Unit 2 - Food Chains & Energy

• What are the 3 levels of the food chain?

  1. Producers - the base of all food chains (ex: plant)

  2. Consumers - an organism that consumes producers

  3. Decomposers
• What are the 3 types of consumers?

  1. Primary - directly eats the producer (ex: cow eats the plant)

  2. Secondary (ex: person eating the cow)

  3. Tertiary (ex: polar bear eating the person)

  NOTE: each level higher has less energy available
• Omnivores


  eat plants and animals
• Herbivores


  eat plants
• Carnivores


  eat animals
• Why are nutrients recycled in a food chain but energy isn't?

  Because the flow of energy goes one way
• What is energy and the what are the 2 types?

  - The capacity to do work

  1. Potential Energy - energy stored in the object

  2. Kinetic Energy - energy of motion
• What are the 2 laws of thermodynamics?


  1. Energy is neither created or destroyed, but only changed from one form to another (energy is constant

  2. In any energy conversion there will be some loss of heat
• What is the relationship between trophic levels and energy?

  The higher you go up the food chain, the less energy there is

  Higher Trophic Level = Less Energy Available
• What are Biogeochemical Cycles?


  - the cycle that moves chemicals around the biosphere

  - unlike energy, nutrients are recyclable
• What 3 things make an ecosystem stable?


  1. The total NUMBER of living species is CONSTANT (or almost), year after year

  2. The SAME SPECIES are present every year

  3. The POPULATION of each species is roughly the SAME every year
• What does a stable ecosystem mean?


  When things changed a little from day to day, month to month or in annual cycles but generally they stayed the same
• Dynamic Equilibrium


  when it isn't exactly the same but goes with the central point
• Biotic Growth Factors (that contribute to population growth) (CRAFA)


  - Reproductive Rate

  - Adaptability

  - Ability to migrate

  - Competitiveness

  - Food Supply
• Abiotic Growth Factors (that contribute to population growth) (FF)


  - Favorable light

  - Favorable temperature or moisture
• Biotic Reduction Factors (that contribute to population decline) (PPFL)


  - Predators

  - Parasites

  - Food Shortage

  - Loss of Habitat
• Abiotic Reduction Factors (that contribute to population decline) (BPW)


  - Bad Weather

  - Water Shortage

  - Pollution
• What are 2 ways an ecosystem changes?


  1. If an ecosystem is stable, it resists change, and the system is said to have inertia (no activity)

  2. If an ecosystem changes significantly, and then bounces back to something like its original state, it's said to have resilience