Please refer to Evolution Class 12 Biology Important Questions with answers below. These solved questions for Chapter 7 Evolution in NCERT Book for Class 12 Biology have been prepared based on the latest syllabus and examination guidelines issued by CBSE, NCERT, and KVS. Students should learn these solved problems properly as these will help them to get better marks in your class tests and examinations. You will also be able to understand how to write answers properly. Revise these questions and answers regularly. We have provided Notes for Class 12 Biology for all chapters in your textbooks.

Important Questions Class 12 Biology Chapter 7 Evolution

All Evolution Class 12 Biology Important Questions provided below have been prepared by expert teachers of Standard 12 Biology. Please learn them and let us know if you have any questions.

Objective Type Questions

Question. Ichthyosaurs was found around
(a) 165 mya
(B) 200 mya
(b) 265 mya
(D) 100 mya

Question. Which of the mammals live wholly in water?
A. Whales
B. Sea cows
C. Seals
D. Dolphins
Options :
(a) All of these
(b) A, C and D
(c) A, B and D
(d) B, C and D

Question. Dryopithecus existed on earth
(a) 50 million years ago
(b) 100 million years ago
(c) 15 million years ago
(d) 115 million years ago

Question. Australopithecines lived in
(a) Australlian grassland
(b) East African grasslands
(c) North American grasslands
(d) East asian grasslands

Question. Match the correct column

Options :
(a) A – I, B – III, C – II
(b) A – II, B – I C – III
(c) A – III, B – II, C – I
(d) A – II, B – III, C – I

Question. Homo sapiens arose in _____ and moved across continents and developed into distinct races.
(a) America
(b) Asia
(c) Africa
(d) Europe

Question. Pre historic cave art came into existence
(a) 28,000 years back
(b) 18,000 years back
(c) 48,000 years back
(d) None of these

115. Which of the following used hides to protect their body and buried their dead?
(a) Remapithecus
(b) Dryopithecus
(c) Homo erectus
(d) Neanderthal man

Question. Coelacanth was caught in 1938 in South Africa. Why is it very significant in the evolutionary history of vertebrates?
Answer : – Coelacanthhasevolvedintothefirstamphibians;theyarefishwithstoutand strong fins that could move on land and go back to water.
– They were thought to be extinct.

Question. Why are lichens regarded as pollution indicators?
Answer : Since, lichens do not grow in polluted areas, they are regarded as pollution indicators.

Question. How does fitness of a population help in evolution?
Answer : Fitness, according to Darwin, refers ultimately only to reproductive fitness. Those who are better fit in an environment would outbreed others and leave more progeny than others.
They will survive better and are selected by nature to reproduce and increase their population size.

Question. Pick out the an cestral line of Angiosperms from the list give below: Conifers, Seedferns, Cycads, Ferns.
Answer : Seed ferns.

Question. Mention the type of evolution that has brought the similarity as seen in potato tube rand sweet potato.
Answer : Sweet potato tubers and potato tubers are analogous structures, evolved for the same function; analogous structures results from convergent evolution.

Question. List the two main propositions of Oparin and Haldane
Answer : The first form of life could have come from, pre-existing non-living organic molecules like RNA, proteins, etc. Formation of life was preceded by chemical evolution that resulted in the formation of diverse organic molecules from inorganic constituents.

Question. How does paleontological evidence support evolution of organisms on Earth?
Answer : Paleontology is the study of fossils. It indicates
The geological time period in which the organisms existed.
The life forms varied over time and certain life forms are restricted to certain geological time span.
That new forms of life have appeared at different times in the history of earth.

Question. List the two characteristics of mutation that help inex plaining evolution according to De Vries.
Answer : Mutations are: Random, Directionless

Question. How is generic drift different from genemigration? Explain.
Answer : Genetic drift
Random changes in the allele frequencies of a population, occurring only by chance, constitute genetic drift.

Gene flow
If refers to the change in allelic frequencies of a given population, when individuals migrate into the population or from the population.

Question. What does the comparison between the eyes of Octopus and those of mammals say about their ancestry and evolution?
Answer : Eyes of octopus and those of mammals are analogous structures, which have resulted from convergent evolution. They have not evolved from common ancestors.

Question. Categorise the following pairs of examples as convergent or divergent evolutions:
(a) Eyes of octopus and mammals.
(b) Wings of butter fly and birds.
(c) Tuber of sweet potatoes and potato.
(d) Thorns in bougainvillea and tendrils in cucurbits.
Answer : (a) Convergent evolution.
(b) Divergent evolution.
(c) Convergent evolution.
(b) Divergent evolution.

Question. What did Louis Pasteur’ sex perimentson’killed yeast’ demonstrate? Name the theory that got disproved on the basis of his experiment.
Answer : Life arise from preexisting life, Theory of spontaneous generation was disproved.

Question. How do Darwin’s finches illustratead a ptiveradiation?
Answer : Adaptive radiation is the process of evolution of different species in a given geographical area starting from a point and literally radiating to other geographical areas. Darwin’s finches were the small black birds, which Darwin observed in Galapagos Islands. Living in isolation for long, new kinds of finches must have evolved, which could survive in the new habitats.

3 Marks Questions

Question. Evolution is the change of genefre quencies in a population in response to changes in environment in the time scale of years and not centuries. Justify the statement with reference to DDT. How does the theory of Hugode Vries support this?
Answer :As the environment changes the organism which are better adapted to the changed environment could survive better and reproduce.
– When DDT was used, initially most of the mosquitoes died, but a few survived.
-These few mosquitoes reproduce and their off springs were also resistant to DDT.
– Today, the population of mosquitoes mostly contains DDT resistance mosquitoes.
– The DDT resistant mosquitoes have envolved in a times cale of years or months and not centuries.
– So, evolution is not a directed process but stochastic process based on chance events.
– According to Hugode Varies, evolution occurs due to mutations. Large differences arising suddenly in a population.
– According to himlarge, single-stepmutation, called saltation, must have been the cause of DDT- resistance in mosquitoes.

Question. How did Darw in theory of naturals election explain the appearance of new form son the earth?
Answer : Darwin’s theory of Natural selection:
Any population has built in variation for every character.
Individuals with those characters which enable them to survive better would outbreed the others, who are less adapted.
Fitness, according to Darwin’s is reproductive fitness, i.e., individuals who are better fit in an environment leaves more progeny than others.
These progenies now comes to possess more fit individuals, i.e., nature selects the better fit individuals and over a long period of time, through a number of generations, the population slowly becomes modified into a different form, or a species, which is called evolution

Question. State the theory of a biogenesis. How does Miller’s experiment support this theory?
Answer : Theory of chemical evolution or a biogenesis was proposed by Oparin and Haldane. It states that the first form of life could have come from pre-existing non-living organic molecules like RNA’s etc., and that formation of life was preceded by chemical evolution, i.e. Formation of diverse organic molecules from in organic constituents.
 Miller’s experiment:
– He created conditions similar to the primitive earth in the laboratory.
– Electric discharge was produced in a closed flask, contain in gmethane, hydrogen, ammonia, and water vapor.
– The temperature was kept at 800oC
– After a week, he observed formation of amino acids.
– Such molecules must have reacted among themselves to form giant, self- replicating molecules, and the first form of life.

5 Marks Question

Question. a) How does Hardy Weinberg equation explain the genetic equilibrium?
b)Describe how this equilibrium gets disturbed which may lead to founder effect.
Answer : a) Hardy-Weinberg Principle:
It states that the allele frequencies in a population are stable and remain constant for generation to generation; it is called genetic equilibrium.
The sum total of all the allelic frequencies is one.
(b) Genetic drift:
– Genetic drift refers to the changes in allele frequencies that occur only by chance events.
– Sometimes the changes in allele frequency is so different in the new sample of population, that they become a different species,
– The orig inally drifted population becomes the founder and suchan effect is called founder effect.

Question. Identify the examples of convergent evolution from the following:
(a) Flippers of penguins and dolphins.
(b) Eyes of octopus and mammals
(c ) Vertebrate brains
Answer : (a), and (b)