In class we discussed lactase persistence, a human trait tha…

In class we discussed lactase persistence, a human trait that recently evolved by natural selection.  In class, you drew a graph showing how lactase persistence changed through time, in areas with access to milk from cows.  Below, I gave you the basic graph framework you used in class.  1.  Sketch this graph, drawing a line to represent the frequency of lactase persistence over time.  (2 points) 2.  List 3 steps of natural selection, and briefly explain how each is represented in the graph.  (3 points)