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NCERT Solutions for Class 10 Biology Chapter 9 : Heredity and Evolution

Heredity and Evolution Class 10 Solutions Chapter 9 are made by our team of subject experts at Toppr. The NCERT textbook questions are answered in a way to provide you with a better understanding of the concepts. Also, the MCQs and long and short questions are all answered according to the weightage and the exam pattern. Heredity and Evolution Class 10 NCERT Solutions are curated strictly in accordance with the CBSE Curriculum and the exam pattern. As Class 10 exams are Board exams, NCERT Solutions provided by Toppr are the best study material to excel in the exams. These solutions will not only help the students in preparing for the board exams but also for the Olympiads. With the help of Heredity and Evolution Class 10 NCERT Solutions Science Chapter 9- Heredity and Evolution you can also analyze your shortcomings and work on them before the exams. These are the best resources designed after proper research and study to assist the students in scoring good marks.

Table of Content
Learn with Videos
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Accumulation of Variation
7 mins
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Inheritance
7 mins
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Heredity
15 mins
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Genetic Terminology - II
11 mins
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Expression Of Traits
4 mins
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Access NCERT Solutions for Class 10 Biology Chapter 9 : Heredity and Evolution

Exercise 9.1
Question 2
How does the creation of variations in a species promote survival?
Medium
Solution
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Explanation:

  • The changes in the environment are happening every day.  

  • With time the genetic variation in an organism helps them to adapt more due to natural selection.

  • These variations in a population enable the stability of various species.

  •  It does that by preventing them from getting wiped out during adverse conditions.

Hence, the creation of variation helps in promoting survival.

 


Question 3
In evolutionary terms, we have more in common with
A
A Chinese school-boy
B
A chimpanzee
C
A spider
D
A bacterium
Medium
Solution
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In terms of evolution, organisms belonging to the same species have more in common than organisms belonging to different species of the same genus or different genus. We have more in common with a Chinese school-boy because both belongs to the same species of Homo sapiens, and thus, share a common ancestor.
Question 4
A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not?
Medium
Solution
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  • Unless we know the genotype of these variants of the trait, it is not possible to tell which is dominant or recessive. 
  • At least, three-generation are required to come to any conclusion about the genotype of a particular trait.
Question 5
How are the areas study of evolution and classification interlinked?
Medium
Solution
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The study of evolution and classification of organisms are interlinked in phylogenetic classification system.

Classification of different types of organisms in groups is based on similarities and dissimilarities between them.

 Phylogenetic classification refers to the classification of organisms based on their descent from a common ancestor.

 The evolutionary ancestry is the foundation of the phylogenetic classification system. It is based on life's evolution and depicts the genetic relationships between organisms. 

 It produces cladograms, which are groups of organisms that include an ancestor species and its descendants. 

Question 6
Explain the terms analogous and homologous organs with examples.
Medium
Solution
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Analogous organs : The organs which have similar functions but are different in anatomical structures are called analogous organs. Examples of analogous organs are as follows:
  • Wings of an insect and bird.
  • Pectoral fins of shark and flippers of dolphin.
  • Eyes of mammal and octopus.
Homologous organs : The organs which have the anatomically same structure but are different in functions are called homologous organs. Examples of homologous organs are as follows:
  • Mouth parts of cockroach, honey bee, butterfly.
  • Forelimb of man, whale, bat, cheetah.
  • Thorns of Bougainvillea and tendril of Curcurbita.
Question 7
Outline a project which aims to find the dominant coat colour in dogs.
Medium
Solution
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Coat colour in dogs is governed by a variety of genes. At least 11 genes have been identified that influence the colour of coat in a dog. A dominant gene is a gene that is expressed in both homozygous as well as heterozygous conditions, whereas recessive gene is only expressed in homozygous condition.
Let us consider, one parent is homozygous black (BB) and another parent is homozygous brown (bb). Cross between the two parent produces the offspring with the genetic make-up: Bb. Now we don't know whether Black is dominant or brown is dominant. By observing the off-springs produced are we can say which one is a dominant trait. If the generation comprisess of black we can say black is dominant and if it is brown then we can say brown is dominant.
Question 8
Explain the importance of fossils in deciding evolutionary relationships.
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Solution
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Fossils are the remains or impression preserved of prehistoric plant or animal embedded in rock. Fossils provide us with the knowledge of animals and plants that lived hundreds of years ago which are now extinct. It helps us to compare the animals that lived during prehistoric times with its present descendants. They provide the missing link in the study of evolution. They are helpful in providing information while forming a sequence of the organisms in the pathway of evolution.
Question 9
What evidence do we have for the origin of life from inanimate matter?
Medium
Solution
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Miller-Urey experiment provided evidence for the origin of life from inanimate matter. In the experiment, they created an atmosphere containing molecules like ammonia, methane and hydrogen sulphide, but no oxygen. This atmosphere was similar to the atmosphere present during the primitive Earth. Temperature was maintained constant at 100C and sparks were passed through the mixture to stimulate lightning. After a particular time, certain amount of the carbon from methane had been converted to simple compounds of carbon like amino acids. Amino acids are the precursors of the proteins and proteins are the molecules that support the life in basic form.
Question 10
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?
Hard
Solution
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Sexual reproduction results from the fusion of gametes produced by male and female. Sexual reproduction causes more viable variations because:
There might be an error in the copying of DNA, though the event is rare.
Segregation of chromosome of maternal and paternal origin at the time of gamete formation is random.
There is an exchange of genetic material between homologous chromosomes during formation of gametes.
In case of asexual reproduction, variation is significantly less since only a single parent is involved. Very small changes occur due to inaccuracies during DNA copying that pass on to the progeny. Thus, offsprings of asexual reproduction are more or less genetically similar to their parents. So, it can be concluded that evolution in sexually reproducing organisms proceeds at a faster pace than in asexually reproducing organisms.
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NCERT Solutions for Class 10 Biology Chapter 9 : Heredity and Evolution

NCERT Solutions for Class 10 Science Chapter 9- Heredity and Evolution

NCERT Solutions for Class 10 Science Chapter 9- Heredity and Evolution deal with the concepts of Heredity and Evolution. Heredity is the process by which an organism's characteristics are passed down from generation to generation. Evolution is the gradual change in a population's heritable features over numerous generations. These changes may result in the emergence of new species, or species may evolve to become more adapted to their surroundings. Class 10 Science Chapter 9 also discusses Inheritance which is the transfer of qualities from one generation to the next and the rules for the inheritance of traits- Mendel’s Contributions. It also describes sex determination, which is the process of determining an individual's sex based on the composition of genetic material. Traits are distinguishing characteristics of an organism that can be seen in its physical shape or in its physiological function. Acquired traits and Inherited traits are discussed in this chapter. Class 10 NCERT Solutions, in addition to this, explains Speciation which is the process of a new species arising from an existing one as a result of many evolutionary pressures such as genetic drift, population isolation, natural selection, and so on. Speciation leads to ecosystem variety, and ecosystem diversity leads to evolution.

Key Features of NCERT Solutions for Heredity and Evolution Class 10 Solutions

  • Class 10 NCERT Solutions provide a better understanding of the subject and concepts.
  • These provide solutions in a systematic and step-by-step manner with appropriate diagrams.
  • These are curated by the experts after thorough research.
  • They are the best means to evaluate your preparations and overcome your shortcomings.
  • The Class 10 NCERT Solutions will help the students in board exams as well as Olympiads.
  • These are absolutely free to download.
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Frequently Asked Questions on NCERT Class 10 Biology Chapter 9 : Heredity and Evolution

Question 1. What do you understand by the term genetic drift?

Answer. Natural selection can have a big influence on which traits survive in a population. Random variations in gene variants are, nonetheless, encountered frequently. Genetic drift is the term for this phenomenon. In a small population, genetic drift is defined as a change in the frequency of an existing allele. A gene variant may vanish from the population due to genetic drift, reducing genetic variation.

Question 2. How is the progeny's genetic contribution from both male and female parents ensured?

Answer. Each human being's body contains 23 pairs of chromosomes in its somatic cells. 22 pairs of chromosomes are known as autosomes, and one pair is known as sex chromosomes, which are symbolised by the letters X and Y. In females, there are two X chromosomes, while males have one X and one Y chromosome. Meiosis happens during gametogenesis (gamete production), and the gametes receive half of their chromosomes. Male gametes have 22 autosomes and either X or Y chromosomes, as a result. In contrast, the female gamete has 22 autosomes and X chromosomes. Male and female gametes merge during sexual reproduction, and the number of chromosomes in the zygote is restored. Thus, From Male - From the male parent, the child obtains 22 autosomes and one X or Y chromosome. From Female - from the female parent, the child obtains 22 autosomes and one X chromosome.

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