Write a note on fertilization of frog?
Structure of Eggs: -
i) Eggs are produced in ovaries present in abdomen.
ii) Each egg is like a small ball spherical structure having
a. One half pigmented part called animal hemisphere.
b. One yellowish part due to storage of food or yolk called vegetal hemisphere.
iii) The middle of these two halves is called equator.
iv) Animal hemisphere contain nucleus of the egg cell.
v) After the sperm enters the egg, small grayish crescent shaped area called grey crescent is formed on one side of the animal hemisphere close to the equator.
External Fertilization: -
i) Male sex cells or sperms are produced in a pair of testes during breeding season.
ii) Female release egg and male release sperm in water where fertilization takes place
iii) This result in formation of zygote. This is called external fertilization.