Download free PDF of NCERT answer keys for Class 10 Science Heredity and Evolution – CBSE Term II
NCERT Solutions for Class 10 Science Chapter 9 Heredity and Evolution contains answers to all textbook problems as well as a comprehensive explanation of the idea. With the NCERT Solutions provided here, you may learn about significant ideas and the methods for solving them, all of which have been meticulously answered by our highly skilled professors. Where necessary, intext inquiries are also answered with adequate explanations. In addition, we ensure that relevant content on NCERT Solutions Class 10 is updated on a regular basis in accordance with the CBSE board. We also make certain that the answers we provide are tailored to fit specific criteria that teachers use to assign grades.
As many questions may arise in the CBSE Term II exams, Chapter 9 of NCERT Solutions is a very important and scoring chapter. Students will gain a thorough understanding of the ideas based on the CBSE board’s most recent syllabus. To assist students with the exercise-by-exercise answers, INFINITY LEARN provides free PDF solutions that may be downloaded at any time. It also expedites syllabus revision a few days before the exam. Students can get a free PDF of NCERT Solutions for Class 10 Science by clicking on the links below.
CHAPTER 9_HEREDITY AND EVOLUTION NCERT SOLUTIONS
1.Explain the importance of fossils in deciding evolutionary relationships.
A. i) Evidences left behind by the extinct organisms are called fossils.
ii) Study of fossils give us important clues about missing links in the evolutionary relationships.
iii) The fossil bird Archeopteryx is a good example of missing link which shows the characteristics of birds and reptiles.
iv) This suggests that birds have evolved from reptiles. This example shows the importance of fossil in deciding the evolutionary relationship.
2. What evidence do we have for the origin of life from inanimate matter?
A. i) The earliest living forms had dumps of nucleoproteins containing one or two DNA molecules which are similar to organisms of Monera.
ii) Harold Urey and Stanley Miller proved the chemical origin of life.
iii) They tried to replicate the primordial conditions in the laboratory.
iv) They sealed a mixture of water vapour, methane, ammonia and hydrogen in a spark chamber which provided all the requirements.
v) After some days, they noticed simple amino acids such as glycine, alanine and aspartic acid in the aqueous solution (similar to prebiotic soup).
vi) Later in similar experiments, formation of all types of amino acids, nitrogen bases were noticed.
3. Explain how sexual reproduction gives rise to more viable variations than asexual reproduction. How does this affect the evolution of these organisms that reproduce sexually?
A. i) In asexual reproduction, offspring will get the same genetic material of the parent.
ii) Due to this, offspring exhibit no or very little variations.
iii) In sexual reproduction, offspring will receive the genetic material of both the parents.
iv) This results in appearance of variations in the offspring.
v) Accumulation of these variations may result in the formation of new species.
vi) Hence, sexual reproduction participate in evolution of species.
4. How is the equal genetic contribution of male and female parents ensured in the progeny?
A. i) Sexual reproduction involves the fusion of male and female gametes (fertilization).
ii) During fertilization, chromosomes of the male gametes, the sperms (paternal chromosomes) and chromosomes of the female gametes, the ova (maternal chromosomes) make up into pairs.
iii) This ensures equal genetic contribution of male and female parents in the progeny.
5. Only variations that confer an advantage to an individual organism will survive in a population. Do you agree with this statement? Why or why not ?
A. i) Depending on the nature of variations, different individuals would have different kinds of advantages.
ii) In a population, bacteria that can withstand the heat will survive better in a heat wave while those which do not have such variation will be eliminated.
iii) Hence, it is true that only variation that confer an advantage to an individual organism will survive in a population.
6. 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?
A. i) Trait ‘B’ is likely to have arisen earlier.
ii) Because it exists in 60% of the same population (large percentage of population).
7. How does the creation of variations in a species promote survival ?
A. Creation of variations in a species help the organisms to adapt to the changes of their environment. Hence, promotes its survival.
Eg: Bacteria that have better variations can withstand the heat and can survive better in a heat wave.
8. How do Mendel’s experiments show that traits may be dominant or recessive?
A. i) According to Mendel’s principle of dominance, when two dissimilar factors are present in an organism, only one expresses itself.
ii) The factor which expresses is called dominant factor and the one which is unexpressed is called recessive factor.
iii) For example, when a tall plant (TT) was cross pollinated with a dwarf plant (tt) the first generation (F1 or first filial) formed were all tall plants.
iv) It shows that tallness is a dominant factor (it expresses itself) and dwarfness is a recessive factor.
9. How do Mendel’s experiments show that traits are inherited independently?
A. i) According to Mendel’s principle of “Independent assortment” Alleles of different characters separate independent from each other during gamete formation. (Or) The factors controlling different characters assort independently without influencing each other during the formation of gametes.
ii) For example, when the plants having round and yellow (RRYY) seeds are crossed with plants having wrinkled and green seeds (rryy), all four traits are independently inherited.
10. A man with blood group ‘A’ marries a women with blood group ‘O’ and their daughter has blood group ‘O’. Is this information enough to tell you which of the traits blood group ‘A’ or ‘O’ is dominant? Why or why not?
A. i) No, this information is not sufficient to determine whether dominant traits are blood group ‘A’ or ‘O’ as their ( parents) genotypes are not mentioned.
ii) If father is homozygous, genotypically (AA), then all the individuals in the progeny will get ‘A’ blood group.
iii) If father is heterozygous, genotypically (AO), then some of the individuals in the progeny will get ‘A’ blood group while some others get ‘O’ blood group.
11. How is the sex of the child determined in human beings ? (Or) “The sex of the children is determined by what they inherit from their father and not their mother”. Justify.
A. i) Human beings have 23 pairs of chromosomes of which 22 pairs are autosomes, the remaining one pair is sex chromosomes.
ii) Women have a perfect pair of sex chromosomes, both called ‘X’.
iii) But men have a mismatched pair in which one is a normal – sized ‘X’, while the other is a short one called ‘Y’.
iv) All children will inherit an ‘X’ chromosome from their mother, regardless of whether they are boys or girls.
v) Thus, the sex of the children will be determined by what they inherit from their father.
vi) A child who inherits an ‘X’ chromosome from father will be a girl and one who inherits a ‘Y’ chromosome from him will be a boy.
12. What are the different ways in which individuals with a particular trait may increase in a population?
A. i) Natural selection
ii) Genetic drift, etc.
13. Why are traits acquired during the life-time of an individual not inherited?
A. The acquired traits during the life time of an individual can not change the genetic material (DNA). Hence, traits are not inherited.
14.Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics?
A. i) When a tiger population is small, the scope and number of variations are limited. This reduces the diversity of traits.
ii) If a tiger is susceptible to disease their offspring shows same kind of susceptibility for a disease.
iii) This leads to the elimination of tiger population (the entire species). Hence, small numbers of tigers is a cause of worry.
15. What factors could lead to the rise of a new species?
A. i) Natural selection ii) Isolation
iii) Gene flow iv) Genetic drift
v) Reproductive isolation vi) Accumulation of variations
16. Will geographical isolation be a major factor in the speciation of a self-pollinating plant species? Why or why not?
A. i) No, in self pollinating plants the pollen grains of one flower are transferred to the stigma of the same flower.
ii) In self pollination there is no recombination of genetic material.
iii) Because of this, new characters will not be developed though they are isolated.
iv) Hence, the geographical isolation in self pollinating plants is not a major factor for speciation.
17. Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually? Why or why not?
A. i) No, geographical isolation will not be a major factor in the speciation of an organism that reproduces asexually.
ii) This is because in asexual reproduction offspring will not get the new genetic material and there is no chance for the production of new characters.
18. Give an example of characteristics being used to determine how close two species are in evolutionary terms.
A. i) Homologous characteristics help to identify an evolutionary relationship between apparently different species.
ii) These characteristics in different organisms would be similar because they are inherited from a common ancestor.
Eg : Forelimbs of a frog and lizard.
19. Can the wing of a butterfly and the wing of a bat be considered homologous organs? Why or why not?
A. No, they are analogous organs as they are dissimilar in origin but perform similar functions.
20. What are fossils? What do they tell us about the process of evolution?
A. Evidences left behind by the extinct organisms are called fossils.
They tell us about the :
types of living organisms that existed at different times during evolution.
evidences of evolution.
evolutionary relationships with present day animals.
21. Why are human beings who look so different from each other in terms of size, colour and looks said to belong to the same species ?
A. i) Human beings look so different from each other in terms of size, colour due to their physiological differences.
ii) They belongs to the same species because they have common origin. They are similar in structure and functions and they can interbreed with each other.
22. In evolutionary terms can we say which among bacteria, spiders, fish and chimpanzees have a better body design? Why or why not?
A. i) All the organisms given have better body designs.
ii) Because, during evolutionary process all the animals acquire the characters to survive in their respective environments.
NCERT Exemplar Solutions for Class 10 Science Chapter 9 are also available.
Class 10 Science Chapter 9 CBSE Notes
NCERT Solutions for Class 10 Science Chapter 9 – Heredity and Evolution – NCERT Solutions for Class 10 Science
Chapter 9 – Heredity and Evolution – NCERT Solutions for Class 10 Science-Based on yearly patterns, heredity, and evolution are predicted to receive 1 to 3 points.
In 2018, nevertheless, only one question (on Inheritance Laws) was asked in the Class 10 Science test. Yet, in order to avoid any hostile shocks, it is prudent to grasp all relevant ideas.
This chapter covers the following topics:
- Inheritance Statutes
- Experiments by Mendel
- Monohybrid cross
- Dihybrid cross
- Evolution and its theories
- Evolutionary evidence
NCERT Solutions for Science Chapter 9 in Class 10 Evolution and Heredity
It’s crucial to understand how physical qualities and attributes are passed down from one generation to the next. Furthermore, heredity gives us a lot of information about how genetics affects organisms. Evolution is a gradual process in which an organism adapts to a variety of factors. It is sometimes influenced by the environment or by competition.
Investigate the concepts of heredity and evolution. Learn about its relevance and ramifications. NCERT Solutions has extra learning tools to help you prepare for the CBSE Term II test and streamline your last-minute revisions.
NCERT Solutions for 10th class Science Chapter 9 Highlights: Evolution and Heredity
- solutions that are comprehensive and detailed
- Designed to meet CBSE requirements
- Simple and easy-to-understand language is used.
- Almost all jargon is well-explained Access to a wealth of additional learning tools and resources, including example papers and solved previous year question papers
NCERT Solutions for Class 10 Science has a lot more to offer.
NCERT Solutions for Class 10 Science Chapter 9: Frequently Asked Questions
In Chapter 9 of NCERT Solutions for Class 10 Science, what are similar organs?
Analogous organs are organs that have similar functions in different animals. These organs may have different morphological traits, but their functions are the same in all creatures. While answering textbook questions, students can refer to Chapter 9 of NCERT Solutions for Class 10 Science to acquire a better understanding of the ideas. There are chapter-by-chapter and exercise-by-exercise solutions available for students to use according to their needs.
What topics are included in NCERT Solutions for Class 10 Science: Heredity and Evolution?
The following topics are addressed in NCERT Solutions for Class 10 Science: Heredity and Evolution:
- Inheritance Laws
- Experiments by Mendel
- 3. Evolution and its theories
- 4. Monohybrid crosses
- 5. Dihybrid cross
- Evolutionary evidence
Is it true that the NCERT Solutions for Class 10 Science Chapter 9 aid students in achieving good results on their board exams?
The solutions are comprehensive and clear in order to ensure that students grasp the topics quickly. INFINITY LEARN faculty creates solutions that adhere to the CBSE syllabus and requirements. To help pupils learn the approach of answering complicated questions, simple and easy-to-understand terminology is employed. Students’ analytical and logical thinking abilities are improved by solving sample papers and previous year exam papers.