describe symbolism in life of pi?

Hi simran11, this is a complex text and it is obviously
difficult to answer simplistically. I am assuming you would like to know the central
symbols Martel employs and why he does so? Here is a
start:

Martel uses the symbolism of light and
dark imagery throughout the text to highlight the importance of
knowledge, literature and wisdom. An example of the association between light imagery
and the importance of education can be seen in Pi's response to gaining knowledge from
his teachers, "...men and women who came into my dark head and lit a match.." Pi
metaphorically compares the gaining of knowledge to the fire emitted from a match
strike, thus demonstrating his passion for enlightenment. The "dark head" is an obvious
reference to Pi's earlier perceived ignorance. Martel also connects religious
enlightenment with light and dark symbolism, through the juxtaposition of beliefs
between Mr Kumar and Pi. Mr Kumar associates religion with oppression and ignorance,
"Religion is darkness," while Pi believes "Religion is light." So light and dark
symbolism is used to demonstrate Martel's concerns of the different ways one may
percieve different types of enlightenment; be it spiritual or
intellectual.

Martel also uses doors, gates,
entrances and exits to symbolise the difference between human, animal and
spiritual worlds. Pi's quest for spiritual enlightenment is represented as both a
journey and an opportunity through the discovery of the Christian Church, "I noted
this, how both the doors were wide open..". The doors are a metaphor for his discovery
of Christianity, and also of Pi's movement from being "locked out" or ignorant to
spiritual awakening as he "..entered the Church" to gain a new understanding. The gates
of the Pondicherry Zoo are also used to symbolise Pi's movement from innocence to
knowledge through Pi's father "special lesson" on the dangers of zoo animals.
Significantly, Martel highlights the crossing of boundaries from the human world into
the world of nature and animals through, "We left the house, went through the gates,
entered the zoo."

Additionally, bars, cages and physical
boundaries and defined territories are also symbolic of mental and physical landscapes
and our desire for security. Martel repeatedly refers to cages and iron bars from the
perspective of Pi, his father and the animals, illustrating the concepts of security,
protection and territory. This builds on the extended metaphor of  the similarities
between humans and animals in the way we are forced to behave and choose to behave, ‘All
around were great big cages divided up by thick, green, iron bars.’ The earlier "special
lesson" Pi witnesses demonstrates that the tiger, like man , has been forced into his
situation. He must kill in order to survive, yet hesitates at first to leave the comfort
and security of his cage.

I hope this
helps:)