Q.1. Variations caused by mutation, as proposed by Hugo de Vries, are (2019)
(a) Small and directionless
(b) Random and directional
(c) Random and directionless
(d) Small and directional
Hugo de Vries (1901) put forward the theory of evolution called mutation theory. He believed that mutation causes evolution. Mutations are discontinuous variations that are random and directionless.
Q.2. A gene locus has two alleles A, a. If the frequency of dominant allele A is 0.4, then what will be the frequency of homozygous dominant, heterozygous and homozygous recessive individuals in the population? (2019)
(a) 0.16 (A A ); 0.36 (Aa); 0.48 (aa)
(b) 0.36 (AA); 0.48 (Aa); 0.16 (aa)
(c) 0.16 (AA); 0.24 (Aa); 0.36 (aa)
(d) 0.16 (AA); 0.48 (Aa); 0.36 (aa)
Frequency of dominant allele (A) = 0.4
Applying Hardy-Weinberg equilibrium; p + q = 1
q = 1 - 0.4 = 0.6 ; p2 + q2 + 2pq = 1
Frequency of homozygous dominant genotype
(p2 ∴ AA)= (0.4)2 = 0.16
Frequency of heterozygous genotype
(2pq Aa) = 2 x 0.4 x 0.6 = 0.48
Frequency of homozygous recessive genotype
(q2 ∴ aa) = (0.6)2 = 0.36
Q.3. In a species, the weight of newborn ranges from 2 to 5 kg. 97% of the newborn with an average weight between 3 to 3.3 kg survive whereas 99% of the infants born with weights from 2 to 2.5 o r 4.5 to 5 kg die. Which type o f selection process is taking place? (2019)
(a) Cyclical selection
(b) Directional selection
(c) Stabilising selection
(d) Disruptive Selection
Stabilising selection is a balancing type of natural selection which favours average sized individuals and eliminates extreme individuals.
Q.4. Match the hominids with their correct brain size. (2019)
Select the correct option.
Q.5. Which of the following statements is correct about the origin and evolution of men? (2019)
(a) Agriculture came around 50,000 years back.
(b) The Dryopithecus and Ramapithecus primates existing 15 million years ago, walked like men.
(c) Homo habilis probably ate meat.
(d) Neanderthal man lived in Asia between 1,00,000 and 40,000 years back.
Q.6. The similarity of bone structure in the forelimbs of many vertebrates is an example of (2018)
(c) Convergent evolution
(d) Adaptive radiation.
Homologous organs are those organs which have the same fundamental structure but are different in functions. Wings of birds and forelimbs of horse show homology because skeletal parts of their forelimbs are similar in structure and arrangement but have different functions.
Q.7. Among the following sets of examples for divergent evolution, select the incorrect option. (2018)
(a) Forelimbs of man, bat and cheetah
(b) Heart of bat, man and cheetah
(c) Brain of bat, man and cheetah
(d) Eye of octopus, bat and man
Eye of octopus, bat and man are examples of analogous organs showing convergent evolution.
Q.8. According to Hugo de Vries, the mechanism of evolution is (2018)
(a) Multiple step mutations
(c) Phenotypic variations
(d) Minor mutations
As per mutation theory given by Hugo de Vries, the evolution is a discontinuous phenomenon or saltatory phenomenon (single step large mutation).
Q.9. Artificial selection to obtain cows yielding higher milk output represents (2017)
(a) Directional as it pushes the mean of the character in one direction
(b) Disruptive as it splits the population into two, one yielding higher output and the other lower output
(c) Stabilization followed by disruptive as it stabilize the population to produce higher yielding cows
(d) Stabilising selection as it stabilize this character in the population
Q.10. Genetic drill operates in (2016)
(a) Small isolated population
(b) Large isolated population
(c) Non-reproductive population
(d) Slow reproductive population
The random changes in gene frequencies in a population occurring by chance alone rather than by natural selection are called genetic drift or Sewall Wright effect. The effects of genetic drift are most marked in very small isolated population, although it occurs in all populations.
Q.11. In Hardy-Weinberg equation, the frequency of heterozygous individual is represented by (2016)
In a stable population, for a gene with two alleles, ‘A’ (dominant) and ‘a’ (recessive), if the frequency of‘A’ is p and the frequency of‘a’ is q, then the frequencies of the three possible genotypes (AA, Aa and aa) can be expressed by the Hardy-Weinberg
p2 + 2pq + q2= 1
p2 = Frequency of AA (homozygous dominant) individuals
q2 = Frequency of aa (homozygous recessive) individuals
2pq = Frequency of Aa (heterozygous) individuals
Q.12. The chronological order of human evolution from early to the recent is (2016)
(a) Australopithecus → Ramapithecus → Homo habit is → Homo erectus
(b) Ramapithecus → Australopithecus → Homo habilis → Homo erectus
(c) Ramapithecus → Homo habilis → Australopithecus → Homo erectus
(d) Australopithecus → Homo habilis → Ramapithecus → Homo erectus
Q.13. Which of the following is the correct sequence of events in the origin of life? (2016)
I. Formation of protobionts
II. Synthesis of organic monomers
III. Synthesis of organic polymers
IV. Formation of DNA-based genetic systems
(a) I, II, III, IV
(b) I, III, II, IV
(c) II, III, I, IV
(d) II, III, IV, I
Q.14. Which of the following structures is homologous to the wing of a bird? (2016)
(a) Hindlimb of rabbit
(b) Flipper,of whale
(c) Dorsal fin of a shark
(d) Wing of a moth
Homologous organs have same fundamental structure but different functions. The wing of a bird and flipper of a whale are structurally forelimbs, which consist of humerus, radius-ulna, carpals, metacarpals and digits but they perform different functions. The wings of birds help them to fly while flipper helps the whale to swim.
Q.15. Analogous structures are a result of (2016)
(a) Shared ancestry
(b) Stabilising selection
(c) Divergent evolution
(d) Convergent evolution
The organs which have similar functions but are dilTercni in their structural details and origin are called analogous organs. The analogous structures arc the result of convergent evolution.
Q.16. Following are the two statements regarding the origin of life.
(A) The earliest organisms that appeared on the earth were non-green and presumably anaerobes,
(B) The first autotrophic organisms were the chemo-autotrophs that never released oxygen.
Of the above statements which one o f the following options is correct? (2016)
(a) Both (A) and (B) are correct.
(b) Both (A) and (B) are false.
(c) (A) is correct but (B) is false.
(d) (B) is correct but (A) is false.
Q.17. Which of the following structures is homologous to the wing of a bird? (2016)
(a) Dorsal fin of a Shark
(b) Wing of a Moth
(c) Hind limb of Rabbit
(d) Flipper of Whale
Wings of a bird and flippers of a whale are modified forelimbs.
Q.18. Following are the two statements regarding the origin of life (2016)
(a) The earliest organisms that appeared on the earth were non-green and presumably anaerobes.
(b) The first autotrophic organisms were the chemo-autotrophs that never released oxygen.
Of the above statements which one of the following options is correct ?
(a) (a) is correct but (b) is false.
(b) (b) is correct but (a) is false.
(c) Both (a) and (b) are correct.
(d) Both (a) and (b) are false.
Both statements are correct because primitive atmosphere was reducing and chlorophyll appeared later on. Chemoautotrophs were the first autotrophic organisms unable to perform photolysis of water and never released oxygen.
Q.19. Analogous structures are a result of (2016)
(a) Divergent evolution
(b) Convergent evolution
(c) Shared ancestry
(d) Stabilizing selection
Analogous structures are those that have the same function, but they are not derived from a common ancestor and have undergone different patterns of development ie., Convergent evolution which is natural selection that favors the same type of structure in different ancestors.
Q.20. Which of the following had the smallest brain capacity ? (2015)
(a) Homo sapiens
(b) Homo neanderthalensis
(c) Homo habilis
(d) Homo erectus
Brain capacity in decreasing order:- Homo sapiens (1300 - 1600 c.c) Homo neander thalensis (approx. 1400 cc) Homo erectus (600 - 700 c.c.) Homo habilis (550 - 687 c.c.) Thus the lowest brain capacity is of Homo habilis as shown above. Homo habilis lived in early pleistocene period and used tools of chipped stones.
Q.21. Forelimbs of cat, lizard used in walking; forelimbs of whale used in swimming and forelimbs of bats used in flying are an example of: (2014)
(a) Analogous organs
(b) Adaptive radiation
(c) Homologous organs
(d) Convergent evolution
Organs which have a common fundamental anatomical plan and similar embryonic origin whatever varied functions they may perform are regarded as homologous organs. For examples the flippers of a whale, a bats wing, fore-limb of a horse, a bird's wings and forelimbs of human are structurally as well as functionally different.
Q.22. Which one of the following are analogous structures? (2014)
(a) Wings of Bat and Wings of Pigeon.
(b) Gills of Prawn and Lungs of Man.
(c) Thorns of Bougainvillea and Tendrils of Cucurbita
(d) Flippers of Dolphin and Legs of Horse
Analogous organs are those that perform similar functions but have entirely different embryonic origins.