Complexity of Organisms

The organization of cells into tissues, organs, and systems helps complex organisms to perform their functions efficiently. 

The ability of complex organisms to survive in their environment is a product of specialization and division of labour.

Simple organisms are small in size at the cell and tissue level with one or more comparatively number of cells. The surface area to volume ratio is large. Consequently, the distance to which substances travel is short but with complex multicellular organisms, the surface area to volume ratio is small, thus creating a problem for the movement of materials.

Advantages of Complexity:

i. Different parts of the body are specialized for the different functions they carry out.

ii. Complexity leads to division of labour. There is mutual interdependence between component cells.

iii. Complex organisms can perform more complicated functions than simple organisms.

iv. Complex organisms can adapt to different environments.

v. Complex organisms can feed on or deal with more complex excretory products.

vi. Complexity makes higher animals or organisms more efficient in carrying out their life processes.

vii. They are able to increase in size because there is enough space between cells for growth.

Disadvantages of Complexity:

i. They require and consume more resources than simple ones because of their size.

ii. Complex organisms have a small surface area to volume ratio compared to simple ones therefore, diffusion is not efficient to supply materials to different parts of the body.

iii. A specialized transport system is needed for the efficient movement of materials within the body of complex organisms.

iv. Complexity leads to difficulty in reproduction in higher organisms.

v. Inability of individual cells to exist on their own.

vi. If an organ or a system in multicellular organisms is damaged or does not function properly, the other organs might not function properly as well or might be damaged.

vii. The regenerationIn Biology, regeneration is the natural process of replacing or restoring damaged or missing cells, tissues, organs, and even entire body parts to full function in plants and animals. More process in complex multicellular organisms, for e.g, mammals is very limited.