The primary purpose of this passage is to

The following passage is adapted from Ricki Lewis, "Did Donkeys Arise from an Inverted Chromosome?", originally published 2018 in PLOSOne Blogs.

In the world of genome sequencing, donkeys haven’t received nearly as much attention as horses. But now a report on a new-and-improved genome sequence of Willy, a donkey (Equus asinus) jack 5 born at the Copenhagen Zoo in 1997, appears in the new issue of Science Advances, from Gabriel Renaud, of the Centre for GeoGenetics, Natural History Museum of Denmark. (A female is a jenny or jennet.) The new view provides clues to how donkeys may have branched from horses along the tree of evolution.

Horses and their relatives, past and present, are genetically peculiar in that their chromosomes are rearranged with respect to each other. That should prevent them from producing viable hybrids – yet they do. Donkeys have 62 chromosomes, and horses have 64. A mule comes from the mating of a male donkey and a female horse and has 63 chromosomes. Mules are known for their intelligence, calm, stamina, and persistence. Their horse-like bodies perched on donkey-like limbs make them ideal for hauling tourists around the Grand Canyon and schlepping supplies in combat situations. The ears are large like those of the horse mom, and mules make a sound that begins as a whinny and becomes a bray.

The complementary couple, a female donkey and a male horse, produces a hinny, smaller than a mule. Hinnies are the flip side of the mule, with a donkey’s physique atop horsey limbs, and short donkey ears. They’re rarer than mules but also have 63 chromosomes. It’s easy to mix them up.

Comparing Willy’s genome to a horse genome revealed their close evolutionary relationship. Only about 15% of horse genes aren’t also in the donkey genome, and only about 10% of a donkey’s genes don’t have counterparts in the horse. Most of the genes that they share provide basic “housekeeping” functions like dismantling proteins, repairing DNA, enabling embryonic development, and controlling cell division. So that’s why a copy of each genome can smush together to yield mules and hinnies.

The second form of information encoded in genomes, in addition to the A, C, T, G sequence, is the pattern of whether the two variants of individual genes are different (heterozygous) or the same (homozygous). Many contiguous homozygous genes form a “run of homozygosity” (ROH).

An ROH indicates a chromosome chunk, perhaps as long as millions of DNA bases, that’s the same from each of an individual’s parents, who in turn inherited it from a shared ancestor, like a grandparent that cousins share. The longer the ROH, the more recent the shared ancestor, because it takes time for mutations to accrue that would break the sameness of the sequence.

Scrutinizing ROHs can reveal recent inbreeding and domestication, help to reconstruct possible branching patterns of evolution, and, more practically, help ancestry companies assign the DNA in spit samples to geographic areas where people’s ancestors might have come from. The new study compared ROHs for the three zebra and three ass species, confirming that Willy’s most recent ancestors were Somali wild asses.

The researchers used the Chicago HiRise assembly technology to up the quality of Willy’s genome sequence. “This new assembly allowed us to identify fine chromosomal rearrangements between the horse and the donkey that likely played an active role in their divergence and, ultimately, speciation,” they write.

The bigger pieces enabled them to zero in on DNA sequences where chromosomes contort, such as inversions (where a sequence flips) or translocations (where different chromosome types exchange parts). These events could have fueled the reproductive isolation of small populations that can expand into speciation.

If eventually sperm with one inverted chromosome fertilized eggs with the same inversion, animals would have been conceived in which both copies of the chromosome are inverted – and they’d be fertile with each other, but not with horses. Once a subpopulation with the inversion became established, further genetic changes would separate them further from the ancestral horse.

The primary purpose of this passage is to

The following passage is adapted from Ricki Lewis, "Did Donkeys Arise from an Inverted Chromosome?", originally published 2018 in PLOSOne Blogs.

In the world of genome sequencing, donkeys haven’t received nearly as much attention as horses. But now a report on a new-and-improved genome sequence of Willy, a donkey (Equus asinus) jack 5 born at the Copenhagen Zoo in 1997, appears in the new issue of Science Advances, from Gabriel Renaud, of the Centre for GeoGenetics, Natural History Museum of Denmark. (A female is a jenny or jennet.) The new view provides clues to how donkeys may have branched from horses along the tree of evolution.

Horses and their relatives, past and present, are genetically peculiar in that their chromosomes are rearranged with respect to each other. That should prevent them from producing viable hybrids – yet they do. Donkeys have 62 chromosomes, and horses have 64. A mule comes from the mating of a male donkey and a female horse and has 63 chromosomes. Mules are known for their intelligence, calm, stamina, and persistence. Their horse-like bodies perched on donkey-like limbs make them ideal for hauling tourists around the Grand Canyon and schlepping supplies in combat situations. The ears are large like those of the horse mom, and mules make a sound that begins as a whinny and becomes a bray.

The complementary couple, a female donkey and a male horse, produces a hinny, smaller than a mule. Hinnies are the flip side of the mule, with a donkey’s physique atop horsey limbs, and short donkey ears. They’re rarer than mules but also have 63 chromosomes. It’s easy to mix them up.

Comparing Willy’s genome to a horse genome revealed their close evolutionary relationship. Only about 15% of horse genes aren’t also in the donkey genome, and only about 10% of a donkey’s genes don’t have counterparts in the horse. Most of the genes that they share provide basic “housekeeping” functions like dismantling proteins, repairing DNA, enabling embryonic development, and controlling cell division. So that’s why a copy of each genome can smush together to yield mules and hinnies.

The second form of information encoded in genomes, in addition to the A, C, T, G sequence, is the pattern of whether the two variants of individual genes are different (heterozygous) or the same (homozygous). Many contiguous homozygous genes form a “run of homozygosity” (ROH).

An ROH indicates a chromosome chunk, perhaps as long as millions of DNA bases, that’s the same from each of an individual’s parents, who in turn inherited it from a shared ancestor, like a grandparent that cousins share. The longer the ROH, the more recent the shared ancestor, because it takes time for mutations to accrue that would break the sameness of the sequence.

Scrutinizing ROHs can reveal recent inbreeding and domestication, help to reconstruct possible branching patterns of evolution, and, more practically, help ancestry companies assign the DNA in spit samples to geographic areas where people’s ancestors might have come from. The new study compared ROHs for the three zebra and three ass species, confirming that Willy’s most recent ancestors were Somali wild asses.

The researchers used the Chicago HiRise assembly technology to up the quality of Willy’s genome sequence. “This new assembly allowed us to identify fine chromosomal rearrangements between the horse and the donkey that likely played an active role in their divergence and, ultimately, speciation,” they write.

The bigger pieces enabled them to zero in on DNA sequences where chromosomes contort, such as inversions (where a sequence flips) or translocations (where different chromosome types exchange parts). These events could have fueled the reproductive isolation of small populations that can expand into speciation.

If eventually sperm with one inverted chromosome fertilized eggs with the same inversion, animals would have been conceived in which both copies of the chromosome are inverted – and they’d be fertile with each other, but not with horses. Once a subpopulation with the inversion became established, further genetic changes would separate them further from the ancestral horse.

The primary purpose of this passage is to

The following passage and corresponding figure are from Emilie Reas. "How the brain learns to read: development of the “word form area”", PLOS Neuro Community, 2018.

The ability to recognize, process and interpret written language is a uniquely human skill that is acquired with remarkable ease at a young age. But as anyone who has attempted to learn a new language will attest, the brain isn’t “hardwired” to understand written language. In fact, it remains somewhat of a mystery how the brain develops this specialized ability. Although researchers have identified brain regions that process written words, how this selectivity for language develops isn’t entirely clear.

Earlier studies have shown that the ventral visual cortex supports recognition of an array of visual stimuli, including objects, faces, and places. Within this area, a subregion in the left hemisphere known as the “visual word form area” (VWFA) shows a particular selectivity for written words. However, this region is characteristically plastic. It’s been proposed that stimuli compete for representation in this malleable area, such that “winner takes all” depending on the strongest input. That is, how a site is ultimately mapped is dependent on what it’s used for in early childhood. But this idea has yet to be confirmed, and the evolution of specialized brain areas for reading in children is still poorly understood.

In their study, Dehaene-Lambertz and colleagues monitored the reading abilities and brain changes of ten six-year-old children to track the emergence of word specialization during a critical development period. Over the course of their first school-year, children were assessed every two months with reading evaluations and functional MRI while viewing words and non-word images (houses, objects, faces, bodies). As expected, reading ability improved over the year of first grade, as demonstrated by increased reading speed, word span, and phoneme knowledge, among other measures.

Even at this young age, when reading ability was newly acquired, words evoked widespread left-lateralized brain activation. This activity increased over the year of school, with the greatest boost occurring after just the first few months. Importantly, there were no similar activation increases in response to other stimuli, confirming that these adaptations were specific to reading ability, not a general effect of development or education. Immediately after school began, the brain volume specialized for reading also significantly increased. Furthermore, reading speed was associated with greater activity, particularly in the VWFA. The researchers found that activation patterns to words became more reliable with learning. In contrast, the patterns for other categories remained stable, with the exception of numbers, which may reflect specialization for symbols (words and numbers) generally, or correlation with the simultaneous development of mathematics skills.

What predisposes one brain region over another to take on this specialized role for reading words? Before school, there was no strong preference for any other category in regions that would later become word-responsive. However, brain areas that were destined to remain “non-word” regions showed more stable responses to non-word stimuli even before learning to read. Thus, perhaps the brain takes advantage of unoccupied real-estate to perform the newly acquired skill of reading.

These findings add a critical piece to the puzzle of how reading skills are acquired in the developing child brain. Though it was already known that reading recruits a specialized brain region for words, this study reveals that this occurs without changing the organization of areas already specialized for other functions. The authors propose an elegant model for the developmental brain changes underlying reading skill acquisition. In the illiterate child, there are adjacent columns or patches of cortex either tuned to a specific category, or not yet assigned a function. With literacy, the free subregions become tuned to words, while the previously specialized subregions remain stable.

The rapid emergence of the word area after just a brief learning period highlights the remarkable plasticity of the developing cortex. In individuals who become literate as adults, the same VWFA is present. However, in contrast to children, the relation between reading speed and activation in this area is weaker in adults, and a single adult case-study by the authors showed a much slower, gradual development of the VWFA over a prolonged learning period of several months. Whatever the reason, this region appears primed to rapidly adopt novel representations of symbolic words, and this priming may peak at a specific period in childhood. This finding underscores the importance of a strong education in youth. The authors surmise that “the success of education might also rely on the right timing to benefit from the highest neural plasticity. Our results might also explain why numerous academic curricula, even in ancient civilizations, propose to teach reading around seven years.”

The figure below shows different skills mapped to different sites in the brain before schooling and then with and without school. Labile sites refer to sites that are not currently mapped to a particular skill.

Which of the following describes the relationship between Passage 1 and Passage 2?

Passage 1 is adapted from Emma Hart Willard, "Improving Female Education." Originally published in 1819.

If the improvement of the American female character, and that alone, could be affected by public liberality, employed in giving better means of instruction; such improvement of one half of society, and that half, which barbarous and despotic nations have ever degraded, would of itself be an object, worthy of the most liberal government on earth; but if the female character be raised, it must inevitably raise that of the other sex; and thus does the plan proposed, offer, as the object of legislative bounty, to elevate the whole character of the community.

As evidence that this statement does not exaggerate the female influence in society, our sex needs but be considered, in the single relation of mothers. In this character, we have the charge of the whole mass of individuals, who are to compose the succeeding generation; during that period of youth, when the pliant mind takes any direction, to which it is steadily guided by a forming hand. How important a power is given by this charge! yet, little do too many of my sex know-how, either to appreciate or improve it. Unprovided with the means of acquiring that knowledge, which flows liberally to the other sex- having our time of education devoted to frivolous acquirements, how should we understand the nature of the mind, so as to be aware of the importance of those early impressions, which we make upon the minds of our children? -or how should we be able to form enlarged and correct views, either of the character, to which we ought to mold them, or of the means most proper to form them aright?

Considered in this point of view, were the interests of male education alone to be consulted, that of females becomes of sufficient importance to engage the public attention. Would we rear the human plant to its perfection, we must first fertilize the soil which produces it. If it acquire its first bent and texture upon a barren plain, it will avail comparatively little, should it be afterwards transplanted to a garden.

Passage 2 is adapted from Benjamin Rush, "Thoughts upon Female Education". Originally published 1787.

A philosopher once said, "let me make all the ballads of a country and I care not who makes its laws." He might with more propriety have said, let the ladies of a country be educated properly, and they will not only make and administer its laws, but form its manners and character. It would require a lively imagination to describe, or even to comprehend, the happiness of a country where knowledge and virtue were generally diffused among the female sex. Our young men would then be restrained from vice by the terror of being banished from their company. The loud laugh and the malignant smile, at the expense of innocence or of personal infirmities– the feats of successful mimicry and the low priced wit which is borrowed from a misapplication of scripture phrases– would no more be considered as recommendations to the society of the ladies. A double-entendre in their presence would then exclude a gentleman forever from the company of both sexes and probably oblige him to seek an asylum from contempt in a foreign country.

If I am wrong in those opinions in which I have taken the liberty of departing from the general and fashionable habits of thinking I am sure you will discover and pardon my mistakes. But if I am right, I am equally sure you will adopt my opinions for to enlightened minds truth is alike acceptable, whether it comes from the lips of age or the hand of antiquity or whether it be obtruded by a person who has no other claim to attention than a desire of adding to the stock of human happiness.

To you, young ladies, an important problem is committed for solution: whether our present plan of education be a wise one and whether it be calculated to prepare you for the duties of social and domestic life. I know that the elevation of the female mind, by means of moral, physical, and religious truth, is considered by some men as unfriendly to the domestic character of a woman. But this is the prejudice of little minds and springs from the same spirit which opposes the general diffusion of knowledge among the citizens of our republics.If men believe that ignorance is favorable to the government of the female sex, they are certainly deceived, for a weak and ignorant woman will always be governed with the greatest difficulty. It will be in your power ladies, to correct the mistakes and practice of our sex upon these subjects by demonstrating that the female temper can only be governed by reason and that the cultivation of reason in women is alike friendly to the order of nature and to private as well as public happiness.

Which of the following best summarizes the entire passage?

The following is an excerpt from Agnes Grey, an autobiographical novel by Anne Bronte that follows the life of a governess working in wealthy British households in the 19th century.

To avoid trouble and confusion, I have taken my pupils one by one, and discussed their various qualities; but this can give no adequate idea of being worried by the whole three together; when, as was often the case, all were determined to ‘be naughty, and to tease Miss Grey, and put her in a passion.’

Sometimes, on such occasions, the thought has suddenly occurred to me—’If they could see me now!’ meaning, of course, my friends at home; and the idea of how they would pity me has made me pity myself—so greatly that I have had the utmost difficulty to restrain my tears: but I have restrained them, till my little tormentors were gone to dessert, or cleared off to bed (my only prospects of deliverance), and then, in all the bliss of solitude, I have given myself up to the luxury of an unrestricted burst of weeping. But this was a weakness I did not often indulge: my employments were too numerous, my leisure moments too precious, to admit of much time being given to fruitless lamentations.

I particularly remember one wild, snowy afternoon, soon after my return in January: the children had all come up from dinner, loudly declaring that they meant ‘to be naughty;’ and they had well kept their resolution, though I had talked myself hoarse, and wearied every muscle in my throat, in the vain attempt to reason them out of it. I had got Tom pinned up in a corner, whence, I told him, he should not escape till he had done his appointed task. Meantime, Fanny had possessed herself of my workbag, and was rifling its contents—and spitting into it besides. I told her to let it alone, but to no purpose, of course. ‘Burn it, Fanny!’ cried Tom: and this command she hastened to obey. I sprang to snatch it from the fire, and Tom darted to the door. ‘Mary Ann, throw her desk out of the window!’ cried he: and my precious desk, containing my letters and papers, my small amount of cash, and all my valuables, was about to be precipitated from the three-story window. I flew to rescue it. Meanwhile, Tom had left the room, and was rushing down the stairs, followed by Fanny. Having secured my desk, I ran to catch them, and Mary Ann came scampering after. All three escaped me, and ran out of the house into the garden, where they plunged about in the snow, shouting and screaming in exultant glee.

What must I do? If I followed them, I should probably be unable to capture one, and only drive them farther away; if I did not, how was I to get them in? And what would their parents think of me, if they saw or heard the children rioting, hatless, bonnetless, gloveless, and bootless, in the deep soft snow?

Which of the following describes the relationship between Passage 1 and Passage 2?

Passage 1 is adapted from Emma Hart Willard, "Improving Female Education." Originally published in 1819.

If the improvement of the American female character, and that alone, could be affected by public liberality, employed in giving better means of instruction; such improvement of one half of society, and that half, which barbarous and despotic nations have ever degraded, would of itself be an object, worthy of the most liberal government on earth; but if the female character be raised, it must inevitably raise that of the other sex; and thus does the plan proposed, offer, as the object of legislative bounty, to elevate the whole character of the community.

As evidence that this statement does not exaggerate the female influence in society, our sex needs but be considered, in the single relation of mothers. In this character, we have the charge of the whole mass of individuals, who are to compose the succeeding generation; during that period of youth, when the pliant mind takes any direction, to which it is steadily guided by a forming hand. How important a power is given by this charge! yet, little do too many of my sex know-how, either to appreciate or improve it. Unprovided with the means of acquiring that knowledge, which flows liberally to the other sex- having our time of education devoted to frivolous acquirements, how should we understand the nature of the mind, so as to be aware of the importance of those early impressions, which we make upon the minds of our children? -or how should we be able to form enlarged and correct views, either of the character, to which we ought to mold them, or of the means most proper to form them aright?

Considered in this point of view, were the interests of male education alone to be consulted, that of females becomes of sufficient importance to engage the public attention. Would we rear the human plant to its perfection, we must first fertilize the soil which produces it. If it acquire its first bent and texture upon a barren plain, it will avail comparatively little, should it be afterwards transplanted to a garden.

Passage 2 is adapted from Benjamin Rush, "Thoughts upon Female Education". Originally published 1787.

A philosopher once said, "let me make all the ballads of a country and I care not who makes its laws." He might with more propriety have said, let the ladies of a country be educated properly, and they will not only make and administer its laws, but form its manners and character. It would require a lively imagination to describe, or even to comprehend, the happiness of a country where knowledge and virtue were generally diffused among the female sex. Our young men would then be restrained from vice by the terror of being banished from their company. The loud laugh and the malignant smile, at the expense of innocence or of personal infirmities– the feats of successful mimicry and the low priced wit which is borrowed from a misapplication of scripture phrases– would no more be considered as recommendations to the society of the ladies. A double-entendre in their presence would then exclude a gentleman forever from the company of both sexes and probably oblige him to seek an asylum from contempt in a foreign country.

If I am wrong in those opinions in which I have taken the liberty of departing from the general and fashionable habits of thinking I am sure you will discover and pardon my mistakes. But if I am right, I am equally sure you will adopt my opinions for to enlightened minds truth is alike acceptable, whether it comes from the lips of age or the hand of antiquity or whether it be obtruded by a person who has no other claim to attention than a desire of adding to the stock of human happiness.

To you, young ladies, an important problem is committed for solution: whether our present plan of education be a wise one and whether it be calculated to prepare you for the duties of social and domestic life. I know that the elevation of the female mind, by means of moral, physical, and religious truth, is considered by some men as unfriendly to the domestic character of a woman. But this is the prejudice of little minds and springs from the same spirit which opposes the general diffusion of knowledge among the citizens of our republics.If men believe that ignorance is favorable to the government of the female sex, they are certainly deceived, for a weak and ignorant woman will always be governed with the greatest difficulty. It will be in your power ladies, to correct the mistakes and practice of our sex upon these subjects by demonstrating that the female temper can only be governed by reason and that the cultivation of reason in women is alike friendly to the order of nature and to private as well as public happiness.

The primary purpose of this passage is to

The following passage and corresponding figure are from Emilie Reas. "How the brain learns to read: development of the “word form area”", PLOS Neuro Community, 2018.

The ability to recognize, process and interpret written language is a uniquely human skill that is acquired with remarkable ease at a young age. But as anyone who has attempted to learn a new language will attest, the brain isn’t “hardwired” to understand written language. In fact, it remains somewhat of a mystery how the brain develops this specialized ability. Although researchers have identified brain regions that process written words, how this selectivity for language develops isn’t entirely clear.

Earlier studies have shown that the ventral visual cortex supports recognition of an array of visual stimuli, including objects, faces, and places. Within this area, a subregion in the left hemisphere known as the “visual word form area” (VWFA) shows a particular selectivity for written words. However, this region is characteristically plastic. It’s been proposed that stimuli compete for representation in this malleable area, such that “winner takes all” depending on the strongest input. That is, how a site is ultimately mapped is dependent on what it’s used for in early childhood. But this idea has yet to be confirmed, and the evolution of specialized brain areas for reading in children is still poorly understood.

In their study, Dehaene-Lambertz and colleagues monitored the reading abilities and brain changes of ten six-year-old children to track the emergence of word specialization during a critical development period. Over the course of their first school-year, children were assessed every two months with reading evaluations and functional MRI while viewing words and non-word images (houses, objects, faces, bodies). As expected, reading ability improved over the year of first grade, as demonstrated by increased reading speed, word span, and phoneme knowledge, among other measures.

Even at this young age, when reading ability was newly acquired, words evoked widespread left-lateralized brain activation. This activity increased over the year of school, with the greatest boost occurring after just the first few months. Importantly, there were no similar activation increases in response to other stimuli, confirming that these adaptations were specific to reading ability, not a general effect of development or education. Immediately after school began, the brain volume specialized for reading also significantly increased. Furthermore, reading speed was associated with greater activity, particularly in the VWFA. The researchers found that activation patterns to words became more reliable with learning. In contrast, the patterns for other categories remained stable, with the exception of numbers, which may reflect specialization for symbols (words and numbers) generally, or correlation with the simultaneous development of mathematics skills.

What predisposes one brain region over another to take on this specialized role for reading words? Before school, there was no strong preference for any other category in regions that would later become word-responsive. However, brain areas that were destined to remain “non-word” regions showed more stable responses to non-word stimuli even before learning to read. Thus, perhaps the brain takes advantage of unoccupied real-estate to perform the newly acquired skill of reading.

These findings add a critical piece to the puzzle of how reading skills are acquired in the developing child brain. Though it was already known that reading recruits a specialized brain region for words, this study reveals that this occurs without changing the organization of areas already specialized for other functions. The authors propose an elegant model for the developmental brain changes underlying reading skill acquisition. In the illiterate child, there are adjacent columns or patches of cortex either tuned to a specific category, or not yet assigned a function. With literacy, the free subregions become tuned to words, while the previously specialized subregions remain stable.

The rapid emergence of the word area after just a brief learning period highlights the remarkable plasticity of the developing cortex. In individuals who become literate as adults, the same VWFA is present. However, in contrast to children, the relation between reading speed and activation in this area is weaker in adults, and a single adult case-study by the authors showed a much slower, gradual development of the VWFA over a prolonged learning period of several months. Whatever the reason, this region appears primed to rapidly adopt novel representations of symbolic words, and this priming may peak at a specific period in childhood. This finding underscores the importance of a strong education in youth. The authors surmise that “the success of education might also rely on the right timing to benefit from the highest neural plasticity. Our results might also explain why numerous academic curricula, even in ancient civilizations, propose to teach reading around seven years.”

The figure below shows different skills mapped to different sites in the brain before schooling and then with and without school. Labile sites refer to sites that are not currently mapped to a particular skill.

Which of the following best summarizes the entire passage?

The following is an excerpt from Agnes Grey, an autobiographical novel by Anne Bronte that follows the life of a governess working in wealthy British households in the 19th century.

To avoid trouble and confusion, I have taken my pupils one by one, and discussed their various qualities; but this can give no adequate idea of being worried by the whole three together; when, as was often the case, all were determined to ‘be naughty, and to tease Miss Grey, and put her in a passion.’

Sometimes, on such occasions, the thought has suddenly occurred to me—’If they could see me now!’ meaning, of course, my friends at home; and the idea of how they would pity me has made me pity myself—so greatly that I have had the utmost difficulty to restrain my tears: but I have restrained them, till my little tormentors were gone to dessert, or cleared off to bed (my only prospects of deliverance), and then, in all the bliss of solitude, I have given myself up to the luxury of an unrestricted burst of weeping. But this was a weakness I did not often indulge: my employments were too numerous, my leisure moments too precious, to admit of much time being given to fruitless lamentations.

I particularly remember one wild, snowy afternoon, soon after my return in January: the children had all come up from dinner, loudly declaring that they meant ‘to be naughty;’ and they had well kept their resolution, though I had talked myself hoarse, and wearied every muscle in my throat, in the vain attempt to reason them out of it. I had got Tom pinned up in a corner, whence, I told him, he should not escape till he had done his appointed task. Meantime, Fanny had possessed herself of my workbag, and was rifling its contents—and spitting into it besides. I told her to let it alone, but to no purpose, of course. ‘Burn it, Fanny!’ cried Tom: and this command she hastened to obey. I sprang to snatch it from the fire, and Tom darted to the door. ‘Mary Ann, throw her desk out of the window!’ cried he: and my precious desk, containing my letters and papers, my small amount of cash, and all my valuables, was about to be precipitated from the three-story window. I flew to rescue it. Meanwhile, Tom had left the room, and was rushing down the stairs, followed by Fanny. Having secured my desk, I ran to catch them, and Mary Ann came scampering after. All three escaped me, and ran out of the house into the garden, where they plunged about in the snow, shouting and screaming in exultant glee.

What must I do? If I followed them, I should probably be unable to capture one, and only drive them farther away; if I did not, how was I to get them in? And what would their parents think of me, if they saw or heard the children rioting, hatless, bonnetless, gloveless, and bootless, in the deep soft snow?

The primary purpose of this passage is to _______.

The passage is adapted from Carter G, Leffer L (2015) “Social Grooming in Bats: Are Vampire Bats Exceptional?” © 2015 Carter, Leffer

Long-term cooperative relationships are most evident in primates, but evidence for similar social relationships has been accumulating for several other social vertebrate groups including cetaceans, bats, elephants, hyenas and ravens. The functional importance of these complex social relationships across different species may have led to similar cognitive or behavioral mechanisms for manipulating social bonds. A prime example of such a mechanism is social grooming—the cleaning of the body by a partner. Experimental and observational studies show that primate social grooming can be ‘exchanged’ for multiple social benefits, including reciprocal grooming, social tolerance, access to food, and agonistic support. Individuals can spend up to 20% of their time grooming others, and the behavior provides proximate physiological rewards for both givers and receivers. Although most of what is known about social grooming comes from studies of primates, evidence for a role of social grooming in maintaining social ties is emerging from several other mammals (marsupials, deer, cows, horses, voles, mice, meerkats, coati, lions) and group-living birds.

In bats, adult social grooming is female-biased in species with female philopatry and has been most studied in the common vampire bat (Desmodus rotundus). Kerth et al. compared social grooming rates of vampire bats with the temperate and insectivorous Bechstein’s bat (Myotis bechsteinii). These two species both have long lifespans and demonstrate fission-fusion social dynamics, where individuals maintain long-term social associations while moving between several roost trees. In both species, social grooming rates among individuals were not predicted by self-grooming or numbers of parasites. Bechstein’s bats spent more time grooming themselves (38% of their time in roosts) compared with vampires (23% of their roosting time), but wild vampire bats spent about 5% of their roosting time grooming others, which is 2–4 times higher than Bechstein’s bats.

Patterns of social grooming among categories of individuals also differed between the two species. In the Bechstein’s bat, adult female social grooming was not detectably symmetrical, and was predicted by kinship, occurring mostly between adult mothers and daughters, sometimes between sisters, and only rarely between non-kin. In vampires, female social grooming was highly symmetrical and relatively common among non-kin, where it correlated with co-roosting association and food sharing.

It is not entirely clear if vampire bat social grooming is typical or exceptional when compared to other bats or non-primate mammals. One hypothesis is that social grooming in vampire bats is exceptional in quantity and quality, because it is related to their uniquely cooperative food-sharing behavior. Like many primates, reciprocal patterns of vampire bat food sharing and social grooming extend beyond mother-offspring bonds, suggesting they may provide both direct and indirect fitness benefits. Among bats, the common vampire has an extraordinarily large brain and neocortex for its body size. In primates, increased neocortex size has been linked to higher metrics of social complexity, such as social grooming network size and strategic deception.

Alternatively, the apparent distinctiveness of vampire bat social grooming might stem from purely ecological factors. Social grooming may be more obvious in vampire bats due to higher levels of ectoparasite infestation. Bat fly density has been linked to species-level grooming rates and the two vampire species that were observed ranked 5th and 6th place out of 53 neotropical bats for average number of parasitic streblid flies per bat. A sampling bias could also over-emphasize social grooming in vampire bats, because there is much effort focused on studying vampire bat social behavior and a lack of data on social grooming in other bats.

Comparing social grooming data across studies can be difficult due to study differences in ectoparasite density, temperature, sampling method, visibility, and level of human disturbance. Still, there are important conclusions that can be made regarding social grooming among vampire bats from the studies that have been conducted. With even better studies in the future – for instance, ones that compare groups of adult bats that have fixed levels of social association (stable group composition) and no insect ectoparasites – we will get a clearer picture of social grooming among vampire bats and its significance.

The primary purpose of this passage is to _______.

The passage is adapted from Carter G, Leffer L (2015) “Social Grooming in Bats: Are Vampire Bats Exceptional?” © 2015 Carter, Leffer

Long-term cooperative relationships are most evident in primates, but evidence for similar social relationships has been accumulating for several other social vertebrate groups including cetaceans, bats, elephants, hyenas and ravens. The functional importance of these complex social relationships across different species may have led to similar cognitive or behavioral mechanisms for manipulating social bonds. A prime example of such a mechanism is social grooming—the cleaning of the body by a partner. Experimental and observational studies show that primate social grooming can be ‘exchanged’ for multiple social benefits, including reciprocal grooming, social tolerance, access to food, and agonistic support. Individuals can spend up to 20% of their time grooming others, and the behavior provides proximate physiological rewards for both givers and receivers. Although most of what is known about social grooming comes from studies of primates, evidence for a role of social grooming in maintaining social ties is emerging from several other mammals (marsupials, deer, cows, horses, voles, mice, meerkats, coati, lions) and group-living birds.

In bats, adult social grooming is female-biased in species with female philopatry and has been most studied in the common vampire bat (Desmodus rotundus). Kerth et al. compared social grooming rates of vampire bats with the temperate and insectivorous Bechstein’s bat (Myotis bechsteinii). These two species both have long lifespans and demonstrate fission-fusion social dynamics, where individuals maintain long-term social associations while moving between several roost trees. In both species, social grooming rates among individuals were not predicted by self-grooming or numbers of parasites. Bechstein’s bats spent more time grooming themselves (38% of their time in roosts) compared with vampires (23% of their roosting time), but wild vampire bats spent about 5% of their roosting time grooming others, which is 2–4 times higher than Bechstein’s bats.

Patterns of social grooming among categories of individuals also differed between the two species. In the Bechstein’s bat, adult female social grooming was not detectably symmetrical, and was predicted by kinship, occurring mostly between adult mothers and daughters, sometimes between sisters, and only rarely between non-kin. In vampires, female social grooming was highly symmetrical and relatively common among non-kin, where it correlated with co-roosting association and food sharing.

It is not entirely clear if vampire bat social grooming is typical or exceptional when compared to other bats or non-primate mammals. One hypothesis is that social grooming in vampire bats is exceptional in quantity and quality, because it is related to their uniquely cooperative food-sharing behavior. Like many primates, reciprocal patterns of vampire bat food sharing and social grooming extend beyond mother-offspring bonds, suggesting they may provide both direct and indirect fitness benefits. Among bats, the common vampire has an extraordinarily large brain and neocortex for its body size. In primates, increased neocortex size has been linked to higher metrics of social complexity, such as social grooming network size and strategic deception.

Alternatively, the apparent distinctiveness of vampire bat social grooming might stem from purely ecological factors. Social grooming may be more obvious in vampire bats due to higher levels of ectoparasite infestation. Bat fly density has been linked to species-level grooming rates and the two vampire species that were observed ranked 5th and 6th place out of 53 neotropical bats for average number of parasitic streblid flies per bat. A sampling bias could also over-emphasize social grooming in vampire bats, because there is much effort focused on studying vampire bat social behavior and a lack of data on social grooming in other bats.

Comparing social grooming data across studies can be difficult due to study differences in ectoparasite density, temperature, sampling method, visibility, and level of human disturbance. Still, there are important conclusions that can be made regarding social grooming among vampire bats from the studies that have been conducted. With even better studies in the future – for instance, ones that compare groups of adult bats that have fixed levels of social association (stable group composition) and no insect ectoparasites – we will get a clearer picture of social grooming among vampire bats and its significance.