Differentiate between (a) oestrus and menstrual cycles; (b) ovipary and vivipary. Cite an example for each type.




Oestrus cycle

Menstrual cycles


These are recurring physiologic changes that occur in non primates females (cow, dog).

These are cyclic physiologic changes that occur in primates females (human, apes).


Oestrous cycles continue until death.

It ends at certain age of life. In human it is at 45 -55 years of age.


No or negligible bleeding takes place from vagina of female.

Profound bleeding takes place from female vagina.


The animals in which Oestrous cycles takes place are sexually reproductive for restricted period of time in a year which is known as the breeding season.

The female are sexually reproductive throughout the year.







Laying eggs that hatch and give birth to young ones.

  (of an animal) it is bringing forth live young ones that have developed inside the body of the parent.

  (of a plant) Reproducing from buds that form plantlets while still attached to the parent plant, or from seeds that germinate within the.


Birds, snake are examples of ovipary.

Humans, dog, mangroves trees are examples of vivipary.


Both internal and external type of fertilization leads to ovipary.

Only internal fertilization leads to vivipary.

  • 19

a ) osterus cycle - in non primates like cow , sheep etc. the cyclical changes that take place during reproduction is called osterus cycle 

menstrual cycles - in primates like monkey , apes , humans etc the the cyclical changes that takes place is called menstrual cycle .
b) oviparous animals means the animals which lays eggs . the eggs have hard calcareous covering which protects the egg from harsh conditions . and this type of act is called ovipary ex- reptiles 
viviparous animals are the ones where the zygote if formed inside the body of the mother . and gets all its nourishment .

  • 4
What are you looking for?