12th biology chapter 5 MCQs ( Origin and Evolution of life )

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Origin and Evolution of Life Class 12 MCQ:.



1. Who proposed that the first form of life could have come from per- existing non-living organic molecules?
a. Alfred Wallace
b. oparin and Haldane
c. Charles Darwin
d. Louis Pasteur

Answer: b 



Explanation: The theory of biogenesis was proposed by Oparin and Haldane. It states that life could have come from pre-existing non-living organic molecules (e.g. RNA, protein, etc.) and that the formation of life was preceded by chemical evolution, i.e. formation of diverse organic molecules from inorganic constituents.




2. In the Hardy – Weinberg equation, the frequency of homozygous recessive individuals is represented by…

a. P2
b. pq
c. q2
d. 2pq

Answer: q2


ExplanationTo estimate the frequency of alleles in a population, we can use the HardyWeinberg equation. For a population in genetic equilibrium: p + q = 1.0 (The sum of the frequencies of both alleles is 100%.) q2 = frequency of aa (homozygous recessive)



3. Select the analogous organs-
a. Forelimbs of whale and bat
b. Flippers of dolphins and penguins
c. Thorn and tendrils of bougainvillea                and cucurbita.
d. Vertebrates hearts or brains.

Answer: b ( Flippers of dolphins and penguins)




4. Archaeopteryx is known as the missing link because it is a fossil and shares characters of both-

a. Fishes and amphibians
b. Annelida and arthropods.
c. Birds and reptiles
d. Chordates and nonchordates

Answer: c


Explanation: Archaeopteryx is an iconic fossil, often thought of as the ‘missing link‘ between birds and reptiles.




5. Identify the wrong statement regarding
evolution.
a. Darwin’s variations are small and directional.
b. Mutations are random and non-directional.
c. Adaptive radiations lead to divergent evolution.
d. Mutations are non-random and directional.

Answer : d (Mutations are non-random and directional.






6. Gene frequency in a population remains constant due to –
a. Mutation
b. Migration
c. Random mating
d. Non-random mating

Answer: Random Mating 

Explanation: There are a few factors such as gene migration (gene flow), genetic drift, mutation, genetic recombinations, natural selection, non-random mating, etc. which affect or change the Hardy-Weinberg equilibrium, If these factors do not occur in the population, that’s why gene frequency in a population is genetically stable or remain constant.




7. Which of the following characteristic is not shown by the ape?
a. Prognathous face
b. tail is present
c. Chin is absent
d. forelimbs are longer than hind limbs

Answer: b ( tail is present )

Explanation: In ape tail is absent.






8. ……………… can be considered as a connecting link between ape and man.
a. Austalopithecus
b. Homo hablis
c. Homo erectus
d. Neanderthal man.

Answer: Australopithecus




9. The Cranial capacity of Neanderthal man was
a. 600 cc
b. 940 cc
c. 1400 cc
d. 1600 cc

Answer: 1400 cc


Explanation: Neanderthals had a brain bigger than modern humans with an average of about 1400 cc, but lacked the complex belief systems and symbolic thinking unique to us.

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