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

Kind of tetrasporic embruo sac, what are the kinds of tetrasporic embryo sa...

what are the kinds of tetrasporic embryo sac...detail information

Intracellular unbound oxygen, Two compartments of equal volume of physiolog...

Two compartments of equal volume of physiological saline are divided by a membrane permeable only to oxygen.  At 1 AM, equal amounts of oxygen are dissolved into both left and

Gluconeogenesis, Gluconeogenesis Gluconeogenesis is the procedure throu...

Gluconeogenesis Gluconeogenesis is the procedure through that glucose is synthesized from smaller easier molecules such as lactate and pyruvate. Although the catabolic linear p

Foods implicated in botulism, The types of foods involved in botulism vary ...

The types of foods involved in botulism vary according to food preservation and eating habits in different regions. Any food that is conducive to outgrowth and toxin production, th

Bioenergetics, role of bioenergetics in our body

role of bioenergetics in our body

Class of coclentrata, ????? # 100 ??????????? #Minimum ?????? ?????

????? # 100 ??????????? #Minimum ?????? ?????

Theory of embryology - pre-formation theory, PR E FORMATION THEORY - ...

PR E FORMATION THEORY - Proposed by Marcello Malpighi. Studied chick egg and proposed his work in "De ova-incubato". According this different part of embryo previousl

Cultural and religious values, Wildlife has influenced language, art, relig...

Wildlife has influenced language, art, religion and social customs of many societies worldwide, and wild animals figure prominently in many cultures even today. In all cultures of

Intracellular sodium concentration of the motor neuron, Intracellular sodiu...

Intracellular sodium concentration of the motor neuron A complete motor neuron is removed from a frog and placed in normal physiological saline at 1 AM.  The neuron is healthy.

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