Biology today

Figure Based Questions

29. Refer to the given figure and answer the following
    questions.
    Peak gets
    higher and
    narrower

Two peaks form

Number of

individuals with

phenotype

Phenotypes favoured

by natural selection

Medium sized

individuals

are favoured

Peak shifts

in one

direction

A

B

C

(a) Identify the graphs A, B and C.

(b) Briefly describe the characteristics of graph C.

(c) Which graph shows progressive selection?

30. Refer to the given figure and answer the following
    questions.

(a) Identify the given figure and the labelled parts A, B, C

and D.

(b) In the given figure, which gases were used to simulate

primitive atmosphere?

(c) Briefly describe the experiment given in the figure.

CHAPTER-5 : PRInCIPlEs of InHERITAnCE And vARIATIon

1. (d) 2. (c) 3. (a) 4. (d) 5. (d)


2. (d) 7. (a) 8. (b) 9. (b) 10. (d)


3. True


4. false : Recessive gene is unable to express itself in the
   presence of dominant allele.


5. True 14. True


6. false : Down’s syndrome is an autosomal aneuploidy
   caused by the presence of an extra chromosome number
   21.


7. false : Allosomes or sex chromosomes in birds are ZW-ZZ
   type.


8. false : Linked genes are located on the same chromosome
   and do not show independent assortment.


9. True 19. True 20. True


10. A-(ii), B-(iii), C-(v), D-(i), E-(iv)


11. A-(ii, v), B-(iii, vi), C-(i, iv), D-(viii, x), E-(vii, ix)
    23.(A) (i) autosomal (ii) recessive
    (iii) homozygous recessive (affected individual)
    (iv) phenylalanine hydroxylase
    (v) phenylalanine
    (vi) tyrosine (vii) liver
    (viii) hyperphenylalaninemia
    (ix) chromosome 12
    (x) substitution

(B) In a pedigree chart, a square represents the female male,

a circle represents the male female, solid (blackened)

symbol shows the trait under study or affected individual;

unaffected or normal individuals are shown by crossed

open or shaded clear symbol and open crossed or clear

shaded symbol signifies the carrier individual. Parents are

shown by vertical horizontal line while their offsprings are

connected to it by a horizontal vertical line. The offsprings

are then shown in the form of a horizontal line above below

the parents and numbered with roman arabic numerals.

Each generation is given an arabic a roman numeral and

a separate row or horizontal line.

24. (a) 25. (a) 26. (c) 27. (d) 28. (a)


25. (a) P – Aa
    Q – aa
    R – Aa
    S – aa
    T – aa
    (b) The trait illustrated in the given figure is an autosomal
    recessive trait. It appears in case of marriage between
    two heterozygous individual (Aa × Aa = 2Aa + 1aa),
    a recessive individual with hybrid (Aa × aa = 2Aa
    
    
    • 2aa) and two recessive (aa × aa = all aa). For
      example, fused ear lobe, alkaptonuria, etc.
    
    
    
    


26. (a) W – Deletion
    X – Duplication
    Y – Inversion
    Z – Reciprocal translocation

SOLUTIONS