Ques. Which of the following is used as an atmospheric pollution indicator?

(a) Lepidoptera
(b) Lichens
(c) Lycopersicon
(d) Lycopodium

Ans. (b)

Sol. Lichens can be used as an atmospheric pollution indicator.

• They do not grow in areas that are polluted, as they are sensitive (especially phycobiont) to oxides of nitrogen and sulphur, hence unable to synthesise organic food and do not grow well.
• Lepidoptera It is insect order.
• Lycopersicon It is scientific name of tomato.
• Lycopodium It is an pteridophyte.

Ques. The theory of spontaneous generation stated that

(a) Life arose from living forms only
(b) Life can arise from both living and non-living
(c) Life can arise from non-living things only
(d) Life arises spontaneously, neither from living nor from the non-living.

Ans. (c)

Sol. The theory of spontaneous generation stated that life can arise from non-living things only.

• It is also known as abiogenesis.

• Louis Pasteur by careful experimentation disapproved this theory and demonstrated that life arose from living forms (pre-existing life).

Ques. Animal husbandry and plant breeding programmes are the examples of

(a) Reverse evolution
(b) Artificial selection
(c) Mutation
(d) Natural selection

Ans. (b)

• Natural selection is a gradual process by which biological traits become either more or less common in a population as a function of the effect of the changing environment.

• Reverse evolution or devolution is a notion that species can change into more primitive forms over time.

Ques. Palaeontological evidences for evolution refer to the

(a) Development of embryo
(b) Homologous organs
(c) Fossils
(d) Analogous organs

Ans. (c)

Ques. The bones of forelimbs of whale, bat, cheetah and man are similar in structure, because

(a) One organism has given rise to another
(b) They share a common ancestor
(c) They perform the same function
(d) The have biochemical similarities

Ans. (b)

Sol. The bones of forelimbs of whale, bat, cheetah and man are similar in structure, because they have a common ancestor.

• These are homologous organs which have different functions across diverse forms, but are developed along same pattern.
• These organs arise due to divergent evolution.

Ques. Analogous organs arise due to

(a) Divergent evolution
(b) Artificial selection
(c) Genetic drift
(d) Convergent evolution

Ans. (d)

Sol. Analogous organs arise due to convergent evolution.

• These are the organs which have similar functions, but are different in their structural details and origin, e.g., wings of insect and bird.

Sol. to be continued

• The other three options are incorrect, because divergent evolution give rise to homologous organs, genetic drift can contribute to speciation and artificial selection is used to produce improved varieties of animals and plants.

Ques. $(p+q)^{2}=p^{2}+2 p q+q^{2}=1$, represents an equation used in

(a) Population genetics
(b) Mendelian genetics
(c) Biometrics
(d) Molecular genetics

Ans. (a)

Sol. $(p+q)^{2}=p^{2}+2 p q+q^{2}=1$ represents an equation used in population genetics.

• It is a mathematical representation of ‘Hardy-Weinberg principle’.
• This principle says that allele frequencies in a population are stable and is constant from generation to generation, i.e., the gene pool remains a constant.

Ques. Appearance of antibiotic-resistant bacteria is an example of

(a) Adaptive radiation
(b) Transduction
(c) Pre-existing variation in the population
(d) Divergent evolution

Ans. (c)

Sol. Appearance of antibiotic-resistant bacteria is an example of pre-existing variation in the population.

• When a bacterial population encounters a particular antibiotic, those sensitive to it die.

• But some bacteria having mutations become resistant to the antibiotic.

• Soon, the resistance providing genes become widespread and the entire population becomes resistant.

Sol. to be continued

• It is not due to adaptive radiation because adaptive radiation is development of different functional structures from a common ancestral form.

• Which is also known as divergent evolution.

• Transduction is a process whereby, foreign DNA is introduced into another cell via a viral vector.

Ques. Evolution of life shows that life forms had a trend of moving from

(a) Land to water
(b) Dryland to wet land
(c) Freshwater to sea water
(d) Water to land

Ans. (d)

Sol. Evolution of life shows that life forms had a trend of moving from water to land.

• The early vertebrates were fishes (which lived in only water).

• Some fishes gradually changed into amphibians (can live both on land and in water).

• Certain amphibians then transformed into the reptiles (live on land) some of the latter finally evolved into birds (can fly) and than mammals.

• Thus, showing life forms moved from water to land.

Ques. Viviparity is considered to be more evolved because

(a) The young ones are left on their own
(b) The young ones are protected by a thicks shell
(c) The young ones are protected inside the mother's body and are looked after they are born leading to more chances of survival
(d) The embryo takes a long time to develop

Ans. (c)

Sol. Viviparity is considered to be more evolved because the youngs ones are protected inside the mother’s body and are looked after once they are born, leading to more chances of survival, e.g., mammals.

• However, in oviparity, the female lays fertilised/unfertilised eggs covered by a hard calcareous shell in a safe place in the environment.
• The chances of survival are less as the young ones are left on their own.

Ques. Fossils are generally found in

(a) Sedimentary rocks
(b) Igneous rocks
(c) Metamorphic rocks
(d) Any type of rock

Ans. (a)

Sol. Fossils are generally found in sedimentary rocks, which are formed by the gradual deposition of silt, sand or calcium carbonate over millions of years in regions such as lakes or sea during their formation, the dead animals are carried to the sea or large lake, sink down and get burried in the rocks.

• The animals, thus preserved in the rocks, are converted into fossils.

Ques. For the $M N$-blood group system, the frequencies of $M$ and $N$ alleles are 0.7 and 0.3 , respectively.

• The expected frequency of $\mathrm{MN}$-blood group bearing organisms is likely to be

(a) $42 \\%$
(b) $49 \\%$
(c) $9 \\%$
(d) $58 \\%$

Ans. (a)

Sol. The expected frequency of MN blood group bearings organisms is likely to be $42 \%$.

• According to Hardy-Weinberg equation, $p^{2}+2 p q+q^{2}=1$

• where, $\quad p=$ Frequency of $\mathrm{M}$ alleles,

• $p^{2}=$ Frequency of homozygous dominant individuals.

• $q=$ frequency of $\mathrm{N}$ alleles

• $q^{2}=$ Frequency of homozygous recessive individuals.

• $2 P q=$ Frequency of heterozygous individuals

Sol. to be continued

• So,

• $(0.7)^{2}+(0.3)^{2}+2 p q=1$

• $0.49+0.09+2 p q=1$

• $\therefore \quad 2 p q=0.42=$ Frequency of heterozygous individuals.

• i.e., $42 \%$

Ques. Which type of selection is industrial melanism observed in moth, Biston betularia

(a) Stabilising
(b) Directional
(c) Disruptive
(d) Artificial

Ans. (b)

Sol. Directional selection is observed in moth, Biston betularia is industrial melanism.

• Under this, individuals at one end of the frequency distribution do well light and so more individuals of that type will be present in next generation.

Sol. to be continued

Ans. (c)

Sol. The most accepted line of descent in human evolution is Ramapithecus $\rightarrow$ Homo habilis $\rightarrow$ Homo erectus $\rightarrow$ Homo sapiens.

Sol. to be continued

Sol. to be continued