In Things Fall Apart, the Igbo culture uses a division of labor (gender segregation), polygamy, communes, and a patriarchal hierarchy in order to sustain an agrarian economy. Survival is the key for the Igbo. Males must work extremely hard to harvest the difficult yam crops. They must take many wives in the hopes of producing many strong offspring. They must use wrestling matches and titles in order to preserve the status of males. What unravels their culture is their belief in superstition (killing of twin babies) and their underestimating the intentions of the colonists.
The white British Christian culture is not agrarian and, therefore, need not be so integrated. The whites separate their religion, judicial system, government, and education into institutions. They rely on individualism instead of communal values. They believe in monotheism and monogamy because it is gives them a more personal sense of love and security. Since they wield greater technology and are more mobile, they focus on a more conceptual view of culture (which is not dependent on the basic physical need for food and survival). Their weakness comes from their failure to understand the complexity of the tribal culture and their heavy-handed institutional punishment of the tribe.