NCERT books are written in the most efficient way with each topic explained in a well-structured format that helps to break the complex problems quite easily. The questions given at the end of each chapter are based on every conceptual topic. Students must solve all these NCERT questions to keep a track of their understanding. Practicing the NCERT questions will assure good results as most of the questions in the board examinations are asked from NCERT textbooks.
In this article we are presenting the NCERT solutions for CBSE Class 10 Science chapter 9, Heredity and Evolution. All the solutions have been prepared in a way to help you easily understand the concept implied in each solution.
All the class 10 Science NCERT solutions have been collated in PDF format which students may easily download free of cost.
Some of the questions and their solutions from NCERT Solutions for Class 10: Heredity and Evolution, are as follows:
Q. If a trait A exists in 10 % of a population of an asexually reproducing species and a trait B exists in 60 % of the same population, which trait is likely to have arisen earlier?
Sol. Trait B. In asexual reproduction traits which are present in the previous generation are carried over to next generation with minimal variations. Therefore, the traits present in higher percentage have greater chances of persisting earlier.
Q. Why are traits acquired during the life time of an individual not inherited?
Sol. Any changes in the somatic cells cannot be passed to DNA of germ cells. Hence, these traits are not inherited.
Q. Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics?
Sol. Smaller number means fewer variations. Number of variation is directly related to the frequency of natural selection. For effective selection, population must consist of infinite number of individuals in a population. For any reason, if these tigers died, chances of their becoming extinct are very high.
Q. Why are human beings who look so different from each other in terms of size, color and looks said to belong to the same species?
Sol. Although human beings look so different from each other in terms of size, color and looks but all of them belong to the same species (homo sapiens) because of the following reasons:
All human beings belong to the same species and are able to interbreed.
Fossil evidences prove that earliest homo sapiens arose in South Africa and moved across the continents and developed into different races during the ice age.
Fossil evidence shows that humans have not changed much anatomically over last 200,000 years.
Q. Explain how sexual reproduction gives rise to more viable variations than asexual reproduction. How does this affect the evolution of those organisms that reproduce sexually?
Sol. We know the fact during sexual reproduction variations arise as the offspring is bi parental. On the contrary, variations are minimal in case of asexually reproducing organisms as it is uni-parental.
After studying the theory of variations and natural selection, we can say that variants help the species to survive in all conditions. Environmental conditions such as heat, light, pests and food availability can change suddenly at any place at any time. At that time only those variants which are resistant to these conditions would be able to survive. Hence, this will slowly lead to the evolution of a better adapted species. Thus variations help in evolution of sexually reproducing organisms.
Get the complete the NCERT solutions for Class 10: Heredity and Evolution, from the following link:
Class 10 Science NCERT Chapter: Heredity and Evolution
Before solving the questions given in the Class 10 Science NCERT chapter- Heredity and Evolution, students should thoroughly read this chapter to grasp all the concepts explained in it. This will help you understand the problem discussed in a question and then come with an appropriate answer.
Main topics discussed in Class 10 Science chapter: Heredity and Evolution are:
- Accumulation of variation during reproduction
- Inherited traits
- Mendel’s contributions to inheritance rules
- Sex determination
- Acquired and inherited traits
- Evolution and classification
- Tracing evolutionary relationships
- Evolution by stages
- Human evolution.
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