Explain various patterns of organisation in animals.

Explanation

Cellular level of organisation: Cells are loosely arranged without the formation of tissues. There is division of labour among the cells. e.g., sponges.
Tissue level of organisation: Cells which perform similar function are grouped into tissues The tissues perform a common function. e.g., cnidarians.
Organ level of organisation: Different kinds of tissues aggregate to form an organ to perform a specific function e.g., flatworms and other hyper phyla.
Organ system level of organisation: The tissues are organised to form organs and organ systems. Al the organ system function in a coordinated manner.