Heredity and Evolution

HEREDITY AND EVOLUTION

SHORT ANSWER TYPES QUESTION (SAQ)

1. In a cross between round yellow seeds (RRYY) and wrinkled green seeds (rryy) of pea plant, what is the ratio of plant...

SHORT ANSWER TYPES QUESTION (SAQ)

1. (a) In a monohybrid cross of tall Pea plants denoted by TT and short pea plants denoted by tt, Preeti obtained only...

2. i. “Organs or features may be adapted to perform new function during evolution.” Justify this statement by giving an...

3. (a) State any two factors that could lead to the rise of a new species. (b) How do analogous organs provide evidenc...

4. (a) Why traits such as intelligence and knowledge connot be passed on to next generation ? (b) How can we say that...

5. Why are some Pea plants tall and others short in nature ? Explain with reference to role of genes in controlling cha...

6. (a) Place the following in correct sequence : Natural selection, migration, new species and gene flow. (b) Why are w...

7. Explain how the sex of the child is determined genetically at the time of conception in human beings. Answer :...

8. (a) Explain giving examples how artificial selection has helped in the formation of newer varieties of Cauliflower/...

9. (a) Explain the terms analogous and homologous organs with examples. (b) How does homologous organs explain the pro...

10. Briefly explain the role of natural selection and genetic drift in spéciation by citing an example. Answer : N...

11. One plant with dominant tall height bearing purple flowers crossed with another plant with recessive dwarf and whit...

12. In Bat the fingers are elongated and the wing is covered by patagium or fold of skin. (a) “Recent fossils are fou...

13. What are fossils ? How are they formed ? Write their one significance. Answer : (a) Definition: Fossils are...

14. Guinea pig having black colour when crossed with guinea pig having same colour produced 100 offspring, out of which...

15. (a) Name an animal which can change sex. What does it indicate ? (b) Explain the importance of fossils in evoluti...

16. Give appropriate terms for the following : (a) The trait which can express itself in next generation. (b) The tr...

17. (a) What is spéciation ? Mention the factors due to which this can happen. (b) Explain whether the traits like ey...

18. State the meaning of recessive and dominant genes. Answer : When dwarf plants show up in the F2 generation,...

19. State how evolutionary relationships can be traced by the study of homologous organs. Answer : Homologous or...

20. (a) “Our teeth and an elephant’s tusks are homologous organs”. Justify this statement. (b) What do the analogous o...

21. (a) Explain geographical isolation. (b) State with reasons whether the following are homologous or analogous organ...

22. (a) What is meant by evolution of species ? (b) List and describe any two evidences for evolution. Answer :...

23. “Red beetles live in bush with green beetles. Eventually, the number of green beetles increases as compared to red...

24. Mendel studied the inheritance pattern of traits in a Pea plant. According to this study, he obtained 9 : 3 : 3 : 1...

25. (a) Define inherited traits. (b) “Inherited traits are capable of directing evolution”. Justify the statement and s...

26. A cross was carried out between a pure bred tall Pea plant and a pure bred dwarf Pea plant and F1 progeny was obtain...

27. Name two homologous structures in vertebrates. Why are they so called ? How these organs help in understanding an ev...

28. An organ like wing in birds is an advantage to the organism. Did it appear in different stages or was formed due to...

29. In situation A, population groups reach each other, in B they cannot. (a) In which situation new species will not b...

30. Rohit will be out of station for a week. He gave his aquarium to Raju, a friend in the neighbourhood for that (a)...

31. Marriage between cousins is a taboo in most of the countries of the world except in some Asian countries (a) Why sh...

32. In one of his experiments with Pea plants, Mendel observed that when a pure tall Pea plant is crossed with a pure dw...

33. How can you say that in Mendel’s monohybrid cross, the F2 dominants are not all the same? Answer : Letting them...

34. “A trait may be inherited but may not be expressed.” Justify this statement with the help of a suitable example....

35. Explain : (a) Speciation (b) Natural selection Answer : (a) Speciation: New species form from existing ones be...

36. (a) What is the approximate ratio obtained in F2 generation ? (b) Under which law do you find this ratio ? (c) Why...

37. “Evolution and classification of organisms are interlinked”. Give reasons to justify this statement. Answer :...

38. (a) Kohlrabi, Cauliflower, Broccoli, Cabbage. (b) Since how long cabbage has been cultivated for ? Answer :...

39. In a monohybrid cross between tall Pea plants (TT) and short Pea plants (tt), a scientist observed only tall Pea pla...

40. Explain the formation of sub-population in neighbourhood by taking the example of beetle. Answer : Beetles usua...

41. (a) Planaria, insects, octopus and vertebrates all have eyes. Can we group eyes of these animals together to establi...

42. What will happen if both the characters present in F1 generation pass together in F2 generation ? Answer : They...

43. A child questioned his teacher that why do organisms resemble their parents more as compared to grand parents. In wh...

44. A boy of 15 years has attached ear lobes and weight of 65 kg. Which of these is an acquired character and which is i...

45. (a) Mention the two characteristics that decides about analogy and homology between two organs. (b) On what basis...

46. Who was Gregor John Mendel ? What was his contribution to heredity ? Answer : Gregor Johann Mendel, born in 182...

47. Insects, octopus, planaria and vertebrates possess eyes. Can we group these animals together on the basis of eyes th...

48.In an area A, the leaf material available to beetles was very less. What are the two consequences seen in these beetl...

49. Explain how do organisms create an exact copy of themselves. Answer : Organisms create an exact copy of themsel...

50. Describe briefly four ways in which individuals with a particular trait may increase in population. Answer : T...

51. Outline a project which aims to find the dominant coat colour in dogs. Answer : Consider a homozygous black co...

52. How is the sex of the child determined in human beings? Answer : In humans, there are two kinds of sex chromos...

53. Gene controls traits. Explain this with an example? Answer : Genes are like a set of instructions made up of...

54. Only variations that confer an advantage to an individual organism will survive in a population. Do you agree with t...

55. How is the equal genetic contribution of male and female parents ensured in the progeny? Answer : Humans have...

56. How many pairs of chromosomes are present in human beings? Out of this how many are sex chromosomes? How many types...

57. If a trait A exists in 10% of a population of an asexually reproducing species and trait B exists in 60% of the same...

58. How do Mendel's experiments show that traits may be dominant or recessive? Answer : When Mendel crossed pure...

59. All the variations in a species do not have equal chances of survival. Why? Answer : Not every difference am...

61. A Mendelian experiment consisted of breeding pea plants bearing violet flowers with pea plants bearing white flowers...

62. Write a difference between inherited traits and acquired traits giving one example of each. Answer : An acqui...

63. List four tools used to study evolutionary relationships. Answer : i. Study of fundamental and correlated...

64. State the importance of chromosomal difference between sperms and eggs of humans. Answer : Human eggs are o...

65. “Variations that confer an advantage to an individual organism only will survive in a population.” Justify. Answe...

66. “The sex of the children are determined by what they inherit from their father and not the mother.” Justify. Ans...

67. Give one example of each of the characters that are inherited and the ones that are acquired in humans. Mention th...

68. Name the information source for making proteins in the cells. Answer : Deoxyribonucleic acid (DNA) present...

69. What is a gene? Answer : A gene is a unit of DNA on a chromosome which governs the synthesis of particular...

70. What is heredity? Answer : The inheritance of characters (or trails) from the parents to their offsprings i...

71. Why is the progeny always tall when a tall pea plant is crossed with a short pea plant? Answer : When a tall...

72. (a) Write foil form of DNA. (b) Why are variations essential for the species? Answer : (a) DNA. Deoxyribose...

73. How do sexual and asexual reproduction lead to spéciation ? Give one point for each. Answer : i. Sexual reprod...

LONG ANSWER TYPES QUESTION (LAQ)

1. (i) What are chromosomes ? Where are they seated? (ii) What is a sex chromosome ? (iii) Explain the mechanism of se...

2. (a) What is geographical isolation ? (b) Illustrate formation of a species with the help of an example where individu...

3. Name any five vegetables generated from a common ancestor through artificial selection rather than natural selection....

4. (a) Why do we say that homozygous plants produce pure progeny ? (b) Define heterozygous. (c) Explain how the process...

5. (a) Define evolution. (b) Mention any four ways by which individuals with -a particular trait may increase in a popul...

6. (i) What is meant by traits of an individual ? (ii) Explain inherited trait and acquired trait. (iii) Define spéciati...

7. What are fossils ? How are they formed ? Explain how fossils support evolution. Answer : Fossils: Fossils are...

8. (a) How many pairs of chromosomes are present in human beings ? Out of these how many are sex chromosomes ? How many...

9. Give reason for the following : (a) Traits acquired during lifetime of an individual are not inherited. (b) All human...

10 . Answer the following questions: (i) What are dominant and recessive traits? (ii) "Is it possible that a trait is in...

11. The sex of a new born child is a matter ofchance and none ofthe parents may be considered responsible for it. Draw a...

12. The given box diagram represents the ratio of females to males or the sex ratio in our country for 10 decades (1901...

13. "Sex determination is an important developmental event in the life cycle of all sexualy reproducing plants. Recent s...

14. How do Mendel's experiments show that the: (i) Traits may be dominant or recessive (ii) Traits are inherited ind...

15. (a) “Evolution has occurred in stages”. Justify the statement. (b) Differentiate between eye and eyespots. Which a...

NCERT SOLUTION

Page No. 143 1. If a trait A exists in 10% of a population of an asexually reproducing...

Page No. 147 1. How do Mendel’s experiments show that traits may be dominant or recessi...

Page: 150 1. What are the different ways in which individuals with a particular trait m...

Page Number: 151 1. What factors would lead to the rise of a new species ?...

Page: 156 1. Give an example of characteristics being used to determine how close two s...

Page Number: 158 1. Why are human beings who look so different from each other in term...

Page No. 1: A Mendelian experiment consisted of breeding tall pea plants bearing viol...