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Games for Formative Assessment
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Management and Globalization Global Management Why companies go global How companies for global Global Business environments Global Business Types of global business Pros and cons of global businesses Ethnic Challenges for global business Culture and Global Diversity Cultural intelligence Silent language of culture Tight and loose cultures Values and national cultures Global Management Learning Are management theories universal? Intercultural competencies Global learning goals Key concepts of the challenges of globalisation: Global economy Resources, markets and competition are worldwide in scope Internationalisation The process of increasing involvement in international operations Globalization/Deglobalization Glob- the growing interdependence among elements in the global economy The worldwide interdependence of resource flows, product markets and business competition World 3.0 Different views: World flat vs. round Distance is a metaphor that represents the degree of dissimilarities between countries Balancing cooperation in the global Global Management Global management - managing things in different countries Managing business and organizations with interests in more than one country What do we expect from global Managers Knowing how to adapt Knowing the language Global Manager Is culturally aware and informed on international affairs International Business Conducting for-profit transactions of goods and services across national boundaries International Motive Why do firms internatioalize their activities Cheaper labour Labour tax Natural resources Enrolments to do business Clientele Exclusive materials Personal benefits: Taxes Reasons why businesses go global Customers Suppluers Capital During (1993) - 4 motive 1. Market seeking 2. Efficiency Seeking 3. Resource seeking 4. Strategic Asset Seeking Cuervo Cazurra, Narula and un (2015) - 4 motive s Internationalization Motives A company may also explore the opportunities in different markets in order to take advantage and in some cases extend the product life cycle What is a Market Entry Strategy Involves the sale of goods or services to foreign markets but do not require expensive investments Franchising Exporting and importing Involve the sale of goods or services to foreign markets but do Types of market entry strategies Global sourcing Exporting Importing Licensing agreement Franchising Types of Foreign Direct Investment (FDI) strategies: Joint venture Strategic alliance Owned Subsidiary (sometimes called WOS) How to go abroad What conditions will affect the decisions of firms on how to internationalize their activities? During (1978)- Eclectic paradigm OLI model OLI- Ownership, Location and Internalization Advantages Ownership advantages Resources owned by the organization that can be transferred across locations include trademarks, production techniques and processes, managerial skills and other resources not available to the competitors Location Advantages Represent the implications of choosing to produce or to perform activities in a specific location (country or region) Internalization Advantages: The ability to internalize or to incorporate activities that add value to its business Evolution of Concepts- New Elements Although economic factors are certainly important to explain the formation, growth and expansion of firms within and across national borders, they are not sufficient to explain the additional complexity when a firm decides to expand its activities across national borders Economic factors Investigate the economic elements that affect the internationalization of firms Behavioural Elements Explaining the additional challenges (and perhaps opportunities) a firm faces in foreign host countries when compared to indigenous (local) firms Behavioural theories Johanson and Wiedersheim-Paul (1975) and Johanson and Vahlne (1977) Included the psychic Distance concept (beckerman,1956) to explain the internationalization behaviour of firms The Uppsala internationalization model Psychic distance is: the sum of factors preventing the flow of infomatio from and to the market Psychic Distance is a broad concept that includes several elements such as: language, culture, political systems, level of education, level of industrial development Firms behave in a āRisk Averseā manner It means that when the perceived risk goes down, the firm increase its commitment to the foreign market \ The Haier Group Data Strategy Big DATA and Small DATA The use of small data to satisfy individual customersā needs, however, the book mentions a huge cultural shock at the plant in Camden, south caroline Ex: top down, hard hat colors and hierarchy Culutral Differnces can have a huge impact on the internationalization of firms Kogut and Singh (1988)- Cultural Distance Index First statsical study on the implication of ciltiral distance to the selection of entry mode When investigating in culturally distant countries, foreign firms can choose to partner with foreign firms in order to gain local knowledge and share the risk associated to the investment (higher commitment = higher risk) How Companies Go Global Global sourcing The process of purchasing materials or services around teh world for local use Exporting Selling locally made products in foreign markets Importing Buying foreign made products and selling them domestically Exports correspond to what percentage of Candain GDP What countries are the major trending partners of Canada Management and Globalization How Companies Go Global Licensing Agreement One firm pays a fee for rights to make or sell another companyās products What are the potential risks associated to licesning The case of new balance in China Franchising A fee is paid for the rights to use another firms name, branding and methods Insourcing Insourcing: refers to local job creation that results from foreign direct investment Types of insourcing Joint ventures: operate in a foreign country through co-ownership by foreign and local partners Strategic alliances: A partnership in which foreign and domestic firms share resources and knowledge for mutual gains Foreign subsidiaries: local operation completely owned by a foreign firm Criteria for choosing a joint venture partner: Familiarity with your firmās major business String local workforce Values its customers Future expansion possibilities Strong local market for partnerās own products Good Profit potential Sound financial standing Global business environments Legal and poliical systems Trade agreements and trade barriers Regional economic alliances Legal and political systems Differing laws and practices regards Business ownership Negotiation and implementation of contracts Foreign currency exchange Protection of intellectual property rights Counterfeit merchandise Political risk Potential loss in value of foreign investment due to instability and political changes in the host country Political risk analysis (expertise/experience) Forecast political disruptions that threaten the value of a foreign investment Changes in the rules of the game Brexit US Trade Wars-mexico-China Other examples Bolivia, Venezuela, China De-globalization The process of weakening interdependence among nations Trade Agreements and trade Barriers World trade organization Most favourd nation status Tariffs Nontariss barriers (quotes, restrictions, etc.) Protectionism Regional Economic Alliances USMCA (replacment for the NAFTA-North American Free trade Agreement) EU- European Union APEC- Aisa Pacific Economic Copperation ASEAN - Association of Southeast Asian Nationas SADC - Southern Africa Development Community MERCOSUR- Chapter 5- Global Management and Cultural Diversity (part 2) Review Types of global business Global corporation MNE (multinational enterprise) or MNC (multinational corporation) with extensive business operations in more than one foreign country Transnational corporation A global corporation that operates worldwide on borderless basis Some host country complaints about MNCs Host Country companits about MNCs: Excessive profits Interference with local government Domination of local economy Interference with local government Hiring the best local talent Limited technology transfer Disrespect for local customers Examples - War in Ukraine Disruption in global -value chains and increased pressure and interference of MNCs with local government Fertilizer imports in Brazil (one of the major producers of agricultural commodities) We must consider the triple bottom line and the impact in society, the environment and the economy $2.5 billion invest in potash mine in Brazill What about Globalization gap Large multinationals adn industrilizednaitons gaining disporoportinonally form globalization Globalization gap: Large multinational and industrialized nations gaining disproportionally from Globalization Some MNC complaints about host countries MNC Complaints about host countries: Profiit limitations Laws and regulations Overpirce resources Exploitative rules Foreign exchange restriction Failure to uphold contracts Mutual benefits for host countries and multinational companies Mutual benefits for host country and global corporation of MNC: Shared growth opportunities Shared income opportunities Shared learning opportunities Share development opportunities Develop projects together What are some of the ethical challenges for global business Ethincal challenges for global business Child labour Employmnet of children for worl otherwise done by adults Sweatshops Employment of workers at very low wages for long hours in poor working conditions Ex: Nike bad labour prices Unsafe working conditions Corruption Illegal practices that further oneās business interests Corrupiotn of froeign public officials Act makes it illegal for Candain firms and their representatives to engage in corrupt practices overseas Bribes to foreign officials Excessive commissions Non-monetary gifts Sweatshops Conflict materials What is culture Culture : The shared set of beliefs, values, and patterns of behvaiourr common to a group of people Food preferences Values and traditions Language and beliefs Religion Art music Life style Hofstede defines culture as: āThe collectiv programing of teh mind distinguishing the members of one group or category of people from othersā What is culture shock Culture Shock: Confusion and discoumfert a person experiences in an unfaamiliar culture Stages to adjusting to a new culture Confusion Small vitorires The honeymoon Irritation and anger Reality Cultural Intelligence The ability to adapt and adjust to new cultures What is Ethnocentrism Tendency to consider oneās own culture as superior others Slinet languages of culture Contect Low context High context Space Proxemics Ex: personal space Time Monochronic Polychronic High and low contexts cultures Edward T.Hall (1959) Def: Part of a discourse that surround a word or passage and can throw on its meaning Low context cultures Emphizes communication via spoken or written words Countries like United States, Canada and Germany High context cultures Rely on nonverbal and situational cues as well as on spoken or written works Thailand Malaysia Time Monochronic cultures People tend to do one thing at a time Canda Polychronic cultures Time is used to accomplish many different things at once Egypt Space Proxemics Study of how people use space to communicate In North American people value āpersonal spaceā Many Latin and Asian cultures expect much less personal space Tight and Loose Cultures Cultural tightness-looseness Tight = Strength of norms that govern social behvaviour Japan, Korea, Malaysia Loose = tolerance for any deviation from norms Australia, Brazil, Hungary Values and national cultures (Hofstede) Power distance Uncertainty avoidance Individalism-collectivism Masculinity-femininty Time Orientation Indulgence vs. Restraint Comparative management How management pratices systematically differ among countries and /or cultures Intercultural competencies Skills and personal characteristics that help us be successful in cross cultural situations Global Managers (know how to adapt) Need to successfully apply management functions across interantional boundaries Global Learning goals Not universal Engage critical thinking Look everywhere for new management ideas Always consider culture
THE SOAR SYSTEM A solar system is a group of planets and other celestial bodies that revolve around a star. A solar nebula- a vast cloud of gas and dust, mostly hydrogen and helium. How the Solar System Form ⢠COLLAPSE AND SPINNING DISK FORMATION - Gravity pulls material inward. The cloud flattens into a spinning disk due to conservation of angular momentum. ⢠PROTOSTAR FORMATION- (BIRTH OF THE SUN). Material collects at the center, and begun to heat up. When it reaches to 10 million KELVIN, nuclear fusion begins. thus, SUN is born. ⢠PLANETESIMALS AND PROTOPLANETS. Dust and gas in the disk stick together via static and gravitational forces. These form planetesimals, which grow into protoplanets collision and accretion. ⢠PLANET FORMATION. Inner disk: too hot for gas rocky planets form Mercury, Venus, Earth, Mars. ⢠PLANET FORMATION. Outer disk: gas and ice giants. Jupiter, Saturn, Uranus, Neptune ⢠LEFTOVER DEBRIS. Remaining materials forms moon, asteroids, comets and dwarf planets. DIFFERENT HYPOTHESIS IN THE FORMATION OF SOLAR SYSTEM. 1. NEBULAR HYPOTHESIS- The Solar system formed from a rotating cloud of Gas and Dust (solar nebula). As it rotates conservation of angular momentum caused the cloud to flatten into a disk. the Sun formed at the center (DISK) while planets formed from the surrounding materials through acceleration. thus, it explains the coplanar and nearly circular orbit of the planets all planets orbits around the sun on the same flat, disk shaped plane. Proposed by Immanuel Kant in 1755 and Modified by Pierre Simon Laplace in 1756. PROTOPLANET HYPOTHESIS. The Solar system formed from a rotating cloud of Gas and Dust (solar nebula). As it rotates conservation of angular momentum caused the cloud to flatten into a disk. 2. Protoplanet hypothesis. Builds on the nebular model but focuses more on the role of planetesimals which then form into full planets. PROCESS: - Small solid particles stick together through collisions. As collisions takes place, it grows into kilometer-sized planetesimals. Gravitational interactions lead to the formation of planets. Lead to formation of steroids belts and varying planet sizes 3. Encounter hypothesis. States that the sun encountered a rogue star. The encounter led to the removal of hot gas from both stars due to their gravitational interaction. The hot gas then accumulated and formed the planets. The materials from the less dense rogue star formed the other planets, while that from the sun formed the inner planets. 4. TIDAL HYPOTHESIS. (also called the Tidal Theory) is an early scientific idea about how the solar system might have formed. Proposed by James Jeans and Harold Jeffreys. A massive star passed very close to the early Sun. The hot gas then accumulated and formed the planets. The materials from the less dense rogue star formed the other planets, while that from the sun formed the inner planets. Streams of hot gas were drawn out from the Sun in elongated shape. These streams eventually condensed and cooled, forming planets, moons, and other bodies in the solar system. 5. Not accepted theory. Later studies showed the streams of hot gas would disperse too quickly into space instead of condensing into planets. The theory also couldnāt explain the specific orbital patterns and compositions we see today. Modern science favors the Nebular Hypothesis, which explains solar system formation through the collapse of a rotating gas cloud. Earth as the only habitable planet 1. Right Distance from the Sun (The Goldilocks Zone). Not too hot, not too cold ā just right for liquid water to exist. 2. Atmosphere with Oxygen. Earth has a mix of gases, especially oxygen, which most living things need to survive. 3. Liquid Water. Earth has oceans, rivers, and rain ā water is essential for all life. 4. Magnetic Field. Earthās magnetic field protects us from harmful solar radiation. 5. Stable Climate. The atmosphere and natural cycles keep temperatures and weather mostly stable over time. 6. Rich Resources. Earth has soil for growing food, minerals, and energy sources that support life and technology. Solar explorations 1. AUGUST 6, 2014. First space craft to orbit a comet (ROSETTA PROBE). Captures the comet photograph. -Comets have coma and tail as it approaches to the sun. 2. JULY 14, 2015. NASAās New Horizons spacecraft made history by becoming the first spacecraft to fly by Pluto, giving us our first close-up look at the dwarf planet. First time visiting Pluto. Before this, Pluto was just a blurry dot in telescope images. Revealed a surprising world New Horizons showed mountains of ice, smooth plains, and a heart-shaped region called Tombaugh Regio. Changed what we knew. Scientists thought Pluto would be dull and frozen ā instead, it turned out to be geologically active and incredibly complex. 3. SEPTEMBER 8, 2016. NASA launched OSIRIS-REx, the first U.S. mission to collect a sample from an asteroid and return it to Earth. Changed what we knew. Scientists thought Pluto would be dull and frozen ā instead, it turned out to be geologically active and incredibly complex. OSIRIS-REx stands for: Origins, Spectral Interpretation, Resource Identification, SecurityāRegolith Explorer It was sent to study the asteroid Bennu, a near-Earth asteroid about 500 meters wide. Mission Goals: Collect a sample of surface material from Bennu Study the asteroidās omposition, structure, and history. Mission Goals: Help scientists understand the origins of the solar system. Learn more about asteroids that could impact Earth. 4. August 12, 2018: Launch of NASAās Parker Solar Probe, the first spacecraft to "touch" the Sun by flying through its outer atmosphere, called the corona. Mission Goal: To study the Sun up close and help scientists understand: How the solar wind (a stream of charged particles) is formed. Why the Sunās corona is hotter than its surface. What causes solar storms that can affect Earthās satellites and power grids. 5. November 26, 2018: NASAās Insight Lander Touches Down on Mars. Its mission was focused on studying the interior of the Red Planet (crust, mantle, and core of the planet). Why the Sunās corona is hotter than its surface. What causes solar storms that can affect Earthās satellites and power grids 6. November 26, 2018: NASAās Insight Lander Touches Down on Mars. Its mission was focused on studying the interior of the Red Planet (crust, mantle, and core of the planet) 7. JULY 30, 2020 PERSEVERANCE PROBE. Perseverance rover as part of the Mars 2020 mission aboard an Atlas V-541 rocket This marked a major step in Mars exploration. 8. DECEMBER 25, 2021-JAMES WEBB SPACE TELESCOPE. Investigate exoplanetsā atmospheres for signs of habitability. Observe the first galaxies formed after the Big Bang. Study the formation of stars and planetary systems. Look deeper into the infrared universe than ever before. RESULTS OF EXPLORATION ⢠Evidence of Ancient Life-friendly Environment. ⢠Sedimentary rocks formed in water-rich environments. ⢠Signs of clay and carbonate minerals, which can preserve biosignatures (traces of past life). ⢠Evidence of Ancient Life-friendly Environment. ⢠Sedimentary rocks formed in water-rich environments. ⢠Signs of clay and carbonate minerals, which can preserve biosignatures (traces of past life). ⢠Evidence of Ancient Life-friendly Environment. ⢠Sedimentary rocks formed in water-rich environments. ⢠Signs of clay and carbonate minerals, which can preserve biosignatures (traces of past life).
⢠There are two groups of animals which are important in agriculture. ⢠The groups are domestic and wild animals. 1. Domestic animals ⢠These are animals which are trained to live with people in their homes. ⢠Some examples includes : Uses of domestic animals ⢠Source of food, for example milk, eggs and meat. ⢠For cultural purposes, for example paying lobola. ⢠Some are used for transport and labour. ⢠Domestic animals can also be a source of income. 2 . Wild animals ⢠These are animals which are found in game reserves and in the forests ⢠They are also called game animals. ⢠Examples of wild animals are: Uses of wild animals ⢠Some of the wild animals give us meat, hides and ivory. ⢠Wild animals attract visitors from other countries, so the country gets money. Wednesday 06 September 2023 Exercise: Domestic animals 1. What is a domestic animal? [2] 2. What is a wild animal? [2] 3. Name any 4 domestic animals that you know. [4] 4. State any 2 uses of domestic animals. [2] 5. Name any 3 wild animals that you know. [3] 6. Give 2 uses of wild ani mals. [2] 7. Wild animals can also be called animals. [1] ⢠Animals, like human beings need good food to help them to grow and reproduce. ⢠The main sources of food for animals include stock feeds, pastures, veld grass, crop remains and cereal grains. ⢠These foods contain the most needed essential nutrients. Nutrient Function carbohydrates Gives energy Fats Give energy and warmth Proteins Helps in growth and repair of body parts Minerals Help in the formation of bones and teeth Vitamins Help develop good sight, improve fertility and help animals fight diseases Water Transports food in the body, cools the body and remove waste from the body. ⢠Livestock are domesticated animals that are kept for food, use or for sale. ⢠Small livestock has many uses. ⢠They are a good source of food. ⢠They also give us manure to use in gardens. ⢠We get clothes and medicine as well from small livestock ⢠Examples of small livestock are rabbits, sheep, goats and all form of poultry Poultry ⢠All animals that are kept by farmers which have wings and feathers and lay eggs are called poultry. ⢠They are a good source of white meat, eggs and manure. ⢠They are also a source of income when we well them and their products. ⢠Poultry includes chicken, guinea fowl, ducks, turkey, pigeons and quail birds. Rabbits ⢠Rabbits have 3 known uses which are: ļ¼They are kept for meat ļ¼Kept for pelts. (pelt is animal skin used to make blankets, hats and jackets) ļ¼They are used at agricultural shows ⢠Rabbits are cheap to buy, easy to keep and feed. ⢠They take about 4 months to mature. ⢠Rabbits are fed using green vegetables and rabbit pellets. Wednesday 20 September 2023 Small livestock 1. Give 3 examples of small livestock. [3] 2. State 3 things that are provided by small livestock. [3] 3. What are the 2 uses of rabbits? [2] 4. Pelts are used to make _________________ [1] 5. State any 4 examples poultry. [4] 6. Rabbits take ___________ months to mature. [1] 7. What is poultry? ⢠Apiculture is the keeping of bees in order for them to produce honey for sale. ⢠Apiculture is very important because: (i) Provides honey - a valuable nutritional food (ii) Provides bees wax - which has many uses in industry Uses of wax ļ¼For making candles ļ¼Polish furniture ļ¼Make crayons ļ¼Prevent tools from rusting (iii) Honey bees are excellent pollinating agents, thus increasing agricultural yields. BEE COLONY Inhabitants of the bee colony and their roles ⢠A honey bee colony typically consists of three kinds of adult bees: ļ¼ļ workers, drones and the queen 1. Workers ⢠Workers are the smallest and constitute the majority of bees occupying the colony. ⢠They do not lay eggs. ⢠Workers have specialized structures, such as brood food glands, scent glands, wax glands, and pollen baskets. ⢠these allow them to perform all the labors of the hive. Roles of the worker bees ļ¼they forage for nectar, pollen, water, and plant sap. ļ¼They clean and polish the cells. ļ¼feed the brood. ļ¼care for the queen. ļ¼remove debris. ļ¼handle incoming nectar. ļ¼build beeswax combs. ļ¼guard the entrance. 2. Drones ⢠Drones (male bees) are the largest bees in the colony. ⢠They are generally present only during late spring and summer. ⢠The droneās head is much larger than that of either the queen or worker. ⢠Drones have no stinger, pollen baskets, or wax glands. ⢠Their main function is to mate with the queen. 3 . Queen ⢠Each colony has only one queen. ⢠The queen is the largest of the bees in a bee colony. ⢠The Queen Bee plays a vital role in the hive because she is the only female with fully developed ovaries. ⢠She produces both fertilized and unfertilized eggs. ⢠Queens lay the greatest number of eggs in the spring and early summer. ⢠The queen also produce chemical scents that help regulate the unity of the colony. 1. What is apiculture? [2] 2. Give 3 reasons why apiculture is important in Zimbabwe. [3] 3. Name the 3 inhabitants of the bee colony. [3] 4. Briefly explain the roles of each inhabitant named in number 3. ⢠Apart from using hand tools, farmers also use some farm implements and machinery to carry out their field work. ⢠Machines help farmers do their work more easily and quickly. ⢠The most common implements used by farmers to grow, harvest and transport their produces are: ļ¼ mouldboard plough ļ¼Cultivator ļ¼Scotch cart ļ¼Harrow ļ¼Planter ļ¼Maize sheller ļ¼ combine harvesters ļ¼Boom sprayers Disc harrow Spike toothed harrow KNAPSACK SPRAYER ⢠Farming is a business. ⢠Communal farmers grow crops and keep animal mainly for their own use. ⢠If there is any extra they sell to get money. ⢠Commercial farmers grow crops and keep animals for sale. ⢠Crops and animals produced are called farm produce. ⢠There are places were farmers have to sell their produce. ⢠Farmers can take their produce to local markets. ⢠A market is a place where buying and selling occurs. ⢠Some of the local markets includes: ļ¼A shopping centre ļ¼A school ļ¼A nearest bus stop ļ¼A local village ļ¼A school ļ¼Local Grain Marketing Board depot (GMB) Types of farm produce ļ¼Beef ļ¼Fruits ļ¼Mutton ļ¼Eggs ļ¼Vegetables ļ¼Pork ļ¼Milk ļ¼Chicken ļ¼Cereals/grains ļ¼beans
Based on the provided sources, here is a comprehensive extraction of the information regarding the water cycle, energy transfer, and Earth's wind systems, organized into key points: The Water Cycle and Its Reservoirs ⢠Definition: The water cycle is the continuous movement of water among various reservoirs on Earth. ⢠Water Reservoirs: These are storage locations for water and include: ⦠Oceans, seas, and lakes. ⦠Rivers, glaciers, soil, and rocks. ⦠The atmosphere and living organisms. ⢠Total Volume: The total amount of water on Earth does not change, even when it changes state, because it is constantly being replaced or recycled through the cycle. Main Processes and Energy Transfer The movement of water through the cycle is driven by energy (thermal energy from the Sun) and force (gravity and wind). ⢠Energy Gain (Absorption): ⦠Melting: Water changes from a solid state (ice) to a liquid state and gains energy. ⦠Evaporation: Liquid water changes into a gas state (water vapor) by gaining thermal energy. ⦠Transpiration: A specialized type of evaporation occurring in plants where water vapor is released through tiny holes in leaves called stomata. Approximately 10% of water vapor in the air comes from transpiration. ⢠Energy Loss (Release): ⦠Condensation: Water vapor (gas) cools down and changes back into liquid water, releasing energy. ⦠Freezing: Liquid water changes into a solid state (ice) and loses energy. ⢠Other Key Steps: ⦠Precipitation: Water falls back to Earth as rain, snow, sleet, or hail (snow pellets). ⦠Runoff: Water flows over Earth's surface into streams, rivers, and eventually larger bodies of water like oceans. ⦠Collection: Rainwater is collected in different water bodies to start the cycle again. Forces Driving Water Movement ⢠Gravity: The main force that pulls water downward. It is responsible for: ⦠Bringing precipitation (rain and snow) from clouds to the surface. ⦠Moving ice in glaciers from higher to lower elevations. ⦠Causing liquid water to flow downhill into rivers and seas. ⦠Leakage: Pulling liquid water down into the ground to reach groundwater reservoirs. ⢠Wind: Another force that affects water movement and transports water to different locations on Earth. Atmospheric Processes ⢠Cloud Formation: Water vapor attaches to particles such as dust or smoke in the air and condenses into tiny droplets. When millions of these droplets join, they become heavy and fall as rain. ⢠Convection: The transfer of heat in liquids and gases. ⦠Warm air/liquid: Becomes less dense, lighter, and rises upward. ⦠Cold air/liquid: Is more dense, heavier, and moves downward to replace the warm fluid. ⦠This process leads to convection currents, which help determine regional climates and drive wind and ocean currents. Solar Radiation and Climate The amount of solar energy reaching Earth differs from place to place, which affects the weather: ⢠Hottest Regions (Equator): Sun rays fall perpendicular (vertical). Heat is concentrated on a small area, making the weather hot. ⢠Moderate Regions: Sun rays fall semi-inclined. Heat is distributed over a larger area, making the weather warm. ⢠Coolest Regions (Poles): Sun rays fall very slanted (inclined). Heat is spread over a very large area, making the weather very cold. Earth's Wind System ⢠Wind Formation: Wind is generated when warm air (heated by the Sun) rises and is replaced by cooler air flowing from nearby areas. ⢠Factors Affecting Wind: The amount of solar radiation and the rotation of Earth determine global wind directions. ⢠Global Wind Cycle: Unequal heating between the equator and the poles generates a constant wind system. Warm air rises at the equator and moves toward the poles, while cold air from the poles moves toward the equator. ⢠Importance: If there were no wind, the equator would become extremely hot, the poles would freeze solid, and many ecosystems would disappear. Practical Examples ⢠Turkeyās Salt Lake: High evaporation in the summer can turn this large lake into a small puddle or dry it up completely. It is a critical site for flamingos, which migrate there to breed and feed on algae in the shallow, warm water.
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 biologyāthe 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 organismās 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 Ā© by Holt, Rinehart and Winston. All rights reserved. ORGANISM (Barn Owl) ORGAN (Owlās 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 lifeās 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 owlās ner- vous system is made up of a brain, sense organs, nerve cells, and other parts that sense and respond to the owlās surroundings. Organ systems are made up of organs. Organs are structures that carry out specialized jobs within an organ system. An owlās 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 stimulusāa 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 āsmall room,ā or āhutā 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 cellās 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 doesnāt 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 owlās temperature is maintained at about 40°C (104°F). To keep a constant temperature, an owlās cells burn fuel to produce body heat. In addition, an owlās feathers can fluff up in cold weather. In this way, they trap an insulating layer of air next to the birdās 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 sunās energy to generate sugar molecules during a process called photosynthesis. Some organisms depend on obtaining food energy from other organisms. For instance, an owlās 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 frogsā 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 booksāgenesāthat 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 frogās sperm can fertilize a femaleās 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 personās 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 donāt 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 ātree of lifeā 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- vidualās 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 ātreeā 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 Ā© 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 researcherās conclusions. SECTION 3 OBJECTIVES ā Outline the main steps in the scientific method. ā Summarize how observations are used to form hypotheses. ā List the elements of a controlled experiment. ā Describe how scientists use data to draw conclusions. ā Compare a scientific hypothesis and a scientific theory. ā 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 Ā© 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 questionāhypotheses. 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 preyās 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 mouseās 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 preyās body heat. 3 1 2 Copyright Ā© 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 mouseās 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 owlās strike relative to each mouseās 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 owlās 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 teacherās 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 owlās strike to the mouseās head. Testing the Experiment Some controlled experiments are conducted āblind.ā 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 variableāthe dependent variable. This measurement provides quantitative data, data measured in numbers. For example, in the experiment above, scientists mea- sured the distance of an owlās strike from the preyās head in cen- timeters, as shown in step of Figure 1-9. An eventās 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 owlās strike relative to the mouseās 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 mouseās 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 Ā© 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 ātheoryā in a different way than scientists use the word. People may say āItās just a theoryā 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 Ā© by Holt, Rinehart and Winston. All rights reserved. Biologists often apply their knowledge of the natural world to practical problems. Studies on the owlās 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 āspend a great deal of time at a lab bench running analysis after analysis.ā Many of the methods used in animal forensics, such as DNA sequenc- ing, are also used in human forensics. Education and Skills ⢠High schoolāthree years of science courses and four years of math courses. ⢠Collegeābachelor of science in biol- ogy, including course work in zoology and genetics, plus experience in per- forming DNA analyses. ⢠Skillsāpatience, 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, āitās just a theoryā misleading? 6. Give another example of a conflict of interest. CRITICAL THINKING 7. Making Hypotheses On a nocturnal owlās 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 owlās 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 otherās 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 drugās 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 drugās 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 Ā© 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 siteās 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 ādot govā or .gov), by educational institutions (ends in ādot eduā or .edu), by organizations (ends in ādot orgā or .org), or by commercial businesses (ends in ādot comā 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 siteās 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 natureās 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 ā List the function of each of the major parts of a compound light microscope. ā Compare two kinds of electron microscopes. ā Describe the importance of having the SI system of measurement. ā 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 Ā© 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 objectās 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 specimenās 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 2 Early Theories on the Origin of Life ⢠Identify the different theories on the origin of life. ⢠Describe each theory and determine their differences What are the characteristics of living things? Before learning about the history of Earth based on geological evidence, early scientists explored the possibilities of how the first life-form existed. There are several theories about the origin of life. Theory of Catastrophism The theory of catastrophism supported by French scientists Georges Cuvier (1769-1832) and Alcide Dessalines d'Orbigny (1802-1857), is said to be a modification of the creation story of the Bible. It states that there have been several living creations from God, each encountered a catastrophe that completely destroyed them. Each new creation consisted of new life-forms, which happen to be different from the previous ones. Theory of Abiogenesis The theory of abiogenesis, or the spontaneous generation theory, states that living things were naturally created from nonliving things such as simple organic compounds. The theory supposes that abiogenesis occurred between 3.8 and 4 Gya. The experiment performed by Stanley Miller in 1953 gave way to many speculations and studies on how life on Earth really began. His research involved a simulation of the possible environment on Earth in the past. He demonstrated how an electric spark (which is a simulation for lightning) when passed through simple organic gases (similar to the early Earth atmosphere), resulted in the formation of amino acids, which are now known as the building blocks of proteins and the components of living tissues. Theory of Biogenesis The theory of biogenesis presented a strong argument against abiogenesis. This theory states that living things come from living things. Experiments of Francesco Redi and Louis Pasteur disproved the thought of spontaneous generation during their time (figure 5-1). Louis Pasteur argued that life comes from preexisting life and not from nonliving material. However, it should be noted that the "abiogenesis" or "spontaneous generation" that he opposed referred to any modern, existing, fully-formed organisms, not the original generation of life. Louis Pasteur's law of biogenesis contradicted the common belief during his time that cattle dung gives rise to flies, or old clothes with rotten food gives rise to mice. The idea of spontaneous generation was popular until near the seventeenth century. Even famous scientists of that period, such as Descartes, Galileo, and Jan Baptista van Helmont, believed in this theory. CIENCE PIONEER Francesco Redi (1626-1697). Francesco Redi is a physician, a naturalist, and a poet. His works challenged the popular theory of spontaneous generation. He disproved the idea that living things may arise from nonliving things. He also worked on toxicology using viper's venom. He discovered and worked on some parasites that caused disease in humans. SCIENCE CAREER Evolutionary Biologist An evolutionary biologist studies the descent of species and the origin of new species of living things. Working as evolutionary biologist means studying and researching species diversity, their interaction with the environment, their adaptation to change, their ancestors, and their possible origins. This career is important in the field of science because it seeks an answer to the questions about how life began on Earth.
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