*BIO* How are chemical and physical properties of amino acids different?

The R groups of the amino acid are different.
Some amino acids do not have a central carbon atom.
Some amino acids have a carbonyl group.
Some amino acids do not have an amino group.

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of