So after sitting through perhaps the most interesting Bio115 Lecture of the semester I realized how many people don't truly understand the definition of Evolution. Evolution is a change in a POPULATION (not a specific individual) over time (more than a life time, multiple generations).
Evolution is driven by multiple factors only two of which I will go over. The first is Natural Selection. An example shown to us was a population of frogs that had two major colors, yellow and green, and their environment consisted of a dry, yellow grass due to a lack of rain in the area. Due to the color of the grass the yellow frogs could blend in and not be found as easily by predators. The same could not be said for the green frogs so naturally there were fewer green frogs in the population becuase the yellow ones were left to repopulate "survival of the fittest" if you must.
Eventually the area starts to recieve a steady amount of precipitation which begins to liven up the foliage and some time later the grass is now a lush green color. Now the large population of yellow frogs cannot hide from predators as easily, thus their population over time begins to drop, and the green takes over the majority.
Artificial selection on the other hand is mainly due to the human population. For example: Cabbage, Kale, and Broccoli are all derived from the wild Mustard plant. Over thousands of years humans began to pick and choose which characteristics they wanted in their plants thus leading to those three (and a few more) new plants that could be grown and harvested.
Please excuse any typos, for I am posting this over my cell.
Enjoy your day fellow products of evolution.