Tag: fertilization in organisms

Sexual reproduction is a characteristic of animals, although many animals reproduce sexually as well asexually. Reproduction is essential to the survival of any species. Most animals are involved in some variety of sexual reproduction. The methods vary greatly from the simultaneous release of sperm and eggs into the water for many marine organisms, to fertilization inside the body for most terrestrial organisms and high degrees of parental care in birds and mammals.

Aquatic animals like fishes and amphibia usually show external fertilisation, whereas terrestrial animals like reptiles, birds and mammals show internal fertilisation. Egg of animal showing external fertilization is not covered by a hard, protective shell and after fertilisation the embryo develops into larva in water. 

In human males the urethra, a tube that exits through the penis, carries urine to the exterior and, alternatively, serves as a conduit for seminal fluid. Sperm is carried in a fluid formed along the male reproductive tract by the seminal vesicles, prostate gland, and cowper's glands, accessory glands of the male reproductive tract. Thus, if cowper's glands are removed process of fertilization will be affected.

Tubectomy is a surgical procedure for sterilization in which a woman's fallopian tubes are clamped and blocked, or severed and sealed, which prevents eggs from reaching the uterus for implantation, thereby no fertilization can takes place. It is considered the permanent method of birth control. 

1)fertilization starts with fusion of male gamete (sperm) and female gamete (zygote). 
2) this fusion results in the formation of zygote. 
3) Zygote divided repeatedly to give rise ball of cells that forms embryo.
4) after the formation of embryo is gets embedded in the wall of uterus where it further forms the foetus so the correct order is in above steps.

Chlorophyceae is a class of algae that is also known as green algae commonly. Different members of this class reproduce differently.

The phenomenon of fertilization was first perceived by the German biologist Oscar Hertwig in sea urchin eggs in 1876. Hertwig observed that the sperm nuclei and egg fused during fertilization resulting in the generation of new organism. Thus the correct answer is option D.

Chlamydomonas reproduces both asexually and sexually.