Interactions between organisms and their surrounding fluid environments (water currents, air eddies, rainfall,etc.), inevitably involve immediate contacts on complex biological substrates (e.g., bird feathers, insect wings, plant leaves, etc.). In this dissertation work, two fluid phenomenon, streaming (flow generations from oscillations) and fragmentations (subdivisions of fluid filaments) are inspected for three distinct biological impact systems: (1) streaming flow near leaves generated by raindrop impacts, (2) fragmentation of raindrops upon impingement on architectured superhydrophobic (SH) surfaces, (3) fragmentation of droplets during onion cutting. The three systems are rationalized via experiments and theories to establish how substrate surface and body properties, such as elasticity and surface topography, mediate the flow characteristics at varying regimes of inertial and capillary forces during collisions. With respect to applications, the work presented here unravels hidden pathways of spore dispersion, showcases self-protection schemes of various organisms against high-inertia raindrops, and elucidates the correlations between cutting parameters and lachrymatory onion droplet release, with implications in biological and culinary flow.