Ecological relationship

Abstract: By controlling nutrient cycling and biomass production at the base of the food web, interactions between phytoplankton and bacteria represent a fundamental ecological relationship in aquatic environments Although typically studied over large spatiotemporal scales, emerging evidence indicates that this relationship is often governed by microscale interactions played out within the region immediately surrounding individual phytoplankton cells This microenvironment, known as the phycosphere, is the planktonic analogue of the rhizosphere in plants The exchange of metabolites and infochemicals at this interface governs phytoplankton-bacteria relationships, which span mutualism, commensalism, antagonism, parasitism and competition The importance of the phycosphere has been postulated for four decades, yet only recently have new technological and conceptual frameworks made it possible to start teasing apart the complex nature of this unique microbial habitat It has subsequently become apparent that the chemical exchanges and ecological interactions between phytoplankton and bacteria are far more sophisticated than previously thought and often require close proximity of the two partners, which is facilitated by bacterial colonization of the phycosphere It is also becoming increasingly clear that while interactions taking place within the phycosphere occur at the scale of individual microorganisms, they exert an ecosystem-scale influence on fundamental processes including nutrient provision and regeneration, primary production, toxin biosynthesis and biogeochemical cycling Here we review the fundamental physical, chemical and ecological features of the phycosphere, with the goal of delivering a fresh perspective on the nature and importance of phytoplankton-bacteria interactions in aquatic ecosystems

Abstract: Species distribution modeling (SDM) links ecological theory of species–environment relationships with statistical learning methods and geospatial data to understand and predict the distributions of species and their habitats. Also called ecological niche modeling , SDM is widely used for biodiversity assessment and to predict the impacts of environmental change on biodiversity in terrestrial and aquatic habitats. It can also provide insight and understanding about ecological relationships.

Abstract: Fungi are a highly diverse group of heterotrophic eukaryotes characterized by the absence of phagotrophy and the presence of a chitinous cell wall. While unicellular fungi are far from rare, part of the evolutionary success of the group resides in their ability to grow indefinitely as a cylindrical multinucleated cell (hypha). Armed with these morphological traits and with an extremely high metabolical diversity, fungi have conquered numerous ecological niches and have shaped a whole world of interactions with other living organisms. Herein we survey the main evolutionary and ecological processes that have guided fungal diversity. We will first review the ecology and evolution of the zoosporic lineages and the process of terrestrialization, as one of the major evolutionary transitions in this kingdom. Several plausible scenarios have been proposed for fungal terrestralization and we here propose a new scenario, which considers icy environments as a transitory niche between water and emerged land. We then focus on exploring the main ecological relationships of Fungi with other organisms (other fungi, protozoans, animals and plants), as well as the origin of adaptations to certain specialized ecological niches within the group (lichens, black fungi and yeasts). Throughout this review we use an evolutionary and comparative-genomics perspective to understand fungal ecological diversity. Finally, we highlight the importance of genome-enabled inferences to envision plausible narratives and scenarios for important transitions.

Abstract: My aim is to show, by one example, why systematics must provide a foundation equal to that of ecology if the structure of tropical forests, and particularly their floristic structure and often extraordinary species richness, is to be understood. Species composition accounts for much of the geographical variation in structure that occurs among forests in different regions sharing the same habitat. Our knowledge of rain forest structure has advanced from the description of whole plant communities, or often their tree component alone, to a contemporary interest in the demography and genetics of species populations, and to the physiological ecology of individuals. Always, though, systematic as well as ecological relationships must be understood if this knowledge is to contribute to understanding of the structure of the whole forest. The biological attributes shared among the individuals of species, and which decide their success in interspecific competition, determine both the ecological guild to which they belong and, in part, their systematic relationships. Systematics aims to classify species into a hierarchy of categories of increasing rank. The hierarchy is aimed to reflect evolutionary relationships, and it thereby provides inferential evidence for the origin of the major species groups constituting tropical rain forest communities. I argue that an understanding of the floristic structure of tropical forests, and more