Organisation

• Biological organization


  The hierarchy of complex biological structures and systems that define life, organized from the simplest to the most complex levels
• Levels of biological organization

  • Cells
  • Tissues
  • Organs
  • Organ Systems
  • Organisms
• Cells


  The basic unit of life, the smallest unit that can carry out all the functions necessary for life
• Prokaryotic Cells


  • Simple cells without a nucleus (e.g., bacteria)
• Eukaryotic Cells


  • More complex cells with a nucleus (e.g., plant and animal cells)
• Tissues


  Groups of similar cells that work together to perform a specific function
• Types of tissues


  • Epithelial Tissue
  • Connective Tissue
  • Muscle Tissue
  • Nervous Tissue
• Organs


  Structures made up of two or more types of tissues that work together to perform a specific function
• Organ Systems


  Groups of organs that work together to perform complex functions
• Organisms


  Individual living entities that can carry out all basic life processes. Organisms can be unicellular (one cell) or multicellular (many cells)
• Unicellular Organisms


  • Bacteria, amoeba
• Multicellular Organisms


  • Humans, plants, animals
• Cell Specialization


  In multicellular organisms, cells become specialized to perform specific functions. This is known as cell differentiation
• Homeostasis


  The ability of an organism or environment to maintain stability despite changes. Organ systems work together to keep the internal environment stable
• Levels of Organization


  Understanding that each level builds upon the previous one, increasing in complexity and specialization
• Diagrams and models are used to illustrate biological organization, including cell diagrams, tissue samples, and organ system charts
• Activities and experiments related to biological organization include microscope work, model building, and dissections (if appropriate)