Important Questions for Class 12 Biology 7th Chapter Evolution MCQ, Very Short, Short Type, Long Type
CBSE Class 12 Important Questions for Class 12 Biology Chapter 7 Evolution all MCQ Type, Very Short Type, Assertion Reason Type, Case Study, Short Type and Long Type Questions with Answers by Expert. Important Questions for Section A, B, C, D Class 12 Biology Chapter 7.
- Answer in one sentence
Q.1) What is panspermia?
Ans. Some scientists believe life on earth came from outer space. Early Greek thinkers believed that spores, or units of life, were transferred to different planets, including Earth. This theory of origin of life on earth is called ‘Panspermia’.
Q.2) What is the founder effect?
Ans. The shift in allele frequency in a new sample of population might sometimes be so different that they become a different species. The founder effect occurs when the original drifting population becomes founders.
Q.3) What is the basis of Darwinian Theory of Evolution?
Ans. The Darwinian Theory of Evolution is based on two basic concepts: branching descent and natural selection.
Q.4) Define: Adaptive radiation
Ans. Adaptive radiation is the process of distinct species in a certain geographical area evolving from a single point and literally radiating to other parts of geography (habitats).
Q.5) what can affect the Hardy-Weinberg equilibrium?
Ans. Hardy-Weinberg equilibrium is influenced by Gene migration, genetic drift, mutation, genetic recombination, and natural selection are examples of these processes.
Q.6) Describe the distinguish feature of Neanderthal man
Ans. Between 1,00,000 and 40,000 years ago, a Neanderthal man with a brain size of 1400cc inhabited in the Near East and Central Asia. They buried their dead and used hides to protect their bodies.
Q.7) What is genetic drift?
Ans. Genetic drift is the evolution of a population’s allelic frequencies, which is a chance phenomenon.
- Answer in short
Q.1) How did Louis Pasteur discredit the spontaneous generation theory?
Ans. 1.) For a long period of time, it was also thought that life came from decaying and rotting matter such as straw, mud, and so forth. This was known as the spontaneous generation theory. 2.) Louis Pasteur demonstrated through careful experimentation that life can only arise from pre-existing life.
3.) He demonstrated that life did not arise from killed yeast in pre-sterilized flasks, whereas in another flask exposed to air, new living organisms arose from ‘killed yeast’.
4.) Thus, the theory of spontaneous generation was finally disproved.
Q.2) Explain the theory of evolution proposed by Lamarck with suitable example?
Ans. 1.) Lamarck, a French naturalist, claimed that life forms evolved as a result of the use and misuse of organs.
2.) He used the example of giraffes, who had to adjust by length of their necks in order to forage leaves on tall branches.
3.) Giraffes gradually gained long necks throughout time as they passed on this acquired attribute of lengthened neck to successive generations.
Q.3) Give details of Homo habilis
Ans. 1.) East African grasslands were most likely home to Australopithecines.
2.) They hunted with stone weapons but mostly ate fruit, according to the evidence. Among the bones unearthed, there were a few that were unique.
3.) This organism was known as Homo habilis, and it was the first human-like creature.
4.) The brain capacity ranged from 650 to 800 cubic centimeters. They didn’t consume meat, most likely.
- Answer in brief
Q.1) What are the factors influencing the Hardy-Weinberg equilibrium?
Ans. 1.) Hardy-Weinberg equilibrium is known to be influenced by five major factors. Gene migration, also known as gene flow, genetic drift, mutation, genetic recombination, and natural selection are examples of these processes.
2.) Gene migration: When a portion of a population migrates to a new location and population, gene frequencies vary in both the original and new populations. New genes/alleles are contributed to the new population, whereas old genes/alleles are removed. If this gene movement occurs numerous times, there will be a gene flow.
3.) Genetic drift: it happens when the same alteration occurs by chance.
4.) Mutations: In microbial investigations, it has been demonstrated that selecting beneficial mutations results in the detection of new phenotypes. This would result in Speciation after a few generations.
5.) Natural selection: it is a process in which heritable changes that improve survival are allowed to replicate and create a larger number of offspring.
6.) Variation owing to mutation or recombination during gametogenesis, or gene flow or genetic drift, resulting in changing frequency of genes and alleles in future generations, according to a careful analysis.
Q.2) State the difference in convergent and divergent evolution?
Ans.
Sr. No. |
Convergent Evolution |
Divergent Evolution |
1. | Unrelated species show similarities | Related species becomes less similar |
2. | No common ancestor | Share common ancestor |
3. | Analogous structures are seen | Homologues structures are seen |
4. | Different structures evolve in same direction | Same structure evolves in different direction |
5. | Wings of butterfly and of birds
|
the thorn and tendrils of Bougainvillea and Cucurbita |
Q.3) Explain natural selection with help of example.
Ans. 1.) There were more white-winged moths on trees than dark-winged or melanised moths in a collection of moths made in the 1850s, i.e., before industrialisation.
2.) However, in a collection made from the same area following industrialisation, i.e., in 1920, there were more dark-winged moths in the same area, indicating that the proportion had shifted.
3.) Predators will identify a moth against a contrasting background, according to the explanation given for this finding.
4.) Due to industrial smoke and soot, tree trunks became dark during the post-industrialisation period. Due to predators, the white-winged moth did not survive in this situation, but the dark-winged moth did.
5.) Before industrialisation, trees were coated in a thick growth of practically white-colored lichen; in this environment, the white winged moth survived, while predators picked out the dark-colored moth.
6.) Polluted regions will not support their growth. As a result, moths that were able to blend in with their surroundings, or camouflage themselves, fared better.
Q.4) Write a short note on mammals
Ans. 1.) Shrews were the first mammals. Their fossils are rather small.
2.) Mammals were viviparous, which meant that their embryonic young were protected within the mother’s body.
3.) At the very least, mammals are more sophisticated in detecting and avoiding danger.
4.) When reptiles descended, mammals occupied most of the planet.
5.) Horses, hippopotamuses, bears, rabbits, and other creatures were found in South America.
6.) When South America joined North America due to continental drift, these animals were displaced by North American fauna.
7.) Due to the same continental drift, Australia’s pouched mammals survived due to a lack of competition from other mammals.
- MCQS
Q.1) Assertion: Fitness is the end result of the ability to adapt and get selected by nature.
Reason: Adaptive ability is inherited and it has a genetic basis.
(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
(c) If Assertion is true but Reason is false.
(d) If both Assertion and Reason are false.
Q.2) Assertion: Genetic drift is the evolution of a population’s allelic frequencies.
Reason: New genes/alleles are added to the new population and these are lost from the old population multiple times due to fixed set of events.
(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
(c) If Assertion is true but Reason is false.
(d) If both Assertion and Reason are false.
Q.3) Assertion: animals with same structure developed along different directions due to adaptations to different needs.
Reason: This is Convergent evolution and these structures are homologous.
If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
If Assertion is true but Reason is false.
If both Assertion and Reason are false.
Q.4) The process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats) is called
a) Character displacement
b) Adaptive radiation
c) Branching descent
d) Natural selection
Q.5) Lamarckism states that long necked giraffes evolved because
a.) continuous stretching of the short neck leads to development of long neck
b.) punctuated equilibrium
c.) natural selection
d.) all the above
Q.6) Which following example to explain directional selection?
a.) robins laying 4 eggs
b.) industrial melanism
c.) human babies birth weight
d.) Galapagos Island finches
Q.7) Assertion: Single step large mutation leads to speciation
Reason: This is called as Saltation
If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
If Assertion is true but Reason is false.
If both Assertion and Reason are false.
Q.8) What are the key concepts of Darwinian Theory of Evolution?
a) Branching descent and natural selection
b) Natural selection only
c) use and disuse
d) all the above
Q.9) Assertion: S.L. Millerob served formation of amino acids in his experiment to prove chemical evolution
Reason: Analysis of meteorite content also revealed similar compounds indicating that similar processes are occurring elsewhere in space.
If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
If Assertion is true but Reason is false.
If both Assertion and Reason are false.
Q.10) ……….are not anatomically similar structures though they perform similar functions.
a.) Homologous organs
b.) Analogues organs
c.) both a.) and b.)
d.) None of the above