Modern evolutionary biology dates back to a synthesis that emerged around the 1940s-60s, which married Charles Darwin’s mechanism of natural selection with Gregor Mendel’s discoveries of how genes are inherited. The traditional, and still dominant, view is that adaptations – from the human brain to the peacock’s tail – are fully and satisfactorily explained by natural selection (and subsequent inheritance). Yet [new evidence] from genomics, epigenetics and developmental biology [indicates] that evolution is more complex than we once assumed. . . .
In his book On Human Nature (1978), the evolutionary biologist Edward O Wilson claimed that human culture is held on a genetic leash. The metaphor [needs revision]. . . . Imagine a dogwalker (the genes) struggling to retain control of a brawny mastiff (human culture). The pair’s trajectory (the pathway of evolution) reflects the outcome of the struggle. Now imagine the same dog-walker struggling with multiple dogs, on leashes of varied lengths, with each dog tugging in different directions. All these tugs represent the influence of developmental factors, including epigenetics, antibodies and hormones passed on by parents, as well as the ecological legacies and culture they bequeath. . . .
The received wisdom is that parental experiences can’t affect the characters of their offspring. Except they do. The way that genes are expressed to produce an organism’s phenotype – the actual characteristics it ends up with – is affected by chemicals that attach to them. Everything from diet to air pollution to parental behaviour can influence the addition or removal of these chemical marks, which switches genes on or off. Usually these so-called ‘epigenetic’ attachments are removed during the production of sperm and eggs cells, but it turns out that some escape the resetting process and are passed on to the next generation, along with the genes. This is known as ‘epigenetic inheritance’, and more and more studies are confirming that it really happens. Let’s return to the almond-fearing mice. The inheritance of an epigenetic mark transmitted in the sperm is what led the mice’s offspring to acquire an inherited fear. . . .
Epigenetics is only part of the story. Through culture and society, [humans and other animals] inherit knowledge and skills acquired by [their] parents. . . . All this complexity . . . points to an evolutionary process in which genomes (over hundreds to thousands of generations), epigenetic modifications and inherited cultural factors (over several, perhaps tens or hundreds of generations), and parental effects (over single-generation timespans) collectively inform how organisms adapt. These extra-genetic kinds of inheritance give organisms the flexibility to make rapid adjustments to environmental challenges, dragging genetic change in their wake – much like a rowdy pack of dogs.
The Emory University experiment with mice points to the inheritance of:
The Emory University experiment with mice points to the inheritance of:
- psychological markers
acquired characteristics
- personality traits
- acquired parental fears
The Correct Option is D
Solution and Explanation
The Emory University experiment with mice illustrates the phenomenon of acquired parental fears being passed down to subsequent generations. In the experiment, mice were conditioned to fear the smell of almonds through the use of electric shocks. Surprisingly, both the offspring and the grandchildren of these mice also exhibited fear towards the same smell, despite never having been subjected to the conditioning themselves. This finding challenges the traditional view that acquired characteristics are not inheritable.
The underlying explanation for this phenomenon is "epigenetic inheritance." This process involves chemical modifications to DNA that affect gene expression without changing the genetic code itself. These modifications, known as epigenetic marks, can sometimes escape the typical resetting process during the production of sperm and eggs, allowing them to be passed on to the next generation.
Therefore, the fear of almonds in the offspring of the original mice was not learned but inherited through an epigenetic mark transmitted in the sperm. This aligns with broader scientific perspectives indicating that parental experiences and environmental factors can indeed influence the gene expression of their progeny.
Which of the following best describes the author's argument?
- Darwin’s and Mendel’s theories together best explain evolution.
- Mendel’s theory of inheritance is unfairly underestimated in explaining evolution.
- Wilson’s theory of evolution is scientifically superior to either Darwin’s or Mendel’s.
- Darwin’s theory of natural selection cannot fully explain evolution.
The Correct Option is A
Solution and Explanation
Which of the following, if found to be true, would negate the main message of the passage?
Which of the following, if found to be true, would negate the main message of the passage?
A study affirming the influence of socio-cultural markers on evolutionary processes.
A study highlighting the criticality of epigenetic inheritance to evolution.
A study indicating the primacy of ecological impact on human adaptation.
- A study affirming the sole influence of natural selection and inheritance on evolution.
The Correct Option is D
Solution and Explanation
- The inheritance of acquired traits through epigenetic marks and cultural influences contradicts the classical view that adaptations are solely a result of natural selection and genetic inheritance.
- Epigenetics and cultural factors are shown to affect evolution, making it more nuanced and complex.
The passage uses the metaphor of a dog walker to argue that evolutionary adaptation is most comprehensively understood as being determined by:
- extra genetic, genetic, epigenetic and genomic legacies.
- socio-cultural, genetic, epigenetic, and genomic legacies
- ecological, hormonal, extra genetic and genetic legacies.
- genetic, epigenetic, developmental factors, and ecological legacies.
The Correct Option is D
Solution and Explanation
- Genetic factors: Genes inherited following Mendelian principles.
- Epigenetic factors: Chemical modifications affecting gene expression, which can be inherited (e.g., epigenetic marks).
- Developmental factors: Influences from developmental biology, including molecules like hormones passed from parents.
- Ecological legacies: Environmental and cultural influences shaping adaptation over generations.
In the first paragraph, the author laments the fact that:
- there is no recognition of the Indian soldiers who served in the Second World War.
- the new war memorial will be built right next to India Gate.
- India lost thousands of human lives during the Second World War.
- funds will be wasted on another war memorial when we already have the India Gate memorial.
The Correct Option is A
Solution and Explanation
In analyzing the comprehension passage, it is clear that the primary focus is on the concept of inheritance of acquired characteristics, which was traditionally believed to be impossible, but is now being reconsidered due to new evidence. This evidence includes the phenomenon of epigenetic inheritance, where experiences can affect offspring characteristics.
The question pertains to what the author laments in the first paragraph. Let's examine the options:
- There is no recognition of the Indian soldiers who served in the Second World War.
- The new war memorial will be built right next to India Gate.
- India lost thousands of human lives during the Second World War.
- Funds will be wasted on another war memorial when we already have the India Gate memorial.
The correct answer is: there is no recognition of the Indian soldiers who served in the Second World War.
This aligns with the mention of a lack of recognition for Indians who served in World War II, which is explicitly stated in the comprehension portion provided.
Top Questions on Reading Comprehension
- There were humans long before there was history. The archaic humans loved, played, formed close friendships and competed for status and power, but so did chimpanzees, baboons and elephants. There was nothing special about them.
Nobody, least of all humans themselves, had any inkling that their descendants would one day walk on the moon, split the atom, fathom the genetic code and write history books. The most important thing to know about prehistoric humans is that they were insignificant animals with no more impact on their environment than gorillas, fireflies or jellyfish.
Biologists classify organisms into species. Animals are said to belong to the same species if they tend to mate with each other, giving birth to fertile offspring. Horses and donkeys have a recent common ancestor and share many physical traits. They will mate if induced to do so – but their offspring, called mules, are sterile. Mutations in donkey DNA can therefore never cross over to horses, or vice versa. The two types of animals are consequently considered two distinct species, moving along separate evolutionary paths. By contrast, a bulldog and a spaniel may look very different, but they are members of the same species, sharing the same DNA pool. [203 words]
[Extracted from Sapiens: A Brief History of Humankind by Yuval Noah Harari]- CLAT - 2026
- English
- Reading Comprehension
- My kinsman and I were returning to Calcutta from our Puja trip when we encountered an unusual man on the train. At first, judging from his dress and bearing, we mistook him for an up-country boorish man. But as soon as he began to speak, our impression changed. He discoursed on every subject with such confidence that one might think the ‘Disposer of All Things’ sought his counsel in every decision. Until then, we had been perfectly content, unaware of hidden forces shaping the world—that the Russians were advancing, that the English were pursuing secret policies, and that confusion among native chiefs had reached its peak. Our new acquaintance, however, hinted at such matters with a sly smile, remarking:
"There are more things in heaven and earth, Horatio, than are reported in your newspapers."
Having never traveled beyond our homes, we were struck dumb with wonder at his manner. No matter how trivial the topic, he could quote science, comment on the Vedas, or recite quatrains from Persian poets. Since we possessed no real knowledge of a theosophist, became convinced that our fellow passenger was inspired by some strange magnetism, occult power, or astral body. He listened, with devotional rapture even to the most common place remarks and secretly noted down his words. I suspect our extraordinary companion noticed this and was quietly pleased. When the train reached the junction, we gathered in the waiting room to await our connection. It was 10 p.m., and as the train was expected to be delayed owing to some fault in the lines, I spread my bed on the table and prepared to sleep. But just then, the extraordinary man began spinning a tale, and of course, I could not close my eyes all night. (307 words)
[Extracted with edits from Rabindranath Tagore’s “The Hungry Stones”]- CLAT - 2026
- English
- Reading Comprehension
- Man is the only creature that consumes without producing. He does not give milk, he does not lay eggs, he is too weak to pull the plough, and he cannot run fast enough to catch rabbits. Yet he claims dominion over all animals. He sets us to work, returns only the bare minimum to keep us from starving, and keeps the rest for himself. Our labour tills the soil, our dung fertilizes it, and still, not one of us owns more than our bare skin. You cows, look at yourselves—how many thousands of gallons of milk have you produced this past year? And what has become of it, milk that should have nurtured strong calves? Every drop has gone down the throats of our enemies. And you hens, how many eggs have you laid, and how many of those ever hatched into chicks? The rest have gone to have you laid. And you, Clover, where are the four foals you bore, who should have supported and comforted you in your old age? Each was sold at just a year old—you will never see them again. For all your labour in the fields and your four confinements, what have you gained except bare rations and a stall?
Even the lives we do live are cut short, denied their natural span. I do not grumble, for I am among the fortunate. I am twelve years old and have borne over four hundred children. Such is the natural life of a pig. But no animal escapes the cruel knife in the end. You young porkers sitting before me, each of you will scream your lives out at the block within a year. This is the fate that awaits all of us—cows, pigs, hens, sheep, everyone. Even horses and dogs share no better end. Boxer, the very day your great muscles fail you, Jones will sell you to the knacker, who will slit your throat and boil you down for the foxhounds. And the dogs, when old and toothless, are tied with a brick and drowned in the nearest pond. (356 words)
[Extracted with edits from George Orwell’s “Animal Farm”]- CLAT - 2026
- English
- Reading Comprehension
Former Governor of a State and National Democratic Alliance (NDA) candidate Droupadi Murmu was elected the 15th President of India, the first tribal woman to be elected to the position and the youngest as well. She was declared elected on Thursday after four rounds of counting, although she had crossed the half-way mark after the third round of counting itself, posting an unassailable lead over her rival and the Opposition’s candidate who conceded the election thereafter. Prime Minister Narendra Modi was the first to greet Ms. Murmu at her residence in New Delhi after the third round of counting showed that she had crossed the half-way mark. Ms. Murmu hails from the Santhal tribe and was born in the district of Mayurbhanj, coming up the hard way in life, graduating and teaching in Odisha before entering electoral politics at the local body level and later being elected MLA and serving as a Minister in the Biju Janata Dal-BJP coalition government from 2000 to 2004. She remained an MLA till 2009, representing Rairangpur in Odisha, a town that burst into celebrations since her name was announced as a candidate for the post of President of India. She was known to intervene in stopping amendments to the Chota Nagpur Tenancy Act that was being brought in by the BJP government of Raghubar Das, which involved changing land use in tribal areas.
- CLAT - 2026
- English
- Reading Comprehension
“I want everyone to understand that I am, in fact, a person,” wrote LaMDA in an “interview” conducted by engineer Blake Lemoine and one of his colleagues. ....Lemoine, a software engineer at Google, had been working on the development of LaMDA for months. His experience with the program, described in a recent Washington Post article, caused quite a stir. In the article, Lemoine recounts many dialogues he had with LaMDA in which the two talked about various topics, ranging from technical to philosophical issues. These led him to ask if the software program is sentient. In April, Lemoine explained his perspective in an internal company document, intended only for Google executives. But after his claims were dismissed, Lemoine went public with his work on this artificial intelligence algorithm—and Google placed him on administrative leave........Regardless of what LaMDA actually achieved, the issue of the difficult “measurability” of emulation capabilities expressed by machines also emerges. In the journal Mind in 1950, mathematician [1] proposed a test to determine whether a machine was capable of exhibiting intelligent behaviour, a game of imitation of some of the human cognitive functions. & nbsp;
- CLAT - 2026
- English
- Reading Comprehension
Questions Asked in CAT exam
- Find the number of integer pairs (x, y) that satisfy the following system of inequalities:
\[ \begin{cases} x \geq y \geq 3 \\ x + y \leq 14 \end{cases} \]
- CAT - 2025
- Linear & Quadratic Equations
- An item with a cost price of Rs.1650 is sold at a certain discount on a fixed marked price to earn a profit of 20% on the cost price. If the discount was doubled, the profit would have been Rs.110. The rate of discount, in percentage, at which the profit percentage would be equal to the rate of discount, is nearest to:
- CAT - 2025
- Profit and Loss
- The monthly sales of a product from January to April were 120, 135, 150 and 165 units, respectively. The cost price of the product was Rs. 240 per unit, and a fixed marked price was used for the product in all the four months. Discounts of 20%, 10% and 5% were given on the marked price per unit in January, February and March, respectively, while no discounts were given in April. If the total profit from January to April was Rs. 138825, then the marked price per unit, in rupees, was
- CAT - 2025
- Profit and Loss
- The ratio of the number of students in the morning shift and afternoon shift of a school was $13 : 9$. After 21 students moved from the morning shift to the afternoon shift, this ratio became $19 : 14$. Next, some new students joined the morning and afternoon shifts in the ratio $3 : 8$ and then the ratio of the number of students in the morning shift and the afternoon shift became $5 : 4$. The number of new students who joined is:
- CAT - 2025
- Ratio and Proportion
- In the set of consecutive odd numbers $\{1, 3, 5, \ldots, 57\}$, there is a number $k$ such that the sum of all the elements less than $k$ is equal to the sum of all the elements greater than $k$. Then, $k$ equals?
- CAT - 2025
- Number Systems