Challenges of moving from an aquatic to a terrestrial environment You have the pleasure of observing wood frog tadpoles in a pond on campus. You see them make the transition from gilled larvae into adults with lungs. In order to make this amazing transformation from an entirely aquatic life to one that includes time on land, your tadpoles will face a series of obstacles, not unlike those that the first vertebrate inhabitants of land faced. Complete the following sentences to correctly examine those changes. circulatory system Because of their large , ancestral amphibians likely faced challenges supporting themselves out of the aquatic environment.
cartilaginous bones feeding Although there was far oxygen available to gills in air than in water, the delicate structure of gills couldn't be supported in the terrestrial environment.
excretory system The costs of locomotion on land and greater oxygen demand from enlarged muscles led to modifications of the heart and
body size
more These early amphibians could not venture too far away from water because was restricted to moist environments.
less
egg deposition