نتایج جستجو برای: biological competition
تعداد نتایج: 545385 فیلتر نتایج به سال:
Invasive plants may compete with native plants by increasing the pressure of native consumers, a mechanism known as "apparent competition." Apparent competition can be as strong as or stronger than direct competition, but the role of apparent competition has rarely been examined in biological invasions. We used four years of demographic data and seed-removal experiments to determine if introduc...
How plant competition varies across environmental gradients has been a long debate among ecologists. We conducted a growth chamber experiment to determine the intensity and importance of competition for plants grown in changed environmental conditions. Festuca rubra and Trifolium pratense were grown in monoculture and in two- and/or three-species mixtures under three environmental treatments. T...
This chapter deals with the modeling and simulation of large systems of interacting entities whose microscopic state includes not only geometrical and mechanical variables (typically position and velocity), but also biological functions or specific activities. The main issue looks at the development of a biological mathematical theory for multicellular systems. The first part is devoted to the ...
Sperm competition theory predicts that males should use cues indicating the risk and intensity of sperm competition to tailor their sperm investment accordingly. Rival males are an important source of social information regarding sperm competition risk. However, revealing such information may not be in the rival males' interest. Here, we use a theoretical approach based on informed and uninform...
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Evolution of sperm quality but not quantity in the internally fertilized fish Xiphophorus nigrensis.
Species with alternative reproductive strategies are characterized by discrete differences among males in suites of traits related to competition for fertilizations. Models predict sneaker males should allocate more resources to their ejaculates because they experience sperm competition more frequently and often occupy a disfavoured 'role' owing to subordinance in intramale competition and fema...
Sperm competition may select for male reproductive traits that influence female mating or oviposition rate. These traits may induce fitness costs to the female; however, they may be costly for the males as well as any decrease in female fitness also affects male fitness. Male adaptations to sperm competition manipulate females by altering not only female behaviour or physiology, but also female...
Seminal fluid proteins show striking effects on reproduction, involving manipulation of female behavior and physiology, mechanisms of sperm competition, and pathogen defense. Strong adaptive pressures are expected for such manifestations of sexual selection and host defense, but the extent of positive selection in seminal fluid proteins from divergent taxa is unknown. We identified adaptive evo...
Higher rates of coding sequence evolution have been observed on the Z chromosome relative to the autosomes across a wide range of species. However, despite a considerable body of theory, we lack empirical evidence explaining variation in the strength of the Faster-Z Effect. To assess the magnitude and drivers of Faster-Z Evolution, we assembled six de novo transcriptomes, spanning 90 million ye...
Sperm morphology evolves rapidly, resulting in an exceptional diversity of sperm size and shape across animal phyla. This swift evolution has been thought to prevent fertilizations between closely related species. Alternatively, recent correlative analyses suggest that competition among sperm from more than one male may cause sperm diversity, but these hypotheses have not been tested. Here, we ...
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