Sim Earth Cheats
To Get Carnifern - Plant an enormous amount of insects. Within seconds a crop of carniferns will spring up! 
SMOOTH - Smoothes the coasts of you planet's continents.
joke - Type this when the Gaia window is in view. His face will be in a frying pan! 
Robots?  - There is another class of life that is not explained in  the manual, robot. Robots are able to survive everywhere,
including on rock, arctic, and ocean. They can evolve sentience, too, but because they are already so advanced, they will not be able to have
stone age, bronze age, or iron age cities.  They will begin civilization at the  level of the industrial age.  To create robots, simply place one
nanotech city of any life form and set an atomic test on it. Robots in the city will escape and live as separate life forms.