The Split Cherry Tree page 39-42

Review questions for the Split Cherry Tree ' כיתה י

Weathering describes the breaking down or dissolving of rocks and minerals on the surface of the Earth. Water, ice, acids, salts, plants, animals, and changes in temperature are all agents of weathering. Once a rock has been broken down, a process called erosion transports the bits of rock and mineral away. No rock on Earth is hard enough to resist the forces of weathering and erosion. Together, these processes carved landmarks such as the Grand Canyon, in the U.S. state of Arizona. This massive canyon is 446 kilometers (277 miles) long, as much as 29 kilometers (18 miles) wide, and 1,600 meters (1 mile) deep. Weathering and erosion constantly change the rocky landscape of Earth. Weathering wears away exposed surfaces over time. The length of exposure often contributes to how vulnerable a rock is to weathering. Rocks, such as lavas, that are quickly buried beneath other rocks are less vulnerable to weathering and erosion than rocks that are exposed to agents such as wind and water, As it smoothes rough, sharp rock surfaces, weathering is often the first step in the production of soils. Tiny bits of weathered minerals mix with plants, animal remains, fungi, bacteria, and other organisms. A single type of weathered rock often produces infertile soil, while weathered materials from a collection of rocks is richer in mineral diversity and contributes to more fertile soil. Soils types associated with a mixture of weathered rock include glacial till, loess, and alluvial sediments. Weathering is often divided into the processes of mechanical weathering and chemical weathering. Biological weathering, in whichliving or once-living organisms contribute to weathering, can be a part of both processes. Mechanical Weathering Mechanical weathering, also called physical weathering and disaggregation, causes rocks to crumble. Water, in either liquid or solid form, is often a key agent of mechanical weathering. For instance, liquid water can seep into cracks and crevices in rock. If temperatures drop low enough, the water will freeze. When water freezes, it expands. The ice then works as a wedge. It slowly widens the cracks and splits the rock. When ice melts, liquid water performs the act of erosion by carrying away the tiny rock fragments lost in the split. This specific process (the freeze-thaw cycle) is called frost weathering or cryofracturing. Figure 4.3 Frost Wedging Temperature changes can also contribute to mechanical weathering in a process called thermal stress. Changes in temperature cause rock to expand (with heat) and contract (with cold). As this happens over and over again. the structure of the rock weakens. Over time, it crumbles. Rocky desert landscapes are particularly vulnerable to thermal stress. The outer layer of desert rocks undergo repeated stress as the temperature changes from day Eventually, Lo outer night. layersflake off in thin sheets, a process called exfoliation. Exfoliation contributes to the formation of bornhardts, one of the most dramatic features in landscapes formed by weathering and erosion. Bornhardts are tall, domed, isolated rocks often found areas. in tropical Sugarloaf Mountain, an iconic landmark in Rio de Janeiro, Brazil, is bornhardt. a Salt also works to weather rock in a process called haloclasty. Saltwater sometimes gets into the cracks and pores of rock. If the saltwater evaporates, salt crystals are left behind. As the crystals grow, they put pressure on the rock, slowly breaking it apart. Plants and animals can be agents of mechanical weathering. The seed of a tree may sprout in soil that has collected in a cracked rock. As the roots grow, they widen the cracks, eventually breaking the rock into pieces. Over time, trees can break apart even large rocks. Even small plants, such as mosses, can enlarge tiny cracks as they grow. Animals that tunnel underground, such as moles and prairie dogs, also work to break apart rock and soil. Other animals dig and trample rock aboveground, causing rock to slowly crumble. Chemical Weathering Chemical weathering changes the molecular structure of rocks and soil.For instance, carbon dioxide from the air or soil sometimes combines with water in a process called carbonation. This produces a weak acid, called carbonic acid, that can dissolve rock. Carbonic acid is especially effective at dissolving limestone. When carbonic acid seeps through limestone underground, it can open up huge cracks or hollow out vast networks of caves. Carlsbad Caverns National Park, in the U.S. state of New Mexico, includes more than 119 limestone caves created by weathering and erosion. The largest is called the Big Room.. With an area of about 33,210 square meters (357,469 square feet), the Big Room is the size of six football fields. Another type of chemical weathering works on rocks that contain iron. These rocks turn to rust in a process called oxidation. Rust is a compound created by the interaction of oxygen and iron in the presence of water. As rust expands, it weakens rock and helps break it apart. Another familiar form of chemical weathering is hydrolysis. In the process of hydrolysis, a new solution (a mixture of two or more substances) is formed as chemicals in rock interact with water. In many rocks, for example, sodium minerals interact with water to form a saltwater solution. Hydration and hydrolysis contribute to flared slopes, another dramatic example of a landscape formed by weathering and erosion. Flared slopes are sometimes nicknamed "wave rocks." Their c-shape is largely concave rock formations a result of subsurface weathering, in which hydration and hydrolysis wear away rocks beneath the landscape's surfaceWeathering and People Weathering is a natural process, but human activities can speed it up. For example, certain kinds of air pollution increase the rate of weathering Burning coal, natural and petroleum releases chemicals such as nitrogen oxide and gas, sulfur dioxide into the atmosphere. When these chemicals combine with sunlight and moisture, they change into acids. They then fall back to Earth as acid rain. Acid rain rapidly weathers limestone, marble, and other kinds of stone. The effects of acid rain can often be seen on gravestones, making names and other inscriptions impossible to read. Acid rain has also damaged many historic buildings and monuments. For example, at 71 meters (233 feet) tall, the Leshan Giant Buddha at Mount Emei, China is the world's largest statue of the Buddha. It was carved 1,300 years ago and sat unharmed for centuries. An innovative drainage system mitigates the natural process of erosion But in recent years, acid rain has turned the statue's nose black and made some of its hair crumble and fall.

Analyze Johannes Gutenberg’s printing press and William Tyndale’s translation of the Bible into the English language as vehicles for the spread of books, growth of literacy, and dissemination of knowledge. C, G, H 7.45 Explain the significant causes of the Protestant Reformation, including: the Catholic Church’s taxation policies, the selling of indulgences, and Martin Luther’s 95 Theses. C, H, P 7.46 Analyze the development of the Protestant Reformation and the split with the Catholic Church, including: the emphasis on scripture alone, salvation by faith, and predestination. C, H, P 7.47 Explain the political and religious roles of Henry VIII and Mary I in England's transition between Catholicism and Protestantism. C, G, H, P 7.48 Analyze how the Catholic Counter-Reformation emerged as a response to Protestantism and revitalized the Catholic Church, including the significance of: St. Ignatius of Loyola, the Jesuits, and the Council of Trent. C, H 7.49 Examine the Golden Age of the Tudor dynasty (i.e., Queen Elizabeth I), including the defeat of the Spanish Armada and the rise of English power in Europe.

Living or once-living organisms contribute to weathering, can be a part of both processes. Mechanical Weathering Mechanical weathering, also called physical weathering and disaggregation, causes rocks to crumble. Water, in either liquid or solid form, is often a key agent of mechanical weathering. For instance, liquid water can seep into cracks and crevices in rock. If temperatures drop low enough, the water will freeze. When water freezes, it expands. The ice then works as a wedge. It slowly widens the cracks and splits the rock. When ice melts, liquid water performs the act of erosion by carrying away the tiny rock fragments lost in the split. This specific process (the freeze-thaw cycle) is called frost weathering or cryofracturing. Figure 4.3 Frost Wedging Temperature changes can also contribute to mechanical weathering in a process called thermal stress. Changes in temperature cause rock to expand (with heat) and contract (with cold). As this happens over and over again. the structure of the rock weakens. Over time, it crumbles. Rocky desert landscapes are particularly vulnerable to thermal stress. The outer layer of desert rocks undergo repeated stress as the temperature changes from day Eventually, Lo outer night. layers

Cells of different organisms and even cells within the same organism are very diverse in terms of shape, size, and internal organization. One theme that occurs again and again throughout biology is that form follows function. In other words, a cell’s function influences its physical features. Cell Shape The diversity in cell shapes reflects the different functions of cells. Compare the cell shapes shown in Figure 4-4. The long extensions that reach out in various directions from the nerve cell shown in Figure 4-4a allow the cell to send and receive nerve impulses. The flat, platelike shape of skin cells in Figure 4-4b suits their function of covering and protecting the surface of the body. As shown below, a cell’s shape can be simple or complex depending on the function of the cell. Each cell has a shape that has evolved to allow the cell to perform its function effectively. SECTION 2 OBJECTIVES ● Explain the relationship between cell shape and cell function. ● Identify the factor that limits cell size. ● Describe the three basic parts of a cell. ● Compare prokaryotic cells and eukaryotic cells. ● Analyze the relationship among cells, tissues, organs, organ systems, and organisms. VOCABULARY plasma membrane cytoplasm cytosol nucleus prokaryote eukaryote organelle tissue organ organ system Cells have various shapes. (a) Nerve cells have long extensions. (b) Skin cells are flat and platelike. (c) Egg cells are spherical. (d) Some bacteria are rod shaped. (e) Some plant cells are rectangular. FIGURE 4-4 (a) Nerve cell (b) Skin cells (c) Egg cell (d) Bacterial cells (e) Plant cells Copyright © by Holt, Rinehart and Winston. All rights reserved. 1. All cubes have volume and surface area. The total surface area is equal to the sum of the areas of each of the six sides (area = length X width). 2. If you split the first cube into eight smaller cubes, you get 48 sides. The volume remains constant, but the total surface area doubles. 3. If you split each of the eight cubes into eight smaller cubes, you have 64 cubes that together contain the same volume as the first cube. The total surface area, however, has doubled again. CELL STRUCTURE AND FUNCTION 73 Cell Size Cells differ not only in their shape but also in their size. A few types of cells are large enough to be seen by the unaided human eye. For example, the nerve cells that extend from a giraffe’s spinal cord to its foot can be 2 m (about 6 1/2 ft) long. A human egg cell is about the size of the period at the end of this sentence. Most cells, how- ever, are only 10 to 50 μm in diameter, or about 1/500 the size of the period at the end of this sentence. The size of a cell is limited by the relationship of the cell’s outer surface area to its volume, or its surface area–to-volume ratio. As a cell grows, its volume increases much faster than its surface area does, as shown in Figure 4-5. This trend is important because the materials needed by a cell (such as nutrients and oxygen) and the wastes produced by a cell (such as carbon dioxide) must pass into and out of the cell through its surface. If a cell were to become very large, the volume would increase much more than the surface area. Therefore, the surface area would not allow materials to enter or leave the cell quickly enough to meet the cell’s needs. As a result, most cells are microscopic in size. Comparing Surface Cells Materials microscope, prepared slides of plant (dicot) stem and ani- mal (human) skin, pencil, paper Procedure Examine slides by using medium magnification (100). Observe and draw the sur- face cells of the plant stem and the animal skin. Analysis How do the surface cells of each organism differ from the cells beneath the surface cells? What is the function of the surface cells? Explain how surface cells are suited to their function based on their shape. Quick Lab Small cells can exchange substances more readily than large cells because small objects have a higher surface area–to-volume ratio. FIGURE 4-5 mb06se_csfs02.qxd 5/18/07 10:54 AM Page 73 74 CHAPTER 4 BASIC PARTS OF A CELL Despite the diversity among cells, three basic features are common to all cell types. All cells have an outer boundary, an interior sub- stance, and a control region. Plasma Membrane The cell’s outer boundary, called the plasma membrane (or the cell membrane), covers a cell’s surface and acts as a barrier between the inside and the outside of a cell. All materials enter or exit through the plasma membrane. The surface of a plasma mem- brane is shown in Figure 4-6a. Cytoplasm The region of the cell that is within the plasma membrane and that includes the fluid, the cytoskeleton, and all of the organelles except the nucleus is called the cytoplasm. The part of the cytoplasm that includes molecules and small particles, such as ribosomes, but not membrane-bound organelles is the cytosol. About 20 percent of the cytosol is made up of protein. Control Center Cells carry coded information in the form of DNA for regulating their functions and reproducing themselves. The DNA in some types of cells floats freely inside the cell. Other cells have a mem- brane-bound organelle that contains a cell’s DNA. This membrane- bound structure is called the nucleus. Most of the functions of a eukaryotic cell are controlled by the cell’s nucleus. The nucleus is often the most prominent structure within a eukaryotic cell. It maintains its shape with the help of a protein skeleton called the nuclear matrix. The nucleus of a typical animal cell is shown in

Rainbows Introduction. When the Sun comes out after it rains, run outside. You may see a rainbow in the sky. Rainbows are tricks made by light. We can see them, but we can't touch them or walk around them. They seem to move away when we try to get close to them. Science can explain how rainbows happen. Where and When Rainbows Appear. Look around the next time you see a rainbow. The Sun will be shining from behind you. There will be rain in front of you, where you'll see the rainbow. Rainbows need water drops and sunlight to form. They can even form under a bright moon. These are called moonbows. We usually see a rainbow as a half circle. It actually forms a full circle. From the ground, we can only see the top half. How Rainbows Form. Years ago, a French scientist studied rainbows. He found that to see a rainbow, you must be in the right spot. Knowing how light moves helps explain rainbows. Think of running on land. Now think of trying to run through water. You will move more slowly through water because it is thicker than air. This pencil seems to bend where it enters the water. In the same way, light moves faster through air than through water. As the light moves through water, it slows down and bend. Rainbows form when water drops meet sunlight. The light bends when it goes into each drop. Then it reflects, or bounces, off the back of each drop. The light bends again as it leaves the drop. This happens in millions of water drops at once, making the colors of a rainbow. The Colors of the Rainbow. Sunlight is made up of many colors. Water drops split the sunlight into different colors. Splitting light makes a rainbow. You have to be in the right spot to see a rainbow. Each water drop reflects colored light at a slightly different angle. The colors of the rainbow always appear in the same order. The name ROY G. BIV can help you remember the seven main colors. They are red, orange, yellow, green, blue, indigo, and violet. Conclusion. Rain stops and the Sun comes out. A beautiful rainbow sweeps across the sky. Most people find it hard not to stop and stare when a rainbow appears. Science explains how rainbows form. Still, a rainbow is always a magical sight to see.

YouGov found 44 per cent were proud of Britain's history of colonialism, with 21 per cent regretting it happened and 23 per cent holding neither view. The same poll also found 43 per cent believed the British Empire was a good thing, 19 per cent said it was bad and 25 per cent said it was "neither". At its height in 1922, the British empire governed a fifth of the world's population and a quarter of the world's total land area. Although the proponents of Empire say it brought various economic developments to parts of the world it controlled, critics point to massacres, famines and the use of concentration camps by the British Empire. 1. Boer concentration camps During the Second Boer War (1899-1902), the British rounded up around a sixth of the Boer population - mainly women and children - and detained them in camps, which were overcrowded and prone to outbreaks of disease, with scant food rations. Of the 107,000 people interned in the camps, 27,927 Boers died, along with an unknown number of black Africans. 2. Amritsar massacre When peaceful protesters defied a government order and demonstrated against British colonial rule in Amritsar, India, on 13 April 1919, they were blocked inside the walled Jallianwala Gardens and fired upon by Gurkha soldiers. The soldiers, under the orders of Brigadier Reginald Dyer, kept firing until they ran out of ammunition, killing between 379 and 1,000 protesters and injuring another 1,100 within 10 minutes. Brigadier Dyer was later lauded a hero by the British public, who raised £26,000 for him as a thank you. 3. Partitioning of India In 1947, Cyril Radcliffe was tasked with drawing the border between India and the newly created state of Pakistan over the course of a single lunch. After Cyril Radcliffe split the subcontinent along religious lines, uprooting over 10 million people, Hindus in Pakistan and Muslims in India were forced to escape their homes as Some estimates suggest up to one million people lost their lives in sectarian killings. 4. Mau Mau Uprising Thousands of elderly Kenyans, who claim British colonial forces mistreated, raped and tortured them during the Mau Mau Uprising (1951-1960), have launched a £200m damages claim against the UK Government. Members of the Kikuyu tribe were detained in camps, since described as "Britain's gulags" or concentration camps, where they allege they were systematically tortured and suffered serious sexual assault. Estimates of the deaths vary widely: historian David Anderson estimates there were 20,000, whereas Caroline Elkins believes up to 100,000 could have died. 5. Famines in India Between 12 and 29 million Indians died of starvation while it was under the control of the British Empire, as millions of tons of wheat were exported to Britain as famine raged in India. In 1943, up to four million Bengalis starved to death when Winston Churchill diverted food to British soldiers and countries such as Greece while a deadly famine swept through Bengal. Talking about the Bengal famine in 1943, Churchill said: “I hate Indians. They are a beastly people with a beastly religion. The famine was their own fault for breeding like rabbits.”

Localisation of the Brain and Split Brain Research

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