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प्रश्न
Higher organisms have resorted to sexual reproduction in spite of its complexity. Why?
उत्तर
Although sexual reproduction involves more time and energy, higher organisms have resorted to sexual reproduction in spite of its complexity. This is because this mode of reproduction helps introduce new variations in progenies through the combination of the DNA from two (usually) different individuals. These variations allow the individual to cope with various environmental conditions and thus, make the organism better suited for the environment. Variations also lead to the evolution of better organisms and therefore, provide better chances of survival. On the other hand, asexual reproduction does not provide genetic differences in the individuals produced.
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संबंधित प्रश्न
Give the importance of variation in survival of species.
No two individuals are absolutely alike in a population. Why?
How do organisms, whether reproduced asexually or sexually maintain a constant chromosome number through several generations? Explain with the help of suitable example.
How does reproduction help in providing stability to populations of species?
Define Reproductive phase
Define Senescent phase.
The number of nuclei present in a zygote is ______.
Complete the crossword puzzle using the hints given below.
Across
1. The process of the fusion of the gametes.
6. The type of fertilisation in hen.
7. The term used for bulges observed on the sides of the body of Hydra.
8. Eggs are produced here
Down
2. Sperms are produced in these male reproductive organs.
3. Another term for the fertilised egg.
4. These animals lay eggs.
5. A type of fission in amoeba.
Which species is likely to have better chances of survival - the one reproducing asexually or the one reproducing sexually? Justify your answer.
name the organ which produces male sex cells.
What are gametes?
State the advantages of sexual reproduction over asexual reproduction.
Name two plants which reproduce by sexual reproduction method and two plants which reproduce by asexual reproduction methods.
What would be the ratio of chromosome number between an egg and its zygote?
The advantage that internal fertilisation has over external fertilisation is that in internal fertilisation :
(a) new off-springs are exactly like the parent
(b) production of large numbers of gametes is unnecessary
(c) copulation and fusion of gametes is passive
(d) fewer individuals are produced
The offsprings formed as a result of sexual reproduction exhibit more variations because ______
One of the following process does not lead to the formation of clones. This is :
(a) fission
(b) fertilisation
(c) fragmentation
(d) tissue culture
Define the term Puberty.
Multiple choice question. Tick (✓) the correct choice:
Butterfly in its development from larva to an adult shows
- multiplication
- metamorphosis
- fertilisation
- none of the above
Differentiate between the following:
External fertilisation and Internal fertilisation.
Mention the common method of reproduction in Flatworm.
Describe the different methods of asexual reproduction in animals.
Meiosis is an essential event in the sexual life cycle of any organism. Give two reasons.
In the sexual mode of reproduction, greater diversities are generated.
Long answer question.
Describe female reproductive system of human.
What is atresia with respect to ovary in human females?
Identify the labels from the given diagram.
What are the different stages of sexual reproduction?
What is parthenogenesis? Give two examples from animals
Give reason for the following:
A male honey bee has 16 chromosomes whereas a female has 32 chromosomes.
Differentiate between the following:
Regeneration in lizard and Planaria
______ fertilisation takes place in frogs and fish.
The zygote divides repeatedly into a group of cells, which develops into different tissues and organs constituting a full body. This structure is known as ______.
The eggshell protects the ______ from the outer environment.
Explain the two types of fertilization.
Zygote develop a thick wall that is resistant to dessication and damage is present in ______.
Between an annual and a perennial plant, which one has a shorter juvenile phase? Give one reason.
Enumerate the differences between asexual and sexual reproduction. Describe the types of asexual reproduction exhibited by unicellular organisms.
