Transport System

Why is Transport System Necessary in Living Organisms? 

• To enable all cells, obtain all essential materials for metabolic activities such as nutrients, oxygen, water, e.t.c.

• To help remove and dispose of metabolic wastes such as water, carbon (IV) oxide, urea, e.t.c.

• Helps to move mineral salts and water from roots to stems and leaves in plants.

• Aids in the movement of hormones in plants and animals from production site to neede site.

Is Transportation Necessary in Lower Organisms (Unicellular Organisms and some simple Multicellular Organisms)? 

• Transportation is necessary in lower organisms too, only it is done simply by diffusion.

• This can be seen in unicellular organisms such as Amoeba, Paramecium, Chlamydomonas, Euglena, etc. It is due to the large surface area to volume ratio.

• Also in simple multicellular organisms such as tapeworms, which are flat and thin, their surface area to volume ratio is also large, hence transportation is done by diffusion.

Is there a need for Transport System in large organisms?

• Large organisms are complex and multicellular, hence substances need to move through a great distance.

• Due to the size of such organisms, the surface area to volume ratio is very small and as such diffusion alone will not work.

• There is need for a conducting or linking system to help with the movement of materials between isolated group of cells.

• Also large quantities of materials are needed to be transported and as such, simple processes such as diffusion, osmosis, and active transport will not be able to accomplish the work. 

What are the media for Transportation?

In organisms, a liquid or fluid material is needed for transportation. there are four (4) major media for transportation in living organisms.

1. Cytoplasm

   • This is mainly found in unicellular organisms

   • Transport materials such as oxygen, water, and carbon (IV) oxide, move from one part of the cell to another.

2. Cell Sap or Latex

   • These are found in multicellular plants

   • It is concentrated solution found in the vacuole of plant cells.

   • Aids in the movement of dissolved mineral salts in water from the soil to the tip of the plant.

3. Blood

   • This is found in most multicellular animals.

   • It is a tissue.

   • It flows through vessels such as arteries, veins, and capillaries

   • It is able to move large materials from production site to needed site.

4. Lymph

   • Also found in multicellular organisms.

   • It is similar in composition to tissue fluid.

   • Although it contains extra lymphocytes, it has no red cells.

   • It returns fluid to the main vein, through an opening in the left subclavian (jugular vein) below the neck.

   • Example is the lateral lymph that transport fatty acids and glycerol.