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- Reproduction plays a pivotal role in every living organism to maintain its existence on earth.
- During this process, one or more offspring are produced from the parent organisms.
- The offspring produced are not identical to their parent organism; they're always a little different.
- The extent of the variation is determined by the mode of reproduction.
- Reproduction is broadly classified into two types: asexual and sexual reproduction.
- In sexual reproduction, two parents of the opposite sex are indulged.
- In asexual reproduction, the single parent is able to reproduce itself.
- Accumulation of Variation is an intrinsic ability that creates a pathway for evolution.
- Sexually reproducing creatures have a high level of variation, whereas asexually reproducing species have limited variation.
| Table of Content |
Key Terms: Accumulation of variation, Reproduction in organisms, Sexual reproduction, Asexual reproduction, DNA, Parent organisms, Fission, Budding, Zygote, Gametes, DNA.
What is Asexual and Sexual Reproduction?
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Asexual reproduction occurs when only one parent participates in the reproduction of children.
- The offspring produced by asexual reproduction are identical replicas of their parents.
- It is most commonly seen in extremely tiny creatures.
- The basic types of asexual reproduction are fission, budding, gemmulation, and fragmentation.
- Binary fission is common in prokaryotes and a few unicellular eukaryotes.
- In most organisms, genetic information is stored on chromosomes in the nucleus of reproductive cells known as gametes.
- These gametes then fuse to produce a diploid zygote. The zygote grows into a new individual.
- Sexual reproduction is the primary mode of reproduction in living organisms.
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| Related Articles | ||
|---|---|---|
| Double Fertilization | Gemmule Formation | Fragmentation |
| Biotechnology | Genetic Engineering | Endangered Species |
Accumulation of Variation
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Accumulation of variation during reproduction refers to the process by which genetic variation increases in a population over time.- There are two major ways of reproduction: asexual reproduction and sexual reproduction.
- Asexual reproduction transfers the genetic composition of a single parent to the offspring.
- Whereas sexual reproduction involves DNA from both parents.
- Asexual reproduction has less variation in physical characteristics, but sexual reproduction has lots of variation among the organisms.
How does Variation occur in Offspring?
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There are two types of variations in reproduction, which are given below:Variation in Asexual Reproduction
In asexual reproduction, only one parent is involved in the process. The genetic materials are transferred from one parent.
- As a result, the frequency of variation is highly reduced among offspring.
- Only little alterations can be noticed due to faults in the DNA copying machinery.
- Vegetables and fruits are the best examples of asexual reproduction.
Variation in Sexual Reproduction
In a sexual mode of reproduction gametes from two separate people are fused. As two separate people are involved, variation takes place at a higher frequency.
- As two people are involved, DNA becomes jumbled up, resulting in the greatest amount of variants in their kids, who look nothing like their parents.
- This accumulated variety in children is handed down from generation to generation, ensuring that an organism's genetic continuity is maintained.
- These variations can be observed from one generation to the next.
- The offspring of human beings are a good example of variation through sexual reproduction.
Importance of Variations
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Variation is an essential and complicated process among various organisms. It allows us to identify the similarities and differences in an individual child. Furthermore, the accumulation of variation during reproduction is crucial for evolution as well.
Some of the advantages of variation through reproduction are
- Variation helps in the selection of the most desirable attributes and assists organisms in a variety of physical attributes.
- It assists organisms to evolve with time to be best suited under environmental circumstances.
- Changes allow species to distinguish from one another. It also allows us to determine if they reproduce sexually or asexually.
- Due to variation, Hybrids can be created. For example, broccoli is a hybrid of cauliflower and cabbage.
- Variations result in the base of healthy genes being passed down from generation to generation.
Needs for Variation
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Each organism reproduces to grow its population and maintain its survival on Earth. As we all know, the environment is not the same everywhere, and adaptation to any adverse circumstance requires variation.- Environmental factors alter with changes in temperature, climate, humidity, resources, and so on.
- To survive under these conditions, one needs to adapt to them.
- These adaptations can be accomplished through individual variation, which is caused by changes in DNA and body design.
- Due to crossing over and recombination, the meiosis process produces DNA that differs from the parent cell.
- A change in the information on DNA indicates the beginning of variation.
Steps Leading to Variation
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A cell is referred to as the structural and functional unit of living organisms. Cells include nuclei within which they carry the genetic information for the upcoming generation in the form of DNA (Deoxyribonucleic Acid).
- So replication of DNA is the main factor that is working behind reproduction.
- This process starts with the help of original DNA and finally, replicas get separated from the original DNA strand.
- We get a new DNA strand and by new DNA strand, a new protein code is also present on the new DNA from this process.
- They look almost similar in nature, but not identical to each other.
- During the process of gametogenesis, the meiosis process takes place.
- For this process, offspring DNA is different from parental DNA due to the crossing over and recombination process.
- Again, for this process, there occur changes in the information present in DNA and therefore there occurs variation in an individual.
- Based on these processes variation can be slow or drastic and this variation is needed for the process of evolution.
Things to Remember
- Reproduction is the process of a parent organism producing one or more children.
- Asexual reproduction occurs when only one parent participates in the reproduction of children.
- In sexual reproduction, a new living being is created by mixing genetic material from two individuals of different sexes.
- Accumulation of Variation is an intrinsic ability that creates a pathway for evolution.
- Accumulation of variation during reproduction in asexual organisms is low as only single parents are involved.
- Accumulation of variation during reproduction in the sexual organism is high as two separate parents are present in the process.
- Evolution among living organisms is the result of Variations.
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Sample Questions
Ques. What do you mean by Heredity? (2 Marks)
Ans.
Heredity is defined as the transfer of genetic inheritance from biological parents to offspring during fertilization. Example: Two blue-eyed parents give birth to a blue-eyed child.Ques. In a species, all the Variations do not have equal chances of Survival. Discuss (2 Marks)
Ans.
It depends on the nature of the variations, as different kinds of organisms have distinct benefits and drawbacks. As a result, organisms that can adapt to their environment will live, while the rest will die. This is why not all variations have the same chances for survival.Ques. Why accumulation of variation during reproduction is essential? Discuss. (3 Marks)
Ans. We all know that reproduction causes diversity from generation to generation. Variation created in organisms throughout consecutive generations is accumulated in an organism over a lengthy period. These differences arise in the organisms after multiple generations, and the organisms begin to exhibit various features, resulting in the emergence of new species. The major benefit of a species' diversity is that it boosts its chances of surviving in a changing environment. Positively varying creatures are more likely to survive. Those who do not exhibit variety face extinction.
Ques. Differentiate between asexual and sexual modes of reproduction? (5 Marks)
Ans.
| Asexual Reproduction | Sexual Reproduction |
|---|---|
| 1. It does not involve the fusion of the male and female gamete. | 1. It involves the fusion of the male and female gamete. |
| 2. It requires only one individual. | 2. It requires two different organisms |
| 3. The individuals produced are identical to the parents and hence called clones. | 3. The individuals produced are not identical to their parents and show variation from each other and also from their parents. |
| 4. Asexual modes of reproduction are common in organisms having simple organisms such as algae and fungi. | 4. Most animals and birds reproduce sexually. In plants, however, sexual and asexual, modes of reproduction are found. |
| 5. Asexual reproduction is a fast process | 5. Sexual reproduction is a slow process |
Ques. Write a short description of Variation in Asexual Reproduction. (2 Marks)
Ans. In the case of asexual reproduction, only one parent is engaged in the process, hence genetic material is only transferred from one parent. As a result, there is little variety in these sorts of children; only little alterations may be noticed due to faults in the DNA copying process.
Ques. Discuss for example, how variation leads to the formation of new species. (1 Mark)
Ans. Broccoli is one of the best examples of a hybrid species. Broccoli is a vegetable that is man-made. It is a result of the hybrid between Cauliflower and Cabbage.
Ques. How is variation important for survival? Explain with examples. (2 Marks)
Ans. Variation is vital for a species' survival because it allows the organism to adapt to changing conditions. Organism species maintain well-defined roles in the ecosystem and use their reproductive potential to survive. For example, The ancient giraffes resembled deer and were significantly shorter than modern giraffes. According to one theory, it happened gradually over time because the trees in the locations where they resided were taller. As a result, deer that attempt to reach there for food have their offspring change into giraffes.
Ques. What is the importance of variation during reproduction? (5 Marks)
Ans. The accumulation of variation during reproduction is crucial for evolution as well. Some of the advantages of variation through reproduction are,
- Variation helps in the selection of the most desirable attributes and assists organisms in a variety of physical attributes.
- It assists organisms to evolve with time to be best suited under environmental circumstances.
- Changes allow species to distinguish from one another. It also allows us to determine if they reproduce sexually or asexually.
- Due to variation, Hybrids can be created. For example, broccoli is a hybrid of cauliflower and cabbage.
- Variations result in the base of healthy genes being passed down from generation to generation.
Ques. What are the steps that lead to variations during reproduction? (4 Marks)
Ans. The steps that lead to the variations during reproduction are:
- A cell is referred to as the structural and functional unit of living organisms.
- Cells include nuclei within which they carry the genetic information for the upcoming generation in the form of DNA (Deoxyribonucleic Acid).
- So replication of DNA is the main factor that is working behind reproduction and this process starts with the help of original DNA and finally, replicas get separated from the original DNA strand.
- We get a new DNA strand and by new DNA strand, a new protein code is also present on the new DNA from this process.
- They look almost similar in nature, but not identical to each other.
Ques. Why variation during reproduction is needed? (3 Marks)
Ans. Variation has contributed to the formation of new species that are significantly more adaptable than their ancestors. It also aids our understanding of the science behind this process on a more detailed level, allowing us to have a better understanding of many unanswered questions. As we've seen, variation is important in the world of science. It contributed to the formation of new species that are significantly more adaptable than their ancestors. It also aids our understanding of the science behind this process on a more detailed level, allowing us to have a better understanding of many unanswered questions.
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