浮游生物对浮游生活的适应.pptVIP

浮游生物对浮游生活的适应 本章重点： 浮游生物适应浮游生活的方式 Adaptation of pelagic life Significance of staying afloat Keep buoyancy(浮力) mechanism Movement Significance of staying afloat Phytoplankton: to get enough light for photosynthesis. Once sinking or being carried out of the photic zone by water movement, in generally, they will stop metabolism and die, unless they can somehow get back into the sunlit layer. zooplankton: they need sunlight for their bio rhythm and their food is in the shallow water. Staying afloat To live in the water layers, organisms must stay in the epipelagic（上层）. All epipelagic organisms face a fundamental problem—— cells and tissue are denser than water. Keep buoyancy mechanism Organisms must avoid sinking to stay in the epipelagic. This is achieved by Increased resistance Increased buoyancy Reduced body density 1、Increased resistance Surface-to-Volume Ratio Organism’s shape Long projections or spines 2 Increased buoyancy The second way that epipelagic organisms can stay near the surface is to have special adaptations that make them more buoyant. Unlike adaptations that help the organism resist sinking, buoyancy reduces the tendency to sink. Store lipids, such as oils or fats Pockets of gas Gas sac of Velella like a sail 外壳或骨骼退化或消失硅藻的细胞壁、浮游甲壳动物的背甲厚度。 3、Reduced body density 4、Movement cilia and flagella 思考题 浮游生物适应浮游生活的方式有哪些？ 太阳辐射能到达水面的强度随太阳高度角、地理纬度、海拔高度、季节和大气状况而变化。一般地理纬度越高，年平均辐射量越小，季节变化在高纬度大于低纬度。 (2)光直接影响植物的光合作用和色素的形成。没有光，绿色植物难以生存。水环境的光照条件远远不及陆地，即使在水的上层，光照强度也较空气中小得多，在水体的深处则是永远黑暗的。因此光在水生植物的生活中具有特别重要的生态意义。 (3)动植物对光的刺激都会产生一定的反应，如视觉、繁殖、发育、行为、分布等。 (4)光对于动物的重要意义，一方面是通过植物和影响其他环境因素的动态而产生的间接关系，另一方面主要起着信号作用，对于动物的行为和生理上有很大影响。在有些情况下光是动物生活中所需要的环境因子之一。然而，光对动物的深刻影响在许多方面还没有充分的了解，因为光对有机体的作用可能是直接的，也可能是间接的，还有可能是通过对其他环境因子的影响而起作用。 * * Alexamdrium tarmarensis Ceratium spp. Peridium spp. Dinophysis spp. 结成群体以扩大表面积 Calanus with oil sac Porpita porpita Porpita mediterranea 分泌胶质物 藻类的群体、原生动物的群体等。 Appendix 纤毛或鞭毛的摆动来运动： 原生动物、轮虫、浮游幼虫等。 肌肉收缩 箭虫、水母等。