Notes on Levels of Organisation

Organisms

  • Human: Homo sapiens

  • Western Gorilla: Gorilla gorilla

  • Mimosa pudica: Known for its protective reflex which recoils when touched

  • Blue-footed Booby: Sula nebouxii

  • Amoeba: Amoeba proteus, moves by extending and contracting pseudopods

  • Temminck’s Pangolin: Smutsia temminckii

Levels of Organisation in Biology

Organelles

  • Definition: Minute structures within a eukaryotic cell with specific functions (Oxford Dictionary of Biology).

  • Key Organelles:

    • Nucleus: Central role in cell function and genetics.

    • Other organelles include mitochondria, endoplasmic reticulum, etc.

Cells

  • The basic unit of life, composed of organelles.

Tissues

  • Definition: A collection of cells of similar structure organized to perform one or more functions (Oxford Dictionary of Biology).

  • Examples of Tissues:

    • Loose connective tissue: Supports and connects other tissues.

    • Smooth muscle tissue: Involuntary muscle found in walls of hollow organs.

    • Cardiac muscle tissue: Specialized muscle tissue forming the heart.

    • Epithelial tissue: Covers body surfaces and lines cavities.

    • Xylem and Phloem: Transport tissues in plants.

Organs

  • Definition: Structures composed of collections of tissues performing specific functions.

  • Examples of Organs:

    • Heart: Pumps blood across the body.

    • Lungs: Facilitate gas exchange.

    • Liver: Processes nutrients and detoxifies substances.

Organ Systems

  • Definition: Collections of organs that work together to perform complex functions.

  • Examples of Organ Systems:

    • Nervous System: Coordinates and controls body activities.

    • Circulatory System: Transports blood and nutrients.

    • Digestive System: Breaks down food and absorbs nutrients.

Structure vs Function

Structure

  • Definition: The arrangement and organization of an entity's parts.

  • Example: The structure of a warehouse involves its layout and the components it contains.

Function

  • Definition: How the parts of a structure interact and the role they play.

  • Example: The function of a warehouse includes storage, shipping, and receiving.

Visual Elements of Organs and Systems

  • Esophagus: Muscularis layers including longitudinal, circular, and oblique.

  • Trachea: Connects to bronchi and facilitates airflow to the lungs.

  • Heart Anatomy: Includes structures such as atria, ventricles, valves, and major arteries/veins.