Adaptations And Other Organisms

Question 1

Features of respiratory surfaces

Answer 1

• Large SA:V
• Thin membrane- reduces diffusion distance/ pathway
• Permeable so gases can diffuse easily
• Mechanism to produce and maintain steep gradient

Question 2

Unicellular organisms

Answer 2

• Small and large SA:V
• Single cell = short diff distance across membrane
• Enough O2 by simple diffusion
• CO2 removed fast enough for no acidity in cell
• No gas exchange system

Question 3

Amoeba (Protocstista Kingdom)

Answer 3

• Simple diffusion provides enough O2 and nutrients for demands
• Large SA:V and thin membrane

Question 4

Flatworm (Animalia Kingdom)

Answer 4

• Thin and flat = large SA:V (smaller than amoeba)
• Cells close to surface so diffusion pathways short and simple diffusion
  -Moist = gases dissolves

Question 5

Earthworm (Animalia Kingdom, terrestrial)

Answer 5

• Low metabolic rate = low O2 required: diffusion across skin into capillaries enough
• Gas exchange surface not in contact with all cells so Hb with high affinity used in circulatory system
• Moist skin from mucus = O2 dissolves

Question 6

Large multicellular organisms

Answer 6

• Larger metabolic rate = more O2
• Smaller SA:V
• Diffusion distances too large as not enough O2 can diffuse fast enough to cells further for surface
• External surface insufficient so exchange system needed

Question 7

Amphibians

Answer 7

• Active use lungs as respiratory surface
• Inactive adults can use moist and permeable skin as larger SA:V and short diffusion pathway
• Lower metabolic rate = less O2 so diffusion from skin enough