Genewars

Here is another golden nugget from the days of Bullfrog productions. It was released in 1996 for the PC and is a real-time strategy game that includes terrain editing and genetic manipulation.

Players move through a series of worlds using a small number of sentient humanoids to build small bases and to stun, kill, research, and ultimately breed a variety of animals. Plants are also important, as different plants can be grown and harvested for different purposes. Players must use the various plant and animal species available to them (as well as hybrid animals) to deal with different environments, enemies, and tasks. For instance, a crab is a good armored defender, while a mule is a perfect detritus transporter. The two can be bred to form a creature that is well armored, but also suited to mule work. The more a particular species has been studied and created, the more effective future individuals will be. The primary resource of the game is goop, which is derived from all kinds of biomass.

Different plants and different animals are better for certain tasks and environments. Off the top of my head there are mules, crabs, frogs, dinosaurs and avian of which any two can be mixed to form two possible hybrids with silly names; muleocrab crabomule etc. There are also aliens which monitor your progress and give you objectives to complete, if you please them they will reward you. If you anger them they will attack you.

It is a rather simple RTS but I found it enjoyable. I don't think there is anywhere to officially buy the game but there are a few places it can be downloaded. Requires DOSbox and some minor tweaking to run.