B18 | Organisms and their Environment

• What is the principal source of energy for all biological system

  Sun
• Producer is a organism that makes its organic nutrients usually from the sun such as plants and algea
• Consumer is an organism that gets its energy by feeding another organism such as rabbit or deer
• Herbivore is a animal that gets its energy by eating plants such as deer or cow
• Carnivore is an animal that gets its energy from by eating other animals such as hawks or snakes
• Decomposer is an organism that gets its energy from dead or organic waste
• Food web illustrates energy flow in the ecosystem although food webs are more complex due to the amount of chains

  
• food chain illustrate energy flow in the ecosystem from one organism to another

  
  

  Food chains normally have less then 5 trophic levels due to the amount of energy lost at each transfer

  
• Trophic levels are positions of an organism in a ecosystem

  1. Producers
  2. Primary consumers
  3. Secondary consumers
  4. Tertiary consumers
• Movement of energy through an ecosystem

  1. Producers use energy from the sun to produce glucose
  2. Then primary consumers eat producers
  3. Then Secondary consumers
  4. To tertiary consumers
• Humans eating plants is more efficient than humans eating animals because:

  • We need only a couple of vegetables to have one meal but to have the meat, we must feed the animal a lot of plant material to get far less meat.
  • When raising an animal, plants lose energy to the environment. Then, the animal loses energy to the environment and does not use up all the plant material, so it is inefficient
• Carbon cycle describes the movement of carbon between the atmosphere, oceans, and land.

  
• Factors that effect oxygen and carbon dioxide in the atmosphere

  1. Burning fossil fuels
  2. Cutting down trees

  Burning fossil fuels releases carbon dioxide into the atmosphere, contributing to the greenhouse effect and global warming. This process decreases the oxygen levels in the atmosphere as it used during combustion

  Deforestation reduces the number of trees available to absorb carbon dioxide through photosynthesis