private void Start()
        {
            UnityEvent.Init();

            ssm_ = new StateMachine("Simulation State Machine", debug: false);

            ssm_.AddState("Phase:Active", StartActivePhase)
            .AddTransition("Phase:Reproduction", IsAllDone, sleep: .5f);

            ssm_.AddState("Phase:Reproduction", StartReproductionPhase)
            .AddTransition("Phase:Extinction", IsExtinct)
            .AddTransition("Phase:Active", () => true, sleep: .5f);

            ssm_.AddState("Phase:Extinction", StartExtinctionState);

            creatures.Add(startCreature);

            ssm_.Start("Phase:Active");
        }