How did one achieve upward mobility in the tribe?
In Things Fall Apart, a male member of the Igbo tribe may advance in terms of wrestlers thrown, cowries collected, wives obtained, children sired, titles garnered, heads taken in war, and yams harvested. Males were thus upwardly mobile within the tribe; females, however, could only be mobile within the family, depending on which wife they were (by age).
In the novel, males can attain upward mobility through great physical labor in the fields, at war, and during the wrestling matches. Females have limited mobility and can only hope to marry a titled male. Luckily, a wife will give birth to several male children who survive. Only then will she be granted her own obi and status among the other wives.
Okonkwo, for example, has three wives and several children who live in separate obis on his compound. He has an obi full of yams for which he has had to toil mercilessly. He has limited cowries (shells used for money) because he has had to repay his father's debts.
Most importantly, Okonkwo has two titles (and two more to go). These are the main status symbols in the tribe; they are like stars on a general. Also of note are Okonkwo's five heads taken in battle. And, don't forget, he first achieved fame by throwing the Cat during a wrestling match. Having been the son of an agbala (titleless male), Okonkwo's hard work has allowed him to move up the social ladder of the tribe to become one of its most respected leaders.