Download App

Heredity and Evolution — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10ScienceHeredity and Evolution3 Marks
Question
There are five animals A, B, C, D and E. The animal A uses its modified forelimbs for flying. The animal B uses its forelimbs for running whereas the animal C uses its forelimbs for grasping. The animal D can live on land as well as in water and uses its forelimbs to prop up the front end of its body when at rest. The animal E which respires by using spiracles and tracheae uses wings for flying but its wings are analogous to the modified forelimbs of animal A.
  1. What could the animals A, B, C, D and E be?
  2. Why are the forelimbs of animals A, B, C, D called homologous organs?
  3. What does the existence of homologous organs in animals A, B, C and D tell us about their ancestors?
  4. Why are the modified forelimbs of animal A and the wings of animal E called analogous organs?
  5. State whether animals A and E have a common ancestor or not.
✓

Answer

  1. The animal A could be a bird or a bat, animal B could be lizard, animal C could be human, animal D could be frog, animal E could be an insect.
  2. Forelimbs of A, B, C, and D are called homologous organs because they have the same basic structure but different functions.
  3. It suggests that these organisms have evolved from a common ancestor.
  4. It is because forelimbs of animal A and wings of animal E have different basic structures but perform a similar function.
  5. Animals A and E do not have a common ancestor.

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

Explore more

More "[3 Mark Questions]" from Heredity and Evolution→Heredity and Evolution — all question types→Science STD 10 question papers→CBSE Board STD 10 question papers→CBSE Board question paper generator→

Similar questions

Mention three advantages of a solar cell?
→
How do variations arise in organisms? ‘‘Variation is useful for the survival of species.’’ Justify this statement with the help of an example.
→
Under what condition in an arrangement of two plane mirrors, incident ray and reflected ray will always be parallel to each other, whatever may be angle of incidence. Show the same with the help of diagram.
→
A large coal-fired power station produces 2000MW of electrical energy. A wind turbine with 33m blades can produce 300kW.
  1. How many turbines would be needed to replace the power station?
  2. Why, in actual practice, this number of turbines could not replace the coal-fired power station?
→
How does the method used for extracting a metal from its ore depend on the metal’s position in the reactivity series? Explain with examples.
→
Of the three metals X, Y and Z. X reacts with cold water, Y with hot water and Z with steam only. Identify X, Y and Z and also arrange them in order of increasing reactivity.
→
Is the position of a star as seen by us its true position? Justify your answer.
→
What is the principle of an electric motor? Name some of the devices in which electric motors are used.
→
A boy uses spectacles of focal length -60cm. Name the defect of vision he is suffering from. Which lens is used for the correction of this defect? Compute the power this lens.
→
When an object is placed at a distance of 50cm from a concave spherical mirror, the magnification produced is,$-\frac{1}{2}$ Where should the object be placed to get a magnification of, $-\frac{1}{5}?$
→