Assistant Laboratory Animal Technician (ALAT) Practice Exam

Where does fertilization typically occur in amphibians?

1. Inside the female's reproductive tract

2. In a controlled environment

3. Outside the female's reproductive tract

4. In aquatic environments only

The correct answer is: Outside the female's reproductive tract

Fertilization in amphibians typically occurs outside the female's reproductive tract. This process is known as external fertilization, which is common in many amphibian species. During mating, the male often fertilizes the eggs as the female lays them in water. This method allows the eggs to develop in a safe, aquatic environment where they are protected from some terrestrial predators. The preference for external fertilization is also tied to the life cycle of amphibians. Their eggs are usually laid in clusters or strings in water and require moist conditions to prevent desiccation. Since fertilization happens in water, it facilitates the meeting of sperm and eggs and ultimately enhances the chances of successful reproduction. While amphibians are primarily aquatic during their larval stages, the other answer choices do not accurately represent the common reproductive strategies of these animals. For instance, fertilization inside the female's reproductive tract is more typical of reptiles and mammals, while a controlled environment isn't a natural occurrence for most amphibian species. Lastly, although aquatic environments are preferred for egg-laying, fertilization can occur in various water bodies and is not limited solely to aquatic environments in a strict sense.