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

Biological evolution, Natural selection is a process which directs all biol...

Natural selection is a process which directs all biological evolution. It is a process that directs genetic changes which when proved to be adapted to the environment are retaine

If jean-baptiste de lamarck was correct so result will be, If jean-Baptiste...

If jean-Baptiste de Lamarck was correct, than a. Natural selection would lead to the spread of favourable traits within a population b. Finches that stretched their beaks to access

How many carbon dioxide molecules are liberated, How many carbon dioxide mo...

How many carbon dioxide molecules are liberated after each cycle of the Krebs cycle? For a single glucose how many carbon dioxide molecules were already liberated by the aerobic re

PHYLUM ANNELIDA, GERENAL CHARACTERICS OF PHYLUM ANNELIDA

GERENAL CHARACTERICS OF PHYLUM ANNELIDA

Define some precautions for measurement of ph, Define some Precautions for ...

Define some Precautions for Measurement of pH? 1. Never touch the membrane of the glass electrode with anything else except soft tissue paper since it is fragile and is easily

Biogeochemical cycle, The cyclic exchange of nutrient material between orga...

The cyclic exchange of nutrient material between organisms and non-living  environment is called biogeochemical  cycle ,'geo means earth: ''chemical' means chemical elements, thus

Explain trichomoniasis, Trichomoniasis  Oral metronidazole has been the...

Trichomoniasis  Oral metronidazole has been the treatment of choice for trichomoniasis. Tinidazole (Tindamax - Medical Letter 2004; 46:70), a nitroimidazole similar to metronid

Explain components of second heart sounds, Explain Components of second hea...

Explain Components of second heart sounds? The first component of S 2 is due to closure of aortic valve (A,). The second component is due to closure of pulmonary valve (P 2 ).

Explain adaptive radiation, Adaptive radiation: The growth of a variety of...

Adaptive radiation: The growth of a variety of species from the single ancestral form; occurs when a new habitat becomes accessible to a population. The evolutionary pattern of di

Trends in succession - ecology, Trends in Succession - Ecology Success...

Trends in Succession - Ecology Succession is an important aspect of change in ecosystems and a simple description of successional communities the beginning of the story. We ne

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