As the plates move farther apart the land on the surface is put into different latitudes. Each change in latitude can mean a change in the temperature and overall climate. Dramatic climate change will ultimately mean dramatic change in the flora and fauna. Think of moving a plant or pet from one side of the room to another. If the plant is living in the sun near the window and thriving and you move it to a dark area, it will have to adapt to a new environment or die. Antarctica is the most extreme example of a biome affected by continental drift. When the continents were still connected it had a climate a ecosystem similar to New Zealand. When it separated and was cut off the temperature dropped dramatically and the ecosystem changed completely.