Management of the recruitment, selection and induction of employees Essay

Management of the recruitment, selection and induction of employees - Essay Example IBM, having one of the most professional workforces in the world, employs approximately 329,000 employees and operates business in 170 countries around the globe (IBM, 2009). They employ staff worldwide across different disciplines ranging from technical IT areas to the non-technical disciplines of Sales, Finance, HR and Legal (Monster, 2008). Being a globally integrated company, they need to keep changing their business model radically and shift its value proposition. Thus, attracting and developing individuals is critical to IBM’s success (Schmidt, 2005). There are three main steps in the recruitment process – identification of the requirements, attracting the right candidates and the selection from the applicants. The right job description and the job specifications help to attract the right candidate and eliminate unwanted work involved in the selection process. IBM has the reputation of being the resilient to market forces and strong leadership. They strongly follow the online recruitment process and it is their key recruitment strategy. Online recruitment includes their own website www.ibm.com apart from key online recruitment websites such as monster.com (Monster, 2008). Online recruitment supplements and complements other forms of recruitment. Online recruitment enables reaching a wider audience, and being in the IT industry, this reflects its nature of business. Besides, online recruitment process is cost effective and it also allows continuous improvement of the process. Online recruitment and selection process has saved time spent by as much as 25 percent (Kumar, 2003). They accept applications online as well as through emails. In addition, they adhere to the traditional forms of recruitment such as sourcing through headhunters and recruitment fairs. Thus, they outsource recruitment as well as keep it in-house their website. For graduate trainees they have a different strategy. Their inclusive work environment makes every

Robert Frosts poem The Mending Wall Essay Example for Free

Robert Frosts poem The Mending Wall Essay Robert Frosts poem The Mending Wall may not seem to be a poem with a lot of meaning but if readers take time to listen to what the author has to say they will discover that it is talking about the basic relationships between people. The author is focusing on an inanimate object that separated two individuals even though it is nothing more than a little stone wall in the middle of a field. Something there is that doesnt love a wall, That sends the frozen-ground swell under it, And spills the upper boulders in the sun; And makes gaps even two can pass abreast The above selection of the poem shows how impersonal the wall is. There is no humanity associated with this object, nor is there any emotion attached to it. Even thought the object has no emotion itself, there is emotion directed toward it as we see in line 1 of the poem. There is something out in the world that doesnt like this wall. Not only does this relate the authors feelings about how it keeps objects separated, This feeling of animosity has gone so far that something has gone as far as to destroy sections of the wall. I have come after them and made repair Where they have left not one stone on a stone, But they would have the rabbit out of hiding, To please the yelping dogs, The gaps I mean, The author goes even further in his description of the emotions directed at the wall, and explains that other dislike the wall as well. Although they dislike it because it is helping to hide the quarry they are after. The hunters express this dislike of the wall but physically destroying the wall, they tear it down even though it is not their wall. This goes a long way at letting the reader understand that this poem is also about relationships between people. Often times others will attack a person to get something they want with little to no regard for the person that is being attacked. But at spring mending-time we find them there. I let my neighbor know beyond the hill; And on a day we meet to walk a line And set the wall between us again. This little wall goes a long way in effecting the authors relationship with his neighbor. They go out of their way to make repairs to this small stone wall, that really has no purpose other than to keep their lives separated. This purpose may seem like a small one but both individuals meet to make sure the wall stays standing and keeps their lives separate. They are meeting and interacting only because the thing that makes them comfortable with each other has fallen in to disrepair and needs to be erected again. My apple trees will never get across And eat the cones under his pines, I tell him He only says, Good fences make good neighbors. The author is trying to get past the barriers that people erect between themselves and the rest of the world in the above section. He tells his neighbor that even without the wall their lives will never interact with each others. Even with his insistence the other man makes sure that the wall will go up again. He is going to do everything he can to ensure that every facet of his life is separated from that of his neighbors. Why do they make good neighbors? Isnt it Where are the cows? But here there are no cows. Before I built a wall Id ask to know What I was walling in or walling out, Here the author is confused because once again he is trying to get past the barriers that keep people separated. The author doesnt feel like there is anything that needs to be separated, he would be able to understand it if there were some sort of object that might cross into his neighbors world, but there is no such object. The only thing to keep separated is the two worlds them selves. He will not go behind his fathers saying, And he likes having thought of it so well He says again, Good fences make good neighbors. Once again the neighbors grasp on an old tradition and saying are all that justify the wall being in existence. The neighbor cannot explain the reason for the wall, he just knows that it has always been there and it adds to his discomfort when there is a hole in the wall, or a section of it missing. The author finally gives up trying to penetrate the barrier between himself and his neighbor, and puts the wall back into place to once again keep their lived from mixing. The whole tone of this poem suggests that the author believes that people should have more interactions with one another and not hide behind thing. If we all stopped hiding behind these wall that we create we would have more time to devote to better pursuits â€Å"Mending Wall† is a poem that presents two opposing attitudes towards keeping barriers up between people. Each neighbor has a different opinion. One neighbor wants a visible line to separate their property lines and the other sees no reason for it. The poem implies a lack of security and trust one person may have towards another, even when it may not seem illogical or necessary. Each year the two neighbors meet annually at the adjoining wall. Both men walk the length of the wall to assess and repair the year’s wear and tear. Frost’ writing style invites the reader to probe the need for communication or, more precisely, the way people put up walls to create barriers between themselves. The visual imagery of the wall helps the reader to shift from just seeing the wall as a basic, natural setting to an abstract consideration of human behavior. In the first stanza of the poem it establishes the sense of mystery, a true color of atmosphere, â€Å"something† that does not want the wall to be there. Whatever it is, it’s a powerful force and it creates a â€Å" frozen ground swell† that disrupts the wall from underneath, forcing stones on top to tumble off. Damage appears each year so the neighbors walk along the wall to repair the gaps and fallen stones that have not been created by either of the two neighbors. Frost then gives the reader an uncertain question as to why should neighbors need walls anyway. Why do good fences make good neighbors? If one or both neighbors had cattle or something that could do possible damage then a fence would be reasonable. However, it is pointed out in the poem that there are no cattle. So, there must be some sort of human distrust between one of the neighbors. What is the distrust? Frost doesn’t let the reader know. Perhaps it is an age difference that results in extreme points of view or tradition. Or maybe there is a religious bias about the other. One neighbor wants to separate and possibly his family. The wall prevents the evil of indifference from entering. The phantom of discomfort seems to be kept in check by this rock structure. Frost gives us the impression that he doesn’t agree with separating people. The poem might have something to do with racism. Maybe one neighbor is black and the other is Caucasian. Perhaps one of the neighbors can’t deal with the difference in ethnicity therefore separates and creates a barrier. He gives a suggestion that good fences make good neighbors but that statement may be a friendly way of saying, â€Å"if I can create a visible way of keeping you away then we can get along because I can fend off your strangeness from me. Frost might be using the simplicity of a common object to allude to a prevalent human dilemma-fear of the unknown. The wall prevents investigation to confirm or negate our presumptions about others. Conversely, the hard, cold rock represents the extreme measures taken to preserve our ridged thinking. Using the tool of visual imagery, Robert Frost challenges the reader to travel deeper within to visit our own personal boundaries. A wall is a physical demonstration of isolating that which we do not wish to trespasses into our domain. I believe Frost wants the reader to question the implications for our emotional limitations. Who do we keep abbey and why? Even the civility of shared responsibility, the fixing of the wall, presents a pretense of cooperation and acceptance. Yet, the very act of repair denotes a willingness to keep distance the trend. It is arguable that the self-righteous speaker of Mending Wall is himself obsessively committed to wall building, far more intractably and instinctively committed than his clichà ©-bound neighbor. While the speaker of Mending Wall justifiably castigates his unthinking neighbor and is himself far more aware of the powers of language for good and for ill, he is nonetheless caught up, ironically perhaps, in the same actual task, wall building, which will have the same results and look no different from his neighbors contribution despite the narrative he brings to it. There are several possibilities for irony here, depending on the level of Frosts self-awareness. Wall imagery pervades his poetry, as a conscious poetic image and as a psychosexual marker of control and limitation. That the speaker is the one who calls the neighbor to mend the wall is vitally important, then, but it is not clear that Frost meant for the speaker to be ironically perceived as a hypocrite. The simple explanation, that the speaker acts out of a sense of inevitability, knowing his neighbors habits, seems hardly enough given the contextual symbolism of the wall in Frosts poetry; the psychological explanation attendant upon this version might suggest that Frosts conscious intent was subverted by his own unconscious need for walls. So while Frost might not mean the speaker to be self-parodic, the reader might judge that there is an ironic discrepancy between what is said and what is meant, both by the speaker and by the poet. On a deeper level even than this is the possibility that Frost was aware of, had taken account of and justified, his own need for barriers. One does, after all, need something against which to push. In this case, the poem might be completely unironic, for while both men are engaged in the same task, each brings a different narrative to it, the one limited to a thoughtless clichJ , the other enriched philosophically. It could be that Frost is illustrating what it means to move from delight to wisdom: the road less traveled may not look any different, but it is made different by the inner progress of the traveler. The one wall becomes, in this reading, two walls, the speakers wall a philosophically differentiated structure, the neighbors wall a mere landmark of past cliches.

Nitration of Acetanilide and Methyl Benzoate

Nitration of Acetanilide and Methyl Benzoate Nitration of Acetanilide and Methyl Benzoate by Electrophilic Aromatic Substitution Abstract The purpose of this experiment was to synthesize methyl nitro benzoate from methyl benzoate, as well as nitroacetanilide from concentrated nitric acid (HNO3), and concentrated sulfuric acid (H2SO4) by using an electrophilic aromatic substitution reaction. The HNO3 and H2SO4 were combined to form a nitrating solution, which was added to a mixture of methyl benzoate and H2SO4, and the same was done with acetanilide. Following recrystallization, melting point was used to identify and characterize the product of the reaction. The melting point was determined to be 74 ËÅ ¡C-80 ËÅ ¡C for methyl nitro benzoate and for nitroacetanilide it was 195 ËÅ ¡C-200 ËÅ ¡C, which indicates meta-regiochemistry for methyl benzoate and para-regiochemistry for nitroacetanilide. The percent yield of this reaction for the recrystallized product was 59.3% of methyl nitrobenzoate, while it was 6.75% for nitroacetanilide. Figure 1: The reaction for the nitration of acetanilide. Figure 2: The reaction for the nitration of methyl benzoate. Experimental Concentrated sulfuric acid (0.6 mL) and concentrated nitric acid (0.5 mL) were added to a reaction flask and placed in an ice bath. Concentrated sulfuric acid (1 mL) was added to methyl benzoate (0.5 g) in a vial which was then packed in ice, and the same was done with acetanilide.ÂÂ   While stirring, the cold H2SO4/HNO3 mixture was added drop-by-drop. After the acid mixture was added, the reaction mixture was removed from the ice to warm to room temperature, with stirring. It was then transferred by Pasteur pipet into a beaker and stirred for five minutes. The methyl benzoate nitration formed white solid, and the acetanilide nitration for a light yellow solid. The crystals were the vacuum filtered with a Buchner funnel. The crude product was recrystallized by adding a distilled water and ethanol slowly while heating the product. While cooling, the solution produced large white crystals for methyl benzoate nitration and light yellow crystals for the acetanilide nitration. The ma ss, melting point percent yield were obtained. Results and Discussion Through the use of electrophilic aromatic substitution, acetanilide is nitrated to nitroacetanilide, while methyl benzoate was nitrated to methyl nitrobezonate. The first step of the reaction involved in the donation of an electron pair, which generates the nitronium ion from nitric acid by protonation and loss of water, using sulphuric acid as the dehydrating agent. The mechanism for methyl benzoate can be seen below. Figure 3: The mechanism of the nitration of methyl benzoate to methyl nitrobenzoate. To prevent acetanilide from dinitrating, the nitrating solution of HNO3 and H2SO4 were added drop by drop to the acetanilide solution, so that the concentration of the nitrating agent is kept at minimum. The cooler temperatures were used to reduce the reaction rate and help to avoid over nitration. The electrophilic aromatic substitutions involved the replacement of a proton on an aromatic ring with an electrophile that becomes substituent. The sulfuric acid protonates the methyl benzoate, which creates the resonance stabilized arenium ion intermediate.3 The electron deficient nitronium ion reacts with the protonated intermediate meta position. The ester group is the meta deactivator and the reaction takes place at the meta position because the ortho and para positions are destabilized by adjacent positives charges on the resonance structure.2 The major product of the methyl benzoate nitration is the meta product due to carboxyl and nitro groups both being powerful electron withdrawing groups. Table 1: The weight, melting point, and percent yield of both Nitroactenilide and Methyl Nitrobenzoate. Product Name Crude Weight (g) Product Weight (g) Percent Yield (%) Melting Point (ËÅ ¡C) Literature Melting Point (ËÅ ¡C) Nitroactenilide 0.585 0.045 6.75% 195-200 214-217 Methyl Nitrobenzoate 0.56 0.32 59.3% 74-80 78-80 The actual yield of methyl nitrobenzoate is 0.32 g while the theoretical yield is 0.54 g. The melting point is 74ËÅ ¡C 80ËÅ ¡C, and the value is closed to the literature value which is 78ËÅ ¡C 80 ËÅ ¡C. The percent yield for the methyl benzoate electrophilic aromatic substitution reaction was 59.3% with 0.32g of methyl nitrobenzoate formed. The percent yield for the reaction with acetanilide was 6.75% with 0.045g of nitroacetanilide formed, which can be seen in table 1. The melting point observed was 195-200 ËÅ ¡C, which can be accounted for impurities in the product, which can be seen below in table 1. Some impurities might be Ortho and Meta directing substances, as well as there could have been some experimental errors that occurred during the experiment such as not overheating solutions during the reactions. These low yields may have resulted from poor recrystallization, product lost during transfer from one apparatus to another, or human error. The miss ing percent accounts for the impurities removed during recrystallization. However, some product must have been lost in the acetanilide reaction recrystallization because of such a low percent yield. The melting point of the final product was 74-80 ËÅ ¡C suggesting that it was formed by meta-substitution. The literature melting point for meta-methyl nitrobenzoate is 78-80 ËÅ ¡C. Therefore, the melting point is lower than it should be suggesting that an impurity is in the product. This impurity may have occurred due to poor recrystallization or it may have been picked up after recrystallization. The melting point of the nitroacetanilide product was 195-200 ËÅ ¡C suggesting the para-regiochemistry. The literature melting point for the p-nitroacetanilide is 214-217 ËÅ ¡C. Therefore, the melting point of the product is a little lower than the literature value, suggesting that an impurity exists in the product from poor recrystallization of contact with an impurity during recrystallization. The methyl nitrobenzoate product was determined to be meta-substituted based on its melting point range. This can also be proved by evaluating the attack of the benzene ring of methyl benzoate on the electrophililic species and nitric acid.4 The C-OCH3 substituent is a meta-deactivator. Therefore, when the benzene ring attacks the nitronium ion, the NO3+ group will add meta-positon. This creates a resonance stabilized arenium ion without a positive charge on the carbon with the C-OCH3 substituent. Then the proton is removed from the meta position by the weak base, the HSO4-, formed in the creation of the nitronium ion, which reforms the sulfuric acid catalyst.3 Once the proton is removed the substitution product, methyl nitrobenzoate remains. The nitroacetanilide product was formed by a para-substitution. This can be determined by examining the melting point and comparing it to the literature values for each position.4 However, this can also be determined when examining the electrophilic aromatic substitution reaction of acetanilide on the electrophile, nitric acid. The NHCOCH3 substituent is an ortho-para-activator. Therefore, when the benzene ring of acetanilide attacks the nitronium ion, it can add ortho or para. The para substitution, if more stable than an ortho substitution, will be added because the para position is a further distance from the position of the NHCOCH3 substituent. Therefore, the benzene ring adds at the para position based on the melting point and resonance in the mechanism shown above. Conclusion The methyl m-nitrobenzoate and p-nitroacetanilide were prepared. The percentage yield is 6.75% for nitroacetanilide and 59.3% for methyl nitrobenzoate. The melting point of the products are 74ËÅ ¡C 80ËÅ ¡C and 195ËÅ ¡C 200ËÅ ¡C. From the given physical constant, the literature melting point of methyl m-nitrobenzoate is 78 80ËÅ ¡C and 214ËÅ ¡C 217ËÅ ¡C for nitroacetailide, so it can be concluded that the products were methyl m-nitrobenzoate and p-nitroacetanilide. References Wade, Jr., L.G. Organic Chemistry 2003, 722-741. Chemistry Laboratory Manual: Susquehanna University 2014, 242-244 250 ChemFinder.Com. Cambridge Soft Corporation. . Anerjee, Dhruv K. Ortho and Par % of Key Reaction. Utkarschemistry. 2013. Appendix A: Finding the Limiting Reagent Grams X 1 mol / molecular weight = moles of reactant Nitric Acid: 0.6 mL X ((1 g/1 mL) X 1 mol) / 98.08 g/mol = 0.0061 mol Nitric Acid: 0.5 mL X ((1 g/1 mL) X 1 mol) / 63.01 g/mol = 0.0079 mol Methyl Benzoate: (0.55 g X 1 mol) / 181.14 g/mol = 0.030 mol Appendix B: Calculating Theoretical Yield of Methyl Nitrobenzoate Moles of limiting reagent X molar ratio X molecular weight of product) / 1 mol = theoretical yield (0.030 X 181.13) / 1 mol = 0.54 g Appendix C: Calculating Percent Yield (Actual / theoretical) X 100% = percent yield (0.32 g/ 0.54 g) X 100% = 59.3%

Atlas Shrugged - Iser and Bakhtin on the Closed Text Essay -- Atlas Sh

Atlas Shrugged - Iser and Bakhtin on the Closed Text The process of reading places the author, text, and reader into a dynamic relationship in which, through a fusion of the author's literary vision and the reader's creativity, the text is transformed into an informative and enjoyable experience. This process is especially apparent in the novel form. As the theorist Wolfgang Iser states, a novel must be "conceived in such a way that it will engage the readers imagination in the task of working things out for himself, for reading is only a pleasure when it is active and creative" (Iser 51). Similarly, another theorist and philosopher, Mikhail Bakhtin, argues that within a novel an author creates numerous different voices and languages, each of which contributes to the dynamic reading process; every word and sentence has a context both inside and outside of the novel. Though there are many other theories regarding reader-response, these two form a cohesive definition of the process: Iser's theory broadly explains the interaction-or inter section-of the three components in the process, while Bakhtin's theory explains the specific subjectivity of the novel language. Both of these theories, however, rely on the basic assumption that all texts are intended to be interpretable; that is, in the words of Umberto Eco, that all texts are 'open'. Eco describes an 'open' text as one that attempts to force the reader "into an interplay of stimulus and response which depends on his unique capacity for sensitive reception of the piece" (Eco 49). In essence, an open text invites the reader to fuse his own unique experiences with that of the text to form an interpretation that is his own. Conversely, Eco also describes an antithesis to the... ...tes reader anticipation. Thus, one must conclude that while Eco's theory is fascinating and may very well have a solid basis outside of the novel form, it is impossible for a novel to be closed; though the author's intentions bay be set in stone, the reader's intentions certainly never will be. A novel, by virtue of being a novel, will always be more open than closed. Works Cited Bakhtin, Mikhail. The Diologic Imagination. Austin: University of Texas Press, 1981. Eco, Umberto. The Role of the Reader: Explorations in the Semiotics of Texts. Bloomington: Indiana University Press, 1979. Iser, Wolfgang. "The Reading Process: A Phenomenological Approach." Published in Tompkins, Jane P. ed., Reader-Response Criticism: From Formalism to Post-Structuralism. Maryland: John Hopkins UP, 1980. Rand, Ayn. Atlas Shrugged. New York: Penguin Books USA, Inc., 1957. Â  

Classroom Assessment Essay

Introduction Assessment is the process of obtaining information about a student academic status in school. According to Gronlund and Waugh (2009), assessment is a continueous process, and an integral part of the classroom instruction process. â€Å"It helps in determining learning readiness, in monitoring and improving learning, and in grading or clarifying students achievement † (p. V). The purpose of assessment is to obtain information about a student academic status in order to make decisions on how to help students, teachers and school improve. Proper interpretation of the assessment result is key component in deciding the implication for both the student and teacher. Interpretation of the results For the purpose of this assignment, the assessment results are based on a formative reading assessment used to measure the extent to which students have mastered a specific learning outcome for vocabulary unit in a hypothetical remedial reading class of struggling readers. According to Gronlund & Waugh (2009), formative assessment is used to monitor student progress during instruction and is designed to measure mastery of the learning outcomes of a limited segment of instruction. The test is a criterion- referenced because Assessment Development and Use According to Gronlund and Waugh (2009), careful consideration must be given in planning and preparing the assessment. Specific questions concerning the goals of the curriculum, instructional objectives, learning outcomes, and procedures for the assessment were major focus in developing the assessment (Gronlund and Waugh, 2009). The institution provided guidelines of what the students should know and able to do. As a result, reviewing the specific instructional objective outcomes and constructing relevant test items were keys in developing the assessment. In constructing each test item, addition, focus was given to the selection type and matching items to specific learning outcomes. Gronlund and Waugh (2009) stated, â€Å" Use the item type that provide the most direct measures of student performance specified by the intended learning outcome† (p. 76) Assessment Interpretation and Grading Gronlund and Waugh (2009), described two types of assessment interpretations. Norm-referenced interpretation compares an individual performance with others. Criterion- referenced interpretation compares the individual with himself and tells what and how each individual performs without comparison to others (Gronlund and Waugh, 2009). The assessment is criterion-referenced, and is one of many assessments throughout the course. The result from the assessment will be used to indicate the extent of which each student master the specific knowledge and skill taught in the unit. Grades assigned to the students work will represent the extent to which the instructional objectives have been achieved (Gronlund and Waugh, 2009). Students will be assigned a letter grade (A, B, C, or D) according to their performance on the assessment. Gronlund and Waugh (2009) stated, â€Å"letter grades are typically assigned by comparing a student’s performance to a prespecified standard of performance† (p. 192). The results will not be used to compare student performance against others, but will aid in planning instruction for future lessons. I chose criterion-referenced assessment as a means of helping students achieve mastery of the instruction, and improve learning by determining what they know and what they don’t know. Grading Rubric References Angelo, T. A. , & Cross, K. P. (1993). Classroom assessment techniques: a handbook for college teachers (2nd ed. ). San Francisco: Jossey-Bass. Gronlund, N. E. , & Waugh, C. K. (2009). Assessment of student achievement (9th ed. ). Upper Saddle River, NJ: Pearson Education.

Formal Charge Definition in Chemistry

Formal Charge Definition in Chemistry Formal charge of FC is the difference between the number of valence electrons of each atom and the number of electrons the atom is associated with. Formal charge assumes any shared electrons are equally shared between the two bonded atoms.Formal charge is calculated using the equation:FC eV - eN - eB/2 whereeV number of valence electrons of the atom as if it were isolated from the moleculeeN number of unbound valence electrons on the atom in the moleculeeB number of electrons shared by the bonds to other atoms in the molecule Formal Charge Example Calculation For example, carbon dioxide or CO2 is a neutral molecule that has 16 valence electrons. There are three different ways to draw the Lewis structure for the molecule to determine formal charge: The carbon atom may be joined to both oxygen atom via double bonds (carbon 0, oxygen 0, formal charge 0)The carbon atom may have a single bond with one oxygen atom and a double bond to the other oxygen atom (carbon 1, oxygen-double 0, oxygen-single -1, formal charge 0)The carbon atom may be joined to each oxygen atom via single bonds (carbon 2, oxygens -1 each, formal charge 0) Each possibility results in a formal charge of zero, but the first choice is the best one because it predicts no charge in the molecule. This is more stable and thus is most likely. See how to calculate formal charge with another  example problem. Formal Charge Key Takeaways Formal charge (FC) is the electric charge of an atom in a molecule.It is calculated as the number of valence electrons minus half the number of electrons shared in a bond minus the number of electrons not bound in the molecule.Formal charge is used to estimate the way electric charge is distributed in a molecule.

10 Fascinating Facts About Ants

10 Fascinating Facts About Ants In many ways, ants can outwit, outlast, and outnumber humans. Their complex, cooperative societies enable them to survive and thrive in conditions that would challenge any individual. Here are 10 fascinating facts about ants that just might convince you that while you wouldnt welcome them to your next picnic, theyre still pretty amazing creatures. 1. Ants Have Super-Human Strength Ants can carry objects 50 times their own body weight in their jaws. Relative to their size, their muscles are thicker than those of larger animals- even humans. This ratio enables them to produce more force and carry larger objects. If you  had muscles in the proportions of ants, youd be able to heave a Hyundai over your head! 2. Soldier Ants Use their Heads to Plug Holes In certain ant species, the soldier ants have modified heads, shaped to match the nest entrance. They block access to the nest by sitting just inside the entrance, with their heads functioning like a cork in a bottle to keep intruders at bay. When a worker ant returns to the nest, it touches the soldier ants head to let the guard know it belongs to the colony. 3. Ants Can Form Symbiotic Relationship with Plants Ant plants, or myrmecophytes, are plants that have naturally occurring hollows in which ants can take shelter or feed. These cavities may be hollow thorns, stems, or even leaf petioles. The ants live in the hollows, feeding on sugary plant secretions or the excretions of sap-sucking insects. What does a plant get for providing such luxurious accommodations? The ants defend the host plant from herbivorous mammals and insects and may even prune away parasitic plants that attempt to grow on it. 4. The Total Biomass of Ants The Biomass of People How can this be? After all, ants are so tiny, and were so much bigger. That said, scientists estimate there are at least 1.5 million ants on the planet for every human being. Over 12,000 species of ants are known to exist, on every continent except Antarctica. Most live in tropical regions. A single acre of Amazon rainforest may be home to 3.5 million ants. 5. Ants Sometimes Herd Insects of Other Species Ants will do just about anything to get the sugary secretions of sap-sucking insects, such as aphids or leafhoppers. To keep the honeydew in close supply, some ants herd aphids, carrying the soft-bodied pests from plant to plant. Leafhoppers sometimes take advantage of this nurturing tendency in ants and leave their young to be raised by the ants. This allows the leafhoppers to raise another brood. 6. Some Ants Enslave Other Ants Quite a few ant species take captives from other ant species, forcing them to do chores for their own colony. Honeypot ants even enslave ants of the same species, taking individuals from foreign colonies to do their bidding. Polyergus queens, also known as Amazon ants, raid the colonies of unsuspecting Formica ants. The Amazon queen finds and kills the Formica queen, then enslaves the Formica workers. The slave workers help the usurping queen rear her own brood. When her Polyergus offspring reach adulthood, their sole purpose is to raid other Formica colonies and bring back their pupae, ensuring a steady supply of slave workers. 7. Ants Lived Alongside Dinosaurs Ants evolved some 130 million years ago during the early Cretaceous period. Most fossil evidence of insects is found in lumps of ancient amber, or fossilized plant resin. The oldest known ant fossil, a primitive and now extinct ant species named Sphercomyrma freyi, was found in Cliffwood Beach, New Jersey. Though that fossil only dates back 92 million years, another fossil ant that proved nearly as old has a clear lineage to present-day ants, which suggests a much longer evolutionary line than previously assumed. 8. Ants Started Farming Long Before Humans Fungus-farming ants began their agricultural ventures about 50 million years before humans thought to raise their own crops. The earliest evidence suggests ants began farming as early as 70 million years ago, in the early Tertiary period. Even more amazing, these ants used sophisticated horticultural techniques to enhance their crop yields, including secreting chemicals with antibiotic properties to inhibit mold growth and devising fertilization protocols using manure. 9. Ant Supercolonies Can Stretch Thousands of Miles Argentine ants, native to South America, now inhabit every continent except Antarctica due to accidental introductions. Each ant colony has a distinctive chemical profile that enables members of the group to recognize one another and alerts the colony to the presence of strangers. Scientists recently discovered that massive supercolonies in Europe, North America, and Japan all share the same chemical profile, meaning they are, in essence, a global supercolony of ants. 10. Scout Ants Lay Scent Trails to Guide Others to Food By following pheromone trails laid by scout ants from their colony, foraging ants can gather and store food efficiently. A scout ant first leaves the nest in search of food, wandering somewhat randomly until it discovers something edible. It then consumes some of the food and returns to the nest in a direct line. It seems scout ants can observe and recall visual cues that enable them to navigate quickly back to the nest. Along the return route, the scout ants leave a trail of pheromones- which are special scents they secrete- that guide their nestmates to the food. The foraging ants then follow the path designated by the scout ant, each one adding more scent to the trail to reinforce it for others. Worker ants continue walking back and forth along the trail until the food source is depleted.