Question
Evolution has exhibited a greater stability of molecular structure when compared with morphological structures. Comment on the statement and justify your opinion.

Answer

The apparent structures in an organism, are termed morphological structures. Morphological structures can be easily seen by all us. Molecular structure is about the structure of biomolecules which are the integral components of organisms.
We see lot of diversity all around us. This diversity is possible because of diversity in morphological structures. This shows that morphological structures are least stable. Life which began as simple forms on the earth in now composed of many complex forms.
But despite all the evolution which have taken place through millions of years, the structure biomolecules remains the same. A DNA is same in a human and in a mouse. A protein has same structure in a bird and in a fungi. So, the molecular basis of life has not changed through all these years. This shows that evolution has exhibited a greater stability of molecular structure when compared with morphological structure.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

There is a pair of bean-shaped organs P in the human body towards the back, just above the waist. A waste product Q formed by the decomposition of unused proteins in the liver is brought into organ P through blood by an artery R. The numerous tiny filters S present in organ P clean the dirty blood by removing the waste product Q. The clean blood goes into circulation through a vein T. The waste substance Q, other waste salts, and excess water form a yellowish liquid U which goes from organ P into a bag-like structure V through two tubes W. This liquid is then thrown out of the body through a tube X.
  1. What is (i) organ P and (ii) waste substance Q?
  2. Name (i) artery R, and (ii) vein T.
  3. What are tiny filters S known as?
  4. Name (i) liquid U, (ii) structure V, (iii) tubes W and (iv) tube X.
Form the image in case an object is moved from infinity to the concave mirror.
  1. You have three unlabelled test tubes containing ethanol, ethanoic acid and soap solution. Explain the method you would use to identify the compounds in different test tubes by chemical tests using litmus paper and sodium metal.
  2. Give the reason of formation of scum when soaps are used with hard water.
On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper oxide (black), oxygen gas and a brown gas X is formed.
  1. Write a balanced chemical equation of the reaction.
  2. Identity the brown gas X evolved.
  3. Identity the type of reaction.
  4. What could be the pH range of aqueous solution of the gas X?
In a village in Karnataka, people started cultivating crops all around a lake which was always filled with water. They added fertilisers to their field in order to enhance the yield. Soon they discovered that the waterbody was completely covered with green floating plants and fishes started dying in large numbers.
Analyse the situation and give reasons for excessive growth of plants and death of fish in the lake.
Explain natural vegetative propagation by roots in plants.
What is meant by ‘positive geotropism’ and ‘negative geotropism’? Give one example of each type. Draw a labelled diagram to illustrate your answer indicating the plant part which shows positive geotropism and the plant part which shows negative geotropism.
  1. What is meant by 'power of a lens'?
  2. State and define the S.I. unit of power of a lens.
  3. A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are placed in close contact with each other. Calculate the lens power of this combination.
Give a detailed explanation on the following.Versatile nature of carbon.
  1. Write the functions of each of the following parts of the human eye:
  1. Cornea.
  2. Iris.
  3. Crystalline (Eye) lens.
  4. Ciliary muscles.
  5. Retina.
  1. A person is unable to see distinctly the objects closer than 1 m. Name the defect of vision he is suffering from. Draw ray diagrams to illustrate the cause of the defect and its correction by suitable lens.