NCERT Solutions for Class 12 Biology Chapter 1
NCERT Solutions for class 12 Biology Chapter 1 Reproduction in Organisms is given to Study Online or Free download in English Medium PDF file format updated for new academic session 2020-21 based on NCERT Books 2020-21.NCERT Books, NCERT Solutions 2020-2021 and Offline Apps based on latest curriculum 2020-2021 is also available in PDF. Discuss you questions through Discussion Forum and share your knowledge with us and other users.
- 1 Chapter 1 Reproduction in Organisms Solutions
- 1.0.1 Higher organisms have resorted to sexual reproduction in spite of its complexity. Why?
- 1.0.2 Bryophytes and Pteridophytes produce a large number of male gametes but relatively very few female gametes. Why?
- 1.0.3 Which characteristic property of Bryophyllum is exploited by gardeners?
- 1.0.4 Mention the unique feature with respect to flowering and fruiting in bamboo species.
- 2 Important Questions on 12th Biology Chapter 1
NCERT Solutions for class 12 Biology Chapter 1
|Chapter 1:||Reproduction in Organisms|
Class 12 Biology Chapter 1 Solutions in English
NCERT Solutions for class 12 Biology Chapter 1 Reproduction in Organisms is given here to download in PDF format or view online without downloading. All the contents are updated for new academic session 2020-21 for all boards using NCERT Books 2020-2021.
Higher organisms have resorted to sexual reproduction in spite of its complexity. Why?
Because of variations, gene pool, vigour and vitality and parental care.
Bryophytes and Pteridophytes produce a large number of male gametes but relatively very few female gametes. Why?
Because male gamete need medium (water) to reach egg/female gamete. A large number of the male gametes fail to reach the female gamete. It increases the probability of fertilisation.
Which characteristic property of Bryophyllum is exploited by gardeners?
Adventitious bud arising from margin of the leaf.
Mention the unique feature with respect to flowering and fruiting in bamboo species.
Flower once in their life time after 50-100 years, produce large no. of fruits and die.
Important Terms on Reproduction in Organisms
1. Monoecious Plants: Plants having both male and female flowers on same plant. e.g. cucurbits and coconut. The term “homothallic” is used in Fungi for same condition.
2. Dioecious Plants: Plants having male and female flowers on separate plant. e.g. Papaya and date palm. The term “heterothallic” is used in fungi for the same condition.
3. Oestrus Cycle: The reproductive cycle in non-primate mammals like cows, sheep, rats, deer, dogs and tigers etc. The sexually active females referred to as being in ‘heat’ at a specific time of 4. Oestrus cycle. They reabsorbs the endometrium if conception does not occur.
Important Questions for practice
1. There are 380 chromosomes in meiocytes of a butterfly. How many chromosomes does male gamete of butterfly have?
2. Mention the unique flowering phenomenon exhibited by strobilanthus kunthiana (Neelakuranji).
3. (a) Why is vegetative propagation also considered as a type of asexual reproduction?
(b) Which is better mode of reproduction: Sexual or Asexual? Why?
1. 190 chromosomes.
2. Flower one in 12 years.
3. (a) Vegetative propagation takes place when new individuals arise from vegetative part of parent and have characters similar to that of parent plant.
(b) Sexual reproduction, it introduces variations in offsprings and has evolutionary significance. It helps offsprings to adjust according to the changes in environment. It produces better off springs due to character combination.
Important Questions on 12th Biology Chapter 1
In the process of asexual reproduction, only one parent is involved and there is no fusion of the male and the female gamete. As a result, the offsprings so produced are morphologically and genetically similar to their parents and are thus, called clones.
Fish, frog, starfish are some organisms that exhibit external fertilization.
Disadvantages of external fertilization:
In external fertilization, eggs have less chances of fertilization. This can lead to the wastage of a large number of eggs produced during the process.
Further, there is an absence of proper parental care to the offspring, which results in a low rate of survival in the progenies.