Assignment-HERIDITY AND EVOLUTON

1. What is heredity? 

The transfer of characters from parents to the next generation. 

2. What is variation?

The tendency of an organism differ from each other is called variation

3. Name the plant on which Mendel performed his experiment? 

Pea plant 

4. Who is called “Father of Genetics”?

Gregor Johann Mendel 

 5. Why did Mandel select pea plant for his experiment? 

1. Pea plant is easy to grow.  

2. Life cycle of pea plant is very short.

3.Controlled breeding is possible.

4. Pea plant shows contrasting pair of characters.

Tall plant.         Short plant

Violet.            White coloured flowers 

Round seeds.   Wrinkled seeds

Yellow.           Green coloured seeds 

6. What are the basic steps of Mendel’s experiment?

 7. Name any four contrasting traits studied by Mendel in garden pea plant.

plant

 8. How do Mendel’s experiments show that traits may be dominant or recessive? 

9. How do Mendel’s experiments show that traits are inherited independently? 

10 What term did Mendel use for what we now call the genes? 

11. Mendel crossed true breeding plants of terminal flower (AA) and axillary (aa) flowers. He found plants of terminal flower appeared in F1 generation. He also carried out F2 generation. Which trait is dominant? What would be the ratio in F2 generation? Show the cross. 

12. The gene for red hair is recessive to the gene for black hair. What will be the hair colour of a person if he inherits a gene for red hair from his mother and a gene for black hair from his father? 

13. In humans, if gene B gives brown eyes and gene b gives blue eyes what will be the colour of eyes of the persons having the following combination of genes? 1) Bb 2) Bb 3) BB

 14. What are genes where are they located in our body?

 15. What do dominant genes and recessive genes mean? Give an example of each 

16. Explain how, characteristic (or traits) are inherited through genes? 17. Study the given data and answer the question following the data. Parental plants cross fertilised and seeds collected 1. Male parent always bore red flowers and female parents always had white flowers 2. 330 seeds sown and observed 3. All 330 gave red flowers in F1 generation 4. Out of 44 seeds 33 seeds gave plants with red flowers and 11 seeds gave plants with white flowers in F1 generation 1. What is the term for this type of cross? 2. What does the data of the column marked F1 indicate? 3. Express the genotype of the a) parents b) F1 progeny c) F2 progeny 18. The genotype of green-stemmed tomato plants is denoted as GG and that of purple-stemmed tomato plants as gg. When these two are crossed, 1. What colour of stem would you expect in their F1 progeny? 2. Give the percentage of purple-stemmed plants if F1 plants are self-pollinated. 3. In what ratio would you find the genotype GG and Gg in the F2 progeny? 

19. How many X – chromosomes are present in the cells of normal female? 20. How many types of gametes do a male produce? 

21. How is the sex of a child determined?

 22. In humans genetically the father or mother determines the sex of a child? 

23. What will be the sex of a child who inherits X- chromosome from the father? 

24. If a sperm carrying Y- chromosome fertilizes an ovum that carries X chromosome what will be sex of the born child?

 25. If a sperm carrying X- chromosome fertilizes an ovum that carries X chromosome what will be sex of the born child? 

26. Name one reptile in each case where higher incubation temperature leads to the development of: a. Male progeny b. Female progeny 

27. Name an animal in which individuals can change sex? What does this indicates? 

28. What is meant by acquired and inherited traits? Explain with one example each. 

29. Why are the traits acquired during the lifetime of an individual not inherited?

 30. Define evolution.

 31. Who gave the idea of evolution of species by natural selection? 

32. Name the various tools of tracing evolutionary relationships which have been used for studying human evolution. 

33. What are homologous organs? Give one example of it. 

34. What are analogous organs? Give one example of it. 

35. Why are wings of birds and bats called as analogous organs? 

36. The forelimbs of frog, reptiles, birds, and a man show the same basic design of bones. What name is given to such organs? 

37. What are fossils? Give any three examples 

38. Explain importance of the fossils in deciding the evolutionary relationships? 

39. How the age of fossils can be estimated? 

40. Answer the following on the basis of the figure given on the page no. 

1 Why the number of green beetle increased in 1st  case? 

2 Why the number of green beetle increased in 2nd case? 

3 What is the cause of evolution in 1st and 2nd case? 

41 What is genetic drift? 

42 What is natural selection? 

43. Is there evolution occurring in the 3rd case? 

44 What is speciation? 

45. How is a new species formed? 

46. What are the factors responsible for speciation? 4

7 Explain why evolution can cot be said to progress from lower forms to higher forms? 

48. How will you conclude that birds are closely related to reptiles? 

49.Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics? 

50.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?

 51.What is artificial selection?

 52.How do five varieties of vegetables produced from wild cabbage by the process of artificial selection?