Organism & its Environment

• Introduction to the concept of ecosystem and the hierarchy in ecology
• Physical environment includes: physical, chemical, and biological conditions, resources, interactions, vertical and horizontal relationships, and functions
• Condition:

  • Environmental factors that organisms respond to
  • Not used up or consumed by the organism
• Resource:

  • Component of the organism's environment that the organism uses up or depletes
• • How do variations in topography and soils across the landscape influence patterns of species composition and diversity in similar communities (e.g., grasslands)?
  • What features of geology and regional climate determine the transition from one type of ecosystems to another?
• Levels of organization in ecology:

  • What characteristics allow the organism to survive, grow, and reproduce in its environment?
  • Is the population of this species increasing, decreasing, or remaining relatively constant from year to year?
  • How does this species interact with other species of plants and animals in the community?
  • How do temporal variations in a physical factor influence the productivity of plants in the ecosystem?
• Climate:

  • Long-term average pattern of weather on local, regional, or global scales
• Weather:

  • Includes temperature, humidity, precipitation, wind, and other atmospheric conditions at a specific place and time
• Disposition of solar energy
• Latitudinal variations in solar energy reaching the Earth's surface lead to a gradient in temperature
• Temporal variations in the angle of rotation lead to seasonal variations in temperature
• Air temperature decreases with increasing altitude due to adiabatic cooling
• Air circulation in non-rotating earth
• Effect of Coriolis force on wind direction
• Air circulation in a rotating earth
• Ocean Currents
• Gyres
• Patterns in precipitation:

  • Where trade winds converge
  • Shifts of ITCZ lead to dry and rainy seasons
  • Effects of topography on precipitation lead to rain shadow, with windward and leeward effects
  • Effects of topography on precipitation lead to desert formation
• How do organisms respond to changing environment?
• The environment is the sum total of all external conditions affecting an organism.
• Organisms are classified into three categories based on their ability to obtain energy from organic compounds: autotrophs, heterotrophs, and saprotrophs.
• Autotrophs can synthesize food using carbon dioxide as a source of carbon and water as a source of hydrogen.
• Environmental factors include physical (abiotic) and biological (biotic).
• Autotrophs can synthesize complex organic molecules using simple inorganic substances as raw materials.
• Physical environmental factors are non-living components that affect living things.
• Heterotrophs cannot make their own food and must consume other living things or dead plant material (saprotrophs) to get nutrients.
• Heterotrophs cannot produce their own food and must consume other living things or dead plant material.
• Biological environmental factors are living components that interact with other living things.
• Physical environmental factors include light intensity, temperature, humidity, atmospheric pressure, air movement, soil moisture, nutrient availability, pH level, oxygen concentration, and gravity.
• Producers use solar energy to convert simple chemicals like CO2 and H2O into complex molecules such as glucose.
• Energy flow through ecosystems involves producers, consumers, and decomposers.
• Saprotrophs break down dead organic matter through decomposition.
• Biological environmental factors are the interactions between organisms and their environment.
• Biological factors refer to living things that interact with other living things or non-living components of the environment.