Evolution in Industry: Putting Natural Selection to Work The concept of natural selection has been applied in many fields outside biology. For example, chemists have applied principles of natural selection to develop new molecules with specific functions. First they create variants of an existing molecule using chemical techniques. They then test the variants for the desired function. The variants that do the best job are used to generate new variants. Repeated rounds of this selection process result in molecules that have a greatly enhanced ability to perform a given task. This technique has been used to create new enzymes that can convert cornstalks and other agricultural wastes into ethanol with increased efficiency.

and additional membranes that allow developing embryos to survive in dry environments, was one of the key developments in the evolution of the reptiles.

The early reptiles split into several major lineages. One lineage led to reptiles, including dinosaurs, and also to birds. Another lineage gave rise to mammals between 200 million and 250 million years ago.

The evolutionary transition from reptiles to mammals is particularly well documented in the fossil record. Successive fossil forms tend to have larger brains and more specialized sense organs, jaws and teeth adapted for more efficient chewing and eating, a gradual movement of the limbs from the sides of the body to under the body, and a female reproductive tract increasingly able to support the internal development and nourishment of young. Many of the biological novelties seen in mammals may be associated with the evolution of warm-bloodedness, which enabled a more active lifestyle over a much larger range of temperatures than in the cold-blooded reptilian ancestors.

Then, between 60 million and 80 million years ago, a group of mammals known as the primates first appeared in the fossil record. These mammals had grasping hands and feet, frontally directed eyes, and even larger and more complex brains. This is the lineage from which ancient and then modern humans evolved.