Comprehension
When researchers at Emory University in Atlanta trained mice to fear the smell of almonds (by pairing it with electric shocks), they found, to their consternation, that both the children and grandchildren of these mice were spontaneously afraid of the same smell. That is not supposed to happen. Generations of schoolchildren have been taught that the inheritance of acquired characteristics is impossible. A mouse should not be born with something its parents have learned during their lifetimes, any more than a mouse that loses its tail in an accident should give birth to tailless mice. . . .
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.
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.
Question: 1
The Emory University experiment with mice points to the inheritance of:
The Emory University experiment with mice points to the inheritance of:
Updated On: Sep 30, 2024
- psychological markers
- acquired characteristics
- personality traits
- acquired parental fears
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The Correct Option is D
Solution and Explanation
The correct answer is (D):
This is a very easy question and right at the start of the passage the clue to the right answer can be found. The passage says “a mouse should not be born with something that its parents have learned during their lifetime”. Thus the author suggests that they should not have been born with acquired characteristics during their lifetime. We should not be tempted with option 4 because though it looks good, it is not the right choice. Fear is just one characteristics that is likely to be inherited, while the passage points at a broader conclusion that can be derived from this experiment. So the inheritance may not necessarily be of fears, but of anything that the parents might have acquired in their lifetime.
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Question: 2
Which of the following best describes the author's argument?
Which of the following best describes the author's argument?
Updated On: Sep 30, 2024
- 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.
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The Correct Option is A
Solution and Explanation
The correct answer is (A):
The hint to the right answer can be found in the second paragraph of the passage. The second para says: 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. .
Thus 1 is the best choice, as the author attributes inheritance to much more than natural selection and mendelian gentics. The other negative opinions expressed in the other options cannot be seen anywhere in the passage.
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Question: 3
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?
Updated On: Sep 30, 2024
- 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.
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The Correct Option is D
Solution and Explanation
The correct answer is (D):
To answer this question correctly, we have to understand the main message of the passage. The main idea is that there is a lot more to inheritance than just natural selection and genetics. So if there is a study that affirms the sole influence of natural selection and inheritance on evolution than the author’s main argument would be weakened.
We can see clear evidence in these lines: 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.
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Question: 4
The passage uses the metaphor of a dog walker to argue that evolutionary adaptation is most comprehensively understood as being determined by:
The passage uses the metaphor of a dog walker to argue that evolutionary adaptation is most comprehensively understood as being determined by:
Updated On: Sep 30, 2024
- 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.
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The Correct Option is D
Solution and Explanation
The correct answer is (A,B,C,D)
This too is an easy question, the clue to the right answer can be seen here in these lines: We can see clear evidence in these lines: 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.
1. extra genetic, genetic, epigenetic and genomic legacies.
2. socio-cultural, genetic, epigenetic, and genomic legacies
3. ecological, hormonal, extra genetic and genetic legacies.
4. genetic, epigenetic, developmental factors, and ecological legacies.
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Question: 5
In the first paragraph, the author laments the fact that:
In the first paragraph, the author laments the fact that:
Updated On: Sep 30, 2024
- 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.
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The Correct Option is A
Solution and Explanation
The correct answer is (A):
The clue to the right answer is there right in the first paragraph. The author says: Between the old imperialist memorial and the proposed nationalist one, India’s contribution to the Second World War is airbrushed out of existence. The phrase ‘airbrushed out of existence’ has that regret in the tone. Thus 1 is the right choice.
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Top Questions on Reading Comprehension
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THE FAIR ISLE METHOD: Fair Isle knitting is a traditional technique that involves using two or more colours of yarn in a single row to create intricate patterns and designs. This method requires careful tension management to ensure even stitches and prevent puckering. To begin, select your colours and cast on the desired number of stitches. As you knit, alternate between colours every few stitches, carrying the unused yarn along the back of the work. Mastering the Fair Isle technique allows you to create stunning visual effects in garments, accessories, and home textiles.
THE CONTINENTAL STYLE: The Continental knitting style, often referred to as “picking,” involves holding the yarn in the left hand while the right hand manipulates the needles. This method allows for greater speed and efficiency, particularly when working with complex patterns or multiple colours. To practice this style, start by casting on your stitches and using your left hand to tension the yarn. With each stitch, simply “pick” the yarn with your right needle, forming a quick and fluid motion. As you become comfortable with this technique, you may find that your overall knitting speed and comfort improve significantly.
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The Story of Coffee
Coffee, a beloved beverage enjoyed by millions around the globe, has a rich and captivating history that spans centuries. The story of coffee begins in the ancient highlands of Ethiopia, where, according to legend, a goat herder named Kaldi discovered the stimulating effects of coffee beans. One day, Kaldi noticed his goats frolicking with unusual energy after eating red berries from a certain tree. Curious, he tried the berries himself and experienced a newfound alertness. This discovery soon spread to monasteries, where monks used it to stay awake during long hours of prayer. From Ethiopia, coffee cultivation and consumption spread to the Arabian Peninsula, particularly in Yemen, where the practice of roasting coffee beans and brewing the drink began to take shape. By the 15th century, coffee had become a popular beverage in the Islamic world, with coffee houses known as ‘qahveh khaneh’ emerging as social hubs for conversation, music, and intellectual exchange. These coffee houses became centers of culture and commerce, influencing the spread of coffee to Turkey and beyond, eventually reaching Europe. In Europe, coffee initially faced resistance from religious authorities who considered it a ‘Muslim drink’ and tried to ban it. However, its popularity persisted, and by the 17th century, coffee houses had sprung up in major European cities, becoming important gathering places for artists, writers, and thinkers. The stimulating effects of coffee were embraced during the Age of Enlightenment, where it was seen as a catalyst for intellectual discussion and innovation. The journey of coffee continued with the establishment of colonial plantations in tropical regions such as the Caribbean, Central and South America, and Southeast Asia. These plantations fuelled the global demand for coffee, transforming it from a regional specialty to a major commodity. The industrial revolution further accelerated coffee production and consumption, leading to innovations in coffee brewing methods and the development of instant coffee. In the modern era, coffee has evolved into a deeply ingrained part of daily life for people worldwide. Its cultural significance spans from the bustling cafes of Paris to the quiet coffee farms of Colombia. Today, coffee remains not only a popular beverage but also a symbol of social interaction, productivity, and enjoyment. Whether sipped slowly over a conversation with friends or grabbed hastily on the way to work, the story of coffee continues to unfold, intertwining with the histories and cultures of countless societies across the globe.- AILET BALLB (Hons.) - 2025
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