首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Niche construction theory (NCT) has been represented as a new and comprehensive theory of evolution, one that breaks the constraints imposed by the dominant and largely gene-selectionist standard evolutionary model that is presently mischaracterized as “Darwinian.” I will argue that NCT is not so much a new theory, as it is a fruitful readmission of a venerable physiological perspective on adaptation, selection and evolution. This perspective is closer in spirit and philosophy to the original (and richer) Darwinian idea developed by Darwin himself, and that animated much of the rich late nineteenth century debate about evolution, heredity, adaptation and development, a debate that was largely eclipsed by the early twentieth century emergence of the Neodarwinian synthesis. I will argue that a full realization of the promise of NCT turns on a full understanding of another intellectual revolution of the nineteenth century, Claude Bernard’s conception of homeostasis, a profound statement of the nature of life that has, through the twentieth century, come to be widely misunderstood and trivialized.  相似文献   

2.
Through the early twentieth century, asthmatics were advised to move to a more suitable climate, or to vacation in one during their worst season. In the late nineteenth century, physicians sought to quantify the ideal temperature, humidity, altitude, and pollen count to help travellers to select a suitable place, but these investigations led some physicians to question contradictions between expected and actual conditions. Given that even the best climate was not perfect at all times, and that many patients could not afford to travel or relocate, a group of physicians—who came to be known as allergists—sought ways to adapt their patients to any climate through changes in their indoor environments and treatments to manage their symptoms. Their approach included changes in household design, furnishings, and cleaning techniques, especially a strict avoidance of dust, which could carry feathers, animal hair, skin debris, pollen, moulds, and an unknown ‘dust’ allergen. Air filtering and air conditioning were also promoted as ways to protect asthmatics and hay fever sufferers. These modifications of patients and their microenvironments signalled both a move away from climactic approaches to asthma and toward the sanitary, modernist home of the twentieth century.  相似文献   

3.
The scope of this paper is to highlight models of reticulate evolution in a dual sense: (1) by stressing the importance of early models of horizontal/lateral transfer instead of models of unilinear vertical transfer in biology, linguistics, anthropology and related disciplines, and (2) by demonstrating that the acceptance of evolutionism as leitmotif in the nineteenth century was only possible by intense and repeated networks between scholars of different academic realms which lead to the assumption that the development of biological species and human cultures could be perceived as part of the same co-evolutionary process. Contrary to these widely popularized models of unilinear evolution, I would like to draw attention to alternative theories emphasizing the horizontal transfer of words, phenotypes/genotypes, and culture traits. Examples are the method of areal typology in linguistics, the theory of endosymbiosis in biology, and the anti-evolutionist attitude in Boasian anthropology, combined with an emphasis on the diffusion of culture traits. Further, it shall be pointed out that, even when—after the general dismissal of evolutionist ideas in the beginning of the twentieth century—the idea of co-evolutionary processes in the development of human populations and languages was again forwarded in the late twentieth century, this ‘modern synthesis’ of genetics, linguistics and archeology relied largely on interdisciplinary reticulations between sciences and humanities and serves as another example of reticulate evolution.  相似文献   

4.
While, historically, the disabled body has appeared in literature as “monstrous,” burgeoning psychological theories of the Victorian period predicated an unusual shift. In a culture of sexual anxiety and fears of devolution and moral decay, the physically disabled and “weak” are portrayed as strangely free from moral corruption. Unlike the cultural link between deviance and disability witnessed in the medical literature and eugenic approach to generation, authors of narrative fiction—particularly Charles Dickens, but Wilkie Collins, Charlotte Yonge, and others as well—portray disabled characters as “purified,” and trauma itself as potentially sanitizing. This present paper argues that such constructions were made possible by developments in the treatment of insanity. “Curing ‘Moral Disability’: Brain Trauma and Self-Control in Victorian Fiction,” examines the concept of trauma-as-cure. Throughout the Victorian period, case studies on brain trauma appeared in widely circulated journals like the Lancet, concurrently with burgeoning theories about psychological disturbance and “moral insanity.” While not widely practiced until the early twentieth century, attempts at surgical “cures” aroused curiosity and speculation—the traumatic event that could free sufferers from deviance. This work provides a unique perspective on representations of disability as cure in the nineteenth century as a means of giving voice to the marginalized, disabled, and disempowered.  相似文献   

5.
Long‐distance calls used for mate attraction and territorial spacing are distinctive signals in the felid vocal repertoire. Their evolution is subject to natural and sexual selection, as well as various constraints. Body size is an important morphological constraint, with the scaling of the spectral characteristics of a species' vocalizations with its body size being established for several vertebrate groups. Alternatively, the structure of long‐distance calls may have been optimized for transmission in species' habitats (acoustic adaptation hypothesis). The present study assessed whether the mean dominant frequency of long‐distance calls in the Felidae (approximately 70% of all species incorporated) is influenced by the species' body size and/or conforms to the acoustic adaptation hypothesis. After controlling for phylogenetic relationships, we found a significant correlation between mean dominant frequency of a taxon's long‐distance calls and conditions for sound transmission in its habitat type (‘open/heterogeneous’ versus ‘dense’), although no significant influence of body size. Taxa living in more open habitat types have long‐distance calls with significantly lower mean dominant frequencies than those living in dense habitats. The result obtained in the present analysis is fairly robust against random removal of single or few taxa from the data, and also against the use of different branch‐length transformation models in phylogenetic regression. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 487–500.  相似文献   

6.
Since the modern evolutionary synthesis was first proposed early in the twentieth century, attention has focused on assessing the relative contribution of mutation versus natural selection on protein evolution. Here we test a model that yields general quantitative predictions on rates of protein evolution by combining principles of individual energetics with Kimura's neutral theory. The model successfully predicts much of the heterogeneity in rates of protein evolution for diverse eukaryotes (i.e. fishes, amphibians, reptiles, birds, mammals) from different thermal environments. Data also show that the ratio of non-synonymous to synonymous nucleotide substitution is independent of body size, and thus presumably of effective population size. These findings indicate that rates of protein evolution are largely controlled by mutation rates, which in turn are strongly influenced by individual metabolic rate.  相似文献   

7.
Sexual size dimorphism (SSD) is widespread in nature and may result from selection operating differentially on males and females. Rensch’s rule, the increase of SSD with body size in male-biased-SSD species (or decrease in female-biased-SSD species), is documented in invertebrates and vertebrates. In turtles, evidence for Rensch’s rule is inconclusive and thus the forces underlying body size evolution remain obscure. Using a phylogenetic approach on 138 turtle species from 9 families, we found that turtles overall and three families follow Rensch’s rule, five families display isometry of SSD with body size, while Podocnemididae potentially follows a pattern opposite to Rensch’s rule. Furthermore, male size evolves at faster rates than female size. Female-biased-SSD appears ancestral in turtles while male-biased-SSD evolved in every polytypic family at least once. Body size follows an Ornstein–Uhlenbeck evolutionary model in both sexes and SSD types, ruling out drift as a driving process. We explored whether habitat type or sex determination might be general drivers of turtle body size evolution using a phylogenetic context. We found that males are proportionally larger in terrestrial habitats and smaller in more aquatic habitats, while the sex-determining mechanism had no influence on body size evolution. Together, our data indicate that Rensch’s rule is not ubiquitous across vertebrates, but rather is prevalent in some lineages and not driven by a single force. Instead, our findings are consistent with the hypotheses that fecundity-selection might operate on females and ecological-selection on males; and that SSD and sex-determining mechanism evolve independently in these long-lived vertebrates.  相似文献   

8.
The distinction between understanding persons as dividuals versus individuals began to develop in the latter half of the twentieth century. Originating in Louis Dumont’s comparative work into the differences between Western and Indian subjects in the 1950s, it perhaps reached its zenith in the 1980s when Marilyn Strathern used it to differentiate between Melanesian and Western concepts of the person. By the end of the century, critique and reconceptualisation of the individual:dividual distinction was so well established in the anthropological literature that its explanatory capacity was largely negated. The aim of this paper is to attempt to clarify the different modes of personhood that the dividual:individual distinction sought to elucidate by introducing a useful distinction between the self and the human subject and further developing Charles Taylor’s distinction between porous and buffered selves.  相似文献   

9.
In the social and historical plan, the ??body?? is not still a datum of evidence. This formulation with a dualist connotation does not appear in all the human societies, certain do not distinguish the man from his flesh. The body is rather a question than an answer, a misleading evidence which reveals a multitude of different representations which assign to it a position determined within the general symbolism of the society, dependent on a social status, on a vision of the world, and inside this last one on a definition of the person. The body is a changeable reality from a society to an other one?: the images which define it, the systems of knowledge which clarify its nature, the accomplished performances are strickingly diverse, contradictory. The body is a symbolic construction. It seems to be obvious, but nothing is more imperceptible.  相似文献   

10.
Anurans emit advertisement calls with the purpose of attracting mates and repelling conspecific competitors. The evolution of call traits is expected to be associated with the evolution of anatomical and behavioural traits due to the physics of call emission and transmission. The evolution of vocalizations might imply trade‐offs with other energetically costly behaviours, such as parental care. Here, we investigated the association between body size, calling site, parental care and call properties (call duration, number of notes, peak frequency, frequency bandwidth and call structure) of the advertisement calls of glassfrogs (Centrolenidae)—a family of Neotropical, leaf‐dwelling anurans—using phylogenetic comparative methods. We also explored the tempo and mode of evolution of these traits and compared them with those of three morphological traits associated with body size, locomotion and feeding. We generated and compiled acoustic data for 72 glassfrog species (46% of total species richness), including representatives of all genera. We found that almost all acoustic traits have significant, but generally modest, phylogenetic signal. Peak frequency of calls is significantly associated with body size, whereas call structure is significantly associated with calling site and paternal care. Thus, the evolution of body size, calling site and paternal care could constrain call evolution. The estimated disparity of acoustic traits was larger than that of morphological traits and the peak in disparity of acoustic traits generally occurred later in the evolution of glassfrogs, indicating a historically recent outset of the acoustic divergence in this clade.  相似文献   

11.
The hypothesis that evolution of body size in birds was a random process coupled with an absolute lower boundary on body mass was tested using data on 6217 species of extant birds. The test was based on the fact that subclades within birds that have body masses much larger than this minimum should not have skewed log body mass distributions, while clades close to this boundary should. Bird species were classified into 23 orders suggested by Sibley and Monroe (1988). Thirteen orders that had average log body masses greater than the average for all birds had significantly skewed log body mass distributions. This is inconsistent with the hypothesis that evolution of body size in birds is random, but is constrained only at the smallest body masses. Most orders of birds cannot be considered random samples from the parental distribution of all birds. When the pattern of body mass evolution in birds is reconstructed using an estimate of the phylogenetic relationships among orders, there are many more instances where a large taxon putatively originated from a smaller one than vice versa. The non-random nature of body mass evolution in birds is consistent with models that postulate that evolution is constrained by the ability of individuals to turn resources into offspring.  相似文献   

12.
An open question in animal evolution is why the phylum- and superphylum-level body plans have changed so little, while the class- and family-level body plans have changed so greatly since the early Cambrian. Davidson and Erwin (Davidson and Erwin, 2006; Erwin and Davidson, 2009) proposed that the hierarchical structure of gene regulatory networks leads to different observed evolutionary rates for terminal properties of the body plan versus major aspects of body plan morphology. Here, we calculated the speed of evolution of genes in these gene regulatory networks. We found that the genes which determine the phylum and superphylum characters evolve slowly, while those genes which determine the classes, families, and speciation evolve more rapidly. This result furnishes genetic support to the hypothesis that the hierarchical structure of developmental regulatory networks provides an organizing structure which guides the evolution of aspects of the body plan.  相似文献   

13.
Recent studies indicated that body size of various animals, including birds, changed during the twentieth century, and these changes were attributed to changes in food availability and climate. We used museum skins of goshawks (Accipiter gentilis) collected between 1854 and 1941 and between 1979 and 1998 in order to check whether body size of this species in Denmark changed during the study period. We compared three body measurements (wing, beak and tarsus length) and the first principal component (PC1) derived from these measurements of four groups of goshawks (adult and immature, females and males). We found that the wing length of goshawks collected after 1979 was significantly smaller in comparison with those collected before this year, and females were more affected than males. Immature birds (but not adults) collected after 1979 had significantly shorter beaks than those from the early period. Immature females collected after 1979 had shorter tarsi than those collected in the early period. There was a significant decrease in body size (as represented by PC1) from the early to late period, which was more pronounced among females and immature birds. In conclusion, body size of goshawks in Denmark decreased during the twentieth century.  相似文献   

14.
Molecular aspects of XY body formation   总被引:1,自引:0,他引:1  
  相似文献   

15.
The purpose of this article is to present the opinions of the Argentine intellectual, Leopoldo Lugones, regarding the Jews and the reasons for his seemingly contradictory attitudes towards them that mirror both the general precariousness of Jewish existence in Argentina and the contradictions of Argentine nationalism. Moreover, these writings also reveal other related aspects of Lugones’ thought and provide a partial overview of Argentine nationalistic thought from the beginning of the twentieth century to the late 1930s, thereby offering insights into the nature and evolution of Argentine nationalism in reaction to Jews and other immigrant groups.  相似文献   

16.
Diffusion theory explains in physical terms how materials move through a medium, e.g. water or a biological fluid. There are strong and widely acknowledged grounds for doubting the applicability of this theory in biology, although it continues to be accepted almost uncritically and taught as a basis of both biology and medicine. Our principal aim is to explore how this situation arose and has been allowed to continue seemingly unchallenged for more than 150 years. The main shortcomings of diffusion theory will be briefly reviewed to show that the entrenchment of this theory in the corpus of biological knowledge needs to be explained, especially as there are equally valid historical grounds for presuming that bulk fluid movement powered by the energy of cell metabolism plays a prominent note in the transport of molecules in the living body. First, the theory's evolution, notably from its origins in connection with the mechanistic materialist philosophy of mid nineteenth century physiology, is discussed. Following this, the entrenchment of the theory in twentieth century biology is analyzed in relation to three situations: the mechanism of oxygen transport between air and mammalian tissues; the structure and function of cell membranes; and the nature of the intermediary metabolism, with its implicit presumptions about the intracellular organization and the movement of molecules within it. In our final section, we consider several historically based alternatives to diffusion theory, all of which have their precursors in nineteenth and twentieth century philosophy of science. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

17.
Pardiñas, Valenzuela, and Salazar‐Bravo (2017) are concerned that eventual differences in species mean body masses and in the phylogenetic hypothesis used in Maestri et al. (2016)—compared with those available on other potential sources—could affect the results of our original article. Here, we used a new phylogenetic hypothesis to conduct the same analyses of the original article, and we randomly sampled 1000 values of body mass within approximately 35% upper and lower intervals around the mean body mass for each species included in our database. We show that our previous results and conclusions are robust and valid, and they persist despite uncertainty in mean body mass estimation. We argue that sampling variation and uncertainty in both species mean body mass estimation and phylogenetic hypothesis are to be expected and should not always be confused with inaccuracies.  相似文献   

18.
Despite its explanatory clout, the theory of evolution has thus far compiled a modest record with respect to predictive power—that other major hallmark of scientific theories. This is considered by many to be an acceptable limitation of a theory that deals with events and processes that are intrinsically random (and historic). However, whether this is an inherent restriction or simply the sign of an incomplete theory is an open question. In an attempt to help answer that question, we propose a classification scheme for several types of prediction that might occur with regard to evolutionary systems, then explore the nature of these predictions in a system that simulates the evolution of neural architectures. This provides a platform from which to consider the relevance of such observations for real biological systems and illuminates a variety of key issues pertaining to prediction in those environments.  相似文献   

19.
Two influential articles published in the 1970s suggested that pressure from Christian fundamentalists, subsequent to the Scopes trial of 1925, forced American high school biology textbook authors and publishers to significantly limit discussion of the topic of evolution. The conclusions reached by these studies have become foundational for historians examining the interplay between science and religion in the United States in the twentieth century. However, a reexamination of key twentieth century biology textbooks suggests that the narrative that the treatment of the theory of evolution was held hostage to anti-rational cultural forces is largely a myth, created first as part of a public relations effort by the Biological Sciences Curriculum Study (BSCS) to differentiate, defend, and promote its work, and later as part of an attempt by scholars to sound a warning concerning the rise of the religious right. A focus on this narrative has not only allowed biologists to sidestep uncomfortable questions regarding the race-biased and class-biased assumptions embedded within the concept of evolutionary progress, it has also limited reliance on the texts in question as reliable reflections of the cultural assumptions of educators and scientists. A reexamination of the most popular American biology textbooks from 1907 to 1963, particularly the work of Ella Thea Smith, provides evidence in support of these contentions.  相似文献   

20.
The use of phylogenetic comparative methods in ecological research has advanced during the last twenty years, mainly due to accurate phylogenetic reconstructions based on molecular data and computational and statistical advances. We used phylogenetic correlograms and phylogenetic eigenvector regression (PVR) to model body size evolution in 35 worldwide Felidae (Mammalia, Carnivora) species using two alternative phylogenies and published body size data. The purpose was not to contrast the phylogenetic hypotheses but to evaluate how analyses of body size evolution patterns can be affected by the phylogeny used for comparative analyses (CA). Both phylogenies produced a strong phylogenetic pattern, with closely related species having similar body sizes and the similarity decreasing with increasing distances in time. The PVR explained 65% to 67% of body size variation and all Moran's I values for the PVR residuals were non-significant, indicating that both these models explained phylogenetic structures in trait variation. Even though our results did not suggest that any phylogeny can be used for CA with the same power, or that "good" phylogenies are unnecessary for the correct interpretation of the evolutionary dynamics of ecological, biogeographical, physiological or behavioral patterns, it does suggest that developments in CA can, and indeed should, proceed without waiting for perfect and fully resolved phylogenies.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号