fertilisation occurs in ampulla of the uterine tube of the fallopian tube.
fertilisation occurs in ampulla of the uterine tube of the fallopian tube.
fertilisation occurs in which part of fallopian tube?
ampulla of the uterine tube
the tube allows passage of the egg from the ovary to the uterus. when an oocyte is developing in an ovary, it is encapsulated in a spherical collection of cells known as an ovarian follicle. just prior to ovulation the primary oocyte completes meiosis i to form the first polar body and a secondary oocyte which is arrested in metaphase of meiosis ii. this secondary oocyte is then ovulated. the follicle and the ovary's wall rupture, allowing the secondary oocyte to escape. the secondary oocyte is caught by the fimbriated end and travels to the ampulla of the uterine tube where typically the sperm are met and fertilization occurs; meiosis ii is promptly completed. the fertilized ovum, now a zygote, travels towards the uterus aided by activity of tubal cilia and activity of the tubal muscle. the early embryo requires critical development in the fallopian tube. after about five days the new embryo enters the uterine cavity and on about the sixth day implants on the wall of the uterus.
fallopian tube
numerous hypotheses exist to explain why male care may be most prevalent in species in which fertilisation occurs externally, and why female care is more common with internal fertilisation. firstly, trivers’ theory (1972) suggests that paternity certainty may influence which sex provides parental care to offspring. the reliability of paternity will be influenced by the mode of fertilisation, where external fertilisation occurs at the time of oviposition or egg laying, and internal fertilisation occurs during sexual reproduction within the body of a parent. the reliability of paternity may be decreased in internal fertilisation. this hypothesis suggests that a male should be less inclined to provide parental care if fertilisation occurs internally, because he is not as certain that the offspring are his.  when fertilisation occurs internally, a male will never be certain about his paternity unless he remains with the female until she lays eggs or gives birth. hence, ‘mate guarding’ may be established to ensure paternity certainty. if a male is not certain that the offspring is his, he may be better off finding another mate to avoid wasting time and resources in rearing young that are not actually his biological offspring.
parental care