Answer:
Colonization ruptured many ecosystems, bringing in new organisms while eliminating others. The Europeans brought many diseases with them that decimated Native American populations. Colonists and Native Americans alike looked to new plants as possible medicinal resources.
Native peoples of America had no immunity to the diseases that European explorers and colonists brought with them. Diseases such as smallpox, influenza, measles, and even chicken pox proved deadly to American Indians. Europeans were used to these diseases, but Indian people had no resistance to them.