public void mouseClicked(MouseEvent event)
  {
    //gets a new location for the mouse click
    Location mouseLoc = new Location(event.getX(), event.getY());

    if(chaserBool == true)//checks for chaser
    {
      currentChaser = new Chaser(mouseLoc, canvas);

      critterArray.add(currentChaser);
    }
    if(runnerBool == true)//checks for runner
    {
      currentRunner = new Runner(mouseLoc, canvas);

      critterArray.add(currentRunner);

    }
    if(randomBool == true)//checks for random
    {
    currentRandom = new Random(mouseLoc, canvas);

    critterArray.add(currentRandom);
    }
    if(startBool == true && critterArray.size() < 2)
    {
      topLabel.setText("Please add two or more Critters.");
    }
    else if(startBool == true && critterArray.size() >= 2)
    {
      topLabel.setText("Simulation is running.");
    }

  }//end mouseClicked()