How did World War I contribute to the fall of the Romanov Dynasty?

World War I was a major contributory factor to the fall of the Romanov dynasty, which had ruled the Russian Empire for over three hundred years. Russia had entered the war enthusiastically out of solidarity with its Serbian brethren, but as the conflict began, it soon became clear that the country was woefully underprepared for the challenges ahead. The weakness of Russia's military and civil infrastructure meant that the war placed a crippling burden on the civilian population, causing severe economic hardship and misery. The initial enthusiasm soon wore off, and as the war dragged on, it became ever more unpopular.
Opponents of the Tsarist regime, such as the Bolsheviks, were able to exploit the prevailing mood to their own advantage. They presented the war as a conflict among the ruling classes of Europe which had nothing to do with the ordinary people, the workers and peasants. The regime was unable to respond effectively to the challenges to its legitimacy. To make matters worse, the creaking Russian administrative system proved so inadequate in conducting the war that chronic shortages developed on the home front.
In turn, this led to protests and serious outbreaks of civil disorder on the streets of Russia's major cities. One such disturbance, a bread riot in the capital city of Petrograd—whose name was changed from St. Petersburg to make it sound less German—turned into a full-scale revolt against the Tsar and his regime. It soon became clear that the Romanov dynasty's days were numbered, and it was no surprise when Tsar Nicholas II was forced to abdicate, ushering in a brief period of liberal democracy under the Provisional Government.