Reproduction, Biology

Assignment Help:

Reproduction

Living things do not arise spontaneously. They arise only from pre-existing living things This is one of the fundamental tenets of biology. The ability of an organism to reproduce its kind is characteristic of living things. Reproduction involves transmission of information by the remarkable hereditary material deoxyribonucleic acid (DNA) contained in the nucleus. The heredity material is subject to change or mutation. When provided with necessary conditions the DNA molecule is capable of replicating itself. The DNA codes for the information regarding structure and function of the organisms.

For example, DNA ensures that cats always produce kittens, never pups. In simple organisms such as protists, reproduction may be asexual. For example, a protist like amoeba reproduces by simple division. When the amoeba grows to a certain size it makes a duplicate copy of its DNA, each copy separating into a nucleus. The amoeba divides into two, each daughter amoeba thus possessing a nucleus with a copy of DNA. However, higher plants and animals reproduce sexually. This involves the union of a male gamete and female gamete. The male gamete is the sperm whereas the female gamete is the egg.

The sperm fertilizes the egg to form a zygote which then develops into a new individual. Each gamete has ope complete copy of genes (DNA) derived from its parents. So gametes are haploid. Union of two gametes and fusion of their nuclei result in the doubling of the DNA content in the zygole, which is hence diploid. All cells derived from the zygote are diploid. Thus, each offspring is not a mere duplicate of a single parent but is the product of the interaction of various genes (DNA) contributed by both mother and father. This results in genetic variation which is important from the point of view of evolution and adaptation. Thus, though an individual dies, it perpetuates itself by the process Of reproduction, and the race continues.

2499_Reproduction.png

Figure: Approaches to reproduction - (a) in asexual reproduction, one individual gives rise to offsprings which are identical to the parent. (b) In sexual reproduction, each parent contributes a sex cell; these join to give rise to the offspring which thus has the genes and traits of both parents.


Related Discussions:- Reproduction

Explain the nutrient requirements during lactation, Normal 0 fa...

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

#to work as expert, Ask question #process for work as expert#

Ask question #process for work as expert#

Basis of classification on form-relationship principle, Q. Basis of Classif...

Q. Basis of Classification on Form-relationship principle? As pointed out earlier, this system is mainly based on Form-relationship principle. thus the various genera were. g

Investigation of aortic regurgitation by surgical therapy, Q. Investigation...

Q. Investigation of aortic regurgitation by Surgical Therapy? The recommendation for Aortic valve replacement is only for those patients with Severe AR. If patients with mild A

Disaccharides, DISACCHARIDES They are oligosaccharides composed of t...

DISACCHARIDES They are oligosaccharides composed of two monosaccharide residues . Three common disaccharides are    sucrose (glucose + fructose) = cane suger maltose

Productivity in medical transcription, Describe several factors which affec...

Describe several factors which affect Productivity in Medical Transcription. Definition of Medical Transcription Show the various factors thataffect Productivity in Medi

Subphylum trilobitomorpha, Subphylum Trilobitomorpha Subphylum Trilobi...

Subphylum Trilobitomorpha Subphylum Trilobitomorpha involves the trilobites. All species are extinct and the fossils point out that they were all marine forms belonging to Pal

Explain casein, Explain Casein Casein is an important example of protei...

Explain Casein Casein is an important example of protein, which can be boiled without apparent change in stability. The exceptional stability of casein makes it possible to boi

Define significance of plants and animals on human life, Define Significanc...

Define Significance and Impact of Plants and Animals on Human Life? Plants and animals both have a great significance and unparalleled impact on human life. Most of our needs a

In hormonal terms why does menses occur, In hormonal terms why does menses ...

In hormonal terms why does menses occur? Menses is the endometrial monthly desquamation that happens as the estrogen and progesterone levels fall after the regression of the co

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