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

Describe the the growth of the plants in the 2 groups, There has not been r...

There has not been rain for several months. A biologist is driving down the highway and notices that a large number of corn fields have corn that is wilted and short. She wonders i

Simple closed circulation and double closed circulation, Q. What is the dif...

Q. What is the difference between simple closed circulation and double closed circulation? Double closed circulation or Closed circulation is that in which the blood circulates

Formation of cocoon in earthworm, Formation of cocoon in earthworm: I...

Formation of cocoon in earthworm: In earthworm segments from 14 to 17 are swollen. Skin on these segments is thick and glandular. This is called clitellum. When ovaries ma

Effect on water bodies - dissolved oxygen (do), Effect on Water Bodies - Di...

Effect on Water Bodies - Dissolved Oxygen (DO) Most aquatic, organisms respire with oxygen dissolved in water. The quantity of dissolved oxygen in a unit volume of aerated wa

5, Air Microbes

Air Microbes

Explain the assessment of zn status, Explain the Assessment of Zn Status? ...

Explain the Assessment of Zn Status? Sensitive indices for assessing zinc status are unknown at present. Static indices, such as zinc concentration in plasma, blood cells and h

Types of ecosystem, Ecosystems are so varied in form and structure that wha...

Ecosystems are so varied in form and structure that whatever has a distinct community of its own, can be called an ecosystem eg. A crop field, grass land, barks etc. all the ecosys

Precautions for determination of fungal and yeast count, Explain Precaution...

Explain Precautions for Determination of Fungal and Yeast Count? 1. Maintain aseptic conditions. 2. Keep alcohol away from flame. 3. To avoid infections and allergies, ca

What is a prion, Q. What is a prion? The prion is an infectious (transm...

Q. What is a prion? The prion is an infectious (transmissible) protein able to replicate by transforming other proteins into a copy of the prion. The mechanism of the copying i

Define sex-linked inheritance of nonmendelian inheritance, Why is sex-linke...

Why is sex-linked inheritance an example of nonmendelian inheritance? The Sex-linked inheritance is a kind of nonmendelian inheritance because it opposes Mendel's first law, wh

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