1. How did the boundaries of Israel change between 1947 and 1949?
A resolution from the UN General Assembly to change partition in Palestine for Independent Arab and Jewish State. There were several proposed change in boundaries the Jewish accepted the decision but the Arabs rejected it.
On the plan, Arab will lessen its boundary. It changes to occupying a piece of Neqev desert and Beersheba. The change will result in the displacement of some villages.
The Jewish will increase its territory with parts of the Dead Sea and other more additionals.
2. Why was it changed?
To stop the territorial conflicts between the two movements, Palestinian and Jewish Nationalism
3. What could future conflicts occur from this change?
Until now they have unresolved land disputes. Continuous war is still in place, passing the problem all throughout the generations.
I hope this helped you with your questions.