List the two types of reproduction. Which one of the two is responsible for bringing in more variations in its progeny and how?
List the two types of reproduction. Which one of the two is responsible for bringing in more variations in its progeny and how?
The two types of reproduction are:
- Asexual Reproduction: A mode of reproduction where a single individual gives rise to a new generation without the fusion of gametes.
- Sexual Reproduction: A mode of reproduction that involves the combination of DNA from two different individuals (typically male and female) to create a new generation.
Sexual reproduction is responsible for bringing in more variations in its progeny.
How it brings more variations:
- Combining DNA from two individuals: During sexual reproduction, DNA from two different parents is combined. This creates a completely novel combination of genetic material in the offspring.
- Accumulated variations: Each parent already carries variations accumulated over previous generations. When these distinct patterns of variations are combined, the resulting offspring has a unique set of traits.
- Meiosis: The specialized germ-cells (gametes) are formed by a process of cell division called meiosis, which halves the chromosome number and introduces genetic recombination, further enhancing variation.
Marking Scheme
- 1Listing the two types of reproduction (Asexual and Sexual) (1 mark)
- 2Identifying Sexual reproduction as the one responsible for more variations (0.5 marks)
- 3Explaining how sexual reproduction brings variations (combining DNA from two individuals, meiosis, and accumulated variations) (1.5 marks)
Hint
Think about the number of parents involved in each type of reproduction and how combining genetic material from two different sources affects the uniqueness of the offspring's DNA.
Quick Oral Answer
The two types of reproduction are asexual and sexual. Sexual reproduction brings more variation because it combines the DNA of two different parents, creating a unique genetic combination in the offspring.
Analysis & Explanation
Asexual reproduction involves only one parent, and the DNA copying mechanism, though prone to minor errors (variations), is highly consistent to maintain the body design. Thus, variations occur very slowly. In contrast, sexual reproduction inherently combines the genetic blueprints of two distinct individuals. Since both parents have survived with their own unique sets of accumulated variations, combining their DNA creates a highly diverse and novel combination in the zygote without causing lethal defects. This rapid generation of diversity is the primary evolutionary advantage of sexual reproduction.
Common Mistakes
- 1Students often forget to mention that the variations combined in sexual reproduction are already tested by survival in previous generations.
- 2Confusing the role of DNA copying errors in asexual reproduction with the active genetic recombination in sexual reproduction.
Interesting Facts
While asexual reproduction is highly efficient and rapid, sexual reproduction is favored in changing environments because the resulting variations help at least some individuals survive drastic ecological shifts.
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Frequently Asked Questions
How many marks does this question carry in CBSE Class 10 Science 2017?
This question carries 3 marks in the CBSE Class 10 Science 2017 examination.
Which chapter does this question come from in Science?
This question is from the chapter "How do Organisms Reproduce?" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Sexual Reproduction vs Asexual Reproduction" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2017 paper?
This is a Short Answer question from Section A in the CBSE Class 10 Science 2017 paper.