Question

Do external fertilisation happen externally explain?

Answer 1

The process of external fertilization is a physio -biochemical process by means of which the haploid sperms and ova unite together to form a diploid zygote.

• External fertilization does not require specialized structures like placenta etc for survival of foetus

• It is prevented from dessication by environment

• There is a potential for high rate of reproduction

• Parental care is not essential

  The main feature of external fertilization are:

• Both the male and female parents interact only during a specific breeding period and spawning is observed
• In some animals like fishes or certain frogs. the process differs a little where parental care is observed as far as care of the young are concerned
• The eggs and the sperm are released together after a little sport ,under appropriate conditions of temperature, light, rainfall etc
• The sperms find their way to the ova by chemo-taxis involving specific chemicals
• The fertilized embryo develops inside the egg covered by thin shell, in certain cases, they may be carried by the mouth, or borne on the back
• The developed embryo hatches into a larva which undergoes further development into fingerling, fry ,then into adult
• The matured larva can undergo progressive metamorphosis as the tadpole larva develops into a frog