Karnataka SSLC Karnataka Secondary Education Examination Board
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Reproduction - Introduction

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description

  • Do organisms create exact copies of themselves
  • DNA (Deoxyribo Nucleic Acid)
  • DNA copying
  • The Importance of Variation

notes

Reproduction is the process by which living organisms produce new individuals similar to themselves. It ensures continuity of the species on earth.

Nucleus of the cell contains DNA (Deoxyribose Nucleic Acid) which is the heredity material.

DO ORGANISMS CREATE EXACT COPIES OF THEMSELVES?

-Chromosomes in the nucleus of a cell contain information for inheritance of features from parents to next generation in the form of DNA molecules.

-The DNA in the cell nucleus is the information for making proteins. If the information is changed different proteins will be made.

-Different proteins will eventually lead to altered body designs , therefore the basic event in reproduction is the creation of a DNA copy.

-The DNA copying is accompanied by the creation of an addition cellular apparatus and then the DNA copies separate each with its own cellular apparatus. The cells divide to give rise to two cells.

-It is only to be expected that the process of copying the DNA will have some variations each time. As a result, the DNA copies generated will be similar, but may not be identical to the original.

IMPORTANCE OF VARIATION:-

-The consistency of DNA copying during reproduction is important for the maintenance of body design features that allow the organism to use that particular niche.

-Reproduction is therefore linked to the stability of populations of species.

-Variation are beneficial to the species because sometimes for a species, the environmental conditions change so drastically that their survival rate becomes difficult.

-If a population of reproducing organisms were suited to a particular niche and if the niche were drastically altered, the population could be wiped out. However, if some variations were to be present in a few individuals in these populations, there would be some chance for them to survive.

-Thus, if there were a population of bacteria living in temperate waters, and if the water temperature were to be increased by global warming, most of these bacteria would die, but the few variants resistant to heat would survive and grow further. Variation is thus useful for the survival of species over time.

Video Tutorials

We have provided more than 1 series of video tutorials for some topics to help you get a better understanding of the topic.

Series 1


Series 2


Shaalaa.com | How Do Organisms Reproduce (Introduction and asexual reproduction)

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How Do Organisms Reproduce (Introduction and asexual reproduction) [00:07:47]
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