Explore topic-wise InterviewSolutions in Current Affairs.

 Correct Option is (D) 15 billion

The single titanic explosion that happened about 15 billion years ago, which resulted in the formation of universe is called Big Bang.

Correct answer is (c) Cretaceous

Huxley, the evolutionary biologist gave this statement after studying the characters of birds and reptiles. The fossil bird, Archaeopteryx was discovered which showed characters of both Reptilia and Aves. It showed transformation of reptilian characters into bird characters. Hence, birds are said to be glorified reptiles with feathery exo-skeleton and other glorious characteristics.

Mesozoic era.

Archaeopteryx is the connecting link between reptiles and birds.

Homo sapiens sapiens is the scientific name of modern man.

1. The primitive broth in which simple organic molecules were suspended, was neutral and free from oxygen. 

2. In this broth polymerisation took place and simple organic molecules aggregated to form new complex organic molecules like polysaccharides, fats, proteins, nucleosides and nucleotides. 

3. Protoproteins were formed by polymerisation of amino acids. These protoproteins later formed proteins. 

4. Formation of protein molecules is considered as landmark in the origin of life. Later the enzymes were formed which accelerated the rate of other chemical reactions.

Organic evolution is a slow, gradual, continuous and irreversible changes through which the present day complex forms have descended from their simple, pre-existing forms of the past.

Correct answer is (b) Java, Peking

Correct answer is (c) actual remains

 Correct Option is (B) Gene pool

There are four main types of fossils : actual remains, moulds, casts and compressions. 

1. Actual remains : The most common type of fossil is actual remains in which the plants, animals and human bodies are seen embedded in permafrost of arctic or alpine snow. Due to severe cold temperature, the bodies remain preserved in the actual state, 

E.g., Fossil of Woolly Mammoth in Siberia. Many insects and smaller arthropods remained embedded and thus preserved in amber or hardened resin. 

2. Moulds : Hardened encasements formed in the outer parts of organic remains of animals or plants form moulds. The organisms later decays leaving cavities or the impression in permanent form. 

E.g. Footprints. 

3. Casts : Casts are hardened pieces of mineral matter which is deposited in the cavities of moulds.

4. Compressions : A thin carbon film indicates the outline of external features of ancient organism, but other structural details are not seen.

Carboniferous is dominant period for Amphibia.

Archaeopteryx is the connecting link between reptiles and aves.

i. Any alteration in allele frequency in the natural population by pure chance is called genetic drift.

ii. For example, elimination of a particular allele from a population due to events like accidental death prior to mating of an organism.

iii. Genetic drift occurs when the sole possessor of a particular allele is removed from the population.

iv. It is also called Sewall Wright effect.

Correct answer is (c) Cretaceous

Correct answer is (a) The origin of life on the earth

Correct answer is (c) Formation of proteins

Correct answer is (a) Georges Lemaitre

Correct answer is (d) Pliocene

Correct answer is (c) Ordovician

The origin of life on the earth is called protobiogenesis.

Primitive earth atmosphere was strongly reducing and contained hydrogen, methane, ammonia and water vapours, free oxygen was absent.

Coacervates are colloidal aggregations of hydrophobic proteins and lipids which grew in size by taking up material from surrounding aqueous medium.

1. Mutations are large, sudden and discontinuous variations in a population. 

2. Changes caused due to mutations are inheritable. 

3. The raw material for organic evolution is provided by mutations. 

4. Mutation can be useful or harmful. Useful mutations are at evolutionary advantage as they are selected by nature.

5. Accumulation of the useful mutations over a period of time leads to the origin and establishment of new species. 

6. Harmful or non-adaptive mutation may persist or get eliminated by nature.

1. Hardy and Weinberg were two scientists who proposed a concept of genetic equilibrium popularly known as Hardy- Weinberg principle or equilibrium. 

2. This principle states that gene, allele or genotype frequencies remain the same from generation to generation unless disturbed by factors like mutation, nonrandom mating, genetic drift, etc. 

3. For explaining the concept of equilibrium they assumed that there are two alleles located at a single locus (A and a). 

4. Their respective frequencies are p and q. 

5. The frequency of genotype AA is p, for 2Aa is 2pq and for aa is q. 

6. The equilibrium equation is p² + 2pq + q² = 1 

7. It says that if sum total of gene frequencies is 1, then sum total of genotype frequencies is also equal to 1. When the equilibrium is disturbed then only evolution occurs.

Correct answer is (b) Hydrogen bonding

August Weismann disproved Lamarck’s theory.

The categories of fossils are as follows:

i. Actual remains:

These are the most common type of fossils.

Actual remains are generally formed in the deep oceans.

Whenever the plants or animals die, their dead bodies sink to the bottom of the sea.

Here, either the entire body or its hard parts get surrounded by minerals forming the parts of stones.

Another way of formation of actual remains is incorporation of the entire body or part of the body in the ice.

ii. Moulds and Casts:

A mould is an impression of the body parts left on the soft mud of the oceanic floor.

When the cavities of the mould get filled with minerals, it hardens into stones and forms cast.

(i) The sum total of genes of all individuals of interbreeding population or Mendelian population is called gene pool.

(ii) The proportion of an allele in the gene pool as compared with other alleles at the same locus is termed as gene frequency.

(iii) Organic evolution can be defined as slow, gradual, continuous and irreversible changes through which the present-day complex forms of the life developed (or evolved) from their simple pre-existing forms.

(iv) All individuals of the same species form a group which is called a population.

(v) Formation of new species from the preexisting single group of organisms is called speciation.

 Correct Option is (A) population

In the condition of no migrations of the organisms, no mutations, no sexually reproduction consisting of crossing over, no genetic drift, no recombinations and variation, the gene frequency of a population will remain constant. Such hypothetical conditions will never exist because even one set of sexually reproducing organisms forms an offspring which is slightly different from its parents. This means that there is constant change of gene frequency.

Gene pool:

i. It refers to the sum total of genes of all individuals of interbreeding population.

ii. Changes in gene pool results in evolution.

Gene frequency: The proportion of an allele in the gene pool as compared with other alleles at the same locus is called gene frequency.

1. Genetic drift is random, directionless fluctuation that takes place in allele frequency. 

2. It occurs by pure chance, in small sized population. 

3. Genetic drift becomes an evolutional factor as it can change the gene frequency. 

4. Sewall wright has given this concept and hence it is also known as Sewall wright effect. 

5. Due to genetic drift, some alleles of a population are lost or reduced by chance and some others may be increased. 

6. Some time, a few individuals become isolated from the large population and they produce new population in new geographical area.

7. Genetic drift is also called founders’ effect because original drifted population becomes ‘founders’ in the new area. E.g. Non-adaptive character of huge horns in Antelope is fixed due to genetic drift.

The origin of life on the earth is called protobiogenesis.

There are different theories put forth to explain the origin of life. They are:

i. Theory of special creation.

ii. Cosmozoic theory.

iii. Theory of spontaneous generation or Theory of abiogenesis.

iv. Theory of biogenesis.

Jurassic period from Mesozoic era is known as age of Reptilia.

1. Earth originated about 4.6 billion years ago as a part of the solar system. 

2. When it was formed, it was a rotating cloud of hot gases and cosmic dust. It was then appearing like a nebula. 

3. Later the condensation and cooling started which resulted in stratification. 

4. Heavier elements like nickel and iron settled to the core. Lighter elements like helium, hydrogen, nitrogen, oxygen, carbon, etc. remained on the surface and they formed the primitive atmosphere. 

5. This atmosphere of the earth was of a reducing type, devoid of free oxygen and very hot.

Human brain is evolved and super- specialised but yet in many aspects human beings are much dependent on other natural factors. Human body is not with any protective exoskeleton, or organs of offence and defence.

Unless well dressed, he cannot cope up with severe cold temperatures as he lacks natural protective fur. He cannot run fast as the other animals can. Neither he can digest uncooked food. He has overcome all his shortcomings by using his brain power.

He has managed to take fur and feathers from other animals by killing them. He also uses other natural fibres from plants to cover his body. He has also finished fish from the oceans by over-exploitation and polluting the natural habitats of these creatures.

He takes meat from other animals by killing them and for the purpose he domesticates them to satisfy his hunger. Before technical age, animals were used as beasts of burden and as means of transport. Thus human history has shown excessive use of horses, camels, elephants, etc.

Man snatches milk from other animals like cows and buffaloes which is for their young ones. But the entire diary industry and human needs for dairy products have been taken care of by these herbivores.

Apart from all such uses, man also uses other animals for experimentations and pharmaceutical industries. In this way, man has mastered other animal kingdom due to his intelligence.

Universe originated about 20 billion years ago by huge titanic explosion called big- bang.

The theory of germplasm says that variations produced in germ cells or germplasm are inherited to next generations, but the somatic variations present in somatoplasm or somatic cells are not inherited.

i. It is useful in reconstructing the phylogeny, i.e. the evolutionary history of the organisms.

ii. Palaeontology helps in studying various other forms and structures of extinct animals.

iii. Fossils are important tools which help in understanding the habit and habitat of the extinct organisms.

iv. Fossil records provide the connecting links between two groups of organisms.

The variations are the differences that occur in morphology, physiology, nutrition, habit, behavioural patterns, etc.

 Correct Option is (C) gene frequency from one generation to another.

The sum total of genes of all individuals of interbreeding population is called gene pool.

1. Gene mutations

2. Mutations in the chromosome structure and number 

3. Genetic recombinations 

4. Natural selection 

5. Reproductive isolation.

Australopithecus, the ancestor of human which is described as man with ape brain.

1. Theory of special creation : Theory of special creation is the oldest theory which is based on religious beliefs. According to this theory, all the living organisms were created by supernatural power. However, since there are no scientific proofs to this theory, it is not accepted. 

2. Cosmozoic theory/Theory of Panspermia : This theory says that life did not originate on the earth but it was exported from the other planets in the form of biological spores or microorganisms which were named as cosmozoa or panspermia. They may have descended to the earth from other planets. Recently, NASA has reported fossils of bacteria-like organisms on a piece of Martian rock recovered from Antarctica. Such facts may throw some light on the cosmozoic theory. 

3. Theory of spontaneous generation or Abiogenesis : There was a belief that life originated from non-living material spontaneously. This theory was later disproved by Louis Pasteur. 

4. Theory of biogenesis : This theory says that living organisms can originate only from preexisting living beings. It is same as reproduction. But this theory of biogenesis was unable to explain origin of life on earth. It explains only the continuity of life.

1. Protobionts or coacervates were colloidal aggregations of hydrophobic proteins and lipids (lipoid bubbles). 

2. They grew in size by taking up material from surrounding aqueous medium. 

3. During their growth they became thermodynamically unstable and split into smaller units. These were called microspheres. 

4. They were proteinoids formed from colloidal hydrophilic complexes surrounded by water molecules. 

5. These bodies were like primitive cells having outer double-membrane. Across this membrane diffusion and osmosis may have occurred. They were more stable than coacervates. 

6. Coacervates and microspheres were non-living colloidal aggregations of lipids and proteinoids respectively. 

7. But they showed growth and division like living cells. 

8. These colloidal aggregations turned into first primitive living system called eobionts or protocell.