Biology

• The biology course is divided into three segments: living organisms in the environment, life processes and diseases, and continuity and variation
• Graph


  Shows the relationship between variables
• Independent variable


  Variable that can be manipulated, stands on its own and can affect other variables
• Dependent variable


  Variable that changes based on changes in the independent variable
• Examples of independent variables

  • Time
  • Temperature
• Examples of dependent variables

  • Rate of photosynthesis
  • Growth or growth rate
  • Water loss in transpiration
• As carbon dioxide increases, the mass of glucose produced also increases, but at a certain point the glucose production remains the same</b>
• Characteristics of a good graph

  • Includes a title
  • Labels the x and y axes
  • Uses a suitable scale to fill at least half the page
• Classification is the way of organizing or grouping organisms based on specific features
• Levels of classification from largest to smallest

  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
• Vertebrates have backbones, invertebrates do not
• Birds and mammals are the only warm-blooded organisms, the rest are cold-blooded
• Insects have 3 body segments, arachnids have 2
• Niche


  The specific role of an organism in an ecosystem or environment
• Habitat


  Where an organism lives
• Population


  The total number of a specific species
• Community

  The interlinked populations or groups of populations interacting
• Ecosystem


  The grouping of all the living and non-living aspects of the environment that interact
• Organisms adapt to their ecosystems through features like camouflage, leaf shape, and protective structures
• Abiotic factors


  The non-living, physical and chemical aspects of the environment
• Biotic factors


  The living aspects of the environment
• Food chain


  One path for energy flow between organisms
• Food web


  Multiple paths for energy flow between organisms, including omnivores
• Removing an organism from a food chain/web

  Causes changes in the populations of other organisms
• Energy decreases along a food chain because organisms use some energy for their own functions and energy is lost as heat
• The number of organisms tends to decrease along a food chain because larger organisms require more energy
• Energy decreases along a food chain
• Reason for energy decrease along food chain

  • Each organism uses some of the energy for their own biological functions
  • Energy is also lost due to heat
• Number of organisms tend to be less as you go up the food chain
• Reason for fewer organisms at higher levels of food chain

  • Greater demand for energy
  • Organisms are larger and require more energy
• Bioaccumulation


  Persistent chemicals remain in a food chain or food web and increase in concentration as you go along the food chain
• Reason for bioaccumulation


  Organisms eat more to sustain themselves and maintain their energy requirement
• Predator-prey relationship


  Predator hunts and preys on other organisms
• Feeding relationships


  • Parasitism
  • Commensalism
  • Mutualism
• Parasitism


  One organism benefits, the other is harmed
• Commensalism


  One organism benefits, the other is not harmed
• Mutualism


  Both organisms benefit
• Examples of feeding relationships

  • Lice and mammals
  • Epiphytes on trees
  • Nitrogen-fixing bacteria in legume roots
• Importance of decomposers


  • Recycle nutrients
  • Decrease waste buildup
  • Decrease diseases
• Carbon cycle


  • Photosynthesis removes CO2 from atmosphere
  • Respiration releases CO2 into atmosphere
  • Decomposition releases CO2