Question

What modifications were made to adjust for life on land ? Briefly explain at least 3 modifications.

Answer 1

Breathing

Early land vertebrates are believed to have arisen from a line of fishes that possessed lungs. The ability to breathe air developed at the same time that land vertebrates were making their first forays onto dry soil. The bigger problem for these creatures to tackle was how to dispose of excess carbon dioxide produced during respiration. This challenge—possibly to an even greater extent than finding how to acquire oxygen—shaped the breathing systems of early land vertebrates.

Water Loss

Dealing with water loss (desiccation) presented early land vertebrates with challenges as well. The loss of water through the skin can be minimized in a number of ways: by developing watertight skin, by secreting a waxy waterproof substance through glands in the skin, or by inhabiting moist terrestrial habitats. Early land vertebrates made use of all of these solutions. Many of these creatures also laid their eggs in water to prevent the eggs from losing moisture.

Adjustment of Sensory Organs

Here, the challenge of adapting to life on land was the adjustment of sensory organs that were meant for life underwater. Modifications in the anatomy of the eye and the ear were necessary to compensate for the differences in light and sound transmission. Additionally, some senses were simply lost when vertebrates moved onto land, such as the lateral line system. In water, this system allows animals to sense vibrations, making them aware of nearby creatures; in the air, however, this system has little value.