Module 2

• System


  Consisting of three kinds of things: elements or structures, interconnections or interactions that hold the elements together, and a function or purpose that produce their pattern of behavior over time
• Biological principles play an important role in understanding the living systems that encompass all the microorganisms, plants, and animals including our human race
• Law of specialization


  The more highly adapted an organism is to a specific environment, the more difficult it is for the organism to adapt to a different environment
• Atoms


  Fundamental units of all substances, living or not
• Molecules are formed when atoms join other atoms. Molecules of life include lipids, proteins, nucleic acids, and complex carbohydrates
• Organelles


  Membrane-enclosed structures that perform specific functions to form the cells
• Cell


  Basic unit of life
• Tissue


  Organized array of cells
• Organ


  Organized array of tissues carrying out specific tasks
• Organism


  Individual that consists of one (unicellular) or more cells (multicellular)
• Population


  Groups of interbreeding individuals of the same type or species living in a given area
• Community


  All populations occupying a given area
• Ecosystem


  Community and the non-living environment functioning together and is the first unit that is complete because it has all the components necessary for survival
• Biosphere/Ecosphere


  Most inclusive level encompassing all regions of Earth's crust, waters, and atmosphere in which organisms live
• The eleven ecological levels of organization of living systems (also called biosystems) from cell to ecosphere are shown in Figure 2

  
• Levels of living systems

  • Unique emergent and collective properties with increasing complexity
  • Seven basic functions: energetics, behavior, development, evolution, diversity, integration, and regulation
• Living System Theory


  Five major elements: structure, process, subsystem, structural and process relationships, and systems process
• Photosynthesis


  Sun-driven process that generates the net increases in material quality on Earth almost entirely
• Living system


  An "open" system that converts energy from sunlight (input) to chemical energy (stored in food molecules such as sugars), which is used by plants to do work, and is then transferred to the higher trophic levels (consumers) and is eventually lost from the ecosystem as heat (output)
• Biogeochemical cycle


  Natural cycle of the cycling of matter from plant to animals through consumption and the breakdown of this matter back to its elemental form through decomposition mostly driven by microorganisms to become utilized again by the plants
• When a living creature dies, it loses its "system-ness" and the multiple interrelations that held it together no longer function, and it dissipates, although its material remains part of a larger food-web system
• Properties of living systems

  • Organization
  • Energy processing
  • Response to stimuli
  • Regulation and homeostasis
  • Growth and development
  • Reproduction (heredity and variation)
  • Adaptation
• Organization


  • Highly organized and coordinated set of structures or units in harmony to produce a specific function
  • Order from single-celled to multicellular organisms

  
• Energy processing


  • Organisms use a source of energy for their metabolic activities
  • Some capture energy from the sun and convert it into chemical energy in food
  • Others obtain energy from prey/food as a source of chemical energy
• Response to stimuli

  • Plants can bend toward light, climb, or respond to touch
  • Bacteria can move toward or away from chemicals or light
  • Movement toward a stimulus is a positive response, while movement away from a stimulus is a negative response.
• Regulation/Homeostasis


  • Organisms require multiple regulatory mechanisms to coordinate internal functions, respond to stimuli, and cope with environmental stresses
  • Maintain internal conditions at a steady state (homeostasis)
  • Examples: polar bears generating heat and reducing heat loss, bees fanning the hive to maintain cool temperature
• Growth and development

  • Increase in size and mass
  • Transition from immature to adult life stage
• Reproduction


  • Ensures continuity of the species
  • Duplication of DNA and cell division
  • Production of specialized reproductive cells
  • Passing of DNA containing genes from parents to offspring
• Adaptation


  • Allows organisms to become fitted to the present environment
  • Adaptations are consequences of past environments, not pre-designed for present or future environments
  • Can take many forms because they allow the population to survive and reproduce
  • Examples: cryptic form larvae, pupa taking on form of excreta
• Adaptations and abaption are different but related terms
• Living systems are organized into hierarchies with progressive specialization of functions and complexity emerging from lower level to higher levels of the organization also known as emergent properties.
• Organ system is the set of interacting organs
• Unutilized decomposed materials become slowly deposited through sedimentation and mineralization and become available again through slow geological cycles such as volcanic eruptions and weathering.
• Abapted means that the organisms only appear to be fitted to their present environment because present environments have not changed that much.