Q21 of 30 Page 1

(a) Classify the following as homologous or analogous pairs:

(i) Broccoli and cabbage


(ii) Ginger and Raddish


(iii) Fore limbs or birds and lizard


(iv) Wings of a bat and wings of a bird


(b) State the main feature that categorises a given pair of organs as homologous and analogous.


(i) Homologous

(ii) Analogous


(iii) Homologous


(iv) Analogous


(b) Homologous characteristics are organs that have the same basic structure and origin, but different functions. For example, mammals, birds, reptiles and amphibians have four limbs with the same basic limb layout because they have inherited the limbs from a common ancestor. These limbs have been modified to perform different functions.


Analogous characteristics are organs that have different structures and are of different origin but perform the same functions. For example, the design of the wings of bats and the wings of birds look similar because they have a common purpose – to fly.


More from this chapter

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19

(a) State the role played by the following in the process of digestion.

(i) Enzyme trypsin


(ii) Enzyme lipase


(b) List two functions of finger like projections present in the small intestine.


 20

A green stemmed rose plant denoted by GG and a brown stemmed rose plant denoted by gg are allowed to undergo a cross with each other.

(a) List your observation regarding


(i) Colour of stem in their F1 progeny


(ii) Percentage of brown stemmed plants in F2 progeny if F1 plants are self pollinated.


(iii) Ratio of GG and Gg in the F2 progeny.


(b) Based on the findings of this cross, what conclusion can be drawn ?


 22

(a) State snell’s law of refraction of light.

(b) When a ray of light travelling in air enters obliquely into a glass slab, it is observed that the light ray emerges parallel to the incident ray but it is shifted sideways slightly . Draw a labelled ray diagram to illustrate it.


 23

(a) With the help of labelled ray diagram show the path followed by a narrow beam of monochromatic light when it passes through a glass prism.

(b) What would happen if this beam is replaced by a narrow beam of white light ?


OR


(a) A person is suffering from both myopia and hypermetropia.


(i) What kind of lenses can correct this defect ?


(ii) How are these lenses prepared ?


(b) A person needs a lens of power + 3D for correcting his near vision and – 3D for correcting his distant vision. Calculate the focal lengths of the lenses required to correct these defects.