Aerobic Respiration:

That occurs by the use of molecular oxygen. And can be direct or indirect on the basis of exchange of gases:

1) Direct             2) Indirect

1) Direct: Direct respiration occurs. Without the use of blood or respiratory organ. Ex: bacteria, protists, plants, roundworms, flatworms, sponges, Coelenterates and arthropods.

2) Indirect:- It occurs by the use of special respiratory organs and blood. Occurs by respiratory organs and blood. Ex. Land animals, amphibians etc. It is further of following types:

i) Cutaneous: occurs through skin. Ex. Crustaceas, amphibians and annelids.

ii) Bucco-pharyngeal: occurs through thin living of bucco-pharyngeal cavity. Ex. Amphibians (frogs and toads)

 iii) Branchial: occurs through gills. Ex. Some amphibians, mollusk annelids, all fishes.

iv) Pulmonary: occurs through lungs. Ex. Land animals (mammals, reptiles, birds and some amphibians)