Classification

Domain- Eukaryafrom microsoft clip art
        The booby is part of the domain Eukarya since this organism has all the defining features of a eukaryotic organism, such as cells with a membrane-bound nucleus.

Kingdom- Animalia
        Blue-footed Boobies fit into the kingdom Animalia since they are multicellular and heterotrophic (getting their nutrients from other organisms as food).

Phylum- Chordata
        Blue-footed Boobies have a spine with a dorsal nerve chord and a post-anal tail. During development they had pharyngeal slits which disappear before birth.

Class- Avesfrom microsoft clip art
        The class Aves consists of birds. Blue-footed Boobies are warm blooded birds that have a vertebrae, two legs and lay eggs, making them part of the class Aves.

In general, there are a number of features unique to Aves. Hollow bone structures relate to the function of flying. The lighter the body frame, the less weight to carry in the air. The less weight to fly with, the easier it is to fly. Birds also have a unique respiratory system. It is smaller in size but is highly efficient. Birds have special air sacs off the lungs that allow the system to exchange fresh oxygen enriched air with waste gas with everything moving in one direction. Birds are able to get rid of all the used air in their lungs, unlike many mammals. The way the air sacs are set up it takes two full inhale-exhale cycles for a batch of air to travel through the system.
                         
Order- Pelecaniformes, though some controversy claims Ciconiidae.
                           taken from microsoft clip art          vs.          taken from microsoft clip art
        Blue-footed boobies fit well into the order Pelecaniformes because they are monogamous water birds and have webbed feet with four toes. They are also hatched naked. There is some debate that they belong in the order Ciconiidae. This order includes the storks. Two main features of this group are possessing a long neck and long legs. Personally, I think the Blue-footed Booby is not elongated enough to be classified in Ciconiidae and is better classified under Pelecaniformes.
taken from microsoft clip art
Family- Sulidae
        The family Sulidae consists of Boobies and Gannets. Blue-footed boobies are part of the family Sulidae because they live in coastal areas and catch fish by plunge-diving.

Genus- Sula
        The genus sula consists entirely of Boobies.

Species- Sula nebouxii
       
Sula nebouxii is the binomial scientific name for the Blue-footed Booby.

Phylogeny

The Blue-footed Booby is most closely related to the Peruvian Booby based on genetic DNA sequences.

based on figure in "Phylogeny and Evolution of the Sulide (Aves: Pelecaniformes): A Test of Alternate Modes of Speciation" by V.L. Friesen and D.J. Anderson

Learn more about the Blue-footed Booby and where it lives by clicking here.