Сборник текстов на казахском, русском, английском языках для формирования навыков по видам речевой деятельности обучающихся уровней среднего образования
жүктеу/скачать 18,66 Mb.
|
- Бұл бет үшін навигация:
- 7. Texts in the natural sciences in english for high school
- Conservation of Natural Resources
- A nano-world of technologies
- What is genetic variation
- Mans influence on nature.
Biotechnology The wide concept of "biotech" or "biotechnology" encompasses a wide range of procedures for modifying living organisms according to human purposes, going back to domestication of animals, cultivation of the plants, and "improvements" to these through breeding programs that employ artificial selection and hybridization. Modern usage also includes genetic engineering as well as cell and tissue culture technologies. The American Chemical Society defines biotechnology as the application of biological organisms, systems, or processes by various industries to learning about the science of life and the improvement of the value of materials and organisms such as pharmaceuticals, crops, and livestock. As per European Federation of Biotechnology, Biotechnology is the integration of natural science and organisms, cells, parts thereof, and molecular analogues for products and services. Biotechnology also writes on the pure biological sciences (animal cell culture, biochemistry, cell biology, embryology, genetics, microbiology, and molecular biology). In many instances, it is also dependent on knowledge and methods from outside the sphere of biology including: bioinformatics, a new brand of computer science bioprocess engineering biorobotics chemical engineering 551
Conversely, modern biological sciences (including even concepts such as molecular ecology) are intimately entwined and heavily dependent on the methods developed through biotechnology and what is commonly thought of as the life sciences industry. Biotechnology is the research and development in the llaboratory using bioinformatics for exploration, extraction, exploitation and production from any living organisms and any source of biomass by means of biochemical engineering where high value-added products could be planned (reproduced by biosynthesis, for example), forecasted, formulated, developed, manufactured and marketed for the purpose of sustainable operations (for the return from bottomless initial investment on R & D) and gaining durable patents rights (for exclusives rights for sales, and prior to this to receive national and international approval from the results on animal experiment and human experiment, especially on the pharmaceutical branch of biotechnology to prevent any undetected side-effects or safety concerns by using the products). By contrast, bioengineering is generally thought of as a related field that more heavily emphasizes higher systems approaches (not necessarily the altering or using of biological materials directly) for interfacing with and utilizing living things. Bioengineering is the application of the principles of engineering and natural sciences to tissues, cells and molecules. This can be considered as the use of knowledge from working with and manipulating biology to achieve a result that can improve functions in plants and animals.[8] Relatedly, biomedical engineering is an overlapping field that often draws upon and applies biotechnology (by various definitions), especially in certain sub-fields of biomedical and/or chemical engineering such as tissue engineering, biopharmaceutical engineering, and genetic engineering. Biophysics Biophysics is an interdisciplinary science that applies the approaches and methods of physics to study biological systems. Biophysics covers all scales of biological organization, from molecular to organismic and populations. Biophysical research shares significant overlap with biochemistry, nanotechnology, bioengineering, computational and systems biology. Molecular biophysics typically addresses biological questions similar to those in biochemistry and molecular biology, but more quantitatively, seeking to find the physical underpinnings of biomolecular phenomena. Scientists in this field conduct research concerned with understanding the interactions between the various systems of a cell, including the interactions between DNA, RNA and protein biosynthesis, as well as how these interactions are regulated. A great variety of techniques are used to answer these questions. Fluorescent imaging techniques, as well as electron microscopy, x-ray crystallography, NMR spectroscopy, atomic force microscopy (AFM) and small-angle scattering (SAS) both with X-rays and neutrons (SAXS/SANS) are often used to visualize structures of biological significance. Protein dynamics can be observed by neutron spectroscopy. Conformational change in structure can be measured using techniques such as dual polarization interferometry, circular dichroism,SAXS and 552
SANS. Direct manipulation of molecules using optical tweezers or AFM, can also be used to monitor biological events where forces and distances are at the nanoscale. Molecular biophysicists often consider complex biological events as systems of interacting entities which can be understood e.g. through statistical mechanics, thermodynamics and chemical kinetics. By drawing knowledge and experimental techniques from a wide variety of disciplines, biophysicists are often able to directly observe, model or even manipulate the structures and interactions of individual molecules or complexes of molecules. In addition to traditional (i.e. molecular and cellular) biophysical topics like structural biology or enzyme kinetics, modern biophysics encompasses an extraordinarily broad range of research, from bioelectronics to quantum biology involving both experimental and theoretical tools. It is becoming increasingly common for biophysicists to apply the models and experimental techniques derived from physics, as well as mathematics and statistics (see biomathematics), to larger systems such as tissues, organs, populations and ecosystems. Biophysical models are used extensively in the study of electrical conduction in single neurons, as well as neural circuit analysis in both tissue and whole brain. Terms And Explanations Regulation - the ability of an organism to respond to a change in its surroundings Ingestion - take in food Digestion - break down and absorb nutrients from food Egestion - removal of indigestible material Reproduction - the production of new offspring that are similar to the parents Synthesis- a chemical reaction that combine small molecules into larger molecules Transport - the absorption of materials into the organism and distributed throughout the organism (oxygen comes in, carbon dioxide goes out of a cell) Respiration - cellular release of chemical energy from food Aerobic - requires oxygen Anaerobic - doesn't require oxygen Excretion - the removal of waste products from chemical reactions Cells - the basic unit of structure in an organism Unicellular - single celled Multicellular - many cells Growth - the process of becoming larger Development - the process of change during the life span to produce a more complex organism Stimulus - a change in an organisms surroundings that causes a reaction Response - the way an organism reacts to a stimulus Carbohydrates - source of cells energy Proteins and Lipids - building materials Nucleic Acids - generic material/ directs cell activities 553
7. Texts in the natural sciences in english for high school listening What Is an Element? An element is a pure substance that cannot be broken down by chemical methods into simpler components. For example, the element gold cannot be broken down into anything other than gold. If you kept hitting gold with a hammer, the pieces would get smaller, but each piece will always be gold. You can think of each kind of element having its own unique fingerprint making it different than other elements. Elements consist of only one type of atom. An atom is the smallest particle of an element that still has the same properties of that element. All atoms of a specific element have exactly the same chemical makeup, size, and mass. There are a total of 118 elements, with the most abundant elements on Earth being helium and hydrogen. Many elements occur naturally on Earth; however, some are created in a laboratory by scientists by nuclear processes. Instead of writing the whole elemental name, elements are often written as a symbol. For example, O is the symbol for oxygen, C is the symbol for carbon, and H is the symbol for hydrogen. Not all elements have just one letter as the symbol, but have two letters - like Al is the symbol for aluminum and Ni is the symbol for nickel. The first letter is always capitalized, but the second letter is not. Symbol names do not always match the letters in the elemental name. For example, Fe is the symbol for iron and Au is the symbol for gold. These symbol names are derived from the Latin names for those elements. Natural resources are available to sustain the very complex interaction between living things and non-living things. Humans also benefit immensely from this interaction. All over the world, people consume resources directly or indirectly. Developed countries consume resources more than under-developed countries. The world economy uses around 60 billion tonnes of resources each year to produce the goods and services which we all consume. On the average, a person in Europe consumes about 36kg of resources per day; a person in North America consumes about 90kg per day, a person in Asia consumes about 14kg and a person in Africa consumes about 10kg of resources per day. In what form do people consume natural resources? The three major forms include Food and drink, Housing and infrastructure, and Mobility. These three make up more than 60% of resource use. International and local trade has its roots in the fact that resources are not evenly distributed on the earth’s surface. Regions with crude oil can drill oil and sell to regions without oil, and also buy resources such as timber and precious metals (gold, diamonds and silver) from other regions that have them in abundance. The uneven distribution is also the root of power and greed in many regions. Some countries use their wealth in resources to control and manipulate regions with fewer resources. Some countries and regions have even gone to war over the management, ownership, allocation, use and protection of natural resources and related ecosystems. 554
Natural Resources A. Overpopulation This is probably the most significant, single threat that natural resources face. The world’s population is increasing at a very fast rate. In the USA, a baby is born every 8 seconds, and a person dies every 13 seconds. The increase in populations mean there will be pressure on almost all natural resources. How? Land Use: With more mouths to feed and people to house, more land will need to be cultivated and developed for housing. More farming chemicals will be applied to increase food production. Many forest or vegetative lands will be converted to settlements for people, roads and farms. These have serious repercussions on natural resources. Forests: Demand for wood (timber), food, roads and forest products will be more. People will therefore use more forest resources than they can naturally recover. Fishing: Fresh water and sea food will face problems too as we will continue to depend heavily on them. Bigger fishing companies are going deeper into sea to catch fish in even larger quantities. Some of the fishing methods they use are not sustainable, thereby destroying much more fish and sea creatures in the process. Need for more: Human's demand for a comfortable life means more items (communication, transport, education, entertainment and recreation) will need to be produced. This means more industrial processes and more need for raw materials and natural resources. B. Climate Change The alteration in climate patterns as a result of excessive anthropogenic is hurting biodiversity and many other a biotic natural resources. Species that have acclimatized to their environments may perish and others will have to move to more favorable conditions to survive. C. Environmental Pollution Land, water and air pollution directly affect the health of the environments in which they occur. Pollution affects the chemical make-up of soils, rocks, lands, ocean water, freshwater and underground water, and other natural phenomena. This often has catastrophic consequences.
555
use again. It involves composting and recycling of materials that are heading to the landfill. Here is an example: Wet organic waste such as food and agricultural waste is considered waste after food consumption or after an agricultural activity. Traditionally, we collect them and send them to a landfill. In Resource Recovery, we collect and divert to composting or anaerobic digestion to produce biomethane. We can also recover nutrients through regulator-approved use of residuals. Conservation of Natural Resources To have an environmentally sustainable secure future where we can still enjoy natural resources, we urgently need to transform the way we use resources, by completely changing the way we produce and consume goods and services. The case of high resource consumption occurs primarily in the bigger cities of the world. Cities worldwide are responsible for 60-80% of global energy consumption and 75% of carbon emissions, consuming more than 75% of the world’s natural resources. To turn this unfortunate way of life around, we all have to play a role. Education and Public Awareness All stakeholders must aim to provide information and raise public awareness about the wonderful natural resources we have and the need to ensure its health. Even though there is a lot of information in the public domain, campaigners must try to use less scientific terms, and avoid complex terminology to send the message across. Once people understand how useful our natural resources are, they will be better placed to preserve it. Individuals, organizations and nations People and organizations in developed nations with high resource consumption rates must be aware of the issues of natural resources. People should understand that it is OK to enjoy all the items and gadgets at home, but also, give back to the environment by way of reducing waste, recycling waste and becoming a part of the solution. We can achieve this in our homes and workplaces by reducing waste and also by recycling the waste we create. Governments and Policy Governments must enforce policies that protect the environment. They must ensure that businesses and industries play fair and are accountable to all people. Incentives must be given to businesses that use recycled raw materials and hefty fines to those that still tap from raw natural resources. Businesses must return a portion of their profits to activities that aim at restoring what they have taken out of the environment. Natural resource is anything that people can use which comes from nature. People do not make natural resources, but gather them from the earth. Examples of natural resources are air, water, wood, oil, wind energy, iron, and coal. Refined oil and hydro-electric energy are not natural resources because people make them. We often say there are two sorts of natural resources: renewable resources and 556
non-renewable resources. A renewable resource is one which can be used again and again. For example, soil, sunlight and water are renewable resources. However, in some circumstances, even water is not renewable easily. Wood is a renewable resource, but it takes time to renew and in some places people use the land for something else. Soil, if it blows away, is not easy to renew. A non-renewable resource is a resource that does not grow and come back, or a resource that would take a very long time to come back. For example, coal is a non-renewable resource. When we use coal, there is less coal afterward. One day, there will be no more of it to make goods. The non-renewable resource can be used directly (for example, burning oil to cook), or we can find a renewable resource to use (for example, using wind energy to make electricity to cook). Most natural resources are limited. This means they will eventually run out. A perpetual resource has a never-ending supply. Some examples of perpetual resources include solar energy, tidal energy, and wind energy. Some of the things influencing supply of resources include whether it is able to be recycled, and the availability of suitable substitutes for the material. Non-renewable resources cannot be recycled. For example, oil, minerals, and other non-renewable resources cannot be recycled. All places have their own natural resources. When people do not have a certain resource they need, they can either replace it with another resource, or trade with another country to get the resource. People have sometimes fought to have them (for example, spices, water, arable land, gold, or petroleum). When people do not have some natural resources, their quality of life can get lower. So, we need to protect our resources from pollution. For example, when they can not get clean water, people may become ill; if there is not enough wood, trees will be cut and the forest will disappear over time (deforestation); if there are not enough fish in a sea, people can die of starvation. Renewable resources include crops, wind, hydroelectric power, fish, and sunlight. Many people carefully save their natural resources so others can use them in future. As energy is the main ‘fuel’ for social and economic development, and since energy-related activities have significant environmental impacts, it is important for decision-makers to have access to reliable and accurate data in a user-friendly format. The World Energy Council has for decades been a pioneer in the field of energy resources and every three years publishes its World Energy Resources report (WER), which is released during the World Energy Congress. The energy sector has long lead times and therefore any long-term strategy should be based on sound information and data. Detailed resource data, selected cost data and a technology overview in the main WER report provide an excellent foundation for assessing different energy options based on factual information supplied by the WEC members from all over the world. The work is divided into twelve resource-specific work groups, called Knowledge Networks; complemented by a further three groups investigating the 557
cross-cutting issues of, carbon capture and storage, energy efficiency and energy storage. These Knowledge Networks provide updated data for the website and publications, as well as working on timely deep-dives with a resource focus. An example of a magnetic force is the pull that attracts metals to the magnet. Now, the electrical field induced causes waves, called electromagnetic waves, and they can travel through a vacuum (air), particles or solids. These waves resemble the ripple (mechanical) waves you see when you drop a rock into a swimming pool, but with electromagnetic waves, you do not see them, but you often can see the effect of it. The energy in the electromagnetic waves is what we call radiant energy. There are different kinds of electromagnetic waves and all of them have different wavelengths, properties, frequencies and power, and all interact with matter differently. The entire wave system from the lowest frequency to the highest frequency is known as the electromagnetic spectrum. The shorter the wavelength, the higher its frequency and vice versa. White light, for example, is a form of radiant energy, and its frequency forms a tiny bit of the entire electromagnetic spectrum. A population comprises all the individuals of a given species in a specific area or region at a certain time. Its significance is more than that of a number of individuals because not all individuals are identical. Populations contain genetic variation within themselves and between other populations. Even fundamental genetic characteristics such as hair color or size may differ slightly from individual to individual. More importantly, not all members of the population are equal in their ability to survive and reproduce. Community refers to all the populations in a specific area or region at a certain time. Its structure involves many types of interactions among species. Some of these involve the acquisition and use of food, space, or other environmental resources. Others involve nutrient cycling through all members of the community and mutual regulation of population sizes. In all of these cases, the structured interactions of populations lead to situations in which individuals are thrown into life or death struggles. In general, ecologists believe that a community that has a high diversity is more complex and stable than a community that has a low diversity. This theory is founded on the observation that the food webs of communities of high diversity are more interconnected. Greater interconnectivity causes these systems to be more resilient to disturbance. If a species is removed, those species that relied on it for food have the option to switch to many other species that occupy a similar role in that ecosystem. In a low diversity ecosystem, possible substitutes for food may be non-existent or limited in abundance. Ecosystems are dynamic entities composed of the biological community and the abiotic environment. An ecosystem's abiotic and biotic composition and structure is determined by the state of a number of interrelated environmental factors. Changes in any of these factors (for example: nutrient availability, temperature, light intensity, grazing intensity, and species population density) will result in dynamic changes to the nature of these systems. For example, a fire in the temperate deciduous forest completely changes the structure of that system. There are no longer any large trees, 558
most of the mosses, herbs, and shrubs that occupy the forest floor are gone, and the nutrients that were stored in the biomass are quickly released into the soil, atmosphere and hydrologic system. After a short time of recovery, the community that was once large mature trees now becomes a community of grasses, herbaceous species, and tree seedlings. An ecosystem includes all of the living things (plants, animals and organisms) in a given area, interacting with each other, and also with their non-living environments (weather, earth, sun, soil, climate, atmosphere). In an ecosystem, each organism has its' own niche or role to play. Consider a small puddle at the back of your home. In it, you may find all sorts of living things, from microorganisms to insects and plants. These may depend on non-living things like water, sunlight, turbulence in the puddle, temperature, atmospheric pressure and even nutrients in the water for life. (Click here to see the five basic needs of living things) This very complex, wonderful interaction of living things and their environment, has been the foundations of energy flow and recycle of carbon and nitrogen. Anytime a ‘stranger’ (living thing(s) or external factor such as rise in temperature) is introduced to an ecosystem, it can be disastrous to that ecosystem. This is because the new organism (or factor) can distort the natural balance of the interaction and potentially harm or destroy the ecosystem. Click to read on ecosystem threats (opens in new page). Usually, biotic members of an ecosystem, together with their abiotic factors depend on each other. This means the absence of one member or one abiotic factor can affect all parties of the ecosystem. Unfortunately, ecosystems have been disrupted, and even destroyed by natural disasters such as fires, floods, storms and volcanic eruptions. Human activities have also contributed to the disturbance of many ecosystems and biomes. Scales of Ecosystems Ecosystems come in indefinite sizes. It can exist in a small area such as underneath a rock, a decaying tree trunk, or a pond in your village, or it can exist in large forms such as an entire rain forest. Technically, the Earth can be called a huge ecosystem. What is energy? Look around you. Is anything moving? Can you hear, see or feel anything? Sure... this is because something is making something happen, and most probably, there is some power at work. This power or ability to make things happen is what we can call energy. It makes things happen. It makes change possible. Look at the sketch below to see an example of things working, moving, or happening... with energy. Energy in action Energy moves cars along the roads and makes aeroplanes fly. It plays our music on the radio, heats our rooms and lights our homes. Energy is needed for our 559
bodies, together with plants to grow and move about. Scientists define ENERGY as the ability to do work. Energy can be neither created nor destroyed. Energy can be (is) stored or transferred from place to place, or object to object in different ways. There are various kinds of energy.
Kinetic Energy All moving things have kinetic energy. It is energy possessed by an object due to its motion or movement. These include very large things, like planets, and very small ones, like atoms. The heavier a thing is, and the faster it moves, the more kinetic energy it has. Now let's see this illustration below. There is a small and large ball resting on a table. Kinetic energy example Let us say both balls will fall into the bucket of water. What is going to happen? Motion energy example You will notice that the smaller ball makes a little splash as it falls into the bucket. The heavier ball makes a very big splash. Why?
Both balls had potential energy as they rested on the table. By resting up on a high table, they also had gravitational energy. By moving and falling off the table (movement), potential and gravitational energy changed to Kinetic Energy. Can you guess which of the balls had more kinetic energy? (The big and heavier ball). Mechanical Energy Mechanical energy is often confused with Kinetic and Potential Energy. We will try to make it very easy to understand and know the difference. Before that, we need to understand the word ‘Work’. ‘Work’ is done when a force acts on an object to cause it to move, change shape, displace, or do something physical. For, example, if I push a door open for my pet dog to walk in, work is done on the door (by causing it to open). But what kind of force caused the door to open? Here is where Mechanical Energy comes in. Mechanical energy is the sum of kinetic and potential energy in an object that is used to do work. In other words, it is energy in an object due to its motion or position, or both. In the 'open door' example above, I possess potential chemical energy (energy stored in me), and by lifting my hands to push the door, my action also had kinetic energy (energy in the motion of my hands). By pushing the door, my potential and kinetic energy was transferred into mechanical energy, which caused work to be done (door opened). Here, the door gained mechanical energy, which caused the door to be displaced temporarily. Note that for work to be done, an object has to supply a force for another object to be displaced. Here is another example of a boy with an iron hammer and nail. 560
The iron hammer on its own has no kinetic energy, but it has some potential energy (because of its weight). To drive a nail into the piece of wood (which is work), he has to lift the iron hammer up, (this increases its potential energy because if its high position). And force it to move at great speed downwards (now has kinetic energy) to hit the nail. The sum of the potential and kinetic energy that the hammer acquired to drive in the nail is called the Mechanical energy, which resulted in the work done. Sound Waves Sound energy is usually measured by its pressure and intensity, in special units called pascals and decibels. Sometimes, loud noise can cause pain to people. This is called the threshold of pain. This threshold is different from person to person. For example, teens can handle a lot higher sound pressure than elderly people, or people who work in factories tend to have a higher threshold pressure because they get used to loud noise in the factories. Heat (Thermal energy) Matter is made up of particles or molecules. These molecules move (or vibrate) constantly. A rise in the temperature of matter makes the particles vibrate faster. Thermal energy is what we call energy that comes from the temperature of matter. The hotter the substance, the more its molecules vibrate, and therefore the higher its thermal energy.
If we want to boil the water in these two beakers, we must increase their 561
temperatures to 100°C. You will notice that will take longer to boil the water in the large beaker than the water in the small beaker. This is because the large beaker contains more water and needs more heat energy to reach 100°C. Polymers are studied in the fields of biophysics and macromolecular science, and polymer science (which includes polymer chemistry and polymer physics). Historically, products arising from the linkage of repeating units by covalent chemical bonds have been the primary focus of polymer science; emerging important areas of the science now focus on non-covalent links. Polyisoprene of latex rubber and the polystyrene of Styrofoam are examples of polymeric natural/biological and synthetic polymers, respectively. In biological contexts, essentially all biological macromolecules—i.e., proteins (polyamides), nucleic acids (polynucleotides), and polysaccharides—are purely polymeric, or are composed in large part of polymeric components—e.g., isoprenylated/lipid-modified glycoproteins, where small lipidic molecules and oligosaccharide modifications occur on the polyamide backbone of the protein. A polymer is a large molecule, or macromolecule, composed of many repeated subunits. Because of their broad range of properties,[4] both synthetic and natural polymers play an essential and ubiquitous role in everyday life.[5] Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass relative to small molecule compounds produces unique physical properties, including toughness, viscoelasticity, and a tendency to form glasses and semi crystalline structures rather than crystals. A nano-world of technologies There are high hopes that research in nanotechnology will translate into many products and devices that will help people. The technology will affect a wide range of fields, including transportation, sports, electronics, and medicine. Some of the current and future possibilities of nanotechnology includes: Medicine: Researchers are working to develop nanorobots to help diagnose and treat health problems. Medical nano robots, also called nanobots, could someday be injected into a person bloodstream. In theory, the nanobots would find and destroy harmful substances, deliver medicines, and repair damage. Sports: Nanotechnology has been incorporated in outdoor fabrics to add insulation from the cold without adding bulk. In sports equipment, nanotech metals in golf clubs make the clubs stronger yet lighter, allowing for greater speed. Tennis balls coated with nanoparticles protect the ball from air, allowing it to bounce far longer than the typical tennis ball. Materials Science: Nanotechnology has led to coatings that make fabric stain proof and paper water resistant. A car bumper developed with nanotechnology is lighter yet a lot harder to dent than conventional bumpers. And nanoparticles added 562
to surfaces and paints could someday make them resistant to bacteria or prevent dirt from sticking. Electronics: The field of nano-electronics is working on miniaturizing and increasing the power of computer parts. If researchers could build wires or computer processing chips out of molecules, it could dramatically shrink the size of many electronics. Heal The World Biotech is helping to heal the world by harnessing nature's own toolbox and using our own genetic makeup to heal and guide lines of research by: Reducing rates of infectious disease; Saving millions of children's lives; Changing the odds of serious, life-threatening conditions affecting millions around the world; Tailoring treatments to individuals to minimize health risks and side effects; Creating more precise tools for disease detection; and Combating serious illnesses and everyday threats confronting the developing world. Fuel The World Biotech uses biological processes such as fermentation and harnesses biocatalysts such as enzymes, yeast, and other microbes to become microscopic manufacturing plants. Biotech is helping to fuel the world by:
Streamlining the steps in chemical manufacturing processes by 80% or more; Lowering the temperature for cleaning clothes and potentially saving $4.1 billion annually; Improving manufacturing process efficiency to save 50% or more on operating costs; Reducing use of and reliance on petrochemicals; Using biofuels to cut greenhouse gas emissions by 52% or more; Decreasing water usage and waste generation; and Tapping into the full potential of traditional biomass waste products. Feed The World Biotech improves crop insect resistance, enhances crop herbicide tolerance and facilitates the use of more environmentally sustainable farming practices. Biotechis helping to feed the world by: Generating higher crop yields with fewer inputs; Lowering volumes of agricultural chemicals required by crops-limiting the run-off of these products into the environment; Using biotech crops that need fewer applications of pesticides and that allow farmers to reduce tilling farmland; Developing crops with enhanced nutrition profiles that solve vitamin and nutrient deficiencies; Producing foods free of allergens and toxins such as mycotoxin; and Improving food and crop oil content to help improve cardiovascular health. 563
Have you ever heard the expression “you can’t tell the players without a program” and found it to be true? Sometimes you need background information, a list of the players, their titles or functions, definitions, explanations of interactions and rules to be able to understand a sporting event, a theatrical play or a game. The same is true for understanding the subtle but important differences among the various components that make up an ecosystem. Terms suchas individual, population, species, community andecosystem all represent distinct ecological levels and are not synonymous, interchangeable terms. Here is your brief guide or program to understanding these ecological players. You are an individual, your pet cat is an individual, a moose in Canada is an individual, a coconut palm tree on an island in the Indian Ocean is an individual, a gray whale cruising in the Pacific Ocean is an individual, and a tapeworm living in the gut of a cow is an individual, as is the cow itself. An individual is one organism and is also one type of organism (e.g., human, cat, moose, palm tree, gray whale, bacterium, or cow in our example). The type of organism is referred to as the species. There are many different definitions of the word species, but for now we’ll leave it simply that it is a unique type of organism. As a grammatical aside, note that the word “species” always ends in an “s”. Even if you are referring to just one type of organism, one species, it is a species; there is no such thing as specie. That’s just one of those grammatical facts of life. So what is a gene? Genes are instruction manuals in our body. They are molecules in our body that explain the information hidden in our DNA, and supervises our bodies to grow in line with that information. It is believed that each cell in our body contains over 25,000 genes, all working together. These genes carry specific biological codes or information that determine what we inherit from our parents. Genes are also a small section of Deoxyribonucleic Acid (DNA), a chemical that has a genetic code for making proteins for living cells. Proteins are the building blocks for living things. Almost everything in our body, bones, blood and muscles are all made up of proteins, and it is the job of the genes to supervise protein production. Genes are not things we see with our bare eyes. They can only be seen with powerful microscopes, and they are thread-like in nature, found in our chromosomes. Altered or mutated genes: Sometimes our genes do not work well. Sometimes we inherit genes that have some problems. Such genes (also called mutated or altered genes) do not perform their functions well, and cause defects in our organs. Some inherited diseases like cancer and sickle cell have been linked to such mutated or bad genes. There is still a lot of research going on in the study of genes to learn more about them. What is a chromosomes? A chromosome is just a compact store of DNA. A chromosome is simply a lot 564
of DNA strands folded and compacted together. This compacting is done in a special way. The Chemical bases in the DNA are held in place by The Double Helix. The Double Helix continues to wrap itself around proteins. They continue to wrap around several protein molecules and into an even bigger compact set which we call Chromosome. Chromosomes are all contained in the nucleus of the cell. nucleus The number of Chromosomes in a cell depends on what cell it is. Chromosomes in a tiny goldfish may be a lot less than that of a human. In fact, humans have 46 chromosomes in each of the cells of our organs. These are organized into two sets of 23 chromosomes.
During sexual activity (mating), the male releases the sperm cell and the female releases the ova (female cell). Remember we said previously that the human body has 23 pairs of chromosomes? Yes, the 23rd chromosome is your sex chromosomes. Boys carry XY chromosomes and girls carry XX cromosomes.sex chromosomes During fertilization, each parent contributes a cell each. The female always contributes and X cell (because that all she has, XX chromosome) The male contributes either an X or a Y cell. The male has no control over this, as it is purely random. If the male releases and X chromosome, it adds to the X chromosome of the female, it forms an XX— and the gender of the baby will be a girl. If the male releases a Y chromosome and adds to the females X chromosome, it forms an XY and the gender of the baby is a boy. In recent years, it is possible to have IVF which means In vitro fertilization. This is where the female and male cells are taken from the parents and fertilized in a lab. In IVF, it is possible to choose which sex chromosomes to fertilize. This means you can choose to have a boy or girl. What is genetic variation? Individuals in a population are not exactly the same. Each individual has its unique set of traits, such as size, color, height, body weight, skin colour and even the ability to find food. Sometimes, offspring’s of the same parents still differ a lot among themselves. You can find that among 3 sisters, one may be very tall, the other may have dark hair and the third may have a rounded nose tip. Such differences in individuals from the same parents are called variation. Characteristics or traits that are inherited are determined by genetic information. Some other traits like dialect or accent, scars, skin texture or even body weight may be determined by some external or environmental factors. These factors include 565
genesbulletDiet genesbulletClimate genesbulletCulture genesbulletLifestyle genesbulletLanguage genesbulletAccidents Sometimes a person may not have inherited a trait, but some conditions have modified the individual to exhibits specific traits. If a child with brown eyes acquires a disease that affects his eyes and turns them yellow, that may be a diseased induced variation. In the same vain, a child my have the tendency to be tall, but diseases and poor diet during his early years my cause him to have stunted growth. Laser surgery is also growing in popularity and application. As its name suggests, surgeons utilize a laser to perform various procedures, including during laparoscopic procedures. For example, lasers currently are used to excise cancerous tissue from the larynx, reshape the cornea of an eye to allow a patient to see better, and even to resurface the skin of a patient's face by burning off old layers skin so that new skin can grow. The growing popularity of lasers as surgical devices is due mainly to their ability to precisely destroy unwanted or abnormal tissue without bleeding. Another well known example of advancing surgical techniques involves combating cardiovascular disease. Because of lifestyle habits or genetic predisposition, fatty acids (plaque) sometimes build up in arterial walls. As more plaque builds up, less blood is able to flow through the artery to the heart. Ultimately, the plaque buildup may completely block the artery, preventing any blood from flowing through it. The result is cardiac arrest, which can be fatal. Surgeons have developed a technique known as angioplasty to combat the onset of cardiovascular disease. Using a technique similar to laparoscopy, a surgeon inserts a thin tube into the patient, working it up the artery to where the blockage resides. At the end of the tube is a small, balloon-like device that inflates, pressing the plaque against the arterial walls so that blood flow through the artery can be increased. Surgeons have also developed another, more popular, procedure for dealing with coronary artery disease: the coronary bypass graft operation. By taking a portion of an artery from elsewhere in the patient's body--usually the internal mammary artery from inside the chest cavity--the new artery is grafted around the blockage of the old artery to allow blood to flow around the blockage via the new arterial route. Despite the fact that this procedure requires open-heart surgery. Man's influence on nature. Man is not only a dweller in nature, he also transforms it. From the very beginning of his existence, and with increasing intensity human society has adapted environing nature and made all kinds of incursions into it. An enormous amount of human labour has been spent on transforming nature. Humanity converts nature's wealth into the means of the cultural, historical life of society. Man has subdued and disciplined electricity and compelled it to serve the 566
interests of society. Not only has man transferred various species of plants and animals to different climatic conditions; he has also changed the shape and climate of his habitation and transformed plants and animals. If we were to strip the geographical environment of the properties created by the labour of many generations, contemporary society would be unable to exist in such primeval conditions. Man and nature interact dialectically in such a way that, as society develops, man tends to become less dependent on nature directly, while indirectly his dependence grows. This is understandable. While he is getting to know more and more about nature, and on this basis transforming it, man's power over nature progressively increases, but in the same process, man comes into more and more extensive and profound contact with nature, bringing into the sphere of his activity growing quantities of matter, energy and information. On the plane of the historical development of man-nature relations we may define certain stages. The first is that of the complete dependence of man on nature. Our distant ancestors floundered amid the immensity of natural formations and lived in fear of nature's menacing and destructive forces. Very often they were unable to obtain the merest necessities of subsistence. However, despite their imperfect tools, they worked together stubbornly, collectively, and were able to attain results. This process of struggle between man and the elements was contradictory and frequently ended in tragedy. Nature also changed its face through interaction with man. Forests were destroyed and the area of arable land increased. Nature with its elemental forces was regarded as something hostile to man. The forest, for example, was something wild and menacing and people tried to force it to retreat. This was all done in the name of civilization, which meant the places where man had made his home, where the earth was cultivated, where the forest had been cut down. But as time goes on the interaction between man and nature is characterized by accelerated subjugation of nature, the taming of its elemental forces . The subjugating power of the implements of labour begins to approach that of natural forces. Mankind becomes increasingly concerned with the question of where and how to obtain irreplaceable natural resources for the needs of production. Science and man's practical transforming activity have made humanity aware of the enormous geological role played by the industrial transformation of earth. At present the interaction between man and nature is determined by the fact that in addition to the two factors of change in the biosphere that have been operating for millions of years—the biogenetic and the a biogenetic—there has been added yet another factor which is acquiring decisive significance—the techno genetic. As a result, the previous dynamic balance between man and nature and between nature and society as a whole has shown ominous signs of breaking down. The problem of the so-called replaceable resources of the biosphere has become particularly acute. It is getting more and more difficult to satisfy the needs of human beings and society even for such a substance, for example, as fresh water. The problem of eliminating industrial waste is also becoming increasingly complex. The threat of a global ecological crisis hangs over humanity like the sword of Damocles. His keen 567
awareness of this fact has led man to pose the question of switching from the irresponsible destructive and polluting subjugation of nature to a reasonable harmonious interaction in the "technology- man-biosphere" system. Whereas nature once frightened us and made us tremble with her mysterious vastness and the uncontrollable energy of its elemental forces, it now frightens us with its limitations and a new-found fragility, the delicacy of its plastic mechanisms. We are faced quite uncompromisingly with the problem of how to stop, or at least moderate, the destructive effect of technology on nature. In socialist societies the problem is being solved on a planned basis, but under capitalism spontaneous forces still operate that despoils nature's riches. Unforeseen paradoxes have arisen in the man-nature relationship. One of them is the paradox of saturation. For millions of years the results of man's influence on nature were relatively insignificant. The biosphere loyally served man as a source of the means of subsistence and a reservoir for the products of his life activity. The contradiction between these vital principles was eliminated by the fact that the relatively modest scale of human productive activity allowed nature to assimilate the waste from labour processes. But as time went on, the growing volume of waste and its increasingly harmful properties destroyed this balance. The human feedback into nature became increasingly disharmonised. Human activity at various times has involved a good deal of irrational behaviour. Labour, which started as a specifically human means of rational survival in the environment, now damages the biosphere on an increasing scale and on the boomerang principle—affecting man himself, his bodily and mental organisation. Under the influence of uncoordinated production processes affecting the biosphere, the chemical properties of water, air, the soil, flora and fauna have acquired a negative shift. Experts maintain that 60 per cent of the pollution in the atmosphere, and the most toxic, comes from motor transport, 20 per cent from power stations, and 20 per cent from other types of industry. жүктеу/скачать 18,66 Mb. Достарыңызбен бөлісу:
|