Is foraging innovation lost following colonization of a less variable environment? A case study in surface‐ vs. cave‐dwelling Asellus aquaticus

Behavioral innovation is a key process for successful colonization of new habitat types. However, it is costly due to the necessary cognitive and neural demands and typically connected to ecological generalism. Therefore, loss of behavioral innovativeness is predicted following colonization of new, simple, and invariable environments. We tested this prediction by studying foraging innovativeness in the freshwater isopod Asellus aquaticus. We sampled its populations along the route of colonizing a thermokarstic water‐filled cave (simple, stable habitat with only bacterial mats as food) from surface habitats (variable environment, wide variety of food). The studied cave population separated from the surface populations at least 60,000 years ago. Animals were tested both with familiar and novel food types (cave food: bacterial mats; surface food: decaying leaves). Irrespective of food type, cave individuals were more likely to feed than surface individuals. Further, animals from all populations fed longer on leaves than on bacteria, even though leaves were novel for the cave animals. Our results support that cave A. aquaticus did not lose the ability to use the ancestral (surface) food type after adapting to a simple, stable, and highly specialized habitat.     

必须十分重视学生的微生物学实验技能的训练

就微生物学专业研究生入学考试面试的实验操作技能测试中暴露出一些考生的微生物学基本实验技能比较差的问题,分析其产生的原因,提出实验基本技能也是创新能力的一部分,没有很强的动手能力,不但不能创新,就连基本的模仿工作也不能开展。希望能引起同行的注意,在培养学生创新能力的同时,要重视对本科生微生物学基本实验技能的培养。     

Are three‐dimensional spider webs defensive adaptations?

Spider webs result from complex behaviours that have evolved under many selective pressures. Webs have been primarily considered to be foraging adaptations, neglecting the potential role of predation risk in the evolution of web architecture. The ecological success of spiders has been attributed to key innovations in how spiders use silk to capture prey, especially the invention of chemically adhesive aerial two‐dimensional orb webs. However, araneoid sheet web weavers transformed the orb architecture into three‐dimensional webs and are the dominant group of aerial web‐building spiders world‐wide, both in numbers and described species diversity. We argue that mud‐dauber wasps are major predators of orbicularian spiders, and exert a directional selective pressure to construct three‐dimensional webs such that three‐dimensional webs are partly defensive innovations. Furthermore, patterns of diversification suggest that escape from wasp predators may have facilitated diversification of three‐dimensional web‐building spiders.     

Primate Innovation: Sex,Age and Social Rank Differences

Analysis of an exhaustive survey of primate behavior collated from the published literature revealed significant variation in rates of innovation among individuals of different sex, age and social rank. We searched approximately 1,000 articles in four primatology journals, together with other relevant databases, for examples of innovation. The reported incidence of innovation is higher in males and adults, and lower in females and nonadults, than would be expected by chance given the estimated relative proportions of these groups. Amongst chimpanzees, the only species for which there are sufficient data to consider alone, there is a similar sex difference in the propensity to innovate, but no effect of age. Chimpanzees of low social rank are reported as innovators more frequently than high-ranking chimpanzees are. Male chimpanzees innovate more often than females in sexual, courtship, mating and display contexts; that is, in contexts likely to increase access to mates. The largest number of recorded observations are in the foraging context, wherein contrary to expectations, there is no evidence for female chimpanzees exhibiting more innovation than males. The study is the first extensive investigation of behavioral innovation in primates and provides evidence that much individual variation in the propensity to innovate can be explained in terms of sex, age, and social rank.     

研究生课程“酶工程”多元化教学改革的探索与思考

酶工程作为一门理论与实践相结合的专业课程,在生物工程专业研究生的课程设置中处于桥梁和纽带地位,对专业型人才的培养发挥着重要的作用。为了适应我国研究生专业学位教育发展的客观需求,提升酶工程课程的实践教学效果,并进一步提高学生的学习兴趣和积极性,培养研究生的应用型创新能力,我们通过在课程教学中引入虚拟仿真技术,开展案例式教学模式探索,并利用"互联网+"技术等多元化方式对该课程的教学模式、方法和手段进行尝试改革和探索,取得了一定的教学效果。本文就此进行了一些探讨,以期能为相关课程的教学改革提供一些思路和启示。     

Decoupled jaws promote trophic diversity in cichlid fishes

Functional decoupling of oral and pharyngeal jaws is widely considered to have expanded the ecological repertoire of cichlid fishes. But, the degree to which the evolution of these jaw systems is decoupled and whether decoupling has impacted trophic diversification remains unknown. Focusing on the large Neotropical radiation of cichlids, we ask whether oral and pharyngeal jaw evolution is correlated and how their evolutionary rates respond to feeding ecology. In support of decoupling, we find relaxed evolutionary integration between the two jaw systems, resulting in novel trait combinations that potentially facilitate feeding mode diversification. These outcomes are made possible by escaping the mechanical trade-off between force transmission and mobility, which characterizes a single jaw system that functions in isolation. In spite of the structural independence of the two jaw systems, results using a Bayesian, state-dependent, relaxed-clock model of multivariate Brownian motion indicate strongly aligned evolutionary responses to feeding ecology. So, although decoupling of prey capture and processing functions released constraints on jaw evolution and promoted trophic diversity in cichlids, the natural diversity of consumed prey has also induced a moderate degree of evolutionary integration between the jaw systems, reminiscent of the original mechanical trade-off between force and mobility.     

Reconstructing the origins of high-alpine niches and cushion life form in the genus Androsace S.L. (Primulaceae)

Relatively, few species have been able to colonize extremely cold alpine environments. We investigate the role played by the cushion life form in the evolution of climatic niches in the plant genus Androsace s.l., which spreads across the mountain ranges of the Northern Hemisphere. Using robust methods that account for phylogenetic uncertainty, intraspecific variability of climatic requirements and different life-history evolution scenarios, we show that climatic niches of Androsace s.l. exhibit low phylogenetic signal and that they evolved relatively recently and punctually. Models of niche evolution fitted onto phylogenies show that the cushion life form has been a key innovation providing the opportunity to occupy extremely cold environments, thus contributing to rapid climatic niche diversification in the genus Androsace s.l. We then propose a plausible scenario for the adaptation of plants to alpine habitats.     

创新微生物实验教学体系的思考与实践

根据微生物学实验教学的实践和体会,从微生物实验教学的组织思路、组织形式、教学内容、教学方法等方面进行了归纳和总结,提出"以科研项目的形式组织实验教学,在实验设计、实验过程和结果分析中以学生为主体,教师为主导"的实验教学模式,并剖析了该模式在试行过程中存在的主要问题及应对措施.     

The intramandibular joint in Girella: A mechanism for increased force production?

Intramandibular joints (IMJ) are novel articulations between bony elements of the lower jaw that have evolved independently in multiple fish lineages and are typically associated with biting herbivory. This novel joint is hypothesized to function by augmenting oral jaw expansion during mouth opening, which would increase contact between the tooth‐bearing area of the jaws and algal substratum during feeding, resulting in more effective food removal from the substrate. Currently, it is not understood if increased flexibility in a double‐jointed mandible also results in increased force generation during herbivorous biting and/or scraping. Therefore, we selected the herbivore Girella laevifrons for a mechanical study of the IMJ lower jaw lever system. For comparative purposes, we selected Graus nigra, a non–IMJ‐bearing species, from a putative sister genus. Shortening of the lower jaw, during flexion at the IMJ, resulted in a more strongly force‐amplifying closing lever system in the lower jaw, even in the absence of notable changes to the sizes of the muscles that power the lever system. To explain how the IMJ itself functions, we use a four‐bar linkage that models the transmission of force and velocity to and through the lower jaw via the IMJ. When combined, the functionally interrelated lever and linkage models predict velocity to be amplified during jaw opening, whereas jaw closing is highly force modified by the presence of the IMJ. Moreover, the function of the IMJ late during jaw closure provides enough velocity to detach sturdy and resilient prey. Thus, this novel jaw system can alternate between amplifying the force or the velocity exerted onto the substrate where food items are attached. This unique mechanical configuration supports the argument that IMJs are functional innovations that have evolved to meet novel mechanical challenges and constraints placed on the feeding apparatus by attached and sturdy food sources. J. Morphol. 2010. © 2009 Wiley‐Liss, Inc.     

医学院校培养本科生科研创新能力的认识与思考

科研能力是科学素质的核心,是运用已有的知识和科学方法去探索新的知识和方法,解决新的问题,并在这个过程中形成创新思维的能力。科学技术的创新是医学事业发展的阶梯,科技引领着医学探究生命的本质,通过对各种疾病的根源、机制、发生、后果进行研究,找到预防和治疗疾病的最佳途径,为人类解除疾病带来的痛苦。医学科技创新使医学得到快速发展的同时,为社会培养了高水平、高素质的医学人才。然而,我国的高等教育体制普遍注重教育方法的革新,而忽视学生综合素质和创新能力的培养。特别是医学高等院校,本科生的教育教学工作没有重视与科研相结合。随着高等教育体制改革的不断深入与现代科学技术的迅速发展,本科生的科研创新能力亟待进一步提高。本科生科研能力的培养已经成为当前高等教育改革的一个重要目标。本文针对医学院校本科生培养创新能力的重要性和必要性进行探讨,为医学教育的发展提供参考的资料。