How are aquatic invertebrates adapted for gas exchange?

Authors Avatar

How are aquatic invertebrates adapted for gas exchange?

Some of the invertebrates that were observed had a large surface area to volume ratio like the flatworm, which was found close to rocks in shallow areas. The flatworms are able to flatten themselves, which increases the surface area meaning there is less distance internally in the flatworm meaning the amount of diffusion is reduced.

In deeper areas of the river oxygen is in short supply so when the organisms go the surface maximum oxygen needs to be collected. This can be done by the use of hairs called plastrons on the under side of the abdomen to collect an air bubble from the surface so the organisms can return to the depths of the water and use the oxygen it has collected until it runs out. This sort of adaptation can be found on water beetles such as platambus maculates.

There were some aquatic invertebrates that have tracheal gills that are seen by the small plates on the side off the organism with are linked to the tracheal system. An example of an aquatic invertebrate with this adaptation is the stonefly nymph, which was located in deep areas of slow moving water as it can get the oxygen it needs through this form of gas exchange.

Join now!

There were also organisms that had a circulatory system meaning that the oxygen they need is quickly transported via the blood that has obtained the oxygen by diffusion. The surface area to volume ratio also contributes to the high oxygen levels taken in. This adaptation was in the leeches that were observed where there is a steep diffusion gradient to supply the organism with oxygen to diffuse to the capillaries to the rest of the body; the oxygen is obtained from the oxygen rich water around the leech that is diffusion through the permeable and very thin skin.  

Some ...

This is a preview of the whole essay

Here's what a teacher thought of this essay


This essay takes a brief look at the various adaptations that exist in aquatic invertebrates which enable them to obtain oxygen from their environment. It is largely based on observations made by the student of stream invertebrates and these first-hand observations lend the essay added interest. However, the essay suffers from a lack of detail and leaves the reader asking a lot of questions. Species names are frequently omitted and the design features of each adaptation are omitted from the discussion. In what way is the skin of a leech ideally suited to gas exchange? How are tracheal gills designed to exchange gases efficiently? Where does the syphon on a drone fly larva actually deliver the oxygen to? And are the lungs of snails like our own? Adaptation is inextricably linked to design, and without describing the design of structures, it is difficult to understand how they adapt the organism to a particular habitat. Finally, both an introduction and summary are needed to give the essay some shape. 3 stars