Reproduction in Organisms Test - 16

The male and female reproductive parts of flower are stamen and carpel. If both stamen and pistil are present in same flower, the flower is called monoecious.

Anthers are produced from diploid cells without undergoing to meiosis cell division so, anther and diploid. Pollens grains are produced inside the anther by meiosis division to produce haploid gametes.

The menstrual cycle in human being is repeated at the interval of 28/29 days. It starts with raptures of inner lining of uterus. In the middle of menstrual cycle ovulation takes place.

In Viviparous, well developed young one is produced by female at the end of gestation period. There is no fear of predator of outer environment as in case of oviparous in which young one comes out of egg. Viviparous mode of development is not influenced by adverse environmental conditions.

In angiosperms, female gametophyte is called embryo sac which is 7-celled but 8-nucleated structure. Embryo sac is formed inside the ovary that changes into seeds after fertilisation.

Meristematic tissue change into permanent tissue by the process of differentiation. The permanent tissue becomes meristematic due to de-differentiation.

Pollen grain is two layered structure. The outer layer is called exine and inner layer is called intine. Exine is a hard covering, except at germ pore, through which pollen grain germinate.

After fertilisation ovule changes into seeds and ovary itself change into fruits. The outer hard integuments of ovary form protective layer of fruit called pericarp followed by mesocarp and endocarp.

The transfer of pollen grain from anther to stigma of same flower is called self-pollination. Both anther and stigma must be ready at same time for this kind of pollination.

Animals reproduce sexually either by producing fertilized egg or by giving birth young ones directly. The viviparous (young one producing) is more evolved method of sexual reproduction.