If black colour is dominant out of every 4 dogs, 3 will be black and if white colour is dominant 3 out of 4 dogs will be white. They travelled down the islands of Indonesia and the Philippines to Australia, and they crossed the Bering land bridge to the Americas. They look different because of interaction of genes with environment which results in change in their appearance. In Mendel’s experiment with pea plants, when he cross-bed a tall pea plant with a short plea plant, he found that the first generation (F1) was of only tall plants. All the MCQs are taken from NCERT Textbooks issued for new academic session 2020-2021. Explain how in sexually reproducing organisms the number of chromosomes in the progeny is maintained. Then by self pollination of F1 tall plants, he produced second generation (F2) consisting of tall and short plants in the ratio of 3 : 1. Presence of homologous organs confirms com-mon ancestry and evolutionary relationship. This/these unpaired chromosome is/are (a) Homologous organs (a) TTWW Example: If in a group of red beetle a colour variation arises during reproduction so that there is a beetle which is green in colour. (2013 OD) Therefore, fossils have an importance in deciding evolutionary relationship. Question 1. Sample Question Papers. More closer the characteristics, the moe doser is the evolution and chances to be in the same group of classification. (d) All of the above, Question 3. DNA copying is accompanied by the creation of an additional cellular apparatus. 1. Tracing Evolutionary Relationships What do they tell us about the process of evolution ? Most of the other variations not only give survival advantage to an individual but also contribute to genetic drift. An experiment conducted by Stanley L. Miller and Harold C. Urey in 1953 proved that origin of life takes place from inanimate matter. Sex of an individual is genetically determined for e.g. Trait A is new and has spread to only 10% of the population. The study of heredity and variations is known as genetics. For example, If we breed some mice, all the progeny of mice will have tails, just like parents. It refers to a gradual evolutionary process by which populations evolve to become different species. Justify your answer giving a suitable reason. (b) colour of skin Archaeopteryx has feathered wings like birds but teeth and tail like those of reptiles. So, life arose afresh on earth. When he cross-bred pea plants of round green seeds with wrinkled yellow seeds, he got F1 generation with all such seeds which were yellow and round. A blue colour flower plant denoted by BB is crossbred with that of white colour flower plant denoted by bb. A man with blood group A marries a woman with blood O and their daughter has blood group O. [AICBSE 2015] Question 3. Question 13. Select the statement that describes characteristics of genes. Give reason to justify your answer. (2015 D) Question 1. For example, The wing of a bat, flipper of a seal, front leg of a horse and arm of a man are homologous organs. Explain how sexual reproduction gives rise to more viable variations than asexual reproduction. [CBSE 2011, 2013] I. DNA undergoes significant changes in germ cells. Homologous: Similar structure different functions. Sometimes even the soft parts (like leaf etc.) For Study plan details. (b) a chimpanzee. When organisms (plants or animals) die, their bodies will decompose by the action of micro-organisms in the presence of oxygen, moisture, etc. (i) When a sperm carrying X chromosome fertilises an egg that contains only X chromosome), the resulting zygote develops into a female (XX condition). Answer: Question 8. Get Heredity and Evolution, Biology Chapter Notes, Questions & Answers, Video Lessons, Practice Test and more for CBSE Class 10 at TopperLearning. Answer: On the basis of this, it cannot be decided light colour trait is dominant or recessive. 3 docs. State its importance. (d) TtWw Answer: Question 2. OR Answer: Join now. (a) Homologous organs. Law of dominance: states that only one character expresses itself in F, generation. Question 1. Law of segregation: states that the two alleles of a character in an individual get separated or segregated during gamete formation and distributed randomly in gametes. (a) Name any four varieties of vegetables which have been produced from ‘wild cabbage’ by the process of artificial selection. Join now. (d) Study of homologous and analogous organs indicates the origin and modification in organisms and study of fossils indicates the age and features of an organism. State the meaning of inherited traits and acquired traits. How is the sex of the child determined in human beings ? For example, reproduction of amoeba by binary fission. They state that angiosperms are developed from pteriodophytes and gymnosperms. Answer: For example, arms of human beings and forelegs of horse, lion, etc. Mendel was the first scientist whose studies lead to the formulation of laws of inheritance. Question 2. Question 4. When two DNA … For example, bats and birds have some similarity in their wings, so they are closely related, while lizard and squirrel do not have wings so these are not closely related to the birds and bats. Complex organs may have evolved because of the survival advantages of the intermediate stage. “DNA copies generated during reproduction will be similar but may not be identical to the original.” Justify the statement. (a) New species may be formed if the DNA changes are severe enough, such as a change in the number of chromosome. Question 11. 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Answer: NCERT Solutions for Class 10 Science Heredity and Evolution Class 10 Science Class book solutions are available in PDF format for free download. This trait is called dominant, while the other which has not shown its effect in the presence of dominant trait is called recessive. ♦ Clones are those organisms which are the carbon copies of one another. Human beings different in size, colour and looks can marry among themselves and produce fertile offspring. Past Year Question Papers. (a) sudden creation by nature. With the help of an example justify the following statement: (2014; 2016 OD) Biology (Science) Guess Paper final exam Class – X; CBSE E-Notes-Heredity and evolution - X Biology September (7) If you have any query regarding this article or  NCERT Solutions For Class 10 Science Chapter 9 Heredity and Evolution, leave your comments in the comment section below and we will get back to you as soon as possible. MCQ Questions for Class 10 Science with Answers was Prepared Based on Latest Exam Pattern. (c) potato and runners of grass. The low weight of this beetle is an acquired trait. A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. Fossils provide direct evidence of past life. When a living object dies and forms fossil, its carbon-14 radioactivity goes on decreasing gradually. These variations are inherited and increase the chances of survival of an organism. All Chapter 9 - Heredity and Evolution Exercise Questions with Solutions to help you to … (a) In Mendel’s experiment with pea plants, when he crossbred a round seed plant with a wrinkled seed plant, he found that the first generation (F1) was only round seed plants. (2011 OD) Question 3. Question 1. (b) embryology Log in. Important Question for Class 10 Science Heredity and Evolution PDF will help you in scoring more marks.. A trait of an organism which is ‘not inherited’ but develops in response to the environment is called an acquired trait. But when plants of F1 generation are selfbred then the two traits of character get separated and the recessive trait also appears in the plant of F2 generation. The transmission of characters from the parents to their offspring is called heredity. A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. (2012 D) Answer: For example: A fossil of a bird called Archaeopteryx looks like a bird but it has many other features found in reptiles. Thus half the sperms will have X chromosomes and the other half will have Y chromosome. They provide following information on the process of evolution. Those organs, which have the same basic structure but different functions, are called homologous organs. Question 3. Class 10 Science Heredity and Evolution – Get here the Notes for Class 10 Science Heredity and Evolution. The progeny all bore violet flowers, but almost half of them were short. Tolls, like excavating, time-dating and studying fossils, determining DNA sequences etc, have been used for studying human evolution. Dinosaurs had feathers not for flying but instead these feathers provided insulation to these warm-blooded animals. Explain the importance of fossils in deciding evolutionary relationships. This is known as Law of Segregation (separation) of traits. Select the incorrect statement. If a round, green seeded pea plant (RRyy) is crossed with wrinkled, yellow seeded pea plant (rrYY), the seeds produced in F1 – generation will be [NCERT Exemplar] (2016 Delhi) Question 1. You can also get free sample papers, Notes, Important Questions. This suggests that the genetic make-up of the tall parent can be depicted as 4. Important factors which could lead to the formation of a new species are as follows: Question 15. Why or why not? (c) Selection of variants by environmental factors forms the basis of evolutionary processes. (a) phylogeny Question 3. Fossils : Fossils are the remains or traces of a dead organism. State two methods of determining the age of fossils. (b) A gene does not code for proteins. This will clear students doubts about any question and improve application skills while preparing for board exams. Examples: (a) Mendel in one of his experiments with pea plants crossed a variety having round seeds with one having wrinkled seeds. Question 2. Page 158 Explain the importance of fossils in deciding evolutionary relationships. Study Material and Notes of Ch 9 Heredity and Evolution Class 10th Science Question 5. According to him life must have developed from the simple inorganic molecules which were present at that time. Similarities among organisms will allow us to group them and study the groups and classify them. Question 16. State the evidence we have for the origin of life from inanimate matter. But these organisms are still surviving in the present conditions after millions of years. CBSE Maths notes, CBSE physics notes, CBSE chemistry notes. What is meant by the term speciation? Define homologous and analogous organs. (b) TTww (Genotypic ratio 1:2:1 for TT:Tt:tt) (d) movement of individuals from one habitat to another (2013 D, 2014 OD) You are advised not to use calculator or any other help while answering. A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. Out of two contrasting traits only one expresses itself in an individual. Observation: F1 generation; all were tall & round i.e. Understanding 10 15 25 3. Study Material and Notes of Ch 9 Heredity and Evolution Class 10th Science What factors would lead to the rise of a new species ? The process by which new species develop from the existing species by evolution or any genetic modification of previous species is known as speciation. (2012 D) All Chapter 9 - Heredity and Evolution Exercise Questions with Solutions to help you … Answer: (c) III and IV 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 ? CBSE Class 10 Science Book Chapter 9 “Heredity and Evolution” Multiple Choice Questions ‌(MCQs) with Answers. Some of the variations may be so drastic that the new DNA copy cannot work with the cellular apparatus it inherits. Homologous organs :  Those organs which have the same basic structure (or same basic design) but different functions are called homologous organs. (2015 OD) Analogous organs are those organs which are different in their basic structure and developmental origin but appear similar and perform similar function. Different ways in which individuals with a particular trait may increase in a population are as follow : Question 2. Question 1. Answer Answer: These heredity and evolution class 10 exercise answers were prepared by the best faculty in India to score good marks in the subject Science. (b) List any two contrasting characters other than roundness of pea plants that Mendel used in his experiments with pea plants. The chromosomes which determine the sex of a person are called sex chromosomes. Students can get good marks in the Science paper of Class 10 Board exam with the help of chapter-wise Science Revision Notes. (2012 D) However, all of them perform the same function, that is, vision. (a) traits may be dominant or recessive, (2016 D) What evidence do we have for the origin of life from inanimate matter ? Question 40. Analogous organs provide evidence for evolution that the organisms from different ancestors perform similar functions to survive, flourish and keep on evolving in prevailing environment. The geographical isolation leads to reproductive isolation and the individuals with a particular trait may increase in population. Answer: In human males all the chromosomes are paired perfectly except one. (b) Analogous organs. Haldane at first in 1929 suggested that life is originated from inanimate matter. (2011 D) But by the self¬pollination of F1 tall plants, the plants of second generation consisted of tall and short pants in the ratio of 3 : 1. It is the carrier of hereditary information from parents to the next generation. For example, the estimation of age of dinosaur fossils have told that they first appeared on earth about 250 million years ago and became extinct about 65 million years ago. Explain various stages of evolution? Class 10 Science Heredity and Evolution – Get here the Notes, Question & Practice Paper for Class 10 10 Science Heredity and Evolution. Biology. (2015 OD) (2012 OD) Answer: Evolution. More and more complex body designs have emerged and evolved over time, but this does not mean that the older designs are inefficient. Question 15. Answer: Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics ? Can we group eyes of these animals together to establish a common evolutionary origin? Describe, in brief, two methods of determining the age of fossils. “Two areas of study namely ‘evolution’ and ‘classification’ are interlinked”. (ii) Small number will lead to little recombination and, therefore, lesser variations. (b) TTww Question 2. (iii) Fossils. Difference between Acquired traits and Inherited traits The experiences and qualifications earned during our lifetime are examples of acquired traits. We can say that light eye colour trait is dominant because only dominant traits are expressed in the first generation. Conclusion: It formulated the law of independent assortment which states that genes of different characters located in different pairs of chromosomes are independent of one another in their segregation during gamete formation. In sexual reproduction, organisms produce gametes through a special type of division, meiosis reductional division, in which the original number of chromosomes becomes half. Question 17. bones of forelimbs in frog, lizard, bird & human. No, many of the times the variations are not advantageous to an individual organism but still survive in a population, e.g., take the case of free ear lobe and attached ear lobe. A trait of an organism which is caused by a change in its gene is called an inherited trait. Sex Determination (ii) Analogous organs. In evolutionary terms, we have more in common with [NCERT] (2016 D) No, because pollination occurs on the same plant in self-pollinating plant species. Answer: How many pairs of chromosomes are present in human beings? 1 Page 143; 2 Page 147; 3 Page 151; 4 Page 156; 5 Page 158; 6 Exercise 159; Page 143. ‘Two areas of study namely ‘evolution’ and ‘classification’ are interlinked”. If a sperm carrying Y-chromosome fertilises an ovum carrying X-chromosome, then the child born will be a boy. (b) In some reptiles, the temperature at which the fertilised egg is incubated before hatching plays a role in determining the sex of the offspring. Classification is the process by which organisms are grouped into convenient categories based on some easily observable characters. Write the contribution of Charles Darwin in the field of ‘evolution’. Q1. (b) B has become extinct recently 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? For e.g. Can the wing of butterfly and the wing of a bat be considered homologous organs ? Question 3. All NCERT textbook questions have been solved by our expert teachers. 4. Evolution. Ask your question. The more characteristics the two species will have in common, the more closely they are related. (b) Paralogous organs Crossing over (recombination) of homologous chromosomes. (a) reptiles and aquatic animals Why? • Thus, eggs laid by a […] Different variations provide different advantages to the population and the variation which provide best survival advantages are inherited to the next generation. (c) clones formed during asexual reproduction. Thus genes are actually units of heredity which transfer characteristics from parents to their offsprings during reproduction. 2 tests. (a) The eyes seen in planaria, insects, octopus and vertebrates vary greatly in their structure. (a) Mendel first crossed pure-bred tall pea plants with pure-bred dwarf pea plants and found that only tall pea plants were produced in the first generation or F1 generation.