Reproduction in Organisms

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Questions:

Generic 5

9 x 5 = 45

Last year, Dadaji was going to meet his old friend in a village near Lucknow. Dadaji's friend was earnings a lot by exporting mangoes. Anil also accompanied Dadaji as he also very found of mangoes. Dadaji's friend invited him to visit the orchard. Anil knew that there are many varieties of mangoes with different shapes, color of skin and tastes. On visiting the orchard, Anil was surprised to see that more than one type of mangoes were growing on the same tree.
(i) Is it possible for Anil to grow for commercial purpose any variety of mango on the tree of mango growing in his garden?
(ii) What type of reproduction is involved in this process?
(iii) Name any other species which can be propagated by this technique for commercial purpose.
(iv) How could Dadaji's friend improve the varieties of mangoes in his garden?

Rachna's father went to Kolkata where he was gifted a pot with new variety of rose. The flowers were very beautiful. On birthday of Rachna's father to bring for her the same variety of rose on his next visit to Kolkata. He smiled and advised her to raise it herself from the plants growing in his home.
Read the above passage and answer the following question:
(i) How can father's advice help Neena to raise new seedling of rose variety present in Ranchna's home?
(ii) Which method of reproduction is involved in this process?
(iii) Can this technique be used for commercial propagation of other ornamental plants?

Rose plants produce large, attractive bisexual flowers but they seldom produce fruits. On the other hand Lady's finger produces plenty of fruits. Analyse the reasons for failure of fruit formation in rose.

Difference between:
(a) Oestrous cycle and menstrual cycle
(b) Ovipary and vivipary. City an example of each type .

Although sexual Reproduction is a long drawn, energy intensive complex from of reproduction, many groups of organisms in Kindom Animalia and Plantae prefer this mode of reproduction. Give atleast three reasons for this.

In nature, i,e in the wild, birds lay eggs seasonally during a particular time of the year, but in a poultry farm, eggs are produced throughout the year.
(a) Give reason for this observation.
(b) Is it ethically/morally correct in your opinion? Justiy your argument.

Jagan has two mango trees in the backyard of his house, which yielded fruits for the first time during this summer. The fruits were small, fibrous and not so sweet. In the next house, where his friend Ajay livers, there is a mango tree, which yields fruits that are fleshy/juicy, very sweet and bigger in size. Ajay, a student of B.sc. (Botany) comes out with an idea and takes some branches from the jagan's garden to his garden and explains the procedure.
(a) What method do you think Ajay has suggested for getting good quality fruits, on the trees of Jagan's house in a short period of time, i.e. during the next season?
(b) Describe how it is carried out to help japan.
(c) What are its advantages over growing a mango tree with the seeds obtained from Ajay's garden?
(d) Mention the values expressed by Ajay in this case.

A farmer cultivates sugar cane and rose by usin stem cuttings. He found that some of the cuttings did not continue to grow into new plants. As a student of Agriculture; Shanu gives some points to be followed.
(a) Can you suggest a reason for this?
(b) Enlist the aspects that Shanu must have given for consideration, while preparing stem cuttings for propagation.
(c) Name two other plants which are also propagated by stem cuttings.
(d) What value (s) is/are shown by Shanu?

You must have seen your mother adding 3-4 globules of yeast to the idli paste she has prepared. Similarly, brewing industry uses yeast in the manufacture of alcohol.
(a) How does such a small amount of yeast added help to produce thousands of litres of alcohol? Explain how yeast multiples so fast.
(b) Name the process carried out by yeast in these cases.
(c) What value is learnt from these?

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Answers Key:

Generic 5

9 x 5 = 45

(i) Yes, by using grafting technique he can grow any variety of mango on the already existing trees.
(ii) Artificial method can also be used for commerecial production of roses.
(iii) This technique can also be used for commercial production of roses.
(iv) Dadaji's friend improved the varieties of mangoes by using grafting techniques .

(i) Father's advice helped Neena to raise new seedlings of rose variety by using 'cuttings' of the desired variety and planting them in soil in favorable season.
(ii) Asexual method of reproduction is involved.
(iii) Yes, this can be used commercially for Bougainvillea, Carnation and Coleus.

Fruit formation fails in rose is due to following reasons:
(i) Rose plants may not produce viable pollen.
(ii) Rose plants may not have functional egg.
(iii) Rose plants may bear abortive ovules.
(iv) Being hybrids, the meiotic process may be abnormal, which leads to formation of non-viable gametes.
(v) There may be self-incompatibility.
(vi) Ther may be internal hinderances for pollen tubes growth and fertilisation.

(a) Differences between oestrous cycle and menstrual cycle

Oestrous Cycle	Menstrual Cycle
1. It refers to the cyclic changes in the female reproductive system of non-primates.	1. It refers to the cyclic changes in the female reproductive system of primate females.
2. There is no menstruation at the end of oestrous cycle.	2. Ther is menstruation at the end of menstrual cycle.
3.At the time of ovulation animals show 'estrus' or 'heat' and copulation occurs only at that period.	3. There is no 'heat period during ovulation and copulation occurs during any part of the cycle.

(b) Differences between oviparous and viviparous animals.

Oviparous animals	Viviparous animals
1. These are the animals which lay fertilized or Unfertilised eggs in a safe place in the environment.	1. These are the animals which give birth to young ones.
2. Offspring of oviparous animals are at a great risk as they are threatened by their predators and unfavorable environmental conditions.	2. Offspring of viviparous animals are protected by the parent organism from predators/enemies and unfavorable climates

(i) By sexual reproduction, variation appears in offspring.
(ii) Genetic recombination appears in gametes due to meiosis-I due to process of crossing over.
(iii) Offspring has better chances of survival in changed environment.

(a) In a poultry farm, many hybrid' varieties of birds are reared.
(i) They yield more number of egg,s (200 to 300 per year) unlike the desi breeds, which lay about 79 to 80 eggs per year.
(ii) Different breeds and hybrids of poultry birds yield eggs during different seasons/times of the year and hence there is production of eggs throughout the year.
(b) Apparently it may be non-ethical to make the birds lay eggs by artificial means. But at the same time, each society has to evaluate for itself the validity of such arguments and decide' the kind of activities that are considered acceptable and those which are not acceptable. Many societies and the government have allowed such activities as they are not harmful to the birds and also to the consumers of eggs.

(a) Grafting a branch from the tree of Ajay's house on a tree of Jagan's garden can be done.
(b) The part of the graft that forms the upper part is called scion and the part of the graft that becomes the supporting portion (the root and base), is called stock.
(i) The scion is selected from a superior quality plant (juicy, larger mango fruits) while the stock belongs to the plant to be improved.
(ii) The scion and stock should be of same diameter and slant cuts are made on both the branches.
(iii) The scion is kept on the stock, covered with grafting clay and polythene; it is tied well and arrangement of water supply/ moisturising is made.
(iv) After a few weeks, you will see buds and leaves appearing on scion.
(c)The mango tree will start producing flowers and fruits very early, may be in the next season itself. - Many branches can be grafted on the tree with poor quality mangoes.
(i) When grown from a seed it takes many years for the tree to produce fruits. - Sometimes the plant produced from the seed may not be of the same quality, as sexual reproduction results in variation.
(d) Values for friendship and generosity.

(a) (i) The polarity of the cutting would not have been correct.
(ii) It can be due to absence of buds.
(iii) The cutting may have been selected from a very old branch.
(b) (i) The cutting must be selected from a branch that is neither very old nor very young.
(ii) There should be enough number of buds.
(iii) The polarity of the cutting should be considered.
(iv) The season of growing must be properly selected.
(c) Bougainvillea, china rose, cotton, etc.(any two)
(d) Shanu's concern for fellow citizen and use of his knowledge for the benefit of the society

(a) Yeast multiplies by budding very fast In yeast, the cell division is unequal and results in a large cell and a small cell, called bud which remains attached to the large cell; the bud gets separated and grows into an adult yeast.
The yeast cells secrete enzymes to produce alcohol.
(b) It carries out the process of fermentation.
(c) Mother shows how to make use of the natural processes and to live with nature and to appreciated how such microbes are useful to us; try to help others.