Is it possible to use an SD card or Micro SD card to save data?
No, of course not. The SD slot on the Ethernet shield, and all the shields that Sparkfun and Adafruit and a host of other companies are just there for decoration.
Hell, there isn't even an SD library delivered with the IDE. That's just a prop, too.
If so, can it be done with the I/O ports?
"it" is a pronoun with no referent. You have to ask more intelligent questions than that.