Cell Theory: Levels of Organization

• Levels of Organization


  • Atoms
  • Molecules
  • Organelles
  • Cells
  • Tissues
  • Organs
  • Organ System
  • Organism
  • Species
  • Population
  • Community
  • Ecosystem
  • Biome
  • Biosphere
• Atoms


  The smallest unit of matter that can be broken down into anything simpler by chemical means
• Molecules


  The smallest units of most compounds formed by the chemical bonding of atoms
• Organelles


  Specialized structures that perform important cellular functions within cells
• Cells


  The smallest unit of life-collections of living matter enclosed by a barrier that separates them from their surroundings
• Tissues


  Groups of similar cells that perform a particular function
• Organs


  Groups of tissues that work together to perform closely related functions
• Organ System


  Group of organ that work together to perform closely related functions
• Organism


  Living things composed of composed cells (Multicellular Organism)
• Species


  A group of organisms so similar to one another that they breed and produce fertile offspring
• Population


  Group of individuals of the same species that live in the same area
• Community


  Group of different populations that live together in a defined place
• Ecosystem


  Groups of all the organisms that live in a particular place, together with their non-living environment
• Biome


  Groups of ecosystems that have the same climate and similar dominant communities
• Biosphere


  Part of the Earth in which life exists including land, water, air and atmosphere