A bus driver who alleges he was fired because of his extreme obesity does not have a claim under the Americans with Disabilities Act, a federal appeals court held.The 7th U.S. Circuit Court of Appeals declined to revive the lawsuit Mark Richardson filed against the Chicago Transit Authority.Ruling on the issue for the first time, the court held extreme obesity qualifies as a disability under the ADA only if it is caused by an underlying physiological disorder.And the court found Richardson failed to present evidence that …