Functional morphology and evolutionary ecology

Functional morphology studies physico-chemical properties and biological roles of organs. If applied to fossils this approach is connected with specific methodological problems. The fields of application of functional morphology in paleontology are illustrated with examples. In a working concept it is shown how the results of functional morphology can be integrated into an account of the evolutionary ecology of fossil taxa.     

Nutritional Ecology: A First Vegetarian Spider

Mutualisms are ubiquitous in nature and equally commonplace is their exploitation. A well-known mutualism has been found to be exploited from a surprising source: the first described vegetarian spider dines on trophic structures produced by acacia trees to reward their mutualistic protective ants.     

灵长类营养生态学的研究进展

营养生态学是现代生态学领域研究动物食物数量和质量、营养适应以及营养对种群特征作用规律的分支学科.目前从营养生态学研究灵长类食性需求主要分为五种假说,1)能量最大化假说;2)氮(蛋白质)最大化假说;3)植物次级代谢产物调节假说;4)膳食纤维调节假说;5)食物营养均衡假说.本文从研究方法和研究内容分别介绍了这些假说在灵长类...     

Functional ecology of feeding in elasmobranchs

Feeding behavior in the species of captive chondrichthyans is studied to clarify the functional mechanisms responsible for feeding ecology. Kinematics and pressure in the buccal, hyoid and pharyngeal regions were quantified in Squalus acanthias, Chiloscyllium plagiosum and Leucoraja erinacea using sonomicrometry and pressure transducers. Means and coefficients of variation were analyzed by species and by behavior to test for stereotypy and flexibility in the feeding mechanism. Several instances of mechanical stereotypy as well as flexibility were found in the feeding kinematics and pressure of the three chondrichthyan species. In general, Squalus acanthias shows more stereotyped feeding behavior than C. plagiosum and L. erinacea. Different aspects of feeding behavior stand out among the three species. Chiloscyllium plagiosum generates lowest pressures, S. acanthias achieves the greatest area changes, and L. erinacea has longer durations for manipulating prey. Capture events are functionally and behaviorally stereotyped while processing events are functionally and behaviorally flexible with the ability to use suction or compression to process the same food item. Squalus acanthias is a functional specialist and C. plagiosum is functionally a generalist, with both species exhibiting behavioral flexibility. Leucoraja erinacea is a functional and behavioral generalist. Using functional morphology to explain mechanical stereotypy and flexibility in the feeding behavior of three suction feeding chondrichthyan species has allowed a better understanding of specialist and generalist trophic behaviors.     

Dynamics and Nutritional Ecology of a Nanoflagellate Preying Upon Bacteria

Ingestion and growth rates of the nanoflagellate predator Ochromonas danica feeding on the bacterium Pseudomonas fluorescens were quantified in laboratory cultures. Bacterial prey were grown under four nutritional conditions with respect to macronutrient elements: C-limited, N-limited, P-limited, and balanced. Ingestion and growth rates were saturating functions of prey abundance when preying upon nutritionally balanced, C-limited, and P-limited bacteria but were unimodal functions of abundance when preying on N-limited bacteria. At saturating prey concentrations, the ingestion rate of C-limited prey was about twice that of prey in other nutritional states, while at subsaturating prey concentrations, the ingestion rates of both C- and N-limited prey were higher than those of prey in other nutritional states. Over all prey concentrations, growth was most rapid on balanced and C-limited prey and generally lowest for P-limited prey. Due to the unimodal response of growth rate to abundance of N-limited prey, growth rate on N-limited prey approached that obtained on balanced and C-limited prey when prey were available at intermediate abundances. The accumulation of recycled N increased with the growth rate of O. danica. Recycling of N was highest when O. danica was feeding upon P-limited prey. The accumulation of recycled P increased with growth rate for balanced and N-limited prey, but not for P-limited prey, which consistently had low accumulation of recycled P. The low growth rate and negligible recycling of P for O. danica preying on P-limited prey is consistent with the theory of ecological stoichiometry and resembles results found for crustacean zooplankton, especially in the genus Daphnia. Potentially, the major predators of bacterioplankton and a major predator of phytoplankton play analogous roles in the trophic dynamics and biogeochemistry of aquatic ecosystems.     

Functional richness, functional evenness and functional divergence: the primary components of functional diversity

Functional diversity is hypothesised as being beneficial for ecosystem functions, such as productivity and resistance to invasion. However, a precise definition of functional diversity, and hence a framework for its quantification, have proved elusive. We present a definition based on the analogy of the components of species diversity – richness, evenness and divergence. These concepts are applied to functional characters to give three components of functional diversity – functional richness, functional evenness and functional divergence. We demonstrate how each of these components may be calculated. It is hoped that our definition of functional diversity and its components will aid in elucidation of the mechanisms behind diversity/ecosystem-function relationships.     

Carbon isotopes in functional soil ecology

Soil is an integral part of terrestrial ecosystems. Many soil ecologists interested in soil ecosystem functioning rely, to some degree, on stable isotope methodologies. The study of the natural abundance of carbon isotopes, especially (13)C but also (14)C, in the environment and the use of stable carbon isotope tracers have proved very useful in investigating the soil carbon cycle and soil trophic relationships. Recent methodological and technical advances have greatly extended the possibilities for the application of stable carbon isotopes to terrestrial ecology and have vastly improved our knowledge of belowground ecosystem functioning and will continue to do so. A better understanding of soil processes is invaluable in predicting the future impacts of global environmental change on terrestrial ecosystems.     

Ecology and Biogenesis of Functional Amyloids in Pseudomonas

Functional amyloids can be found in the extracellular matrix produced by many bacteria during biofilm growth. They mediate the initial attachment of bacteria to surfaces and provide stability and functionality to mature biofilms. Efficient amyloid biogenesis requires a highly coordinated system of amyloid subunits, molecular chaperones and transport systems. The functional amyloid of Pseudomonas (Fap) represents such a system. Here, we review the phylogenetic diversification of the Fap system, its potential ecological role and the dedicated machinery required for Fap biogenesis, with a particular focus on the amyloid exporter FapF, the structure of which has been recently resolved. We also present a sequence covariance-based in silico model of the FapC fiber-forming subunit. Finally, we highlight key questions that remain unanswered and we believe deserve further attention by the scientific community.     

Diet, Nutritional Ecology, and Birth Season of Eulemur macaco in an Anthropogenic Forest in Madagascar

We investigated the feeding ecology of Eulemur macaco macaco in an old coastal secondary forest of northwestern Madagascar. We analyzed whether the local combination of introduced and native plant species could provide viable anthropic conditions for sustaining the black lemurs. Fruits (79 spp.) dominated the annual diet (>104 species from 50 families via observations ad libitum and use of a feeding frequency methods). Records from the early dry (mating) and late dry (birth) seasons show that a few major fruit species are staples in conjunction with a variety of other plant items in much lower proportions. We further estimated daily food intake and analyzed nutrient/antinutrient content in the diet during the birth season to evaluate the possibility that black lemurs undergo nutritional stress. They exhibited a high-energy input/low energy output foraging strategy then and had limited use of alternative resources such as leaves throughout the study period. We conclude that the potential for feeding flexibility is low because specialization on fruit results in protein requirements being achieved probably by a narrow margin. We hypothesize that patchy distribution of preferred cash-crop plants and indigenous species currently has a major limiting effect on population size through feeding competition.     

生态学的多样性指数:功能与系统发育

生物多样性是生态学的核心问题。传统的多样性指数仅包含物种数和相对多度的信息,这类基于分类学的多样性指数并不能很好地帮助理解群落构建和生态系统功能。不同物种对群落构建和生态系统功能所起到的作用类型和贡献也不完全相同,且物种在生态过程中的作用和贡献往往与性状密切相关,因此功能多样性已经成为反映物种群落构建、干扰以及环境因素对群落影响的重要指标。同时,由于亲缘关系相近的物种往往具有相似的性状,系统发育多样性也可以作为功能多样性的一个替代。功能多样性和系统发育多样性各自具有优缺点,但二者均比分类多样性更能揭示群落和生态系统的构建、维持与功能。     

Comparative functional plant ecology: rationale and potentials

The long tradition and early training in plant taxonomy and evolutionary theory have led to the preconceived notion among plant ecologists that plant diversity represents the sum of distinct classes, rather than a continuum of variation. Thus, broad-scale comparisons across different taxa are viewed with scepticism. Yet, the unarticulated reluctance to compare the functional properties of phototrophic organisms across broad ranges of plant types is not well-grounded. Broad comparisons are likely to capture most of the functional variance that these organisms display and lead to general conclusions, albeit sometimes imprecise for individual species. Ecological synthesis could be fostered if scientists working with the different plant types made efforts to Increase connectance between them by highlighting similarities, instead of formulating Independent theories to account for similar phenomena.     

Functional morphology, ecology, and evolution of the Scaphitaceae Gill, 1871 (cephalopoda)

Scaphitids are heteromorph ammonites exhibiting morphologicaltrends counter to of those of the other main heteromorph ammonitegroups. These trends include the shortening of the body chamber,lateral compression of the whorl, closure of the coil, and moreregular, spiral coiling. Scaphitid-like morphologies may haveappeared in other heteromorphs, but the Scaphitaceae are monophyletic.The most primitive scaphitids are known from the Albian, butan important radiation occurred in the Western Interior Seawayof North America from the Santonian to Maastrichtian, some ofwhich spread to the Old World. The scaphitid morphology is consistentwith improved swimming abilities, but scaphitids remained associatedwith the seafloor and are best considered to have been nektobenthossimilar to modern nautiluses.