CBSE Class 12 Biology VBQs Genetics And Evolution Set B

UNIT VII GENETICS AND EVOLUTION

1. A couple was blessed with a child,there was a healthy argument between the parents regarding the resemblance of the child to either of them. Grand mother intervened and said the child will definitely resemble the parents and also will exhibit some variations.
a) What values are depicted by the parents?
b) How did Messelson and Stahl prove that DNA is semiconservative?
Values:- love and affection or parental bonding.
b) textual answer

2. Rita was an orphan by birth. One day she was seen crying by her friend Sita. When Sita enquired Rita told that a couple had claimed her to be their daughter. Though it is a happy news for her, Rita felt that she didnt belong to them. So Sita requested the orphanage authority, for a DNA testing to be conducted to investigate the validity of the couples claim.

a. List the values displayed in this situation? Empathy helping tendency
b. Describe the technique of DNA finger printing.

      Pg.no.122

3. A child born to a couple was claimed by another man in the hospital. What is the methodology used to solve the paternity disputes. Explain. DNA fingerprinting

Values:- problem solving, critical thinking, decision making

4. A man with blood group A and his wife Group B have a son with blood group O.Father claims that it is not his son.
a.Explain the genetics of blood grouping
b. What moral counseling can you impart through your explanation?

    Trust, critical thinking

5. Thalassemic patients need frequent administration of specific factors.
a) Describe the genetics of different types of β Thalassemi

     textual answer

b) As a fellow human being how can you help such patients? 

    Provide blood , love, empathy.

Question. After complete utilization of lactose from the medium Lac operon is switched off. Explain how? How does the working of this system reflect conservation of energy and resources?
Answer: textual answer.
Switched on only when needed. So judicious use of the system. Critical thinking, aware of the surrounding.

Question. a) Who are the rediscoverers of Mendel’s work?
b) What positive attributes were demonstrated by this?
Answer: scientists name
Appreciation of fellow beings, empathy

Important Questions for NCERT Class 12 Biology Evolution

Question. Which of the following structures is homologous to the wing of a bird?
(a) Hindlimb of rabbit
(b) Flipper of whale
(c) Dorsal fin of a shark
(d) Wing of a moth 

Answer: B

Question. Analogous structures are a result of
(a) shared ancestry
(b) stabilising selection
(c) divergent evolution
(d) convergent evolution.

Answer: D

Question. The wings of a bird and the wings of an insect are
(a) phylogenetic structures and represent divergent evolution
(b) homologous structures and represent convergent evolution
(c) homologous structures and represent divergent evolution
(d) analogous structures and represent convergent evolution. 

Answer: D

Question. Industrial melanism is an example of
(a) mutation
(b) Neo-Lamarckism
(c) Neo-Darwinism
(d) natural selection.

Answer: D

Question. Forelimbs of cat, lizard used in walking; forelimbs of whale used in swimming and forelimbs of bats used in flying are an example of
(a) analogous organs
(b) adaptive radiation
(c) homologous organs
(d) convergent evolution. 

Answer: C

Question. Which one of the following are analogous structures?
(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 

Answer: A

Question. The process by which organisms with different evolutionary history evolve similar phenotypic adaptations in response to a common environmental challenge, is called
(a) non-random evolution
(b) adaptive radiation
(c) natural selection
(d) convergent evolution. 

Answer: D

Question. The eye of octopus and eye of cat show different patterns of structure, yet they perform similar function. This is an example of
(a) analogous organs that have evolved due to convergent evolution
(b) analogous organs that have evolved due to divergent evolution
(c) homologous organs that have evolved due to convergent evolution
(d) homologous organs that have evolved due to divergent evolution. 

Answer: A

Question. Which one of the following options gives one correct example each of convergent evolution and divergent evolution?
Convergent evolution                                                        Divergent evolution       
(a) Eyes of octopus and mammals                                   Bones of forelimbs of vertebrates
(b) Thorns of Bougainvillea and tendrils of Cucurbita            Wings of butterflies and bird
(c) Bones of forelimbs of vertebrates                                   Wings of butterfly and birds
(d) Thorns of Bougainvillea and tendrils of Cucurbita           Eyes of octopus and mammals

Answer: A

Question. Given below are four statements (A-D) each with one or two blanks. Select the option which correctly fills up the blanks in two statements.
Statements:
(A) Wings of butterfly and birds look alike and are the results of (i) evolution.
(B) Miller showed that CH4, H2, NH3 and (i) when exposed to electric discharge in a flask resulted in formation of (ii) .
(C) Vermiform appendix is a (i) organ and an (ii) evidence of evolution.
(D) According to Darwin evolution took place due to (i) and (ii) of the fittest.
(a) (D) – (i) small variations, (ii) survival,
(A) – (i) convergent
(b) (A) – (i) convergent,
(B) – (i) oxygen, (ii) nucleosides
(c) (B) – (i) water vapour, (ii) amino acids
(C) – (i) rudimentary, (ii) anatomical
(d) (C) – (i) vestigial, (ii) anatomical
(D) – (i) mutations, (ii) multiplication

Answer: A

Question. Peripatus is a connecting link between
(a) mollusca and echinodermata
(b) annelida and arthropoda
(c) coelenterata and porifera
(d) ctenophora and platyhelminthes. 

Answer: B

Question. In the case of peppered moth (Biston betularia) the black-coloured form became dominant over the light-coloured form in England during industrial revolution. This is an example of
(a) appearance of the darker coloured individuals due to very poor sunlight
(b) protective mimicry
(c) inheritance of darker colour character acquired due to the darker environment
(d) natural selection whereby the darker forms were selected.

Answer: D

Question. Thorn of Bougainvillea and tendril of Cucurbita are examples of
(a) vestigial organs
(b) retrogressive evolution
(c) analogous organs
(d) homologous organs. 

Answer: D

Question. Which one of the following pairs of items correctly belongs to the category of organs mentioned against it?
(a) Nephridia of earthworm and Malpighian tubules of cockroach - excretory organs
(b) Wings of honeybee and wings of crow - homologous organs
(c) Thorn of Bougainvillea and tendrils of Cucurbita - analogous organs
(d) Nictitating membrane and blind spot in human eye - vestigial organs

Answer: A

Question. Which one of the following statements is correct?
(a) There is no evidence of the existence of gills during embryogenesis of mammals.
(b) All plant and animal cells are totipotent.
(c) Ontogeny repeats phylogeny.
(d) Stem cells are specialised cells. 

Answer: C

Question. When two species of different genealogy come to resemble each other as a result of adaptation, the phenomenon is termed
(a) microevolution
(b) co-evolution
(c) convergent evolution
(d) divergent evolution.

Answer: C

Question. An important evidence in favour of organic evolution is the occurrence of
(a) homologous and analogous organs
(b) homologous and vestigial organs
(c) analogous and vestigial organs
(d) homologous organs only.

Answer: B

Question. Which one of the following is not a living fossil?
(a) Peripatus
(b) King crab
(c) Sphenodon
(d) Archaeopteryx 

Answer: D

Question. Which of the following is the relatively most accurate method for dating of fossils?
(a) Radio-carbon method
(b) Potassium-argon method
(c) Electron-spin resonance method
(d) Uranium-lead method 

Answer: C

Question. Age of fossils in the past was generally determined by radio-carbon method and other methods involve radioactive elements found in the rocks. More precise methods, which were used recently and led to the revision of the evolutionary periods for different groups of organisms, includes
(a) study of carbohydrates/proteins in fossils
(b) study of the conditions of fossilisation
(c) electron spin resonance (ESR) and fossil DNA
(d) study of carbohydrates / proteins in rocks.

Answer: C

Refer to the below link to download CBSE Class 12 Biology VBQs Genetics and Evolution Set A