Question

Define external fertilization. Mention its disadvantages,Give step by step details.

Answer 1

When fusion of the gametes takes place outside the body of the organisms, it is called external fertilization or external syngamy. The external medium like water is required for this form of fertilization. This form, is found in many aquatic animals like fishes, amphibians, majority of algae.

In this, parents release eggs and sperms in the surrounding water, then fertilization and development of offspring occur externally. Disadvantages of external fertilization:

(i)if occurs only in aquatic medium.

(ii)A chance factor is involved requiring synchronous release of gametes nearby and absence of turbulence of water.

(iii)There is no protection to young ones. They are vulnerable to a number of predators.

When fusion of the gametes takes place outside the body of the organisms, it is called external fertilization or external syngamy. The external medium like water is required for this form of fertilization. This form, is found in many aquatic animals like fishes, amphibians, majority of algae.

In this, parents release eggs and sperms in the surrounding water, then fertilization and development of offspring occur externally.