Science Common Sense


1234 - What are the levels of organization of a multicellular organism?

In a multicellular organism, there are six main levels of organization from smallest to largest.

  1. Cells: These are the tiny building blocks of life.
  2. Tissues: A group of similar cells working together.
  3. Organs: A group of different tissues working together, like the heart or lungs.
  4. Organ systems: A group of organs working together to do a specific job, like the circulatory system (heart and blood vessels).
  5. Organism: The whole living thing, like you or a plant.
  6. Population (optional): This is not part of an individual organism but multiple organisms of the same species living in one area. But the first 5 are what make up an individual multicellular organism.