"Individual commitment to a group effort ... that is what makes a team work, a company work, a society work, a civilization work." - Vince Lombardi
Birds often fly in a V formation. They recognize that they get further faster and with less effort if they pull together as a team. They also recognize that those with the greatest responsibility sometimes need a break, and they rotate the lead roles. The evidence of strength in togetherness is again demonstrated by the king of the jungle. Lions travel in groups, known as prides, to indicate their strength especially when they are hunting. Nature is replete with examples of the importance and success of teamwork.
Teamwork is the result of individual contribution and commitment toward a group goal. Is your team moving in the same direction or do you have individuals tearing away the fabric of the team? Do you rotate the lead roles in your team based on talent and opportunity or do the same few people take the lead on every project? The strength of your team is not in the numbers, it is in the level of togetherness, the level of individual commitment to the group effort.