- false : The new world monkeys possess a flat nose with
widely separated and outwardly directed nostrils.
- false : Increase in the number of chromosome sets due
to coming together of genome of two or more organisms
is called allopolyploidy.
- True
- True
- True
- A-(iv), B-(iii), C-(v), D-(ii), E-(i)
- A-(iii, vii), B-(v, x), C-(i,ix), D-(iv, viii), E-(ii, vi)
23.(A) (i) metabolism (ii) favism
(iii) beans (iv) primaquin
(v) H 2 O 2 (vi) NADPH 2
(vii) schizogony (viii) RBCs
(B) Each gorilla human somatic cell contains 46 chromosomes.
Out of these chromosomes, 44 are allosomes autosomes
and 2 are autosomes allosomes. In female XY XX and in
male XX XY are the sex chromosomes. Human chromosomes
are normally taken from Red blood corpuscles (RBCs) White
blood corpuscles (WBCs) from the peripheral blood. The
banding patterns of chromosomes indicate that all human
races such as Asian, African and European possess different
same chromosome number.
- (a) 25. (c) 26. (d) 27. (a) 28. (b)
- (a) A – Stabilising selection
B – Directional selection
C – Disruptive selection
(b) The given graph represents the operation of natural
selection on different traits. Graph C shows disruptive
selection. This type of selection favours both small-
sized and large-sized individuals. It eliminates most of
the members with mean expression, so produces two
peaks in the distribution of the trait that may lead to
development of two different populations. This kind
of selection is opposite to stabilising selection and is
rare in nature but is very important in bringing about
evolutionary change.
(c) Graph B (Directional selection) is also known as
progressive selection. In this selection, the population
changes towards one particular direction. It means
this type of selection favours small or large-sized
individuals and more individuals of that type will be
present in the next generation. The mean size of the
population changes.
- (a) The given figure is the diagrammatic representation
of Miller’s experiment.
A – Electrodes
B – Spark discharge
C – Condenser
D – Vacuum pump
(b) The given figure is the diagrammatic representation
of Miller’s experiment. In the given figure methane
(CH 4 ), ammonia (NH 3 ), water vapour and hydrogen
(H 2 ) were used to simulate primitive atmosphere.
(c) Stanley Miller in 1953 took an air tight apparatus
and circulated four gases - CH 4 , NH 3 , H 2 and water
vapour through it and passed electrical discharges
from electrodes at 800°C. Then he passed the mixture
through a condenser. He performed this experiment
continuously in this way for few days and analysed
the composition of the liquid inside the apparatus. He
found a large number of simple organic compounds
including some amino acids such as alanine, glycine
and aspartic acid. Miller, thus, proved that organic
compounds would have formed in the primitive
reducing environment of Earth, which were further
the essential building blocks of living organisms.
