adaptations for gas exchange

• Why must gas movement in organisms occur rapidly and efficiently?

  To meet the organism's metabolic needs
• What is a respiratory surface?

  A surface for gas exchange
• Name one type of respiratory surface in fish.

  Gills
• What respiratory surface is found in mammals?

  Alveoli
• What respiratory surface do insects have?

  Tracheoles
• What respiratory surface is found in plant leaves?

  Spongy mesophyll cells
• What are the essential features of exchange surfaces for gas diffusion?

  • Large surface area relative to volume
  • Thin structure for short diffusion pathways
  • Permeable to respiratory gases
  • Mechanism for steep diffusion gradient
• Why must a respiratory surface have a large surface area?

  To satisfy the organism's gas exchange needs
• Why should a respiratory surface be thin?

  To shorten diffusion pathways
• What is the importance of permeability in respiratory surfaces?

  It allows easy diffusion of gases
• How is a steep diffusion gradient maintained?

  By rapidly bringing in oxygen or removing carbon dioxide
• What type of organisms are unicellular organisms?

  Single-celled organisms
• Why do single-celled organisms like Amoeba have a large surface area to volume ratio?

  To facilitate efficient gas exchange
• How does the thin cell membrane benefit unicellular organisms?

  It allows rapid diffusion into the cell
• Why can unicellular organisms absorb enough oxygen?

  Due to their large surface area to volume ratio
• What happens if carbon dioxide builds up in unicellular organisms?

  It makes the cytoplasm too acidic
• How do larger multicellular animals differ in gas exchange efficiency?

  They have a lower surface area to volume ratio
• What is the key term for the surface involved in gas exchange?

  Respiratory surface
• What is the process of exchanging gases called?

  Gas exchange
• What challenges do larger multicellular organisms face regarding gas exchange?

  • Lower surface area to volume ratio
  • Inefficient diffusion across surfaces
  • Need for specialized respiratory systems
• What type of organisms are flatworms?

  Aquatic organisms
• Why do flatworms have a larger surface area to volume ratio?

  Being flat increases their surface area
• How does a larger surface area help flatworms?

  It shortens diffusion paths for substances
• What is the relationship between surface area to volume ratio and diffusion rate?

  Greater ratio increases the rate of diffusion
• What type of organism is an earthworm?

  Terrestrial organism
• How does the shape of an earthworm affect its surface area to volume ratio?

  Cylindrical shape reduces the ratio
• Why does the earthworm secrete mucus?

  To keep its respiratory surface moist
• What is the consequence of the earthworm's skin being its respiratory surface?

  It restricts the earthworm to damp environments
• Why does the earthworm have a low oxygen requirement?

  It is slow moving with a low metabolic rate
• How does haemoglobin function in the earthworm?

  It carries oxygen around the body
• What role does haemoglobin play in maintaining a diffusion gradient?

  It carries oxygen away from the surface
• How is carbon dioxide transported in the earthworm?

  It diffuses out across the skin
• Where does oxygen diffuse in the earthworm?

  At the surface of the worm's cuticle
• What are the three main types of respiratory structures in animals?

  • Gills
  • Lungs
  • Tracheal systems
• What is the function of gills in aquatic animals?

  They facilitate gas exchange in water
• What is the role of lungs in terrestrial animals?

  They facilitate gas exchange in air
• What do tracheal systems do in terrestrial insects?

  They facilitate gas exchange
• What is a ventilation mechanism?

  Movement of air or water to respiratory surface
• How do animals with lungs manage gas exchange?

  They have internal tubes for air transport
• How do fish absorb oxygen from water?

  Through gills that extract dissolved oxygen