Class 10: How do organism reproduce
Exemplar Problems with Solutions
Very Short Answer Type Questions:
- What is reproduction
- What is DNA replication?
Write True/False for the following:
- Reproduction is one of the life processes.
- DNAs are present on chromosomes.
- Reproduction is essential to continue life.
- A large variation often results in the death of daughter cells.
Short Answer Type Questions:
- What is the significance of variation?
- What is the significance of reproduction?
Long Answer Type Questions:
- How does DNA replication facilitate variations?
Brainstorming Session
- Why is variation beneficial to the species but not necessarily for the individual? (NCERT)
ANSWER
Very Short Answer Type Questions:
- Answer: The process by which an organism produces its offspring is called reproduction.
- Answer: The process by which additional copies of DNA are created is called DNA replication.
Write True/False for the following:
Answer: 1 à F, 2 à T, 3 à F, 4 à T
Short Answer Type Questions:
- Answer: Following are the significance of variation:
- Variations facilitate the solution of new species.
- Variations help a particular species to survive the changes in external environment.
- Answer: Had there been no reproduction, we would not have seen so many organisms around us. The whole concept of biodiversity can be said to be based on reproduction. This is because of reproduction that numerous types of organisms exist on the earth. The life forms would not have thrived on the earth in the absence of reproduction.
Long Answer Type Questions:
- Answer: DNA replication is the process by which additional copies of DNA are created. This process is of very high precision which creates exact copies of DNA. But no biological process is foolproof. As a result, there would be some alterations in the daughter DNAs. If the alterations are too many then the new DNA would not be able to survive and the daughter cell would die eventually. If the alterations are minor then the new DNA shall survive and so would the daughter cells. Thus, the daughter cells would carry some minor variations which shall be incorporated in future generations. This is the key reason for the appearance of variations in subsequent generations of a species.
Brainstorming Session
- Answer: Variations accumulate over many generations and eventually result in the evolution of new species. Variations also help an existing species to develop adaptations in order to survive under changed environmental conditions. Thus, variations are beneficial to the species. But an individual has to go through the stress of suffering the changes in the external environment because the cumulative effect of variations takes too much time to show results. Hence, variations are not necessarily beneficial for the individual.