Freedom of Movement, Open borders and Cultural Integrity

Come join us for some informal philosophical discussion. No prior knowledge or research is needed, but an open mind is.

For most of early human history, humans have been as free to move & migrate around as chimpanzees or eagles, but not quite in the modern world. Today most of us assume that passports have always been an integral part of the society but they are a relatively new invention. Passports were adopted about a 100 years ago (after WW1); although, some form of "travel documents" have existed since many centuries that gave permission & protection to the bearer to travel through different kingdoms & states. These travel-documents can symbolize freedom and at the same time they can also be a tool to control the free-movement of people by the authorities.

The modern progressive world typically values equality, liberty, fundamental human rights, and attempts to eliminate discrimination based on traits that one is born into like race, gender, religion, wealth class, appearance by providing equal rights regardless of these traits. However, nationality / country-of-citizenship is a trait that is legally used to confer different rights & privileges based on it, in many countries.
Is this a helpful & necessary policy to preserve the integrity and culture of a nation? Or could it be considered as a new way of dividing the "plebs" across the world by the ruling "global elites"?

This raises some interesting questions:
1. Do animals have more freedom to move around than humans do in the modern world? What is this a consequence of?
2. What purpose do these restrictions serve?
3. Many cultures would consider "freedom of movement" to be a fundamental human right. Is it possible to achieve this?
4. What is a nation, nationality and country?
5. What would happen if a country had "open borders" allowing any person to freely move across its border as long as the laws of the land applied them?
* Imagine this for various countries like - the US, Japan, India, Argentina, Germany, Egypt
* Would this result in occupation & cultural makeover of a country?
* How do the countries in EU maintain their cultural integrity while having open borders across diverse nations in the EU?
6. What does a good balance between cultural exchange, cultural integrity, and cultural evolution look like?
7. Does having open borders benefit or burden the economy of a country? Perhaps it depends on the policies / laws of the country?
8. Is there a tension between economical progress and cultural integrity of a nation?