Q14
3 marksShort AnswerSection A

“We cannot pass on to our progeny the experiences and qualifications earned during our life time”. Justify the statement giving reason and examples.

Heredity
Acquired and Inherited Traits
Official Answer

The statement "We cannot pass on to our progeny the experiences and qualifications earned during our lifetime" is scientifically correct.


Justification and Reason:

  1. Somatic vs. Germ Cells: Human bodies consist of two types of cells: somatic cells (non-reproductive body cells) and germ cells (reproductive cells/gametes).
  2. No Change in DNA: Experiences, skills, and qualifications acquired during a lifetime (such as learning to play an instrument, studying for a degree, or building muscles) only bring about changes in the somatic tissues. They do not alter the cellular DNA of the germ cells.
  3. Mechanism of Inheritance: According to the rules of heredity, only the genetic information present in the DNA of germ cells (sperm and egg) is transmitted to the next generation during reproduction. Since acquired traits do not modify the DNA sequence of germ cells, they cannot be inherited by the progeny.

Examples:

  • Example 1: If a parent learns to speak multiple languages or obtains a PhD degree (qualification), their child will not automatically inherit these languages or knowledge at birth. The child must learn them from scratch.
  • Example 2: If a person loses a limb in an accident or develops strong muscles through weightlifting, these physical changes are not passed on to their offspring because the DNA in their gametes remains unaffected.
Acquired traitsSomatic cellsGerm cellsDNAReproductionNon-heritable

Marking Scheme

  • 1State that experiences/qualifications are acquired traits and do not alter the DNA of germ cells. (1 mark)
  • 2Explain that only changes in the DNA of germ cells (reproductive cells) are passed on to the progeny. (1 mark)
  • 3Provide suitable examples (e.g., learning a language, muscle building, or surgical scars) to support the justification. (1 mark)

Hint

Think about where genetic information is stored and which cells are involved in reproduction. Do your daily activities or studies change the DNA inside your sperm or egg cells?

Quick Oral Answer

Acquired traits are those developed during an organism's lifetime and do not affect germ-cell DNA (e.g., learning to swim). Inherited traits are genetically determined and passed from parents to offspring via DNA (e.g., eye color).

Analysis & Explanation

This question tests the fundamental difference between acquired traits and inherited traits. Inherited traits are genetically determined and passed from parents to offspring because they are encoded in the DNA of germ cells. Acquired traits are developed by an organism during its lifetime in response to the environment or personal efforts. Since these changes do not affect the DNA of the reproductive cells, they perish with the death of the individual and cannot be transmitted to the next generation.

Common Mistakes

  1. 1Confusing acquired traits with inherited genetic mutations.
  2. 2Failing to mention that changes must occur in the germ cells/gametes to be inherited.

Interesting Facts

Jean-Baptiste Lamarck originally proposed that acquired characteristics could be inherited, but this theory was later disproven by August Weismann, who cut off the tails of mice for 21 generations and showed that the 22nd generation was still born with normal-sized tails!

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2015?

This question carries 3 marks in the CBSE Class 10 Science 2015 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Heredity" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Acquired and Inherited Traits" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2015 paper?

This is a Short Answer question from Section A in the CBSE Class 10 Science 2015 paper.