Question

What is Animalia?

Answer 1

The kingdom animalia was first introduced by Linneaus. Later, Whittaker organized the organisms into five kingdoms. He classified organisms according to cell structure, type and source of nutrition, and physique. The five kingdoms suggested by Whittaker are Monera, Protista, Fungi, Plantae, and Animalia. Basis of five kingdom classification is the nutritional differences between the organisms.

Complete answer:
Definition:
The kingdom animalia includes organisms which are
Multicellular and Eukaryotic
Animal cells lack cell walls.
They have a body layout that is a tube within a tube.
Symmetry of the body may be radial or bilateral.
Heterotrophic – they obtain their food from others.
Breathe oxygen (Aerobic)
Motile (example- humans, birds etc) while some are non-motile (example – mussels, obelia etc.)
Can reproduce asexually and sexually, and develop from a whole sphere of cells, the blastula, at some stage in embryonic development.
Fertilization may be external or internal.
Development can be direct or indirect.
The kingdom animalia has been classified into the following phylums:
Porifera (e.g. - Spongilla)
Coelenterata (Cnidaria) (e.g. - Physalia)
Platyhelminthes (e.g.- flatworm)
Nematoda (e.g. – tapeworm)
Annelida (e.g. – earthworm)
Arthropoda (e.g. – honey bee)
Mollusca (e.g. – pila)
Echinodermata (e.g. – starfish)
Hemichordata (e.g. – balanoglossus)
Chordata (e.g. – human beings)

Note:
In the broadest classification scheme- kingdom animalia can be divided into chordates (vertebrates) and non-chordates (invertebrates) based on the presence or absence of vertebral column. Kingdom animalia is one of the largest kingdoms having a diverse range of organisms which are found in terrestrial and aquatic habitats. Examples include insects, birds, reptiles etc.