1. Discovering the Tiger Within Richard Parker saves the day.
When the hyena kills Orange Juice, Pi discovers a new side of himself. This set of shots shows the developing relationship between Pi and Richard Parker

2. A low angle head and shoulder shot reveals Pi's fury
A low angle head and shoulder shot reveals Pi's fury.  Up until this point in the film he has cowered and just watched - too distraught to really participate in his own survival or the survival of the others.  When Orange Juice (his mother?) dies, Pi discovers his inner strength (the tiger).  His fiercely determined facial expression reveals this change and the low angle shot with the cloudy heavens behind him suggests his empowerment. A low angle head and shoulders shot reveals the change in Pi's demeanour as he discovers his inner strength.

3. Pi is depicted in a long shot, standing against the heavens
Pi is depicted in a long shot, standing against the heavens.  Richard Parker bursts from under the tarp on which Pi stands, filling the screen in the foreground and replacing Pi's figure.  This symbolises Pi's transformation as he discovers his inner strength and more bestial side.

4. The symbolism of Richard Parker Richard Parker symbolises the inner beast - the primitive survival instincts in all of us.  Part of the struggle for any individual in the modern world is to tame these instincts so as to fit into society and live in harmony with others.  Pi discovers the value of these instincts when he is forced to survive outside of society in the wilderness.  Pi's relationship with Richard Parker is not a comfortable one.  Richard Parker threatens to eat him, just as Pi's inner beast threatens to consume his true vegetarian, moral and spiritual self.  At first he wants to be rid of the tiger.  

5. Taming Richard Parker - rediscovering balance
A low angle shot depicts Pi as the one in control at this point in the film.  He has the power to destroy Richard Parker (or metaphorically destroy his most primal urges and instincts). 

6. The high angle shot of Richard Parker evokes pathos for the creature, humanising it.  Pi discovers he cannot bring himself to destroy the tiger.  Ironically, Pi's rescue of Richard Parker proves his own humanity.  So Pi discovers his own human nature that includes the 'tiger within'. 

7. A low angle head and shoulders shot shows Pi's emotions and his power.
The similar positions of each face reinforces the link between these two : Pi and the Tiger = a circle of the “self”
A high angle close up of the tiger evokes pathos as we discover his vulnerability.

8. "Maybe Richard Parker can't be tamed, but by God's will, he can be trained"
Pi embarks on a mission to tame Richard Parker.  The dialogue, "Maybe Richard Parker can't be tamed, but by God's will, he can be trained" represents Pi's determination to rediscover his humanity by finding a balance between his more primitive side and his spiritual and moral self.  The short training scene (below) depicts Pi striking this balance.  Eye level shots replace the high and low angles to suggest a less antagonistic relationship.  Perhaps Pi recognises he is not 'above' his base self, but in harmony with it.

9. Eye level shot

10. Eye level long shot :shows the relationship

11. High angle – the tiger is tamed

12. Finally the tiger is tamed and Pi tells him to "go home"
Finally the tiger is tamed and Pi tells him to "go home". Richard Parker retreats back under the tarpaulin leaving Pi with a new discovery. A zoom in to close-up on Pi's face, accompanied by sombre music with deeper, serious strings suggest Pi's unexpected sense of loss and isolation when the tiger is 'trained' and made to disappear.
In the literal interpretation of the scene, Pi is sad because he is all alone again. Even a vicious tiger is better than no company at all.
Metaphorically, in controlling Richard Parker, Pi is left alone to act on his own, more civilised morals and values.
Whichever interpretation you put on the scene, Pi is clearly distressed by the loss.

13. Close up eye level shot

14. "My fear of him keeps me alert
"My fear of him keeps me alert.  Tending to his needs gives my life purpose"
Pi's voice-over, "My fear of him keeps me alert.  Tending to his needs gives my life purpose" highlights the value of his relationship with his companion. Psychologically and spiritually this could also represent man's fear of, and need to control, his primitive urges and needs.  Through Pi's experience and the symbolism of the tiger, we can explore and discover the protective, primitive nature inside of us all.  We see its dangers and its value and learn, through Pi, the importance of balance and harmony between our civilised and uncivilised selves.