Levels of Organisation

Levels of Organisation

• The organisation of an organism describes the arrangement of its body starting from the smallest unit to the whole.
• Cells are the basic building blocks of life. Each cell performs specific functions depending on its type.

Cells and Specialised Cells

• Some cells are specialised to carry out specific tasks. For example, red blood cells carry oxygen because of their unique shape and absence of nucleus.
• Examples of other specialised cells include sperm cells, root hair cells, and nerve cells, each designed for reproduction, absorption, and transmitting impulses respectively.

Tissues

• When similar cells group together, they form a tissue. For example, muscle tissue is made up of specialised muscle cells.
• Different types of tissues include muscle tissue, epithelial tissue (lining of organs and skin), connective tissue (provides support) and nervous tissue (sends electrical signals).

Organs

• An organ is composed of different tissues working together to perform a specific function.
• Examples include the heart (made from muscle, nerve and connective tissues), lungs and kidneys.

Organ Systems

• An organ system is a group of organs working as a cohesive unit for a specific function.
• For example, the circulatory system is composed of the heart, blood vessels and blood working together to transport nutrients, oxygen and waste around the body.

Organisms

• An organism consists of multiple organ systems functioning together to support life.
• Complex organisms like humans have numerous systems including the digestive system, respiratory system, circulatory system and nervous system.

The transition from cells to organism provides an insight into biological organisation and the complexity of life, incorporating concepts of structure, function and coordination.