AP BIOLOGY

Detailed explanation-1: -Among vertebrates, external fertilization is most common in amphibians and fish. Invertebrates utilizing external fertilization are mostly benthic, sessile, or both, including animals such as coral, sea anemones, and tube-dwelling polychaetes.

Detailed explanation-2: -External fertilisation can occur both in water and on land.

Detailed explanation-3: -External fertilization is most common in aquatic habitats, where both eggs and sperm are released into the water. Fertilization can begin once the sperm reaches the egg. Fish, frogs and starfish reproduce externally by releasing their eggs into the water and releasing the sperms over the secreted eggs.

Detailed explanation-4: -In aquatic animals, fertilization takes place in water. They release their gamete (sperm and egg ) in water which fuses to form a zygote. As fertilization takes place outside the body so it is known as external fertilization and such animals are known as oviparous as the embryo development takes place in the egg.

Detailed explanation-5: -External fertilization in an aquatic environment protects the eggs from drying out. Broadcast spawning can result in a greater mixture of the genes within a group, leading to higher genetic diversity and a greater chance of species survival in a hostile environment.