26 research outputs found
A New Biology: A Modern Perspective on the Challenge of Closing the Gap between the Islands of Knowledge
This paper discusses the rebirth of the old quest for the principles of biology along the discourse line of machine-organism disanalogy and within the context of biocomputation from a modern perspective. It reviews some new attempts to revise the existing body of research and enhance it with new developments in some promising fields of mathematics and computation. The major challenge is that the latter are expected to also answer the need for a new framework, a new language and a new methodology capable of closing the existing gap between the different levels of complex system organization
Basis of selective predation by the aquatic larvae of the salamander, Ambystoma tigrinum
The effect of several factors on feeding selectivity by three size classes of larvae of Ambystoma tigrinum (Green) was examined. Five types of invertebrate prey were used: Chaoborus, Daphnia, damselflies, Hyalella and water boatmen. Five variables were examined in relation to the electivity indices associated with each prey type: ease of prey consumption, ease of prey capture, relative prey size, prey activity, and microhabitat overlap. No single variable explained the observed electivity. For small larvae (snout-vent length, SVL,6.5cm), ease of prey consumption, prey activity, and relative prey size predicted electivity values. However, none of the measured variables was related to electivity values found for medium sized larvae (SVL \u3e3.5 and \u3c5.5cm)
Dorsal body pigmentation and sexual dimorphism in the marbled salamander ( Ambystoma opacum
Efeito da temperatura e do fotoperÃodo sobre o desenvolvimento do aparelho reprodutor de rã-touro (Rana catesbeiana Shaw, 1802) Effect of the temperature and the photoperiod on the development of bullfrog (Rana catesbeiana Shaw, 1802) reproduction apparel
Foram avaliados os efeitos da temperatura e do fotoperÃodo sobre a maturação sexual de rãs-touro pesando 94,22 g ± 12,03, mantidas durante trinta dias em temperaturas de 20, 23, 26, 29, 32 e 35°C, com fotoperÃodo de 12/12 horas de luz/horas de escuridão (h L/E). A temperatura afetou os pesos do corpo gorduroso e do fÃgado, os quais variaram de acordo com modelos quadráticos, estimando-se maiores pesos de corpo gorduroso a 27,27°C e de fÃgado a 26,81°C. Estimaram-se ovários mais pesados a 28,36°C e ovidutos mais pesados a 28,77°C. Temperatura afetou a maturação sexual das rãs, avaliada por Ãndices numéricos. Num experimento mais longo, rãs com peso médio inicial de 95,31 ± 8,46 g foram submetidas à combinação das temperaturas de 26 e 29°C com os fotoperÃodos de 8/16, 12/12 e 16/8 h L/E, até atingirem a maturidade gonadal. Temperatura interagiu com fotoperÃodo em seus efeitos sobre o desenvolvimento dos órgãos reprodutivos de rã-touro. Temperatura afetou a relação diâmetro do abdômen/distância entre os olhos, com maiores valores calculados para 26°C. Verificou-se que os maiores diâmetros dos ovócitos são obtidos a uma temperatura de 26°C, com fotoperÃodo de 12,6/11,4 h L/E.<br>The effects of the temperature and of the photoperiod on the bull frog sexual maturation of frogs weighing 94.22 g ± 12.03, maintained for thirty days under temperatures of 20, 23, 26, 29, 32 and 35°C, with photoperiod of 12/12 hours of light/hours of darkness (h L/D), were evaluated. Temperature affected the weights of the fat body and liver, that varied according to quadratic models, and higher weights of fat body at 27.27°C and of liver at 26.81°C were considered. The ovaries heavier than 28.36°C and oviducts heavier than 28.77°C were estimated. Temperature affected the sexual maturation of the frogs, evaluated by numeric indexes. In a longer experiment, frogs with initial weight of 95.31 g ± 8.46, were submitted to the combination of the temperatures of 26.0 and 29.0°C with photoperiods of 8/16, 12/12 and 16/8 h L/D, until they reach the gonadal maturity. Temperature interacted with photoperiod in its effects on the development of the reproductive organs of bullfrog. Temperature affected the diameter of the abdomen/distance relation between the eyes, with higher values calculated for 26°C. It was considered that the highest ovocites diameters are obtained under a temperature of 26.0°C, with photoperiod of 12.6/11.4 h L/D