Orb Farm is a fun addicting fish tank simulator in which you can create life, from tiny living beings like bacteria and daphnia to goldfish. You can play this game online and for free on Silvergames.com. Biology has its own twist, and once you start to understand how it really works, you can achieve amazing things and play god creating strange little life forms.
Start placing different elements on your farm and try to balance the O2 and the CO2 level to be able to grow some sort of life. Use water, algae, stone, grass, wood and sand to create a nice environment. Then start placing different types of life forms and see what happens. Have fun developing your own Orb Farm!