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1.
Teams in animal societies   总被引:9,自引:1,他引:8  
We review the existence of teams in animal societies. Teamshave previously been dismissed in all but a tiny minority ofinsect societies. "Team" is a term not generally used in studiesof vertebrates. We propose a new rigorous definition of a teamthat may be applied to both vertebrate and invertebrate societies.We reconsider what it means to work as a team or group andsuggest that there are many more teams in insect societies than previously thought. A team task requires different subtasksto be performed concurrently for successful completion. Thereis a division of labor within a team. Contrary to previousreviews of teams in social insects, we do not constrain teamsto consist of members of different castes and argue that teammembers may be interchangeable. Consequently, we suggest thata team is simply the set of individuals that performs a teamtask. We contrast teams with groups and suggest that a grouptask requires the simultaneous performance and cooperationof two or more individuals for successful completion. In agroup, there is no division of labor—each individual performs the same task. We also contrast vertebrate and invertebrateteams and find that vertebrate teams tend to be associatedwith hunting and are based on individual recognition. Invertebrateteams occur in societies characterized by a great deal of redundancy,and we predict that teams in insect societies are more likelyto be found in large polymorphic ("complex") societies thanin small monomorphic ("simple") societies.  相似文献   

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The species pool concept has played a central role in the development of ecological theory for at least 60 yr. Surprisingly, there is little consensus as to how one should define the species pool, and consequently, no systematic approach exists. Because the definition of the species pool is essential to infer the processes that shape ecological communities, there is a strong incentive to develop an ecologically realistic definition of the species pool based on repeatable and transparent analytical approaches. Recently, several methodological tools have become available to summarize repeated patterns in the geographic distribution of species, phylogenetic clades and taxonomically broad lineages. Here, we present three analytical approaches that can be used to define what we term ‘the biogeographic species pool’: distance‐based clustering analysis, network modularity analysis, and assemblage dispersion fields. The biogeographic species pool defines the pool of potential community members in a broad sense and represents a first step towards a standardized definition of the species pool for the purpose of comparative ecological, evolutionary and biogeographic studies.  相似文献   

4.
In the institutional sense of the term "discipline" (laboratories, societies, congresses, curricula, etc.), genetics remains a discipline. In the intellectual sense of the term (consensus on a definite array of concepts, methods and theoretical purposes), it is doubtful that genetics is still a discipline. At first, molecular biology seemed to have introduced an unequivocal structural (or molecular) definition of the gene: a definite sequence of nucleotides that code for a protein. In fact, as it appears in retrospect, this was not the case. Even in 1961, when Jacob and Monod proposed their first model of genetic regulation in bacteria, there was no possibility of constructing a non equivocal concept of the gene. More recent developments in molecular genetics have made this situation worse. There is no possible definition of the gene as a general category. The reasons why biologists keep the word are pragmatic rather than theoretical: communication among scientists, economic interests and ideology.  相似文献   

5.
"生态环境"内涵界定探讨   总被引:5,自引:1,他引:4  
“生态环境”是在中国使用频率较高的一个名词,由于一直没有明确而公认的定义,使用者往往误用,不利于今后理论研究和实践工作。本文追溯了生态环境概念的起源,对比分析了“生态环境”内涵的不同理解,基于生态学、环境科学理论,认为生态环境是以特定生物体(包括人类)为中心,多元复合生态系统各要素和生态关系的总和,强调生态系统的整体性、连续性、稳定性和协同进化性,以及在此基础上对主体提供的环境功能。  相似文献   

6.
P. S. Stephenson 《CMAJ》1975,113(8):764-9
There is much controversy in the literature concerning prevalence, cause, diagnosis and treatment of hyperkinesis. The subject is complex; there is much ambiguity, and many research studies and reports of successful treatment appear to be overly simplistic in their approach to the problem. The use of the term "hyperkinesis" as synonymous with "hyperactivity" and often also with "minimal cerebral dysfunction" causes much confusion. There appear to be some common underlying beliefs about hyperkinetic children; these are critically examined. From integration of reports in the literature with clinical experience, it is contended that the term hyperkinesis should be restricted to the definition used in the British studies, and hyperactivity should be considered only a symptom. Hyperactivity has a large number of underlying causes, and management plans need to be individualized.  相似文献   

7.
Screening for gestational diabetes is commonly recommended despite the absence of a common definition of gestational diabetes. Furthermore, there is no consensus about management or treatment. Those who recommend screening do so largely on the basis of fetal morbidity, which seems to be predominantly "macrosomia"--another term without an agreed definition. The implications of macrosomia in terms of actual morbidity are also not clear. R J Jarrett reviews the history of the subject and concludes that gestational diabetes is simply impaired glucose tolerance temporally associated with pregnancy. Its main importance is as a predictor of subsequent non-insulin dependent diabetes, but it fails the major tests for a condition suitable for a screening programme.  相似文献   

8.
The importance of harmonizing the group of terms used to indicate ‘natural’ forests is reported in several studies. In a recent paper the term virgin forest is proposed as a unifying concept for forests which are not influenced by man in their development. In response to that paper my aim is to clarify the terms virgin and old-growth. My response focuses on two points: the term virgin forest is generally used to indicate forests that have not been influenced by people even in the distant past, therefore something different from what described by the authors; the definition drawn up for the proposed term substantially overlaps with the definition of old-growth forest resulting from a long history of studies on this theme. I think that the overlap between the two analyzed terms can ultimately only increase the existing confusion on this group of forest terms.  相似文献   

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Anthropomorphism (and its obverse, zoomorphism) continues to shift and propel us toward changing perspectives on ourselves and other animals. Discussions of anthropomorphism in primate behavior are ostensibly about our use and definition of terms, but ultimately reflect our views of what is unique to humans or unknowable in other animals. Primatologists doing long-term fieldwork report on the bonds that are inevitably formed through familiarity with their study subjects and how anecdotes and anthropomorphism help them to gain a contextualized view of animal lives. This fuller view of animal society serves as an aid to understanding different rationalities and provides a more effective modern role for anthropomorphism than does seeking to demonstrate isomorphic capacities in alloprimates. Although most ordinary language terms are accepted among primatologists, "primate culture" serves as an example of a term and a concept that overreached acceptable anthropomorphic limits when defined to accord with definitions of modern human culture. Comparing similar behavioral forms as the product of similar selective pressures acting on specific early traits, producing homoplasies through convergent evolution, provides a nonanthropomorphic basis for seeking similarities in human and alloprimate behavior.  相似文献   

11.
The term “social niche” is rapidly increasing in usage, particularly in the context of “social niche construction.” But what (if anything) is a social niche? Here, we survey papers that have used the term to uncover commonalities and discrepancies in its definition. We aim to alert researchers to the need for more consistency in how the term is used in the literature, and we provide a working definition of “social niche:” the set of social environments in which the focal individual has non-zero inclusive fitness. We consider the extent to which a social niche is analogous to an ecological niche, discuss whether a population-level social niche can be meaningfully identified, and describe conceptual insights about the properties of social niches, focusing on social niche construction. We highlight questions about social niches that demand more theoretical and empirical attention.  相似文献   

12.
To show that the input pattern of chromosomal mutations is highly organized relative to the band patterns along human chromosomes, a new term, "metaphase chromatin flavor," is introduced. Five different flavors of euchromatic metaphase bands are cytologically identified along a human ideogram. These are G-bands and, based upon combinations of extreme Alu richness and GC richness, four different R-band flavors. The two flavors with extremely GC-rich components, traditionally called "T-bands," represent only 15% of all bands. However, they contain 65% of mapped genes, 19 of 25 mapped oncogenes, most cancer-associated rearrangements, evolutionary rearrangements, meiotic chiasmata, and X-ray-induced breaks. Flavors with extremely Alu-rich flavors are also involved in melphalan-induced rearrangements, pachytene stretching, and mitotic chiasmata. Frequencies of CpG islands, CCGCCC boxes, retroposon families, and genes are characteristic to each chromatin flavor and will facilitate alignment of genome sequences onto ideograms of chromatin flavor. The influence of chromatin flavor on the evolution of a gene's sequence is so strong that one can infer the flavor of the band in which a gene resides from the sequence of the gene itself. Correlation coefficients for many pairs of mapped genetic variables, while globally high, are quite low within bands of one flavor, implicating a concerted mode of evolution for bands of one chromatin flavor.  相似文献   

13.
Let the concept of trait be functional!   总被引:22,自引:0,他引:22  
In its simplest definition, a trait is a surrogate of organismal performance, and this meaning of the term has been used by evolutionists for a long time. Over the last three decades, developments in community and ecosystem ecology have forced the concept of trait beyond these original boundaries, and trait-based approaches are now widely used in studies ranging from the level of organisms to that of ecosystems. Despite some attempts to fix the terminology, especially in plant ecology, there is currently a high degree of confusion in the use, not only of the term "trait" itself, but also in the underlying concepts it refers to. We therefore give an unambiguous definition of plant trait, with a particular emphasis on functional trait. A hierarchical perspective is proposed, extending the "performance paradigm" to plant ecology. "Functional traits" are defined as morpho-physio-phenological traits which impact fitness indirectly via their effects on growth, reproduction and survival, the three components of individual performance. We finally present an integrative framework explaining how changes in trait values due to environmental variations are translated into organismal performance, and how these changes may influence processes at higher organizational levels. We argue that this can be achieved by developing "integration functions" which can be grouped into functional response (community level) and effect (ecosystem level) algorithms.  相似文献   

14.
15.
A K Dua  C Pinsky  F S LaBella 《Life sciences》1985,37(11):985-992
The term "enkephalinase" has been frequently applied to enzyme activity in a variety of tissue preparations. In some cases there has been the implication that cleavage of a specific peptide bond in the enkephalin molecule results from the action of a single enzyme with the major responsibility of inactivating synaptic enkephalin. It is not known to what extent diverse enkephalin-degrading enzymes, with differing peptide bond specificities, may act in concert at any given synapse. There do exist, however, enzymes having known characteristic specificities with respect both to peptide substrates, including enkephalins, and to identifiable peptide bonds. Thus, at any given site of enkephalin release there probably resides a characteristic assembly of peptidases concerned with inactivation of this neuromediator. We propose that the term "enkephalinase" be used to encompass the entire family of enkephalin-degrading enzymes, and that "aminoenkephalinase", "carboxyenkephalinase", "endoenkephalinase" and "pseudoenkephalinase" should designate enzymes of known specificities with respect to both peptide substrates and particular peptide bonds.  相似文献   

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17.
The term biodiversity may help us to reach beyond the nature–culture dualism that has a debilitating effect on conservation thinking. This, however, depends on how the term is actually used. The opportunity is that the term connects dialectically together biological entities and their conditions of reproduction and may, consequently, facilitate a shift from atomistic to processual thinking in ecology and conservation. Analogously, the term offers resources for analyzing the dynamic dependence of human activities on natural processes. Health offers a fruitful metaphor for evaluating the resilience and conditions of reproduction of ecosocial systems. On the other hand, problems and contradictions in the application of the term arise from too schematic a perception of the relationship between scientific knowledge and human, social agency. Science influences human agency primarily on the long term, by helping to form new perspectives on what it means to lead a human life. Conservation concerns have a great influence on such perspectives. However, an emphasis on crisis may be counterproductive: scientific arguments perform poorly in a crisis situation in which, instead, short-term interests of powerful social actors such as corporations, state agencies or professional groups may gain the upper hand.  相似文献   

18.
Su EW  Lin JY  Kane LP 《Cytokine》2008,44(1):9-13
Over the last several years, there has been increasing interest in the role of proteins of the TIM (T cell immunoglobulin and mucin domain) family in regulating immune responses. Despite what the name suggests, proteins of this family function in a much more widespread manner than just on T cells, as we will discuss in this review. We therefore propose that the definition of TIM be adjusted to "transmembrane immunoglobulin and mucin".  相似文献   

19.
Mark Schwartz has done a fine job in a systematic attempt to define applied psychophysiology. The present author disagrees on a few points concerning what areas will be included and what areas excluded from Schwatz's definition of this term.  相似文献   

20.
Available evidence provides little support for a recent proposal that the term "trophoblast" be applied solely to eutherian mammals. Arguments for such a restricted usage are based on a dichotomous interpretation of therian reproduction that underestimates the developmental, structural, and functional diversity of trophoblastic tissues occurring within the infraclass Eutherian. The occurrence of developmental patterns that are phenotypically intermediate between those of commonly studied eutherians and metatherians suggests that blastocyst development is not fundamentally different in marsupials and eutherians. The trophoblast of marsupials accomplishes most or all of the major functions of the eutherian trophoblast, including maternal-fetal physiological exchange, implantation, contribution to placental membranes, steroid metabolism, and possibly, immunological protection of the conceptus. Furthermore, application of the term "trophoblast" to marsupials is consistent with present and past usage, as well as with the original definition and etymological derivation of the term. Therefore, we recommend that the term "trophoblast" continue to be applied in a functional-morphological sense to the appropriate extraembryonic tissues of marsupials. Such use of functional (rather than taxonomic) criteria for application of this term avoids biasing interpretations of mammalian reproductive evolution.  相似文献   

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