The need for exchange surfaces

• What is the primary function of the human respiratory system?

  It is adapted for efficient gas exchange.
• What are the levels of organization in multicellular organisms?

  • Cells
  • Tissues
  • Organs
  • Systems
• What do organisms need to take in from the environment?

  Food, oxygen, water, and other essential substances.
• What is the role of carbon dioxide in plants?

  It is needed for photosynthesis.
• What is photosynthesis?

  A chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy.
• What do small organisms use to exchange essential and waste substances?

  They exchange these substances over their body surface.
• How do simple chemical substances move in small organisms?

  They diffuse in and out of their bodies.
• What defines how quickly small organisms can absorb substances?

  The size of their surface area defines the absorption rate.
• What happens to the surface area and volume of a cube as it increases in size?

  As the volume increases, surface area does not increase at the same rate.
• What problems do multicellular organisms face as they increase in size?

  1. Surface area does not increase as fast as volume.
  2. Diffusion is not quick enough to move substances where needed.
• What solutions do multicellular organisms have for their size-related problems?

  • Body systems that add additional absorbing area to exchange surfaces.
  • A transport system to move substances efficiently.
• What is the gaseous element needed by living organisms for respiration?

  Oxygen
• What is the by-product of respiration that plants need for photosynthesis?

  Carbon dioxide
• What is the significance of diffusion in small organisms?

  It allows for the movement of substances in and out of their bodies.
• How does the size of an organism affect its gas exchange needs?

  Larger organisms require more efficient systems for gas exchange due to increased volume.