NCERT Class 12 Biology Exemplar Chapter – 7 Evolution Part 4 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 9:

When we talk of functional macromolecules (e. g. proteins as enzymes, hormones, receptors, antibodies etc.) , towards what are they evolving?


Functional macromolecules are evolving towards the creation of a complex organism.

The proof for this comes from the fact that there are various evidences which are common to simple as well as complex life forms.

For example, if we look at the genetic code for any life form, it is found to be identical, whether we talk about bacteria or plants or even animals.

Question 10:

In a certain population, the frequency of three genotypes is as follows:

What is the likely frequency of B and b alleles?


The likely frequency of B alleles is sum total of all of BB alleles frequency plus half of the combined frequency of Bb alleles.

i.e.. , Frequency of

Similarly the likely frequency of b alleles can be calculated as

Frequency of

Hence the likely frequency of B and b alleles is and respectively.

Question 11:

Among the five factors that are known to affect Hardy-Weinberg equilibrium, three factors are gene flow, genetic drift and genetic recombination. What are the other two factors?


Five factors are known to affect Hardy-Weinberg equilibrium. These are gene migration or gene flow, genetic drift, mutation, genetic recombination and natural selection.

So the other two factors are mutation and natural selection.

Mutation – is the large difference arising suddenly in a population.

Natural Selection – is a process in which heritable variations enabling better survival are enabled to reproduce and leave greater number of progeny.

Question 12:

What is founder effect?


It is the phenomenon that occurs when a small group of organisms becomes isolated from a larger population and becomes so genetically different from the original population that they become a new population altogether.

The smaller the population higher are the chances of the founder effect.

Question 13:

Who among the Dryopithecus and Ramapithecus was more man-like?



Question 14:

By what Latin name the first hominid was known?


The Latin name for the first known hominid is Homo habilis.

Homo habilis are the oldest known species of our genus. They were man-like primates.

They hunted with stone weapons and ate fruits.

Question 15:

Among Ramapithecus, Australopithecines and Homo habilis – who probably did not eat meat?


Among Ramapithecus, Australopithecines and Homo habilis – Homo habilis did not eat meat.

Homo habilis were first human-like being with brain capacities between 650 - 800cc.