Question

What behavioural modifications allow for this grasshopper to be well adapted to its environment? Think about respiration in the grasshopper. Would the same system work on a larger organism? Why or why not? How does this respiration compare to the worms that you examined last week?

Answer 1

There are many adaptations that a grasshopper has. The most common is the small pores known as spiracles that are used for breathing. Spiracles are small holes in their exoskeleton that allow air to enter their body. The air then diffuses into a tracheal system of tubes and branches to get oxygen into the cells of an insect. If the environment is arid and dry, the insect can close its spiracles and use the air stored in special air sacs to get water. This adaptation allows insects to be found in almost every terrestrial environment.

The same system on a larger organism won't work efficiently since the trachea would require greater proportion of body due to increase in their body size. The situation becomes more complex in larger animals in which the spiracles may dynamically vary their opening areas according to changes in power requirements. This opening can get only so big, and limits the size of the trachea that runs through it. When tracheal size is limited, so is oxygen supply and so is growth.