BIOL108 Lecture 31: Nov. 25 (Amphibians)

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL108
• Professor: Lien Luong

Document Summary

Amphibious life: aquatic larvae (tadpole) and terrestrial adults. They lose their tail as they mature and come onto land. As tadpoles, they have gills and lateral lines, as well as their tail but no legs. They have external fertilization: the male holds onto the female, she releases her eggs, and then he releases the sperm over top of the eggs. The eggs lack a shell, and so the eggs are laid in the water. They are not fully adapted to life on land. They have front and hind legs, and they are jointed. The adults live on land, but they mate in the water. They lack a tail in the adult stage. Some frogs take care of eggs or tadpoles. They carry them on their back, in their mouth, or stomach. Therefore, the embryos can develop without drying out. Eggs can remain in the female reproductive tract and "hatch" as tiny froglets (ovoviviparous and viviparous).