Tag: parthenogenesis

Questions Related to parthenogenesis

Match List I with List II and select the correct answer using the codes given the lists.

List-I(Meaning) List-II(Phenomenon)
a. Embryos arise directly from diploid saprophytic cells(nucleus or integuments) $1$. Parthenogenesis
b. An arcbesporium differentiates but the megaspore mother cell develops into an unreduced embryo sac $2$. Polyeznbryony
c. Many embryos arising in one ovule $3$. Adventives embryonic
d. The development of embryo from unfertilized egg $4$. Delusory
zoology reproduction in organisms parthenocarpic fruits parthenogenesis the life cycle of plants

  1. A-$1$, B-$2$, C-$3$, D-$4$

  2. A-$3$, B-$4$, C-$2$, D-$1$

  3. A-$3$, B-$2$, C-$4$, D-$1$

  4. A-$3$, B-$1$, C-$4$, D-$2$

Show answer
Correct Option: A

Development of new individual from female gamete without fertilisation is termed as

zoology reproduction in organisms parthenocarpic fruits parthenogenesis the life cycle of plants

  1. Syngamy

  2. Embryogenesis

  3. Oogamy

  4. Parthenogenesis

Show answer
Correct Option: D
Explanation:
Development of an egg (ovum) into a complete individual without fertilisation is known as parthenogenesis. It is observed in many invertebrates (rotifers, arthropods), insects (bees, wasps) and some birds, etc.

So, the correct answer is 'Parthenogenesis'.

Parthenogenesis is the development of a female egg into a new individual without the contribution of a male set of chromosomes.
In a hypothetical pond, two populations of fish are found; one reproduces through sexual reproduction, the other through parthenogenesis. Initially, the parthenogenetic fish are a larger population when the pond is first studied. However, researchers soon observe that the parthenogenetic fish are more frequent hosts for a new blood-borne parasite than the sexually reproducing fish. As a result, the sexually reproducing population increases and the parthenogenetic population decreases.
Which of the following best explains the reason for the shift in population numbers?

zoology reproduction in organisms parthenocarpic fruits parthenogenesis the life cycle of plants

  1. Sexual reproduction increases genetic variation. Some individuals in the sexually reproducing population will be adapted to a change in environment, in this case, the addition of a new parasite. These individuals will survive and reproduce at a higher rate than those affected by the parasite.

  2. The asexual fish are more susceptible to the parasites because they are an all female population, and typically less aggressive. The sexually reproducing population is protected by aggressive adult males fighting off the invading parasites.

  3. The asexually reproducing fish are intentionally reducing their population density as a mechanism to slow the spread of the parasite.

  4. The sexually reproducing population can reproduce faster than the parthenogenesis population, allowing them to produce so much offspring that not all can be affected by the new parasite.

Show answer
Correct Option: A
Explanation:

Parthenogenetic fish are produced by asexual reproduction. Hence, genetic variation does not takes place in them. Whereas fishes that are produced sexually increases genetic variation. Due to genetic variation, this population can adapt to changing environment. When the pond is infected by blood-borne parasite, parthenogenetic fish could not adapt to this changed environment. However, fishes produced sexually will adapt to it. Due to genetic variation, it will survive and reproduce at a higher rate.

Thus, the correct answer is 'Sexual reproduction increases genetic variation. Some individuals in the sexually reproducing population will be adapted to a change in environment, in this case, the addition of a new parasite. These individuals will survive and reproduce at a higher rate than those affected by the parasite.'

Choose odd one with respect to parthenocarpic fruit

zoology reproduction in organisms parthenocarpic fruits parthenogenesis the life cycle of plants

  1. Mango

  2. Banana

  3. Oranges

  4. Grapes

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Correct Option: A
Explanation:

  • Parthenocarpic fruits refer to seedless fruits that are formed asexually without fertilization of the ovules. Banana, grape, and orange are included under parthenocarpy, and they occur naturally. Mango can also be included under parthenocarpic fruit as some new varieties of seedless mango are also produced. Mango is also cultivated sexually through seeds.

So, the correct answer is 'Mango'.

A phenomenon is termed as parthenogenesis when 

zoology reproduction in organisms parthenocarpic fruits parthenogenesis the life cycle of plants

  1. Artificial fertilization occurs

  2. Egg is fertilized by a sperm

  3. Egg undergoes cleavage without fertilization

  4. Sperm dies before fertilization

Show answer
Correct Option: C
Explanation:

The term parthenogenesis was coined by Charles Bonnet. It is also called the virgin birth. Parthenogenesis refers to the process of formation of the organism from an unfertilized egg (it is a special type of asexual reproduction). Parthenogenesis is of the following three types:

1) Arrhenotoky: male develops parthenogenically.
2) Thelytoky: Female develops parthenogenically.
3) Amphytoky: Parthenogenesis results in any sex depending on environmental conditions.
So, considering all the information the correct answer is 'Egg undergoes cleavage without fertilization'.

In apomictic/parthenogenetic development the individuals are

zoology reproduction in organisms parthenocarpic fruits parthenogenesis the life cycle of plants

  1. Morphologically and genetically similar

  2. Morphologically and genetically different

  3. Morphologically similar but genetically different

  4. None of the above

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Correct Option: A
Explanation:

Development of an embryo from an unfertilized egg cell is called as parthenogenesis. The offsprings produced through apomictic are similar in morphological and genetical characters.

So the correct answer is 'Morphologically and genetically similar.'

State whether the following statements are true or false.
Formation of fruit without fertilization is called parthenogenesis.

zoology reproduction in organisms parthenocarpic fruits parthenogenesis the life cycle of plants

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Parthenocarpy (literally meaning "virgin fruit") is the natural or artificially induced production of fruit without fertilization of ovules, which makes the fruit seedless. Pathogenesis is the reproduction from an ovum without fertilization, especially as a normal process in some invertebrates and lower plants.

So, the correct option is, 'False'.

Which of the following characterizes parthenogenesis?

zoology reproduction in organisms parthenocarpic fruits parthenogenesis the life cycle of plants

  1. An individual may change its sex during its lifetime

  2. Specialized groups of cells may be released and grow into new individuals

  3. An egg develops without being fertilized

  4. Both members of a mating pair have male and female reproductive organs

Show answer
Correct Option: C
Explanation:

Parthenogenesis, a reproductive strategy that involves the development of a female gamete (sex cell) without fertilization. An egg produced parthenogenetically may be either haploid (i.e., with one set of dissimilar chromosomes) or diploid (i.e., with a paired set of chromosomes). Parthenogenesis has received considerable attention as a tool for the production of stem cells. The possibility of deriving stem cells from parthenogenetic embryos could eliminate the requirement to produce and destroy viable embryos and may reduce the ethical concerns surrounding stem cell research. 

So the correct option is 'an egg develops without being fertilized'.