Plate tectonics is the mechanism that allows continents to move around. It is believed that 2 and half million years ago, some geologic changes occurred related to plate tectonics such as the formation of of the Isthmus of Panama and continued formation of the Indonesian Archipelago. This caused changes in ocean currents. The currents that used to travel between the Americas was cut off and perhaps the Gulf Stream was formed.

Also plates continued to move northward and crowded around the Arctic Circle which created a trap for ice to form. This ice reflects light from the sun cooling the planet.

Obviously the moving of continents can create bridges where species can cross. What sometimes happens is when one continent is connected with another, some species travel across bringing with them their suite of diseases and parasites and biodiversity is reduced rather than increased as you might assume.

Plate tectonics influences the formation of continents and the shape of ocean basins, ultimately responsible for long-term climate and biodiversity.

The timespan for this is millions to billions of years.

On time scales less than a million years, climate variations such as ice ages along with evolution and human activity such as hunting, agriculture, landscape modification, widespread importation of species and fossil fuel use are far more important.

1. Affects continent/ocean position and mountain ranges, which affects ocean currents, weather patterns, and climate.

2. Change in plate elevation affects ocean level/shoreline position.

3. Plate boundaries produce mountains, volcanic activity, ocean trenches... extremes in temperature and elevation. These affect creation of new species or extinction of old species.

open your text book and read. this is why you are in summer school and asking these questions now.

good idea