Geographically speaking, the Arctic and Antarctica are polar opposites. Where the Arctic consists of sea surrounded by land, Antarctica is land surrounded by sea. This is the main point of difference between the two, and the reason why the climate and native marine species are so different.
To put this into perspective, it’s worth looking at the location of the North Pole and the South Pole. While the North Pole is located at sea, around 435 miles from the nearest landmass, the South Pole is located in the centre of the Antarctic continent, 745 miles from the coast.
Of course, for much of the year, the Arctic is frozen, with sea ice stretching for around 4 million square miles. The Antarctic, too, is extended by sea ice, though on a much smaller scale, with much of its ice lying on land – some of which is up to 3 miles thick.