Hello! I answered a question similar to this some months ago, although it doesn't cover everything: http://www.reddit.com/r/AskHistorians/comments/24ggf8/how_did_turkey_prevent_being_colonized_after_the/

To go into more depth, the Ottoman Empire was a failed state at the end of the First World War, to the extent that it only really existed on maps; by 1919, the interior of Anatolia was under the control of either bandits, rogue army columns or the Nationalists and Eastern Thrace and Western and Northern Anatolia were controlled by the Entente, with the Sultan remaining as a figurehead in Constantinople. Also, Anatolia was undergoing a significant famine at the time, largely as a consequence of the dislocation caused by the war.

To cut a long story short (which is covered on the other thread), the Turks were only able to regain control of Anatolia, the Kurdish provinces and Eastern Thrace from the victorious Allies, although there were failed attempts to create a pan-Turkish state across Central Asia. This led to the creation of the nation of Turkey as we see it today.

In terms of politics, in many ways Turkey is the anti-Ottoman Empire and is the outcome of very long term political trends that had been part of Ottoman society since the mid-19th century.

• Turkey is a Republic. The Ottoman Empire was a hereditary monarchy.
• Turkey is vociferously secular. The Ottoman Sultan was also a Caliph, meaning that Islam and the state were intertwined.
• Turkey is a nation-state that is focused on maintaining the dominance of Turkish culture. The Ottoman Empire was a polyglot state, with many different ethnicities.

On this second point, (peaceful) Islamism has been growing in Turkey for a number of decades and the present ruling party are Islamist. I don't know enough about modern Turkish politics to explain why this is, but the consequence of the growth of Islamism is that the present government are very keen to reintroduce Islam into the Turkish state; however, a significant portion of the populace reject this, some violently.

Sources are in my previous comment.

Well for the Ottoman Empire it ended it altogether. One could argue that it was dying and on its way out anyways, but it certainly sped up the process. Instead of internal revolts bringing down the Empire, the Europeans got to split up the Middle East in the "Mandates" and made arbitrary borders that had absolutely nothing to do with the ethnic or religious makeup of the Middle East (hence why the Sunnis, Shia, and Kurds are all crammed into Iraq when it was a terrible idea and we are seeing the implications of this, again, with ISIS). So basically World War I killed the Ottoman Empire.

As for Turkey, it was supposed to be split into lots of little territories and occupied by the European powers and ruled as a colonial power. However, Kemal Ataturk led a war for independence between 1919 and 1922 and unified Turkey and kept the Europeans out (didn't take that much, Europeans didn't really want to fight). The Caliphate was abolished and the Republic of Turkey was established, making Turkey one of the more Western Middle Eastern Nations (some don't even really consider it the Middle East even). Islamic law was separated from Secular Law soon thereafter.