DEAR STUDENTS THE   CHAPTER FOR STUDY FOR MAY MONTH:   REPRODUCTION IN ORGANISMS CHAPTER-I

PLEASE READ THE CHAPTER AND SEE THE  RELATED VIDEOS GIVEN  HERE UNDER.  THEN ANSWER THE QUESTIONS GIVEN.

FURTHER  FOR CBSE 12 TH  BIOLOGY  PRACTICALS PREPARE A PROJECT AS DONE BY YOU EARLIER IN 11 TH CLASS. PLEASE COMPLETE THE WORK ALLOTTED FOR YOU. AS THE INTERNAL MARKS DEPEND ON THESE ASSIGNMENTS.   

IF YOU COMPLETE THESE ASSIGNMENTS QUICKLY, THEN CONTACT ME THROUGH E-MAIL AND I WILL GIVE SOME ADDITIONAL ASSIGNMENTS.

Q.1. What are the two inherent characteristics of amoeba and yeast that favour asexual reproduction in them?

Q.2. “The offsprings produced by asexual reproduction are referred to as clones”. Why?

Q.3. Why is potato tuber considered as a stem though it is an underground part? Give two reasons in support of your answer?

Q.4. Among the annual and the perennial plants, which one has a shorter juvenile period. Explain.

Q.5. Rearrange the following events in the sequence in which they occur in the sexual reproduction of flowering plants: embryogenesis, fertilization, gametogenesis, pollination.

Q.6. How is it that the chances of fruit set in a self-pollinated bisexual flower of a plant are far greater than a dioecious plant?

Q.7. Is sexual reproduction hindered by the presence of a large number of chromosomes in an organism?

Q.8. Explain giving two examples if there is a relationship between the size and the lifespan of an organism.

Q.9. There are two different types of flowers marked A and B in the image given below. Identify the flower types and the kind of pollination that will occur in each of them.

Q.10. Why can’t multicellular organisms reproduce by cell division?

Q.11. Mark the ovule and the pericarp in the figure given below.

Q.12. Why is it so that the gametes produced in the organisms in large numbers exhibit external fertilization?

Q.13. Identify the monoecious and dioecious organisms.

• Earthworm
• Chara
• Marchantia
• Cockroach

Q.14. Match the following:

Column A	Column B
Bryophyllum	Offset
Agave	Eyes
Potato	Leaf Buds
Water hyacinth	Bulbils

Q.15. Post-fertilization, what do the following parts of the flower grow into?

• Ovary
• Ovules

Short Answer Type Questions

Q.1. Name the stage in the life-cycle during meiosis in the haploid organisms that undergo sexual reproduction. Give reasons as well.

Q.2. In higher plants and higher animals, the number of taxa exhibiting asexual reproduction is drastically reduced as compared to the lower groups of plants and animals. Explain.

Q.3. Name the haploid and diploid individuals in the family of honey bees and analyze the reasons behind their formation.

Q.4. Which type of reproduction is a reduction division associated with? Give reasons in support of your answer.

Q.5. Is vegetative propagation considered a type of asexual reproduction? Give reasons.

Q.6. Why is fertilization not a compulsory event for the production of fruits in certain plants?

Q.7. What will be the consequences if cell division is not followed by cell differentiation in a developing embryo?

Q.8. What are the changes that take place in an angiosperm after pollination and fertilization have occurred?

Q.9. Why are the seeds scattered in the juicy pulp of tomato and arranged in a row in a pea pod?

Q.10. Mention two differences and one similarity between zoospore and conidium. Draw diagrams of each.

Q.11.What is Embryogenesis?

Q.12.What is Fragmentation?

Q.13.What is vegetative propagation?

Q.14.What is Sexual Reproduction?

Q.15.What is Gametogenesis?

Q.16.What is a bisexual flower?

Q.17.What is Asexual Reproduction?

Q.18.What are the different types of asexual reproduction

Q.19.What is the complete process of sexual reproduction?

Q.20.Define  Pollination?

Long Answer Type Questions

Q.1. State the differences between sexual and asexual reproduction. Explain different types of asexual reproduction in unicellular organisms.

Q.2. Explain the process of gametogenesis in animals with suitable examples.

Q.3. State the differences between:

1. Oestrous and menstrual cycle
2. Ovipary and vivipary

Q.4. Rose plants have large flowers but rarely do they produce fruits. On the contrary, the tomato plant produces fruit but has very small flowers. Comment with suitable reasons.

Q.5. List the important differences between zoospore and zygote.

Q.6. What are the post-fertilization changes that occur in plants?

                    Dear students of class XII,
                                 
                                               Please read chapter 14 Ecosystem in text book. Then you can watch the videos in the blog to clear doubts if any. After these try to answer the Questions given. The answers have to be submitted on the date of re-opening of the school for internal evaluation.

IMPORTANT QUESTIONS FOR ECOSYSTEM

                                                                                ECOSYSTEMS

1.       How is a food web formed?

2.       What is stratification in a forest?

3.       Define standing crop? How is it measured?

4.       What is the importance of humus?

5.       Why is secondary succession faster than primary succession?

6.       Name the pioneers and climax of primary succession in water and on rocks.

7.       As succession proceeds the type and number of animals and decomposers also change.

8.       Define Ecological succession? What is SERE?

9.       What characteristic  features seen in Ecological succession?

10.   Why is there a restriction on tropic levels in a grazing food chain? Is there  such a limitation in the detritus food chain? Explain.

11.   Schematically show the flow of energy in a grazing food chain from the sun.

12.   Justify the statement succession and evolution would have been parallel  process at that time when life started on Earth.

13.   In general all pyramids are upright. Explain. What are the exceptions to this generalization?

14.   What are the limitations of Ecological pyramids?

15.   What are the producers in grassland and oceans. How is GPP different from NPP? Why is the productivity in oceans lesser than in land?

16.   Why is it reasonable to think that biodiversity should carry a hefty price tag? Justify.

17.   a)    Why are Carbon and Phosphorus essential to living organism?

b)    What are the natural reservoirs  of these elements and in what form?

c)    Give the important  differences between two cycles in nature?

18.    With a flow chart explain the process of decomposition. What factors affect this process Work as a unit to perform the function?

19.   Humans do a disservice to nature by creating a desert from a forest. Comment and say why should it be a cause of concern

20.   What is primary productivity? Why does it vary in different types of ecosystems?

CHAPTER 14 ECOSYSTEM

Dear students of class XII,

                Please  read chapter 8 Human health and diseases in text book.  Then you can watch the videos in the blog to clear doubts if any.  After these try to answer the Questions given.  The answers have to be submitted on the date of re-opening of the school for internal evaluation.