Subject: chlorophyll / hemoglobin

The molecular structure of chlorophyll greatly resembles 
the structure of the heme part of hemoglobin.  Is it 
possible that hemoglobin in animals evolved from a 
chlorophyll-like molecule in an early life form?  Could the
hemoglobin molecule effectively carry oxygen if its iron 
atom were replaced with chlorophyll's magnesium atom?
Could a chlorophyll molecule effectively harness sunlight 
with an iron atom in place of its magnesium atom?

Re:chlorophyll / hemoglobin