This project will be due no later than 11:59:59 PM, on Friday, December 6th, by normal electronic submission.

The intertidal zone is the zone of land where that is underwater at high tide and exposed at low tide. It is a tough place to survive (though a nice place for us to visit), as creatures must be able to survive both open exposure to the air and sun, and immersion in water and pounding waves.

The starfish is a voracious predator of the intertidal zone. It feeds on a variety of mollusks and barnacles by everting its stomach and wrapping it around its immobile prey. The starfish is relatively mobile, and will wander looking for prey (though the motion is too slow to see with the naked eye, it is clear in time lapse photos).

The starfish reproduces by expelling sperm and eggs into the water. This happens periodically, when the water temperature and tides are right, at which time a whole population releases their sperm and eggs. Fertilized eggs form larvae, which drift about eating plankton until they grow enough to settle on the seabed and develop into adults. The small starfish grow until they are large enough to reproduce, and the sycle repeats.

Scientists use the starfish and its prey as an example of the complexity of the predator-prey cycle. In this cycle, the number of predators and prey are related in that as the number of prey items grow, more predators breed and are able to feed on them, increasing the number of predators. As the predators increase, the prey item becomes consumed, and there is less food for the predators, and their number decreases. The decrease in predators means the prey item can expand, starting the cycle again.

For project 5, we will be creating a simulation of the predator-prey cycle for when starfish are introduced to a small island that contains an exisiting population of barnacles. In order to assist you with this, I have created a high-level description of classes and methods to use. I have also included a RandomNumber function you can use to generate random numbers as required.

The rules for the simulation are simple.

• A seashore consists of a number of smaller plots in a ring around the edge of the island.
• Each plot has a population of starfish, and beds of barnacles that the starfish prey upon.
• In each turn, each starfish will eat a barnacle from the bed.
  • If there are multiple starfish, they eat the barnacles in the order in which the starfish arrived, with ones that were there first given preference.
  • Starfish that eat grow bigger (if they haven't reached full growth).
  • Starfish that don't eat move to an adjacent plot in search of food.
  • A starfish that does not eat two times in a row starves to death.
• The barnacles grow as well.
  • In each turn, the bed of barnacles will expand if there are already barnacles there and if is any room for them to do so. They expand at the rate of one per time unit
  • If there are no barnacles in a particular plot, no new ones will grow if there are any starfish present. If there are no starfish there, new barnacles will grow back at the rate of one per time unit.
• Periodically, the starfish will spawn.
  • Only starfish that have recently eaten and are large enough will spawn
  • Each spawning starfish will produce a number of surviving larvae betweem zero (none survive) and its size (larger starfish produce more sperm and eggs)
  • The larvae will drift about and land randomly on some plot, and will develop from there.
• The simulation commences with the arrival of a single starfish.