Home
Class 12
BIOLOGY
Axolotl larva shows i. Neoteny and paedo...

Axolotl larva shows i. Neoteny and paedogenesis ii. Absence of thyroxine affects metamorphosis iii. It is hemichordata

A

I, ii and iii correct

B

I and ii correct

C

ii and iii correct

D

iii correct

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding the characteristics exhibited by the axolotl larva, we will analyze each statement provided in the question. ### Step 1: Understanding Neoteny and Paedogenesis - **Neoteny** refers to the retention of juvenile features in the adult stage of an organism. In the case of axolotls, they retain their larval characteristics throughout their life, which is a classic example of neoteny. - **Paedogenesis** is the ability of an organism to reproduce while still in its larval form. Axolotls can reproduce without undergoing metamorphosis, which is another trait that aligns with paedogenesis. **Conclusion for Step 1:** The axolotl larva does exhibit both neoteny and paedogenesis. ### Step 2: Absence of Thyroxine and Metamorphosis - Thyroxine is a hormone produced by the thyroid gland that plays a crucial role in regulating metabolism and development, including the process of metamorphosis in amphibians. - In axolotls, the absence of thyroxine prevents them from undergoing metamorphosis, meaning they will not transition from their larval form to the adult form. This is significant because it highlights the role of thyroxine in development. **Conclusion for Step 2:** The absence of thyroxine does indeed affect the metamorphosis of axolotls. ### Step 3: Classification of Axolotl - Axolotls belong to the class Amphibia and are specifically part of the family Ambystomatidae, which includes mole salamanders. They are not classified under Hemichordata. - Hemichordata is a separate phylum that includes organisms like acorn worms and is distinct from amphibians. **Conclusion for Step 3:** The statement that axolotls are hemichordates is incorrect. ### Final Conclusion: Based on the analysis: - Statement i (Neoteny and paedogenesis) is correct. - Statement ii (Absence of thyroxine affects metamorphosis) is correct. - Statement iii (It is hemichordata) is incorrect. Thus, the correct answer is that statements i and ii are correct.
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • GROWTH, REPAIR, REGENERATION AND AGEING

    DINESH PUBLICATION ENGLISH|Exercise Check your Grasp|10 Videos

  • GROWTH, REPAIR, REGENERATION AND AGEING

    DINESH PUBLICATION ENGLISH|Exercise Brain Teasers-VI[B]|6 Videos

  • GROWTH, REPAIR, REGENERATION AND AGEING

    DINESH PUBLICATION ENGLISH|Exercise Brain Teasers-VI[B]|6 Videos

  • GENETIC BASIS OF INHERITANCE

    DINESH PUBLICATION ENGLISH|Exercise Check your Grasp|30 Videos

  • HUMAN EVOLUTION

    DINESH PUBLICATION ENGLISH|Exercise Brain Teasers-VII|181 Videos

Similar Questions

Explore conceptually related problems

A health disorder that results from the deficiency of thyroxine in adults and is characterized by (i) a low metabolic rate, (ii) increase in body weight, and (iii) tendency to retain water in tissues is

Examine the given defective crystal : Answer the following questions : (i) Is the above defect stoichiometric or non-stoichiometric ? (ii) Write the term used for this type of defect. Give an example of the compound which shows this type of defect. (iii) How does this defect affect the density of the crystal ?

(i) Write the scientific names of the two species of filarial worms causing filariasis. (ii) How do they affect the body of infected persons(s)? (iii) How does the disease spread?

How are the (i) mass, (ii) volume, and (iii) densilty of a metallic piece affected, if at all with increase in temperatur?

A reaction is first order in A secod order in B : (i) write differential rate equation. (ii) How is the rate affected when the concentration of B is tripled ? (iii) How is the rate affected when the concentration of both A and B is doubled?

Show how would you synthesisse the following alcohols form approprite alkenes. i. ii. iii. iv.

Examiine the given defective crystal (i) What type of stoichiometric defect is shown by the the crystal ? (ii) How is the density of the crystal affected by this defect ? (iii) What type of ionic substance show such defect ?

Which of the following are incorrect as a criterion for the essentiality of an element . i. If the concerned element is deficient another element can fulfil the need of it ii. The plants would complete their life cycle irrespective of the absence of deficiency of the elements. iii. The elements have indirect involvement in the metabolism of plants . iv.The elements must be absolutely necessary for supporting normal growth and reproduction. (a) i ,ii ,iii ,iv (b) i,ii (c) i, ii, iii (d) ii , iii

How is the reading of a barometer affected when it is taken to (i) a mine, and (ii) a hill ?

The velocity-time graph shows the motion of a cyclist. Find (i) its acceleration (ii) its velocity and (iii) the distance covered by the cyclist in 15 seconds.

Home
Profile