advanced multicultural animals

• finish the sentence: as size increases SA:V ratio


  decreases
• what is meant by a animal being more metabolically active


  they have a higher oxygen demand
• list reasons why multi cellular organisms need specialised gas exchange surfaces


  they need more oxygen, the diffusion pathway is too long to efficiently diffuse, they need a method of circulation
• what is meant by circulation


  the movement of gasses around the body via blood
• give examples of specialised gas exchange surfaces


  gill lamellae , alveoli and the ends of tracheoles
• what is needed in order to achieve the maximum rate of diffusion in organisms


  a large surface area:volume ratio , a thin membrane , partially permeable and moist
• why does a exchange surface need to be moist


  to allow gases to dissolve for diffusion
• why does a exchange surface need to be partially permeable


  so gasses can diffuse easily
• why does a exchange surface need to be thin


  so the diffusion pathway is short
• why does a exchange surface need to have a large SA:V ratio


  to have a greater space over which to diffuse
• what is the importance of blood circulation in respiration


  to maintain a concentration gradient and to transport the oxygen around the body