Answer:
Many evolutionary changes resulted in the transition of aquatic vertebrates into terrestrial organisms. Some of these are:
In terrestrial organisms, the respiratory system is more complex and enhanced than the aquatic vertebrates. For instance, the early amphibians had gills for respiration. But with the passage of time, lungs appeared which made life on land more feasible.
The formation of rigid and insulated body coverings also was an adaptation that emerged for making life feasible on land.
Limbs allowed movement on land. With the passage of time, feet developed from the limbs.
