Give examples and explain what is meant by external fertilisation?
Answers
external fertilization is a case in which fusion of male and female gametes takes place in outside environment/ medium and not in the body of the female .
for example, in case of frogs , fertilization takes place in water medium . the female releases eggs in the water at the same time sperms are released too. the water current helps the meeting and fusion of gametes .
The release of eggs and sperm into the water is known as spawning.
likewise many fish follow similar method .
since the probability of sperm meeting the right egg is low ( due to factors like predators and unfavorable conditions , a large number of these( gametes ) are produced to compensate the loss .
Answer:
(i) The fusion of Male and Female gametes is called Fertilisation.
(ii) If the fertilisation occurs outside the body of the female organism, then it is called as External Fertilisation.
(iii) For Example, It can be seen in a Fish, Frog, Earthworm etc.