What is the difference between double circulation and single circulation?

Answer 1

Single circulation

1. Occurrence: Found in only fishes.

2. Mode of circulation: Blood passes only once through the heart to supply once to the body.

3. Nature of blood: Only venous blood passes through the heart.

4. Efficiency: Less efficient as gill capillaries slow down the blood flow so the body receives blood at a low pressure which decreases the rate of oxygen supply to the cells.

Double circulation

1. Occurrence: Found in amphibians, reptiles, birds and mammals.

2. Mode of circulation: Blood passes twice through the heart to supply once to the body.

3. Nature of blood: Mixed or oxygenated or venous blood passes through heart.

4. Efficiency: More efficient as blood flows at higher pressure, especially in birds and mammals, which increases the rate of food and oxygen supply to the cell and also rapid removal of wastes from them.

Answer 2

1-The single circuit circulation involves the movement of blood from heart to gills to body and then back to the heart while double circuit circulation involves the movement of blood from heart to lungs then back to the heart and then to the body.

2-double circuit circulation is more efficient than single circuit circulation.

3-double circuit circulation is found in mammals, birds and some reptiles while single circuit circulation is found in fishes.