How does evolution work?

How does evolution work?

Answer: 

To survive, living things adapt to their surroundings. Occasionally a genetic variation gives one member of a species an edge. That individual passes the beneficial gene on to its descendents. More individuals with the new trait survive and pass it on to their descendents. If many beneficial traits arise over time, a new species—better equipped to meet the challenges of its environment—evolves.

How Does Evolution Work