Main entities:

• Humans:Can reproduce, the more humans -> more reproduction
  Can kill each other in wars, the bigger the "evilness" attribute of the humans the more they kill each other
  Can produce food and consume it when soil fertility = 0, if there is no food produced all the humans die
  Have an impact on the environment, the more humans -> the faster the world temperature increases (global warming), this also decreases the world humidity
  Can make the world's soil more fertile
  Die when the water amount of the world = 100% or 0%
  Have a set of world requirements that the world needs to adhere to for them to live
  

• Sharks: Slow reproduction
  Can kill each other but do so less often than humans
  Die when the water amount of the world = 0%
  Have a set of world requirements that the world needs to adhere to for them to live
  

• Rats : The fastest reproduction
  Can kill each other but do so rarely (less often than sharks/humans)
  By eating crops they decrease the soil fertility
  Die when the water amount of the world = 100% or 0%
  Have a set of world requirements that the world needs to adhere to for them to live
  

• Weapons : Produced by humans, the more humans->the bigger the weapon amount
  Is used by humans in their "wars", the more weapons->the more they kill each other
  Have a destruction level, just one weapon with a high enough destruction level can eliminate the entire human population!
  

• Tsunami's : Have a destruction level and a duration
  The bigger the destruction level and duration -> the more they increase the total water amount in the world and the world humidity
  Each year they have a chance of 1/12 of happening
  

• Earthquake's : Have a destruction level and a duration
  The bigger the destruction level and duration -> the more they decrease fertility of the world's soil and increase the world's temperature
  Each year they have a chance of 1/12 of happening
  Just like in real life, earthquakes have a chance of producting tsunami's. So after an earthquake the probability of a tsunami happening immediately after it decreases from 1/12 to 1/8
  

  Polymorphism can be seen in the following: the classes Humans, Sharks and Rats all override certain methods from the abstract class Organisms. We can also see method overloading in the classes Natural Calamities, Earthquakes and Tsunami's.
  Further information can be seen in this image of the simulation hierarchy