Bi-parental reproduction, Biology

Assignment Help:

Bi-Parental Reproduction

In sexually reproducing metazoans, there are separate and distinct male and female individuals. Each has its own reproductive system and produces one kid of sex cell, spermatozoon or egg. Nearly all vertebrates and many invertebrates have separate sexes, and such a condition is celled dioecious and this type of reproduction is called biparental reproduction. However, some animals such as most flatworms, some hydroids, annelids, crustaceans and some fishes have both male and female organs in the same individual. Such a condition is called hermaphroditism. In contrast to the dioecious state of separate sexes, hermaphrodites are monoecious, having both male and female organs in the same organism Most of the hermaphrodites avoid self-fertilization by exchanging germ cells with each other.

For example, although the earthworm bears both male and female organs, its eggs are fertilised by the copulating male and vice versa. Hermaphrodites also prevent self-fertilisation by developing eggs and sperms at different times. If we admit that all living things are mortal, that every living organism is endowed with a life span that must eventually end, then reproduction is indispensable for the continuance of species. During evolution the efficiency of reproduction increased where the parents protect and provide nutrition for the young before or after birth. The adaptations that are found in vertebrates are internal fertilisation, the cleidoic (enclosed in shell) egg, and the foetal membranes. Parallel adaptations are also found in lower animals.


Related Discussions:- Bi-parental reproduction

Other complications in prosthetic valves, Other Complications :  Bioprosth...

Other Complications :  Bioprosthetic valves have a tendency for degeneration, calcification or cusp perforation. Current models have overcome many of these problems. Calcification

Food processing and preservation, various changes that occur during concent...

various changes that occur during concentration of food

Intro to Genetics and Punnett Squares , "Height" is an example of a gene, b...

"Height" is an example of a gene, but "Short" is an example of...

Prosthetic valve endocarditis, The risk of PVE is greatest during the initi...

The risk of PVE is greatest during the initial 6 months after valve surgery (particularly during the initial 5 to 6 weeks) and thereafter declines to a lower but persistent risk (0

Production of healthcare - contestability and measurability, Normal 0 ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

What is its function of cardia, Q. What is the route of the ingested food f...

Q. What is the route of the ingested food from swallowing until the duodenum? Until reaching the duodenum the food enters the mouth, passes the pharynx, passes the stomach and

General requirements of implant materials, General requirements of implant ...

General requirements of implant materials 1) Biologically compatibility: an ideal implant material will elicit mainly physiological reactions within the surrounding tissues (bo

Classification, what is binomial nomenclature? What are the importance of i...

what is binomial nomenclature? What are the importance of it?

Explain the neuritic type of infantile beriberi, Explain the neuritic type ...

Explain the neuritic type of infantile beriberi? It is also referred to as Wernicke korsakoff syndrome or cerebral beriberi. It shows typical manifestations of peripheral neuro

Why poriferans and cnidarians do not have excretory systems, Poriferans and...

Poriferans and cnidarians do not have excretory systems. Do platyhelminthes have an excretory system? Platyhelminthes have a primitive excretory system made of flame cells (als

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd