Question

how did westward expansion influence the lives of Native Americans

Answer 1

It caused their displacement and genocide. Europeans not only killed them outright (even forming hunting parties to seek out and kill entire groups), but also changed the land so drastically that the native populations could no longer subsist in the same way they had for generations (causing the loss of culture, group members, and ancestral traditions [look into the Ghost Dance religious revival of 1890]). They were promised land that was subsequently taken away from them, they were forced to live on reservations, and became, in effect, less than third class citizens (more like animals to be used in whatever fashion "necessary"). It wasn't until very recently that natives were given any real rights as a people at all and only if they are part of a recognized "nation".
Also, if you can find anything by Les Field, read it. He's a very knowledgeable anthropologist who works with native groups in California and South America. His most recent book is Abalone Tales.

this would be your answer read it :) :) :) @morrisls