Which are the two major groups of animal kingdom?

Animal kingdom:

1. This group includes all eukaryotic, multicellular and heterotrophic organisms.
2. They have a complex body differentiation.
3. Animal kingdom can be broadly classified into two major groups i.e. vertebrates and invertebrates.

Vertebrates:

1. These are more complex organisms as compared to invertebrates.
2. They are marked by the presence of a vertebral column.
3. These animals also possess a well-defined internal skeletal system.
4. Porifera, cnidaria, echinodermata, mollusca, annelida and arthropoda come under the group invertebrata.

Invertebrates:

1. These are less complex organisms as compared to invertebrates.
2. Organisms belonging to this group do not have a vertebral column.
3. These animals do not possess a well-defined internal skeletal system.
4. Fishes, amphibians, reptiles, birds and mammals come under the group vertebrata.