What is the difference between the I-90 and the I-485?

"Under immigration law, form I-90, (Application to Replace Permanent Resident Card), is used by permanent residents to apply for a replacement or renewal of their existing green cards. Form I-485, (Application to Register Permanent Residence or Adjust Status), is used by a person to obtain their initial green card, while they are living inside the U.S CITATION:I-485; http://www.uscis.gov/i-485 CITATION:I-90: http://www.uscis.gov/sites/default/files/files/form/i-90instr.pdf"