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

Define intravascular fluid compartment - extracellular fluid, Explain intra...

Explain intravascular fluid compartment - extracellular fluid? The extracellular fluid compartment is sub-divided into the intravascular fluid compartment (fluid within the blo

Proteins, Amino Acid - compound with an amino group and a carboxyl group a...

Amino Acid - compound with an amino group and a carboxyl group attached to a central carbon Proteins make up 50% of dry mass of cells in our bodies E.g. of proteins are

Telophase of karyokinesis, - The chromosomes at each pole uncoil and elonga...

- The chromosomes at each pole uncoil and elongate to form the chromatin. - A nucleolus reappears at each pole. - Spindle fibers and asters disappear and centrioles split. - A nu

Which aqueous solution has the lowest ph, The aqueous solution with the low...

The aqueous solution with the lowest pH is: Select one: a. 0.01 M HCl. b. 0.1 M acetic acid (pKa = 4.86). c. 0.1 M formic acid (pKa = 3.75). d. 0.1 M HCl. e. 10 t

Psychosocial problems, PSYCHOSOCIA L PROBLEMS  - 1 .       Accidental...

PSYCHOSOCIA L PROBLEMS  - 1 .       Accidental injury - Automobile accidents are no. 1 killers of adolescents, as they drive often fast. 2 .       Depression - I

What is the general function of leukocytes, Q. What is the general function...

Q. What is the general function of leukocytes? What are leukopenia and leukocytosis? The general function of leukocytes is to participate in the made inside the body or defense

Community-based health insurance systems, Normal 0 false fals...

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

How does the swim bladder of fishes work, Q. How does the swim bladder of f...

Q. How does the swim bladder of fishes work allowing fishes to control their depth under water? From Hydrostatics it is known that an object does not sink if its density is les

How do you define normal pulmonary vasculature, Q. How do you define Normal...

Q. How do you define Normal Pulmonary Vasculature? Pulmonary vessels are seen in the medial 2/3 of the lung. Vessels are generally not identified in the lateral third. The rad

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