK inhibitor: 50 microM) and transfection of ES cells with dominant negative (DN)-MEK completely inhibited 8-Br-cAMP-induced PLD activation, suggesting that ERK1/2 mediates the PLD activation. To investigate the involvement of protein kinase A (PKA), Src, and Ras in 8-Br-cAMP-induced PLD activation, we used PKA inhibitor, H89 and Rp-cAMPs, and transfections of DN-Src and DN-Ras. H-89 and Rp-cAMPs completely blocked 8-Br-cAMP-mediated PLD and ERK activation, implying the involvement of PKA in this PLD activation. In addition, transfection of ES cells with DN-Src, or DN-Ras partially inhibited 8-Br-cAMP-induced ERK1/2 and consequently PLD activation, whereas cotransfection of DN-Src and DN-Ras completely inhibited ERK1/2 and PLD activation, suggesting that Src and Ras independently regulate ERK/PLD activation. Taken together, these results demonstrate a novel pathway in ES cells that 8-Br-cAMP activate PLD through PKA and ERK1/2 and this ERK/PLD activation by 8-Br-cAMP is mediated by Src and Ras, separately. 相似文献
19.
20.
Ferdinand A. Sibbing 《Environmental Biology of Fishes》1988,22(3):161-178
Synopsis The wide variety of aquatic food is considered to be instrumental for the diversification in fish species. Yet their abilities
and inabilities of handling food are poorly known. For these reasons the food processing and feeding repertoire of the adult
carp, Cyprinus carpio, fed on a variety of food types, were analyzed by light and X-ray cinematography of the head parts and by electromyography
of the head and body muscles during feeding. Nine stereotyped movement patterns (particulate intake, gulping, rinsing, spitting,
selective retention of food, transport, crushing, grinding and deglutition) compose the feeding process, their sequence and
frequency were adjusted to the type of food. Following quantitative morphological analysis at macroscopic, light- and electronmicroscopical
level, the relations between the functioning and architecture of the feeding apparatus were established. The structure and
dimensions of the mouth opening, the protrusible upper jaw, the slit-shaped pharyngeal cavity, the palatal and postlingual
organ, the branchial sieve, the pharyngeal masticatory apparatus and the distribution of taste buds, mucous cells and muscle
fibers along the oropharyngeal surface were the directive structural characters used for estimating the abilities in food
processing. The specializations for utilizing food items and its limitations, derived from structural and functional data,
are compared with diet data found in the literature in order to evaluate the relative position of the carp in competition
for food in the aquatic environment. It is established that the ‘omnivorous’ carp is specialized in effective handling of
several categories of aquatic food, even when these are mixed with non-food (bottom invertebrates <4% SL in diameter) since
the palatal organ enables the carp to separate food from non-food. This includes very hard-skinned food items, processed with
the powerful pharyngeal jaws of the fish, and to a lesser extent zooplankton (>250 μm). The carp is at the same time very
limited in processing long and struggling prey (e.g. fish) as well as vegetable matter, due to the lack of oral teeth and
the specialized morphology of its pharyngeal chewing apparatus. These feeding abilities agree with diet data from literature.
The reported herbivorism of carp illustrates its opportunism in feeding behaviour. Specialization in feeding is discussed
and the necessity to take into account the total series of post-capture feeding actions for a more complete view on trophic
specialization. Food intake and the intra-oral food processing of carp are bound to the structures of its sensory, central
processing and effector apparatus and to the plasticity in their functioning. These together determine its feeding efficiency
in exploiting the available aquatic food resources. Next to ethological and ecological studies functional morphology is another
important tool to explain the trophic interactions of fish. 相似文献