Tracheal Systems and Environmental Factors Influencing Dissolved O2 in Aquatic Organisms -, Study notes of Entomology

Download Tracheal Systems and Environmental Factors Influencing Dissolved O2 in Aquatic Organisms - and more Study notes Entomology in PDF only on Docsity! Tracheal Systems Environmental Conditions Result in Increases in: Dissolved O2 Temperature - Salinity - Altitude - Depth + Turbulence + Typical Scenario • Dissolved O2 is higher in lotic (flowing) water. • Dissolved O2 on warm algae rich pond may be higher than levels on a cold, turbulent stream….Why? • P/R Ground Water • O2 nearly absent due to bacterial respiration occurring during movement through soil. • At surface O2 dissolves in, but is controlled by: – sediment type – gradient – current – turbulence Diffusion • Rate of diffusion depends on: – molecular weight of gas – permeability of the medium through which it passes – concentration of gradient over distance to be moved – distance moved • O2 diffuses 324,000 times slower in water than air! • Actually 850,000 slower because of cuticle. Respiratory Surfaces • Gas distribution takes place through a network of internal air-filled tubules, tracheal system. • Blood (hemolymph) plays little or no role. • Exchange with atmospheric gases occurs at spiracles (primitively 8-10 pair). • Terrestrial blueprint is polypneustic system. • Oligopneustic system has 1-2 pair of functional spiracles, generally located posteriorly. Tracheal Systems Closed Systems Open Systems Tracheal Systems • Open Systems - with functional spiracles – Polypneustic – 8-10 pair of spiracles – Oligopneustic – 1-2 pair of spiracles • Metapneustic – only single terminal spiracle • Closed System - lacking functional spiracles – Apneustic – rely on gasses diffusing through cuticle