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Hi, I'm John Green, this is Crash Course U.S. History, and today, we're going to talk about slavery, which is not funny. 0:06 Yeah, so we put a lei on the eagle to try and cheer you up, but let's face it, this is going to be depressing. 0:10 With slavery, every time you think, like, "Aw, it couldn't have been that bad," it turns out to have been much worse. 0:14 Mr. Green, Mr. Green! But what about – 0:15 Yeah, Me from the Past, I'm going to stop you right there, because you're going to embarrass yourself. Slavery was hugely important to America. 0:20 I mean, it led to a civil war and it also lasted what, at least in U.S. history, counts as a long-ass time, from 1619 to 1865. 0:29 And yes, I know there's a 1200-year-old church in your neighborhood in Denmark, but we're not talking about Denmark! 0:35 But slavery is most important because we still struggle with its legacy. 0:38 So, yes, today's episode will probably not be funny, but it will be important. 0:42 [Theme Music] North & South economic ties 0:51 So the slave-based economy in the South is sometimes characterized as having been separate from the Market Revolution, but that's not really the case. 0:57 Without southern cotton, the North wouldn't have been able to industrialize, at least not as quickly, because cotton textiles were one of the first industrially products. 1:04 And the most important commodity in world trade by the nineteenth century, and 3/4 of the world's cotton came from the American South. 1:11 And speaking of cotton, why has no one mentioned to me that my collar has been half popped this entire episode, like I'm trying to recreate the Flying Nun's hat. 1:18 And although there were increasingly fewer slaves in the North as northern states outlawed slavery, cotton shipments overseas made northern merchants rich. 1:26 Northern bankers financed the purchase of land for plantations. 1:29 Northern insurance companies insured slaves who were, after all, considered property, and very valuable property. 1:35 And in addition to turning cotton into cloth for sale overseas, northern manufacturers sold cloth back to the South, where it was used to clothe the very slaves who had cultivated it. 1:45 But certainly the most prominent effects of the slave-based economy were seen in the South. Slave-based agriculture in the South 1:49 The profitability of slaved-based agriculture, especially King Cotton, meant that the South would remain largely agricultural and rural. 1:56 Slave states were home to a few cities, like St. Louis and Baltimore, but with the exception of New Orleans, 2:00 almost all southern urbanization took place in the upper South, further away from the large cotton plantations. 2:06 And slave-based agriculture was so profitable that it siphoned money away from other economic endeavors. 2:11 Like, there was very little industry in the South. 2:13 It produced only 10% of the nation's manufactured goods. 2:16 And, as most of the capital was being plowed into the purchase of slaves, there was very little room for technological innovation, like, for instance, railroads. 2:23 This lack of industry and railroads would eventually make the South suck at the Civil War, thankfully. 2:27 In short, slavery dominated the South, shaping it both economically and culturally, and slavery wasn't a minor aspect of American society. Popular attitudes concerning slavery 2:35 By 1860, there were four million slaves in the U.S., and in the South, they made up one third of the total population. 2:42 Although in the popular imagination, most plantations were these sprawling affairs with hundreds of slaves, 2:47 in reality, the majority of slaveholders owned five or fewer slaves. 2:51 And, of course, most white people in the South owned no slaves at all, though, if they could afford to, they would sometimes rent slaves to help with their work. 2:57 These were the so-called yeoman farmers who lived self-sufficiently, raised their own food, and purchased very little in the Market Economy. 3:04 They worked the poorest land and, as a result, were mostly pretty poor themselves. 3:08 But even they largely supported slavery, partly, perhaps, for aspirational reasons, and partly because the racism inherent to the system gave even the poorest whites legal and social status. 3:18 And southern intellectuals worked hard to encourage these ideas of white solidarity and to make the case for slavery. 3:23 Many of the founders, a bunch of whom you'll remember, held slaves, saw slavery as a necessary evil. 3:29 Jefferson once wrote, quote, "As it is, we have the wolf by the ear, and we can neither hold him, nor safely let him go. 3:37 Justice is on one scale, and self-preservation in the other." 3:41 The belief that justice and self-preservation couldn't sit on the same side of the scale was really opposed to the American idea, 3:47 and, in the end, it would make the Civil War inevitable. 3:50 But as slavery became more entrenched in these ideas of liberty and political equality were embraced by more people, 3:55 some southerners began to make the case that slavery wasn't just a necessary evil. 3:59 They argued, for instance, that slaves benefited from slavery. 4:03 Because, you know, because their masters fed them and clothed them and took care of them in their old age. 4:07 You still hear this argument today, astonishingly. 4:09 In fact, you'll probably see asshats in the comments saying that in the comments. 4:12 I will remind you, it's not cursing if you are referring to an actual ass. 4:15 This paternalism allowed masters to see themselves as benevolent and to contrast their family-oriented slavery with the cold, mercenary Capitalism of the free-labor North. 4:26 So yeah, in the face of rising criticism of slavery, some southerners began to argue that the institution was actually good for the social order. 4:33 One of the best-known proponents of this view was John C. Calhoun, who, in 1837, said this in a speech on the Senate floor: 4:40 "I hold that, in the present state of civilization, 4:43 where two races of different origin and distinguished by color and other physical differences as well as intellectual, are brought together, 4:51 the relation now existing in the slave-holding states between the two is, instead of an evil, a good. A positive good." 4:59 Now, of course, John C. Calhoun was a fringe politician, and nobody took his views particularly seriously. 5:04 Stan: Well, he was Secretary of State from 1844 to 1845. 5:07 John: Well, I mean, who really cares about the Secretary of State, Stan? 5:10 Danica: Eh, he was also Secretary of War from 1817 to 1825. 5:13 John: All right, but we don't even have a Secretary of War anymore, so... 5:16 Meredith: And he was Vice President from 1825 to 1832. 5:19 John: Oh my god, were we insane?! 5:21 We were, of course, but we justified the insanity with Biblical passages and with the examples of the Greeks and Romans, 5:28 and with outright racism, arguing that black people were inherently inferior to whites. 5:33 And that not to keep them in slavery would upset the natural order of things. 5:37 A worldview popularized millennia ago by my nemesis, Aristotle. God, I hate Aristotle. 5:42 You know what defenders of Aristotle always say? 5:44 "He was the first person to identify dolphins." 5:47 Well, ok, dolphin identifier. 5:50 Yes, that is what he should be remembered for, but he's a terrible philosopher! Lives & experiences of enslaved people 5:53 Here's the truth about slavery: 5:55 It was coerced labor that relied upon intimidation and brutality and dehumanization. 6:00 And this wasn't just a cultural system, it was a legal one. 6:03 I mean, Louisiana law proclaimed that a slave "owes his master... a respect without bounds, and an absolute obedience." 6:09 The signal feature of slaves' lives was work. 6:12 I mean, conditions and tasks varied, but all slaves labored, usually from sunup to sundown, and almost always without any pay. 6:20 Most slaves worked in agriculture on plantations, and conditions were different, depending on which crops are grown. 6:25 Like, slaves on the rice plantations of South Carolina had terrible working conditions, 6:29 but they labored under the task system, which meant that once they had completed their allotted daily work, they would have time to do other things. 6:36 But lest you imagine this is like how we have work and leisure time, bear in mind that they were owned and treated as property. 6:42 On cotton plantations, most slaves worked in gangs, usually under the control of an overseer, or another slave who was called a "driver." 6:49 This was back-breaking work done in the southern sun and humidity, and so it's not surprising that whippings – or the threat of them – were often necessary to get slaves to work. 6:58 It's easy enough to talk about the brutality of slave discipline, but it can be difficult to internalize it. 7:03 Like, you look at these pictures, but because you've seen them over and over again, they don't have the power they once might have. 7:09 The pictures can tell a story about cruelty, but they don't necessarily communicate how arbitrary it all was. 7:14 As, for example, in this story, told by a woman who was a slave as a young girl: 7:18 "[The] overseer... went to my father one morning and said, "Bob, I'm gonna whip you this morning." 7:22 Daddy said, "I ain't done nothing," and he said, "I know it, I'm going to whip you to keep you from doing nothing," 7:28 and he hit him with that cowhide – you know it would cut the blood out of you with every lick if they hit you hard." 7:33 That brutality – the whippings, the brandings, the rape – was real, and it was intentional, because, in order for slavery to function, slaves had to be dehumanized. 7:43 This enabled slaveholders to rationalize what they were doing, and it was hoped to reduce slaves to the animal property that is implied by the term "chattel slavery." 7:51 So the idea was that slaveholders wouldn't think of their slaves as human, and slaves wouldn't think of themselves as human. 7:57 But it didn't work. Let's go to the Thought Bubble. 7:59 Slaves' resistance to their dehumanization took many forms, but the primary way was by forming families. Family, love, & religion of enslaved people 8:05 Family was a refuge for slaves and a source of dignity that masters recognized and sought to stifle. 8:10 A paternalistic slave owner named Bennet H. Barrow wrote in his rules for the Highland Plantation: 8:15 "No rule that I have stated is of more importance than that relating to Negroes marrying outside of the plantation... It creates a feeling of independence." 8:23 Most slaves did marry, usually for life, and, when possible, slaves grew up in two-parent households. 8:28 Single-parent households were common, though, as a result of one parent being sold. 8:32 In the upper South, where the economy was shifting from tobacco to different, less labor-intensive cash crops, the sale of slaves was common. 8:40 Perhaps one-third of slave marriages in states like Virginia were broken up by sale. 8:45 Religion was also an important part of life in slavery. 8:47 While masters wanted their slaves to learn the parts of the Bible that talked about being happy in bondage, 8:52 slave worship tended to focus on the stories of Exodus, where Moses brought the slaves out of bondage, 8:57 or Biblical heroes, who overcame great odds, like Daniel and David. 9:01 And, although most slaves were forbidden to learn to read and write, many did anyway. And some became preachers. 9:07 Slave preachers were often very charismatic leaders, and they roused the suspicion of slave owners, and not without reason. 9:13 Two of the most important slave uprisings in the South were led by preachers. 9:16 Thanks, Thought Bubble. 9:17 Oh, it's time for the Mystery Document? Mystery Document 9:19 We're doing two set pieces in a row? All right. [buzzing noise] [music] 9:24 The rules here are simple. 9:26 I wanted to re-shoot that, but Stan said no. 9:29 I guess the author of the Mystery Document. 9:30 If I am wrong, I get shocked with the shock pen. 9:33 "Since I have been in the Queen's dominions I have been well contented, yes well contented for sure, man is as God intended he should be. 9:40 That is, all are born free and equal. 9:43 This is a wholesome law, not like the southern laws which puts man made in the image of God on level with brutes. 9:49 O, what will become of the people, and where will they stand in the day of judgment. 9:53 Would that the 5th verse of the 3rd chapter of Malachi were written as with a bar of iron, 9:59 and the point of a diamond upon every oppressor's heart that they might repent of this evil, and let the oppressed go free..." 10:06 All right, it's definitely a preacher, because only preachers have read Malachi. 10:10 Probably African American, probably not someone from the South. 10:13 I'm going to guess that it is Richard Allen, the founder of the African Methodist Episcopal Church? 10:18 [buzzing noise] DAAAH, DANG IT! 10:19 It's Joseph Taper, and Stan just pointed out to me that I should have known it was Joseph Taper because it starts out, 10:24 "Since I have been in the Queen's dominions..." 10:27 He was in Canada. He escaped slavery to Canada. The Queen's dominions! 10:31 All right, Canadians, I blame you for this, although, thank you for abolishing slavery decades before we did. 10:36 [electric sounds] AHHH! How people resisted & escaped slavery 10:37 So, the Mystery Document shows one of the primary ways that slaves resisted their oppression: by running away. 10:42 Although some slaves like Joseph Taper escaped for good by running away to northern free states, 10:47 or even to Canada, where they wouldn't have to worry about fugitive slave laws, even more slaves ran away temporarily, hiding out in the woods or the swamps, and eventually returning. 10:55 No one knows exactly how many slaves escaped to freedom, but the best estimate is that a thousand or so a year made the journey northward. 11:01 Most fugitive slaves were young men, but the most famous runaway has been hanging out behind me all day long: Harriet Tubman. 11:07 Harriet Tubman escaped to Philadelphia at the age of 29, and over the course of her life, she made about 20 trips back to Maryland to help friends and relatives make the journey north on the Underground Railroad. 11:17 But a more dramatic form of resistance to slavery was actual, armed rebellion, which was attempted. 11:22 Now, individuals sometimes took matters into their own hands and beat or even killed their white overseers or masters. 11:27 Like Bob, the guy who received the arbitrary beating, responded to it by killing his overseer with a hoe. 11:33 But that said, large-scale slave uprisings were relatively rare. 11:36 The four most famous ones all took place in a 35-year period at the beginning of the 19th century. Slave rebellions 11:41 Gabriel's Rebellion in 1800 – which we've talked about before – was discovered before he was able to carry out his plot. 11:45 Then, in 1811, a group of slaves upriver from New Orleans seized cane, knives, and guns, and marched on the city before militia stopped them. 11:52 And in 1822, Denmark Vesey, a former slave who had purchased his freedom, may have organized a plot to destroy Charleston, South Carolina. 11:59 I say "may have" because the evidence against him is disputed and comes from a trial that was not fair. 12:05 But regardless, the end result of that trial was that he was executed, as were 34 slaves. Nat Turner's Rebellion 12:09 But the most successful slave rebellion, at least in the sense that they actually killed some people, was Nat Turner's in August 1831. 12:15 Turner was a preacher, and with a group of about 80 slaves, he marched from farm to farm in South Hampton County, Virginia, 12:21 killing the inhabitants, most of whom were women and children, because the men were attending a religious revival meeting in North Carolina. 12:27 Turner and 17 other rebels were captured and executed, but not before they struck terror into the hearts of whites all across the American South. 12:34 Virginia's response was to make slavery worse, passing even harsher laws that forbade slaves from preaching, and prohibited teaching them to read. 12:42 Other slave states followed Virginia's lead and, by the 1830s, slavery had grown, if anything, more harsh. 12:47 So, this shows that large-scaled armed resistance was – Django Unchained aside – not just suicidal, but also a threat to loved ones and, really, to all slaves. How enslaved people resisted their oppression & why it matters 12:55 But, it is hugely important to emphasize that slaves did resist their oppression. 12:59 Sometimes this meant taking up arms, but usually it meant more subtle forms of resistance, 13:03 like intentional work slowdowns or sabotaging equipment, or pretending not to understand instructions. 13:08 And, most importantly, in the face of systematic legal and cultural degradation, they re-affirmed their humanity through family and through faith. 13:16 Why is this so important? 13:17 Because too often in America, we still talk about slaves as if they failed to rise up, 13:21 when, in fact, rising up would not have made life better for them or for their families. 13:26 The truth is, sometimes carving out an identity as a human being in a social order that is constantly seeking to dehumanize you, is the most powerful form of resistance. 13:34 Refusing to become the chattel that their masters believed them to be is what made slavery untenable and the Civil War inevitable, so make no mistake, slaves fought back. 13:45 And in the end, they won. I'll see you next week. Credits 13:48 Crash Course is produced and directed by Stan Muller. 13:50 The script supervisor is Meredith Danko. 13:52 Our associate producer is Danica Johnson. 13:54 The show is written by my high school history teacher Raoul Meyer and myself. 13:57 And our graphics team is Thought Cafe. 13:58 Every week, there's a new caption to the Libertage, but today's episode was so sad that we couldn't fit a Libertage in... 14:04 UNTIL NOW! [Libertage Rock Music] 14:08 Suggest Libertage caption in comments, where you can also ask questions about today's video that will be answered by our team of historians. 14:13 Thanks for watching Crash Course, and as we say in my home town, don't forget to be abolitionist.
Owls, such as the young snowy owls on the previous page, have for centuries been symbols of both wisdom and mystery. To many cultures their piercing eyes have conveyed a look of intelligence. Their silent flight through darkened landscapes in search of prey has projected an air of power or wonder. For this chapter and this book, owls are an engaging example of a living organism from the world of biology—the study of life. BIOLOGY AND YOU Living in a small town, in the country, or at the edge of the suburbs, one may be lucky enough to hear an owl's hooting. This experience can lead to questions about where the bird lives, what it hunts, and how it finds its prey on dark, moonless nights. Biology, or the study of life, offers an organized and scientific framework for posing and answering such questions about the natural world. Biologists study questions about how living things work, how they interact with the environment, and how they change over time. Biologists study many different kinds of living things ranging from tiny organisms, such as bacteria, to very large organisms, such as elephants. Each day, biologists investigate subjects that affect you and the way you live. For example, biologists determine which foods are healthy. As shown in Figure 1-1, everyone is affected by this impor- tant topic. Biologists also study how much a person should exer- cise and how one can avoid getting sick. Biologists also study what CHARACTERISTICS OF LIFE The world is filled with familiar objects, such as tables, rocks, plants, pets, and automobiles. Which of these objects are living or were once living? What are the criteria for assigning something to the living world or the nonliving world? Biologists have established that living things share seven characteristics of life. These characteristics are organization and the presence of one or more cells, response to a stimulus (plural, stimuli), homeostasis, metabolism, growth and development, reproduction, and change through time. Organization and Cells Organization is the high degree of order within an organism’s internal and external parts and in its interactions with the living world. For example, compare an owl to a rock. The rock has a spe- cific shape, but that shape is usually irregular. Furthermore, differ- ent rocks, even rocks of the same type, are likely to have different shapes and sizes. In contrast, the owl is an amazingly organized individual, as shown in Figure 1-2. Owls of the same species have the same body parts arranged in nearly the same way and interact with the environment in the same way. Copyright © by Holt, Rinehart and Winston. All rights reserved. ORGANISM (Barn Owl) ORGAN (Owl’s Ear) TISSUE (Nervous Tissue Within the Ear) CELL (Nerve Cell) your air, land, and fAll living organisms, whether made up of one cell or many cells, have some degree of organization. A cell is the smallest unit that can perform all life’s processes. Some organisms, such as bacteria, are made up of one cell and are called unicellular (YOON-uh-SEL-yoo-luhr) organisms. Other organisms, such as humans or trees, are made up of multiple cells and are called multicellular (MUHL-ti-SEL-yoo-luhr) organisms. Complex multicellular organisms have the level of orga- nization shown in Figure 1-2. In the highest level, the organism is made up of organ systems, or groups of specialized parts that carry out a certain function in the organism. For example, an owl’s ner- vous system is made up of a brain, sense organs, nerve cells, and other parts that sense and respond to the owl’s surroundings. Organ systems are made up of organs. Organs are structures that carry out specialized jobs within an organ system. An owl’s ear is an organ that allows the owl to hear. All organs are made up of tissues. Tissues are groups of cells that have similar abilities and that allow the organ to function. For example, nervous tissue in the ear allows the ear to detect sound. Tissues are made up of cells. A cell must be covered by a membrane, contain all genetic information necessary for replication, and be able to carry out all cell functions. Within each cell are organelles. Organelles are tiny structures that carry out functions necessary for the cell to stay alive. Organelles contain biological molecules, the chemical compounds that provide physical structure and that bring about movement, energy use, and other cellular functions. All biological molecules are made up of atoms. Atoms are the simplest particle of an ele- ment that retains all the properties of a certain element. Response to Stimuli Another characteristic of life is that an organism can respond to a stimulus—a physical or chemical change in the internal or external environment. For example, an owl dilates its pupils to keep the level of light entering the eye constant. Organisms must be able to respond and react to changes in their environment to stay alive. ORGANELLE (Mitochondrion) BIOLOGICAL MOLECULE (Phospholipid) ATOM (Oxygen) cell from the Latin, cella meaning “small room,” or “hut” Word Roots and Origins www.scilinks.org Topic: Characteristics of Life Keyword: HM60257 mb06se_bios01.qxd 5/18/07 10:37 AM Page 7 8 CHAPTER 1 Homeostasis All living things, from single cells to entire organisms, have mecha- nisms that allow them to maintain stable internal conditions. Without these mechanisms, organisms can die. For example, a cell’s water content is closely controlled by the taking in or releas- ing of water. A cell that takes in too much water will rupture and die. A cell that doesn’t get enough water will also shrivel and die. Homeostasis (HOH-mee-OH-STAY-sis) is the maintenance of a stable level of internal conditions even though environmental conditions are constantly changing. Organisms have regulatory systems that maintain internal conditions, such as temperature, water content, and uptake of nutrients by the cell. In fact, multi- cellular organisms usually have more than one way of maintain- ing important aspects of their internal environment. For example, an owl’s temperature is maintained at about 40°C (104°F). To keep a constant temperature, an owl’s cells burn fuel to produce body heat. In addition, an owl’s feathers can fluff up in cold weather. In this way, they trap an insulating layer of air next to the bird’s body to maintain its body temperature. Metabolism Living organisms use energy to power all the life processes, such as repair, movement, and growth. This energy use depends on metabolism (muh-TAB-uh-LIZ-uhm). Metabolism is the sum of all the chemical reactions that take in and transform energy and materials from the environment. For example, plants, algae, and some bacteria use the sun’s energy to generate sugar molecules during a process called photosynthesis. Some organisms depend on obtaining food energy from other organisms. For instance, an owl’s metabolism allows the owl to extract and modify the chemi- cals trapped in its nightly prey and use them as energy to fuel activities and growth. Growth and Development All living things grow and increase in size. Some nonliving things, such as crystals or icicles, grow by accumulating more of the same material of which they are made. In contrast, the growth of living things results from the division and enlargement of cells. Cell division is the formation of two new cells from an existing cell, as shown in Figure 1-3. In unicellular organisms, the primary change that occurs following cell division is cell enlargement. In multi- cellular life, however, organisms mature through cell division, cell enlargement, and development. Development is the process by which an organism becomes a mature adult. Development involves cell division and cell differen- tiation, or specialization. As a result of development, an adult organism is composed of many cells specialized for different func- tions, such as carrying oxygen in the blood or hearing. In fact, the human body is composed of trillions of specialized cells, all of which originated from a single cell, the fertilized egg. This unicellular organism, Escherichia coli, inhabits the human intestines. E. coli reproduces by means of cell division, during which the original cell splits into two identical offspring cells. FIGURE 1-3 Observing Homeostasis Materials 500 mL beakers (3), wax pen, tap water, thermometer, ice, hot water, goldfish, small dip net, watch or clock with a second hand Procedure 1. Use a wax pen to label three 500 mL beakers as follows: 27°C (80°F), 20°C (68°F), 10°C (50°F). Put 250 mL of tap water in each beaker. Use hot water or ice to adjust the tem- perature of the water in each beaker to match the temperature on the label. 2. Put the goldfish in the beaker of 27°C water. Record the number of times the gills move in 1 minute. 3. Move the goldfish to the beaker of 20°C water. Repeat observations. Move the goldfish to the beaker of 10°C. Repeat observations. Analysis What happens to the rate at which gills move when the temp- erature changes? Why? How do gills help fish maintain homeostasis? Quick Lab mb06se_bios01.qxd 5/18/07 10:37 AM Page 8 THE SCIENCE OF LIFE 9 Reproduction All organisms produce new organisms like themselves in a process called reproduction. Reproduction, unlike other characteristics, is not essential to the survival of an individual organism. However, because no organism lives forever, reproduction is essential for the continuation of a species. Glass frogs, as shown in Figure 1-4, lay many eggs in their lifetime. However, only a few of the frogs’ off- spring reach adulthood and successfully reproduce. During reproduction, organisms transmit hereditary informa- tion to their offspring. Hereditary information is encoded in a large molecule called deoxyribonucleic acid, or DNA. A short segment of DNA that contains the instructions for a single trait of an organism is called a gene. DNA is like a large library. It contains all the books—genes—that the cell will ever need for making all the struc- tures and chemicals necessary for life. Hereditary information is transferred to offspring during two kinds of reproduction. In sexual reproduction, hereditary information recombines from two organisms of the same species. The resulting offspring are similar but not identical to their parents. For example, a male frog’s sperm can fertilize a female’s egg and form a single fer- tilized egg cell. The fertilized egg then develops into a new frog. In asexual reproduction, hereditary information from different organisms is not combined; thus the original organism and the new organism are genetically the same. A bacterium, for example, reproduces asexually when it splits into two identical cells. Change Through Time Although individual organisms experience many changes during their lifetime, their basic genetic characteristics do not change. However, populations of living organisms evolve or change through time. The ability of populations of organisms to change over time is important for survival in a changing world. This factor is also impor- tant in explaining the diversity of life-forms we see on Earth today. 1. How does biology affect a person’s daily life? 2. How does biology affect society? 3. Name the characteristics shared by living things. 4. Summarize the hierarchy of organization found in complex multicellular organisms. 5. What are the different functions of homeostasis and metabolism in living organisms? 6. How does the growth among living and nonliv- ing things differ? 7. Why is reproduction an important characteristic of life? CRITICAL THINKING 8. Applying Information Crystals of salt grow and are highly organized. Why don’t biologists con- sider them to be alive? 9. Analyzing Models When a scientist designs a space probe to detect life on a distant planet, what kinds of things should it measure? 10. Making Comparisons Both cells and organisms share the characteristics of life. How are cells and organismsood supply will be like in the near future.EVOLUTION OF LIFE Individual organisms change during their lifetime, but their basic genetic characteristics do not change. However, populations of liv- ing organisms do change through time, or evolve. Evolution, or descent with modification, is the process in which the inherited characteristics within populations change over generations, such that genetically distinct populations and new species can develop. Evolution as a theme in biology helps us understand how the various branches of the “tree of life” came into existence and have changed over time. It also explains how organisms alive today are related to those that lived in the past. Finally, it helps us understand the mechanisms that underlie the way organisms look and behave. Natural Selection The ability of populations of organisms to change over time is important for survival in a changing world. According to the theory of evolution by natural selection, organisms that have certain favorable traits are better able to survive and reproduce success- fully than organisms that lack these traits. One product of natural selection is the adaptation of organisms to their environment. Adaptations are traits that improve an indi- vidual’s ability to survive and reproduce. For example, rabbits with white fur and short ears in a snowy place, such as the one in Figure 1-7a, may avoid predators and frostbitten ears more often than those with dark fur and long ears. Thus, the next generation of rabbits will have a greater percentage of animals carrying the genes for white fur and short ears. In contrast, the brown, long- eared rabbit, as shown in Figure 1-7b, would survive and reproduce more successfully in a hot desert environment. The survival and reproductive success of organisms with favor- able traits cause a change in populations of organisms over gener- ations. This descent with modification is an important factor in explaining the diversity of organisms we see on Earth today. 1. Name three unifying themes found in biology. 2. How is the unity and diversity in the living world represented? 3. Identify the three domains and the kingdoms found in each domain. 4. How are organisms interdependent? 5. Describe why evolution is important in explain- ing the diversity of life. 6. Distinguish between evolution and natural selection. CRITICAL THINKING 7. Applying Information Assign the various top- pings you put on pizza to the appropriate domains and kingdoms of life. 8. Analyzing Graphics According to the “tree” in Figure 1-5, which of these pairs are more closely related: Archaea:Bacteria or Archaea:Eukarya? 9. Making Hypotheses Fossil evidence shows that bats descended from shrewlike organisms that could not fly. Write a hypothesis for how natural selection might have led to flying bats. SECTION 2 REVIEW (a) This short-eared arctic hare, Lepus arcticus, is hidden from predators and protected from frostbite in a snowy environment. (b) The mottled brown coats of desert rabbits blend in with the dirt and dry grasses, and their long ears help them radiate excess heat and thus avoid overheating. FIGURE 1-7 (a) (b) Copyright © by Holt, Rinehart and Winston. All rights reserved. THE SCIENCE OF LIFE 13 TH E STUDY OF BIOLOGY Curiosity leads us to ask questions about life. Science provides a way of answering such questions about the natural world. Science is a systematic method that involves forming and testing hypotheses. More importantly, science relies on evidence, not beliefs, for drawing conclusions. SCIENCE AS A PROCESS Science is characterized by an organized approach, called the scientific method, to learn how the natural world works. The methods of science are based on two important principles. The first principle is that events in the natural world have natural causes. For example, the ancient Greeks believed that lightning and thunder occurred because a supernatural god Zeus hurled thunderbolts from the heavens. By contrast, a scientist considers lightning and thunder to result from electric charges in the atmos- phere. When trying to solve a puzzle from nature, all scientists, such as the one in Figure 1-8, accept that there is a natural cause to solve that puzzle. A second principle of science is uniformity. Uniformity is the idea that the fundamental laws of nature operate the same way at all places and at all times. For example, scientists assume that the law of gravity works the same way on Mars as it does on Earth. Steps of the Scientific Method Although there is no single method for doing science, scientific studies involve a series of common steps. 1. The process of science begins with an observation. An observation is the act of perceiving a natural occurrence that causes someone to pose a question. 2. One tries to answer the question by forming hypotheses (singular, hypothesis). A hypothesis is a proposed explanation for the way a particular aspect of the natural world functions. 3. A prediction is a statement that forecasts what would happen in a test situation if the hypothesis were true. A prediction is recorded for each hypothesis. 4. An experiment is used to test a hypothesis and its predictions. 5. Once the experiment has been concluded, the data are analyzed and used to draw conclusions. 6. After the data have been analyzed, the data and conclusions are communicated to scientific peers and to the public. This way oth- ers can verify, reject, or modify the researcher’s conclusions. SECTION 3 OBJECTIVES ● Outline the main steps in the scientific method. ● Summarize how observations are used to form hypotheses. ● List the elements of a controlled experiment. ● Describe how scientists use data to draw conclusions. ● Compare a scientific hypothesis and a scientific theory. ● State how communication in science helps prevent dishonesty and bias. VOCABULARY scientific method observation hypothesis prediction experiment control group experimental group independent variable dependent variable theory peer review All researchers, such as the one releasing an owl above, use the scientific method to answer the questions they have about nature. FIGURE 1-8 Copyright © by Holt, Rinehart and Winston. All rights reserved. 14 CHAPTER 1 OBSERVING AND ASKING QUESTIONS The scientific method generally begins with an unexplained observa- tion about nature. For example, people have noticed for thousands of years that owls can catch prey in near total darkness. As shown in steps and of Figure 1-9, an observation may then raise ques- tions. The owl observation raises the question: How does an owl detect prey in the dark? FORMING A HYPOTHESIS After stating a question, a biologist lists possible answers to a sci- entific question—hypotheses. Good hypotheses answer a question and are testable in the natural world. For example, as shown in step Figure 1-9, there are several possible hypotheses for the question of how owls hunt at night: (a) owls hunt by keen vision in the dark; (b) owls hunt by superb hearing; or (c) owls hunt by detecting the prey’s body heat. Predicting To test a hypothesis, scientists make a prediction that logically fol- lows from the hypothesis. A prediction is what is expected to hap- pen if each hypothesis were true. For example, if hypothesis (a) is true, (owls hunt by keen night vision) then one can predict that the owl will pounce only on the mouse in either a light or a dark room. If hypothesis (b) is true (owls hunt by hearing), then one can pre- dict that in a lighted room, the owl will pounce closer to the mouse’s head. But, in a dark room, the owl should pounce closer to a rustling leaf attached to the mouse. Finally, if hypothesis (c) is true (owls hunt by sensing body heat), then an owl would strike only the prey no matter the room conditions, because owls hunt by detecting the prey’s body heat. 3 1 2 Copyright © by Holt, Rinehart and Winston. All rights reserved. A scientific study includes observations, questions, hypotheses, predictions, experiments, data analysis, and conclu- sions. A biologist can use the scientific method to set up an experiment to learn how an owl captures prey at night. FIGURE 1-9 1 OBSERVATION Owls capture prey on dark nights. 2 QUESTION How do owls detect prey on dark nights? 3 HYPOTHESES a) Owls hunt in the dark by vision. b) Owls hunt in the dark by hearing. c) Owls hunt in the dark by sensing body heat. THE SCIENCE OF LIFE 15 Notice that these predictions make it difficult to distinguish be- tween the vision and body heat hypotheses. The reason is that both hypotheses predict that the owl could grab the mouse in a dark room. Also, these three hypotheses do not eliminate all other factors that could influence how the owl finds its prey. However, testing predictions can allow one to begin rejecting hypotheses and thus to get closer to determining the answer(s) to a question. DESIGNING AN EXPERIMENT Biologists often test hypotheses by setting up an experiment. Step in Figure 1-9 outlines an experiment to test the hypotheses about how an owl hunts at night. First, experimenters set up a room with an owl perch high on one side and a small trap door on the other side for releasing mice. Then, they tied a leaf to each mouse’s tail with a string and released each mouse into the room. Next, each mouse ran silently across the room, but the leaf trailed behind, making a rustling noise. During half of the trials, the lights were on. During the other half, the room was dark. Technicians videotaped all the action in the chamber with an infrared light, which owls cannot see. The researchers then viewed the videos and measured the position of the owl’s strike relative to each mouse’s head. Performing the Experiment Many scientists use a controlled experiment to test their hypotheses. A controlled experiment compares an experimental group and a control group and only has one variable. The control group pro- vides a normal standard against which the biologist can compare results of the experimental group. The experimental group is iden- tical to the control group except for one factor, the independent variable. The experimenter manipulates the independent variable, sometimes called the manipulated variable. 4 4 EXPERIMENT 5 DATA COLLECTION AND ANALYSIS Measure and compare the distance from the owl’s strike to the mouse and to the leaf in light and dark. 6 CONCLUSION Data supported the hearing hypothesis: Owls hunt in the dark by hearing. prey Test predictions of the three hypotheses. Control: In the light Experimental: In the dark 1 2 3 4 5 6 7 8 9 10 11 Predicting Results Materials 2 Petri dishes with agar, cellophane tape, wax pen Procedure 1. Open one of the Petri dishes, and streak your finger across the surface of the agar. 2. Replace the lid, and seal it with the tape. Label this Petri dish with your name and a number 1. 3. Seal the second Petri dish with- out removing the lid. Label this Petri dish with your name and the number 2. 4. Write a prediction about what will happen in each dish. Store your dishes as your teacher directs. Record your observations. Follow your teacher’s directions for disposal of your dishes. Analysis Was your prediction accurate? What evidence can you cite to support your prediction? If you did not obtain the results you predicted, would you change your testing method or your prediction? Explain. Evaluate the importance of obtaining a result that does not support your prediction. Quick Lab mb06se_bios03.qxd 5/18/07 10:40 AM Page 15 16 CHAPTER 1 The independent variable in the owl experiment is the presence or absence of light. In the owl experiment, the control group hunts in the light, and the experimental group hunts in the dark. In addi- tion to varying the independent variable, a scientist observes or measures another factor called the dependent variable, or respond- ing variable, because it is affected by the independent variable. In the owl experiment, the dependent variable is distance from the owl’s strike to the mouse’s head. Testing the Experiment Some controlled experiments are conducted “blind.” In other words, the biologist who scores the results is unaware of whether a given subject is part of the experimental or control group. This factor helps eliminate experimenter bias. Experiments should also be repeated, because living systems are variable. Moreover, scien- tists must collect enough data to find meaningful results. COLLECTING AND ANALYZING DATA Most experiments measure a variable—the dependent variable. This measurement provides quantitative data, data measured in numbers. For example, in the experiment above, scientists mea- sured the distance of an owl’s strike from the prey’s head in cen- timeters, as shown in step of Figure 1-9. An event’s duration in milliseconds is also an example of quantitative data. Biologists usually score the results of an experiment by using one of their senses. They might see or hear the results of an experiment. Scientists also extend their senses with a micro- scope for tiny objects or a microphone for soft sounds. In the owl experiment, biologists extended their vision with infrared cameras. Analyzing and Comparing Data After collecting data from a field study or an experiment and then organizing it, biologists then analyze the data. In analyzing data, the goal is to determine whether the data are reliable, and whether they support or fail to support the predictions of the hypothesis. To do so, scientists may use statistics to help determine relation- ships between the variables involved. They can then compare their data with other data that were obtained in other similar studies. It is also important at this time to determine possible sources of error in the experiment just per- formed. Scientists usually display their data in tables or graphs when analyzing it. For the owl study, biologists could have made a bar graph such as the one in Figure 1-10, which shows the average distance from the owl’s strike relative to the mouse’s head or the leaf in the light and in the dark. 5 5 0 10 15 20 25 In the light In the dark Average distance from strike (cm) Distance Between Owl Strike and a Mouse or From a Leaf Attached to Mouse 30 Mouse Leaf Mouse Leaf The data below are hypothetical results that might occur from the described owl experiment.The independent variable is the darkness of the room, and the dependent variable is how far the owl struck from the mouse’s head.The data show that the owl strikes more accurately at the mouse in the light but strikes more accurately at the leaf in the dark. FIGURE 1-10 Copyright © by Holt, Rinehart and Winston. All rights reserved. THE SCIENCE OF LIFE 17 DRAWING CONCLUSIONS Biologists analyze their tables, graphs, and charts to draw conclu- sions about whether or not a hypothesis is supported, as shown in step of Figure 1-9. The hypothetical owl data show that in the light, owls struck with greater accuracy at the mouse than at the leaf, but in the dark, owls struck with greater accuracy at the leaf than the mouse. Thus, the findings support the hearing hypothe- sis, but not the vision hypothesis. An experiment can only disprove, not prove, a hypothesis. For example, one cannot conclude from the results that the hearing hypothesis is proven to be true. Perhaps the owl uses an unknown smell to strike at the mouse. One can only reject the vision hypothe- sis because it did not predict the results of the experiment correctly. Acceptance of a hypothesis is always tentative in science. The scientific community revises its understanding of phenomena, based on new data. Having ruled out one hypothesis, a biologist will devise more tests to try to rule out any remaining hypotheses. Making Inferences Scientists often draw inferences from data gathered during a field study or experiment. An inference (IN-fuhr-uhns) is a conclusion made on the basis of facts and previous knowledge rather than on direct observations. Unlike a hypothesis, an inference is not directly testable. In the owl study, it is inferred that the owl detects prey from a distance rather than by direct touch. Applying Results and Building Models As shown in Figure 1-11, scientists often apply their findings to solve practical problems. They also build models to represent or describe things. For example in 1953, James Watson and Francis Crick used cardboard balls and wire bars to build physical models of atoms in an attempt to understand the structure of DNA. Mathematical models are sets of equations that describe how dif- ferent measurable items interact in a system. The experimenter can adjust variables to better model the real-world data. CONSTRUCTING A THEORY When a set of related hypotheses is confirmed to be true many times, and it can explain a great amount of data, scientists often reclassify it as a theory. Some examples include the quantum the- ory, the cell theory, or the theory of evolution. People commonly use the word “theory” in a different way than scientists use the word. People may say “It’s just a theory” suggesting that an idea is untested, but scientists view a theory as a highly tested, generally accepted principle that explains a vast number of observations and experimental data. 6 Copyright © by Holt, Rinehart and Winston. All rights reserved. Biologists often apply their knowledge of the natural world to practical problems. Studies on the owl’s keen ability to locate sounds in space despite background noise are helping biotechnologists and bioengineers develop better solutions for people with impaired hearing, such as the people shown in this picture. FIGURE 1-11 18 CHAPTER 1 COMMUNICATING IDEAS An essential aspect of scientific research is scientists working together. Scientists often work together in research teams or sim- ply share research results with other scientists. This is done by publishing findings in scientific journals or presenting them at sci- entific meetings, as shown in Figure 1-12. Sharing information allows others working independently to verify findings or to con- tinue work on established results. For example, Roger Payne pub- lished the results of his owl experiments in a journal in 1971. Then, other biologists could repeat it for verification or use it to study the mechanisms introduced by the paper. With the growing impor- tance of science in solving societal issues, it is becoming increas- ingly vital for scientists to be able to communicate with the public at large. Publishing a Paper Scientists submit research papers to scientific journals for publica- tion. A typical research paper has four sections. First, the Introduction poses the problem and hypotheses to be investigated. Next, the Materials and Methods describe how researchers proceeded with the experiment. Third, the Results state the findings the experiment presented, and finally, the Discussion gives the significance of the experiment and future directions the scientists will take. Job Description Forensic biolo- gists are scientists who study biological materials to investigate potential crimes and other legal issues against humans and animals. Forensic scientists have knowledge in areas of biology, such as DNA and blood pattern analysis, and work in private sector and public laboratories. Focus On a Forensic Biologist As a law enforcement forensic specialist for the Texas Parks and Wildlife Department, Beverly Villarreal assists the game warden in investigations of fish and wildlife violations, such as illegal hunting and fishing. Villarreal analyzes blood and tissue samples to identify species of animals such as fish, birds, and reptiles. Her work helps game wardens as they enforce state laws regarding hunting and fishing. Most people think of forensic scientists as the glamorous crime investigators on TV, but according to Villarreal real forensic scientists “spend a great deal of time at a lab bench running analysis after analysis.” Many of the methods used in animal forensics, such as DNA sequenc- ing, are also used in human forensics. Education and Skills • High school—three years of science courses and four years of math courses. • College—bachelor of science in biol- ogy, including course work in zoology and genetics, plus experience in per- forming DNA analyses. • Skills—patience, attention to detail, and ability to use fine tools. Careers in BIOLOGY Forensic Biologist For more about careers, visit go.hrw.com and type in the keyword HM6 Careers. www.scilinks.org Topic: Scientific Investigations Keyword: HM61358 mb06se_bios03.qxd 5/18/07 10:40 AM Page 18 THE SCIENCE OF LIFE 19 1. What two principles make the scientific method a unique process? 2. Define the roles of observations and hypotheses in science. 3. Summarize the parts of a controlled experiment. 4. Summarize how we make conclusions about the results of an experiment. 5. Why is the phrase, “it’s just a theory” misleading? 6. Give another example of a conflict of interest. CRITICAL THINKING 7. Making Hypotheses On a nocturnal owl’s skull, one ear points up, and the other ear points down. Suggest a hypothesis for this observation. 8. Designing Experiments Design an experiment to establish if owls hunt by keen sight or hunt by heat seeking. 9. Calculating Information What was the average distance between the owl’s strike and the mouse if the recorded differences in this experiment were 25, 22, 19, 19, and 15? SECTION 3 REVIEW After scientists submit their papers to a scientific journal, the editors of that journal will send the paper out for peer review. In a peer review, scientists who are experts in the field anonymously read and critique that research paper. They determine if a paper pro- vides enough information so that the experiment can be duplicated and if the author used good experimental controls and reached an accurate conclusion. They also check if the paper is written clearly enough for broad understanding. Careful analysis of each other’s research by fellow scientists is essential to making scientific progress and preventing scientific dishonesty. HONESTY AND BIAS The scientific community depends on both honesty and good sci- ence. While designing new studies, experimenters must be very careful to prevent previous ideas and biases from tainting both the experimental process and the conclusions. Scientists have to keep in mind that they are always trying to disprove their favorite ideas. Scientists repeat experiments to verify previous findings. This allows for science to have a method for self-correction and it also keeps researchers honest and credible to their peers in the field. Conflict of Interest For most scientists, maintaining a good reputation for collecting and presenting valid data is more important than temporary prestige or income. So, scientists try to avoid any potential conflicts of interest. For example, a scientist who owns a biotechnology company and manufactures a drug would not be the best researcher to critically test that drug’s safety and effectiveness. To avoid this potential con- flict of interest, the scientist allows an unaffected party, such as a research group, to test the drug’s effectiveness. The threat of a potential scandal based on misleading data or conclusions is a pow- erful force in science that helps keep scientists honest and fair. Scientists present their experiments in various forms. The scientists above are presenting their work in the form of a poster at a scientific meeting. FIGURE 1-12 Copyright © by Holt, Rinehart and Winston. All rights reserved. The Internet can provide a wealth of scientific information for a report, but the information may not always be credible or accurate. You can use the methods above to check the accuracy and credibility of your sources. SCIENCE TECHNOLOGY SOCIETY SCIENCE ON THE INTERNET: A New Information Age I n the past, students research- ing a science topic would typ- ically begin their research by visiting a library to use printed reference materials, such as encyclopedias. Today, most stu- dents research topics by using a computer and searching for information on the Internet. The Internet can provide students with a wealth of infor- mation. But which Web sites have accurate information, and which Web sites do not? Checking Web Addresses Students should use the Web address, or URL, to establish the Web site’s credibility. Usually, the domain name can suggest who has published the Web site. Web sites can be pub- lished by governmental agen- cies (ends in “dot gov” or .gov), by educational institutions (ends in “dot edu” or .edu), by organizations (ends in “dot org” or .org), or by commercial businesses (ends in “dot com” or .com). Government Web sites are usually reliable. Examples of credible governmental Web sites are the National Institutes of Health (NIH) and the Food and Drug Administration (FDA). University and medical school sites are also reliable sources of information. Many organiza- tions that research and teach the public about specific diseases and conditions can also provide reliable information. Examples of such organizations are the American Cancer Society and the American Heart Association. Evaluating Web Sites The credibility of the author of the Web site should also be checked. Make sure the author is not trying to sell anything and is established in his or her field. For example, a health Web site’s author should be a med- ical professional. It is also important to check the date that the information was posted on the Web to ensure that the information is current. Also, the Web site should provide ref- erences from valid sources, such as scientific journals or govern- ment publications. Finally, the student should always double-check informa- tion between several reliable Web sites. If two or three reliable sites provide the same informa- tion, the student can feel confi- dent in using that information. Web Sites for Students The Internet Connect boxes in this textbook have all been reviewed by professionals at the National Science Teachers Association (NSTA). Students can trust that these sites are reliable sources for science- or health-related topics. REVIEW 1. Which types of Web addresses are the most reliable? 2. List four important features to evaluate when using a Web site for research. 3. Supporting Reasoned Opinions Why do you think a Web site that is advertising a product may not offer accurate information? REVIEW 20 www.scilinks.org Topic: Using the Internet Keyword: HM61589 mb06se_biosts.qxd 5/18/07 10:42 AM Page 20 TOOLS AND TECHNIQUES With proper equipment and good methods, biologists can see, manipulate, and understand the natural world in new ways. Microscopes are one of many useful tools used to unlock nature’s biological secrets. MICROSCOPES AS TOOLS Tools are objects used to improve the performance of a task. Microscopes are tools that extend human vision by making enlarged images of objects. Biologists use microscopes to study organisms, cells, cell parts, and molecules. Microscopes reveal details that otherwise might be difficult or impossible to see. Light Microscopes To see small organisms and cells, biologists typically use a light microscope, such as the one shown in Figure 1-13. A compound light microscope is a microscope that shines light through a spec- imen and has two lenses to magnify an image. To use this micro- scope, one first mounts the specimen to be viewed on a glass slide. The specimen must be thin enough for light to pass through it. For tiny pond organisms, such as the single-celled paramecium, light passing through the organism is not a problem. For thick objects, such as plant stems, biologists must cut thin slices for viewing. There are four major parts of a compound light microscope. For further description of the parts of a micro- scope, see the Appendix. 1. Eyepiece The eyepiece (ocular (AHK-yoo-luhr) lens) magnifies the image, usually 10 times. 2. Objective Lens Light passes through the specimen and then through the objective lens, which is located directly above the specimen. The objective lens enlarges the image of the specimen. Scientists sometimes use stains to make the image easier to see. 3. Stage The stage is a platform that supports a slide holding the specimen. The slide is placed over the opening in the stage of the microscope. 4. Light Source The light source is a light bulb that provides light for viewing the image. It can be either light reflected with a mirror or an incandescent light from a small lamp. SECTION 4 OBJECTIVES ● List the function of each of the major parts of a compound light microscope. ● Compare two kinds of electron microscopes. ● Describe the importance of having the SI system of measurement. ● State some examples of good laboratory practice. VOCABULARY compound light microscope eyepiece (ocular lens) objective lens stage light source magnification nosepiece resolution scanning electron microscope transmission electron microscope metric system base unit Compound light microscopes open the human eye to an interesting world including tiny pond organisms, healthy and diseased cells, and the functioning of cell parts. FIGURE 1-13 Objective lens Eyepiece (ocular lens) Stage Light THE SCIENCE OF LIFE 21 Copyright © by Holt, Rinehart and Winston. All rights reserved. 22 CHAPTER 1 Magnification and Resolution Microscopes vary in powers of magnification and resolution. Magnification is the increase of an object’s apparent size. Revolving the nosepiece, the structure that holds the set of objective lens, rotates these lenses into place above the specimen. In a typical com- pound light microscope, the most powerful objective lens produces an image up to 100 times (100) the specimen’s actual size. The degree of enlargement is called the power of magnification of the lens. The standard ocular lens magnifies a specimen 10 times (10). To compute the power of magnification of a microscope, the power of magnification of the strongest objective lens (in this case, 100) is multiplied by the power of magnification of the ocular lens (10). The result is a total power of magnification of 1000. Resolution (REZ-uh-LOO-shuhn) is the power to show details clearly in an image. The physical properties of light limit the ability of light microscopes to resolve images, as shown in Figure 1-14a. At pow- ers of magnification beyond about 2,000, the image of the speci- men becomes fuzzy. For this reason, scientists use other microscopes to view very small cells
LESSON 1 Origin of Life on Earth Learning Objectives • Describe how Earth was formed. • Describe the events that happened during Earth's formation. When and where did life possibly start? Many cultures develop different versions about the origin of life. However, modern scientists are still exploring the works of some well-known experts in the history of science in search of the true origin of life. Earth is said to be a little over 4.5 billion years (Gigaannum or Ga) old. The oldest material found on Earth that is estimated to be 4.3 billion years old is a zircon crystal. No one witnessed how Earth was formed and what exactly happened during that moment, but there are evidence that show how it all started. Earth's earliest times were geologically violent. There were continuous bombardment from meteorites. As Earth cooled and the surface solidified, the first solid rocks formed. Continents were not yet present; only a huge ocean with scattered small islands. Events such as erosion, sedimentation, and volcanic activities that were assisted by possible meteor impacts, gradually created the oceanic plates, which later evolved into continents. About 3.8 Ga, life on Earth initially began with single-celled organisms called prokaryotes. Over a billion year later, multicellular life evolved. Some studies show that life-forms began to evolve around 570 million years ago (Ma). This evolution started with early arthropods, followed by the fish (530 Ma), and land plants and forests (475 Ma and 385 Ma, respectively). It was only at around 200 Ma that early mammals emerged. Homo sapiens is believed to have evolved about 200000 years ago. Many things were revealed using fossil evidence, yet many questions remain unanswered about the origin of life. Science is continuously searching for answers on what was in the beginning.
New Trends in Agriculture Extension approaches Extension has been, and still is, under attack from a wide spectrum of politicians and economists over its cost and financing. As a result, Extension Systems have had to make changes, by restating the system’s mission, developing a new vision for the future, and formulating plans for the necessary transition to achieve the desired change. 1. Privatization of Agricultural Extension Service Privatization: Process of funding and delivering the extension services by private individual or organization is called Private Extension. Concept: Privatization of extension refers to services rendered in rural area & allied aspects of extension personnel working in private agencies or organization for which farmers are expected to pay a fee & it can be viewed as supplementary or alternative to public extension services (Sarvanan & Shivalinge 1980). Privatization approaches ➢ Share cropping system ➢ Village extension contract system ➢ Public extension through private delivery ➢ Service for vouchers Strengths of Private Extension System ➢ More demand - driven rather than supply – driven ➢ High quality of services in terms of satisfying information needs of clientele, trained manpower, sustained finances and resource allocation ➢ Provides for an information mix and choices available to farmers ➢ Enhanced efficiency of staff ➢ Assure continuous supply and quality agricultural products ➢ More effective because farmer can select an adviser who is the best able to help ➢ Healthy competition among service provider will lead to better quality and lower costs for service Weakness of Private Extension System ➢ Concentrate on area having favorable physical environment ➢ More face-to-face contacts (person oriented) ➢ Increased dependence of farmers and hence exploitation ➢ No education role ➢ Deprivation of small farmers ➢ Hamper the free flow of information 2. Cyber Extension or e-extension Concepts Cyber space: it is the imaginary or virtual space of computers connected with each other on Networks, across the Globe. Cyber extension: it means 'using the power of online networks, computer communications and digital interactive multimedia to facilitate dissemination of agriculture technology. Cyber Extension thus can be defined as the extension over cyber space. Important tools of cyber extension E-Mail, Telnet, File Transfer Protocol (FTP), Gopher, Archie and World Wide Web (WWW) Strengths of Cyber Extension ➢ Access to the astounding information and continuously available ➢ Information rich and instantaneously available of information ➢ Interactive communication ➢ The information is available from any point on the globe ➢ Communication is dynamic ➢ Cut steps from traditional process ➢ Save money, time and effort ➢ Multiplicity of purpose Issues and Concerns of Cyber Extension ➢ Lack of Reliable Telecom Infrastructure in Rural Areas ➢ Erratic or no Power Supply ➢ Lack of ICT Trained manpower (willing to serve) in Rural Areas ➢ Lack of content (locally relevant and in local languages) ➢ Lack of Information Services to Rural Clientele ➢ Low Purchasing power of the Rural communities ➢ Lack of Holistic Approaches ➢ Issues of Sustainability Application of cyber extension ➢ Village information shops Dr. M.S. SwaminathanResearch Foundation, Chennai ➢ Information villagers MANAGE in Ranga Reddy District in Andhra pradesh ➢ Gyandoot net initiative of District Dhar, Madhya Pradesh. ➢ Warna wired village of National Informatics Center (NIC) in Kolhapur- Sangli Districts of Maharashtra 3. Market-Led-Extension (MLE) Concepts Market: A congregation of prospective buyers & sellers with a common motive of trading a particular commodity. Extension: It is the spreading/reaching out to the mass Market-led-extension: Agriculture & economics coupled with extension is the perfect blend for reaching at the door steps of common man with the help of technology. Dimensions of market-led extension ➢ Marketing mix: A planned mix of the controllable elements of a product's marketing plan commonly termed as 4Ps: product, price, place, and promotion. These four elements are adjusted until the right combination is found that serves the needs of the product's customers, while generating optimum income. ➢ Marketing plan: A marketing plan is a comprehensive document that outlines a business and marketing efforts for the coming year. It describes business activities involved in accomplishing specific marketing objectives within a set time frame. A marketing plan also includes a description of the current marketing position of a business, a discussion of the target market and a description of the marketing mix that a business will use to achieve their marketing goals. ➢ Market Intelligence: It is the information relevant to a company’s markets, gathered and analyzed specifically for the purpose of accurate and confident decision making. Market intelligence includes the process of gathering data from the company’s external environment, whereas the business intelligence process is primarily based on internal recorded events – such as sales, shipments and purchases. ➢ Market oriented production ➢ Use of Technology Strengths of market-led extension ➢ SWOT analysis of the market ➢ Organization of Farmers’ Interest Groups (FIGs) ➢ Enhancing the interactive and communication skills of the farmers ➢ Establishing marketing and agro-processing linkages ➢ Advice on product planning ➢ Educating the farming community ➢ Direct marketing ➢ Acquiring complete market intelligence ➢ Publication of agricultural market information Production of video films of success stories ➢ Challenges to market-led extension ➢ Gigantic size of extension system ➢ Information technology Diverse conditions ➢ Market intelligence ➢ Reforms in agricultural extension system Government Initiatives ➢ Central warehousing Corporation-1965 ➢ MSP by Commission for Agricultural Cost and Price (CACP) ➢ Food Corporation of India ➢ Then some others as: Cotton Corporation of India (CCI), Jute Corporation of India (JCI), National Dairy Development Board (NDDB), Agriculture and Processed food Export Development Authority (APEDA) etc. 4. Farmer--Led-Extension (FLE) Farmer--led-extension is defined as 'the provision of training by farmers to farmers, often through the creation of a structure of farmer promoters and farmer trainers' (Scarborough et al., 1997). Philosophy and principles ➢ Farmers and local institutions (e.g. producer organizations or village leaders) should play a key role in selecting farmer-trainers and monitoring and evaluating them. This helps make the programmes more accountable to the community or groups that they serve. ➢ Farmer-trainers are ‘of the community’; they communicate in local languages and are more sensitive to local cultures, mannerisms, farming practices, and farmers’ needs. ➢ Farmer-trainers should be selected on the basis of their skills and interest in sharing information, not just on their farming expertise. ➢ Farmer-trainers need strong linkages with and support from development agents (whether government, non-government organization (NGO), or private), the people who train and backstop them. Farmer-trainers generally serve as a complement to existing extension systems, rather than being a substitute for them. ➢ Facilitating organizations and local institutions need to be proactive in ensuring that women as well as men become farmer-trainers. ➢ Simple and appropriate reference materials should be made available to the farmer trainers. Essential Elements of Farmer--led-extension ➢ The group ➢ The Field ➢ The Facilitator ➢ The curriculum ➢ Programme leader ➢ Financing Special features of Farmer--led-extension ➢ All learning is field based & it is primary venue for learning ➢ FLE group learning constantly over the experimentation period ➢ FLE promotes healthy decisions & quality decisions ➢ Farmers conduct their own field studies with comparisons or treatments ➢ Facilitates Farmer-to-Farmer communication ➢ Field staff serve as facilitators ➢ FLE is a unique way to educate farmers ➢ It is an effective platform for sharing of experiences and collectively solving agriculture related problems. 5. Expert system Expert system is an intelligent computer program that uses knowledge and inferences procedures to solve problems (Daniel Hunt, 1986). Objectives of developing expert system ➢ To enhance the performance of agricultural extension personnel and farmer ➢ To make farming more efficient and profitable ➢ To reduce the time required in solving the problems ➢ To maintain the expert system by continuously upgrading the database Advantages of expert system ➢ Solves critical problems by making logical deductions without taking much time ➢ It combines experimental and conventional knowledge with the reasoning skills of specialists ➢ To enhance the performance of average worker to the level of an expert Limitations of expert system ➢ Expensive computer program ➢ Mostly developed not in regional languages ➢ Requires AC power and internet connection all the time ➢ Complex software requires computer skilled personnel Modules of expert system in agriculture ➢ COMAX: Integrated crop management in cotton ➢ SOYEX: Soybean oil extraction expert system ➢ PLANT/ds: Diagnosis of soybean diseases ➢ MAIZE: Maize expert system for field crop management ➢ SEMAGI: Weed control decision making in sunflowers ➢ Rice Crop Doctor: Developed by National Institute of Agricultural Extension Management (MANAGE) Difference between conventional and expert system of extension Conventional Extension ➢ Universal approachability of same information is a problem ➢ Information is given whatever is available without considering needs and resources ➢ No Cost benefit analysis ➢ Information flow depends on availability of agent ➢ Require users to draw their own conclusion from facts Expert System of Extension ➢ Universal approachability of same information is possible ➢ Information is chosen based on their needs and resources ➢ Cost benefit analysis ➢ Information through Cyber Cafe at any place at any time ➢ Conclusion is drawn based on the decision given by the expert
Translator: Joseph Geni Reviewer: Morton Bast Before March, 2011, I was a photographic retoucher based in New York City. We're pale, gray creatures. We hide in dark, windowless rooms, and generally avoid sunlight. We make skinny models skinnier, perfect skin more perfect, and the impossible possible, and we get criticized in the press all the time, but some of us are actually talented artists with years of experience and a real appreciation for images and photography. On March 11, 2011, I watched from home, as the rest of the world did, as the tragic events unfolded in Japan. Soon after, an organization I volunteer with, All Hands Volunteers, were on the ground, within days, working as part of the response efforts. I, along with hundreds of other volunteers, knew we couldn't just sit at home, so I decided to join them for three weeks. On May the 13th, I made my way to the town of Ōfunato. It's a small fishing town in Iwate Prefecture, about 50,000 people, one of the first that was hit by the wave. The waters here have been recorded at reaching over 24 meters in height, and traveled over two miles inland. As you can imagine, the town had been devastated. We pulled debris from canals and ditches. We cleaned schools. We de-mudded and gutted homes ready for renovation and rehabilitation. We cleared tons and tons of stinking, rotting fish carcasses from the local fish processing plant. We got dirty, and we loved it. For weeks, all the volunteers and locals alike had been finding similar things. They'd been finding photos and photo albums and cameras and SD cards. And everyone was doing the same. They were collecting them up, and handing them in to various places around the different towns for safekeeping. Now, it wasn't until this point that I realized that these photos were such a huge part of the personal loss these people had felt. As they had run from the wave, and for their lives, absolutely everything they had, everything had to be left behind. At the end of my first week there, I found myself helping out in an evacuation center in the town. I was helping clean the onsen, the communal onsen, the huge giant bathtubs. This happened to also be a place in the town where the evacuation center was collecting the photos. This is where people were handing them in, and I was honored that day that they actually trusted me to help them start hand-cleaning them. Now, it was emotional and it was inspiring, and I've always heard about thinking outside the box, but it wasn't until I had actually gotten outside of my box that something happened. As I looked through the photos, there were some were over a hundred years old, some still in the envelope from the processing lab, I couldn't help but think as a retoucher that I could fix that tear and mend that scratch, and I knew hundreds of people who could do the same. So that evening, I just reached out on Facebook and asked a few of them, and by morning the response had been so overwhelming and so positive, I knew we had to give it a go. So we started retouching photos. This was the very first. Not terribly damaged, but where the water had caused that discoloration on the girl's face had to be repaired with such accuracy and delicacy. Otherwise, that little girl isn't going to look like that little girl anymore, and surely that's as tragic as having the photo damaged. (Applause) Over time, more photos came in, thankfully, and more retouchers were needed, and so I reached out again on Facebook and LinkedIn, and within five days, 80 people wanted to help from 12 different countries. Within two weeks, I had 150 people wanting to join in. Within Japan, by July, we'd branched out to the neighboring town of Rikuzentakata, further north to a town called Yamada. Once a week, we would set up our scanning equipment in the temporary photo libraries that had been set up, where people were reclaiming their photos. The older ladies sometimes hadn't seen a scanner before, but within 10 minutes of them finding their lost photo, they could give it to us, have it scanned, uploaded to a cloud server, it would be downloaded by a gaijin, a stranger, somewhere on the other side of the globe, and it'd start being fixed. The time it took, however, to get it back is a completely different story, and it depended obviously on the damage involved. It could take an hour. It could take weeks. It could take months. The kimono in this shot pretty much had to be hand-drawn, or pieced together, picking out the remaining parts of color and detail that the water hadn't damaged. It was very time-consuming. Now, all these photos had been damaged by water, submerged in salt water, covered in bacteria, in sewage, sometimes even in oil, all of which over time is going to continue to damage them, so hand-cleaning them was a huge part of the project. We couldn't retouch the photo unless it was cleaned, dry and reclaimed. Now, we were lucky with our hand-cleaning. We had an amazing local woman who guided us. It's very easy to do more damage to those damaged photos. As my team leader Wynne once said, it's like doing a tattoo on someone. You don't get a chance to mess it up. The lady who brought us these photos was lucky, as far as the photos go. She had started hand-cleaning them herself and stopped when she realized she was doing more damage. She also had duplicates. Areas like her husband and her face, which otherwise would have been completely impossible to fix, we could just put them together in one good photo, and remake the whole photo. When she collected the photos from us, she shared a bit of her story with us. Her photos were found by her husband's colleagues at a local fire department in the debris a long way from where the home had once stood, and they'd recognized him. The day of the tsunami, he'd actually been in charge of making sure the tsunami gates were closed. He had to go towards the water as the sirens sounded. Her two little boys, not so little anymore, but her two boys were both at school, separate schools. One of them got caught up in the water. It took her a week to find them all again and find out that they had all survived. The day I gave her the photos also happened to be her youngest son's 14th birthday. For her, despite all of this, those photos were the perfect gift back to him, something he could look at again, something he remembered from before that wasn't still scarred from that day in March when absolutely everything else in his life had changed or been destroyed. After six months in Japan, 1,100 volunteers had passed through All Hands, hundreds of whom had helped us hand-clean over 135,000 photographs, the large majority — (Applause) — a large majority of which did actually find their home again, importantly. Over five hundred volunteers around the globe helped us get 90 families hundreds of photographs back, fully restored and retouched. During this time, we hadn't really spent more than about a thousand dollars in equipment and materials, most of which was printer inks. We take photos constantly. A photo is a reminder of someone or something, a place, a relationship, a loved one. They're our memory-keepers and our histories, the last thing we would grab and the first thing you'd go back to look for. That's all this project was about, about restoring those little bits of humanity, giving someone that connection back. When a photo like this can be returned to someone like this, it makes a huge difference in the lives of the person receiving it. The project's also made a big difference in the lives of the retouchers. For some of them, it's given them a connection to something bigger, giving something back, using their talents on something other than skinny models and perfect skin. I would like to conclude by reading an email I got from one of them, Cindy, the day I finally got back from Japan after six months. "As I worked, I couldn't help but think about the individuals and the stories represented in the images. One in particular, a photo of women of all ages, from grandmother to little girl, gathered around a baby, struck a chord, because a similar photo from my family, my grandmother and mother, myself, and newborn daughter, hangs on our wall. Across the globe, throughout the ages, our basic needs are just the same, aren't they?" Thank you. (Applause) (Applause)
Create a vocabulary quiz for 10th grade EFL students at CEFR B1 level. For example: adequate means: 1. sufficient 2. more and more 3. not enough. Use all the vocabulary below and provide accompanying definitions per the example to create this vocabulary quiz. The vocabulary quiz must contain at least 226 questions including the following vocabulary: addition advance advanced advertising among other things analysis appear approach as at least average be responsible for something be responsible for doing something before besides can challenge chance change characteristic claim come after come first come last common complicated concern conditions conduct consequence considerable cope critic current decrease delayed deliberately demonstrate design destruction development disagreement disaster discovery dislike do doubt drop educate efficient emphasis enjoyable essay essentially even if even though event exactly except that exist extraordinary feature feedback figure financial finding findings flexible flood flu focus on somebody or something focus frequent fresh frighten from gain generate guidance hopefully ideal illness illustrate image in terms of something in actual fact in connection with something in that case in the meantime initial instruction intelligence interest introduce invest investigate just about just about keep on doing something kind of knowledge lack landscape likely limited little look at something low material mean means measure mention miss misunderstand more or less must naturally nature necessarily nevertheless not at all not only notice objective occasional official on the one hand on the other hand once others otherwise out of date participate particular past perform personality personally planet planning plant point of view policy pollution popular population prevent priority private probable produce profession professor proof proposed protest provided (that) psychology public purpose quality question question questionnaire react reasonable recommend recycle regard region regular relevant reliable rely on/upon sb/sth request research result review revise risk run out of rural salary sample seldom sense set up sth or set sth up significant skilled slight specialist specific still structure study supposed surface take advantage of sth thanks to somebody or something theory throw away throw out something throw something away throw out transport trash treatment unfortunately unhealthy unique united universe unknown unlike unlikely urban vary view visible vision volume whom wildlife within worthwhile would additional analyze analyst appearance on average change characterize complicate concerned concerning concerned with something consequently cope with something criticize criticism currently deliberate demonstration designer developing developed educated educator efficiency efficiently emphasize enjoyment existence existing figure out something finance flexibility frequency hopeful illustration initially intelligent interested in something investor investment investigation investigator limitation meaning occasionally old-fashioned participant participation particularly performance planned pollute prevention producer professional psychological psychologist publicly reaction reasonably recommendation regardless regarding regional relevance researcher resulting revision sensible set out something set something out significantly significance skillful slightly specialize specifically specify theoretical transportation unfortunate unity unite universal variation viewer
______ the sun set, the temperature began to drop. A) After B) While C) Since She studied all night for her test. ______, she was confident when she walked into class. A) Meanwhile B) As a result C) Before We arrived at the park early. ______, we set up our picnic and waited for the others to arrive. A) First B) Later C) Then The alarm rang loudly. ______, I jumped out of bed and rushed to get ready. A) Before B) Immediately C) Eventually The Wright brothers made their first successful flight in 1903. ______, air travel has advanced significantly. A) Since then B) Before C) Meanwhile Example Paragraphs (Choose the Best Transition Word) Cooking Instructions First, preheat the oven to 375°F. ______, mix the flour, sugar, and baking powder in a large bowl. Next, add the eggs and milk, stirring until smooth. (Options: Then, Before, While) Historical Events The Declaration of Independence was signed in 1776. ______, the United States officially became a separate nation from Britain. (Options: As a result, Before, However) Personal Narrative I packed my bags and headed to the airport. ______, I realized I had forgotten my passport at home. (Options: Later, Suddenly, Before) Daily Routine Every morning, I wake up at 6 AM. ______, I brush my teeth and make a cup of coffee. (Options: First, Afterward, Meanwhile) Science Explanation The caterpillar forms a chrysalis. ______, it undergoes metamorphosis and transforms into a butterfly. (Options: Eventually, Meanwhile, Before)
By the late 1800s, the Spanish were losing control of Cuba. Concerned about insurrection in the countryside, they moved rural Cubans to “reconcentration” camps where the Spanish claimed they would be better able to protect them. U.S. Consul-General Fitzhugh Lee forwarded the following account of the conditions of the camps to the U.S. Assistant Secretary of State on November 27, 1897. Lee said the author of the note was “a man of integrity and character.” “[W]e will relate to you what we saw with our own eyes: “Four hundred and sixty women and children thrown on the ground, heaped pellet-mell as animals, some in a dying condition, others sick and others dead. . . . “There is still alive the only living witness, a young girl of 18 years, whom we found seemingly lifeless on the ground; on her right-hand side was the body of a young mother, cold and rigid, but with her young child still alive clinging to her dead body; on her left-hand side was also the corpse of a dead woman holding her son in a dead embrace. . . . “The circumstances are the following: complete accumulation of bodies dead and alive, so that it was impossible to take one step without walking over them; the greatest want of cleanliness, want of light, air, and water; the food lacking in quality and quantity what was necessary to sustain life. . . . From all this we deduct that the number of deaths among the reconcentrados has amounted to 77 per cent.” Source: Unsigned note that was included in a telegram sent by Fitzhugh Lee, U.S. Consul-General in Cuba, to the U.S. Assistant Secretary of State November 27, 1897. consul-general: a government official living in a foreign country charged with overseeing the protection of U.S. citizens and promoting trade pell-mell: state of disorder accumulation: pile want: lack reconcentrados: the reconcentration camp prisoners; The following is an excerpt from Albert J. Beveridge’s speech, delivered September 16, 1898. Beveridge gave this speech while he was campaigning to become a senator for Indiana. The speech helped him win the election and made him one of the leading advocates of American expansion. “Fellow citizens, it is a noble land that God has given us; a land that can feed and clothe the world;. . . . It is a mighty people that he has planted on this soil . . . It is a glorious history our God has bestowed upon his chosen people; . . .a history of soldiers who carried the flag across the blazing deserts and through the ranks of hostile mountains, even to the gates of sunset. . . . “The Opposition tells us that we ought not to govern a people without their consent. I answer: The rule of liberty that all just government derives its authority from the consent of the governed, applies only to those who are capable of self-government. I answer, We govern the Indians without their consent, we govern our territories without their consent, we govern our children without their consent. “They ask us how we will govern these new possessions. I answer: If England can govern foreign lands, so can America. If Germany can govern foreign lands, so can America. . . . “What does all this mean for every one of us? It means opportunity for all the glorious young manhood of the republic, the most virile, ambitious, impatient, militant manhood the world has ever seen. It means that the resources and the commerce of these immensely rich dominions will be increased. . . . “In Cuba, alone, there are 15,000,000 acres of forest unacquainted with the axe. There are exhaustless mines of iron. . . . There are millions of acres yet unexplored. . . . It means new employment and better wages for every laboring man in the Union. . . .