Immigration and evolutionary theory
As for the second, evo-psych predicts people would be wary of immigration, because most immigrants are not kin (note that this theory perfectly explains the special case of people favoring immigration from their own ancestral regions). Evo-psych predicts, on a very strong basis, that people would rather preserve the economic bounty where they are for their own kin.
Even an economist must agree that (a) immigrants themselves only move because they expect to be better off in their new homes than their old, and (b) once they arrive they will compete with natives for existing economic resources. To genes competing in evolution's rat-race, there is no reason to help immigrants better themselves, and every reason to discourage local competition from immigrants.
(It's true that immigrants may help expand economic resources--in a society where greater availability of labor fuels economic expansion. However, the notion, oft-repeated by economists, that labor availability necessarily fuels industrial expansion is obviously false (if it were true, Bangladesh would be rich). History shows that industrial economic growth depends on high-IQ labor, and is retarded where chiefly low-IQ labor is available no matter how cheaply.
Since IQ is at least 60% heritable, only an ideologically-blinded economist would suppose that unlimited immigration by low-IQ people would certainly fuel economic expansion. In fact, there are strong economic reasons to think otherwise, because in the presence of many low-IQ people, society diverts the labor of many high-IQ people from industry to simply managing (or exploiting) the low-IQ crowds.