Living Systems from the Biological Perspective

INTRODUCTION TO LIVING SYSTEMS

Systems

  • Systems are interconnected set of elements that are coherently organized to perform a specific function/purpose
  • Are Coherently Organized
    • Its elements are unified and working together and are able to perform their function and purpose
  • Ex: Organ systems
    • Elements → several organs that work together to perform each of their functions
    • Digestive system - organs that function for digestion of food and absorption of nutrients
    • Circulatory system - transports nutrients + exchange of gasses
    • These systems are embedded in another system and are also embedded in a larger system
    • These organ systems all comprise an organism

Categories of Systems

  • Man-made systems
    • Highly influenced, governed, and controlled by humans
    • Most of the elements of this kind of system are created by humans
    • Ex: Computer Systems
    • Different elements - keyboard, screen, mouse, etc → all work together and they ultimately perform their function
    • Other examples: Telecommunication Systems, Political Systems
    • Without humans, these systems will not be working.
  • Natural Systems
    • Naturally exist in nature
    • Ex: Solar Systems, Molecular Systems, Cellular Systems
    • Cellular System → organelles function and perform together for the survival of the cells
  • Living Systems
    • Majority of its components are living
  • Non-living
    • Majority or all of its components are non-living

LIVING SYSTEMS

  • Living systems should have elements or components
    • These elements and components should all be interacting with each other, having relationships with each other
  • Living systems should also have a function or purpose
    • Usually, the main function of living systems is to survive

Properties of Living Systems

  1. Living Systems are organized into hierarchies with specialization of functions and complexity emerging from lover level to higher levels of organization, also known as emergent properties.
  • Ecological Hierarchy: (Atoms → Molecules → Organelles →) Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Landscape → Biome → Ecosphere
  • Each level in the ecological hierarchy exists in physical space and time
  • They are also expected to have unique emergent and collective properties with increasing complexity
    • This is brought about by internal dynamic interactions and exchanges with their environments
  • There are also seven basic functions operating at all levels
    • Energetics → studies energy and matter conversion because living systems need specific types and amounts of matter-energy for stability
    • Behavior and Development
    • Evolution
    • Diversity
    • Integration and Regulation → brings separate components or subsystems together into a unified or stable unity
  1. Living Systems are Open Systems with Purposes and Goals.
  • Living Systems continue indefinitely within the natural cycles to attain sustainability
  • Photosynthesis makes Living System an Open System
    • During photosynthesis, plants convert energy from sunlight (input) to chemical energy which is used by plants to do work
    • This energy is then transferred to higher trophic levels and eventually lost from the ecosystem as heat (output).
  • However matter makes the living system relatively closed
    • Cycling of matter from plant to animals (through consumption) and the breakdown of these matter back to its elemental form (through decomposition)
    • Matter is only being cycled and recycled
  • Living Systems form a Feedback Mechanism.
    • Purpose → keeping the cycle in control
    • Negative Feedback
    • Decreasing the quality and quantity of resources, which eventually decreases population and alleviates pressure on the environment
    • Positive Feedback
    • Happens when humans depart from this natural cycle.
    • Failure of the human society to continue indefinitely within these natural cycles due to greed or self-interest will eventually lead to the collapse of the human system

Living Systems are Open Systems

  • Living systems are open systems  → Their boundaries are permeable and can be penetrated
  • Living systems are open systems with respect to energy (Photosynthesis)
    • During photosynthesis, plants convert energy from sunlight (input) to chemical energy which is used by plants to do work
    • This energy is then transferred to higher trophic levels and eventually lost from the ecosystem as heat (output).
  • However, matter is already a closed system
    • Matter present in the earth is only being cycled and recycled by different biogeochemical cycles
    • Thus, the matter present now has already been present years ago → we are simply reusing it