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Unit 2: Physical Geography
Quiz by Armando Morfin
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To the Lakota, and other indigenous people on North America's Great Plains, the bison was an essential part of their culture ( expressed in the quote on the previous page). The bison provided meat for nutrition, a hide for clothing and shelter, bones for tools, and fat for soap. The bison was also central to their religious beliefs. So, when European settlers hunted the bison nearly to extinction, Lakota culture suffered. Culture is central to a society and the identity of its people, as well as its continued existence. Therefore, geographers study culture as a way to understand similarities and differences among societies across the world, and in some cases, to help preserve these societies. Analyzing Culture All of a group's learned behaviors, actions, beliefs, and objects are a part of culture. It is a visible force seen in a group's actions, possessions, and influence on the landscape. For example, in a large city you can see people working in offices, factories, and stores, and living in high-rise apartments or suburban homes. You might observe them attending movies, concerts, or sporting events. Culture is also an invisible force guiding people through shared belief systems, customs, and traditions. Culture is learned, in that it develops through experiences, and not merely transmitted through genetics. For example, many people in the United States have developed a strong sense of competitiveness in school and business, and believe that hard work is a key to success. These types of elements, visible and invisible, are cultural traits. A series of interrelated traits make up a cultural complex, such as the process of steps and acceptable behaviors related to greeting a person in different cultures. A single cultural artifact, such as an automobile, may represent many different values, beliefs, behaviors and traditions and be representative of a cultural complex. Since culture is learned there are many ways that one generation passes its culture to the next. Children and adults learn traits three ways: • imitation, as when learning a language by repeating sounds or behaviors from a person or television • informal instruction, as when a parent reminds a child to say "please" • formal instruction, as when students learn history in school 132 HUMAN GEOGRAPHY: AP" EDITION CULTURAL COMPLEX OF THE AUTOMOBILE The automobile provides much more than just transportation, as it reflects many values that are central to American culture. Origins of Culture The area in which a unique culture or a specific trait develops is a culture hearth. Classical Greece was a culture hearth for democracy more than 2,000 years ago. New York City was a culture hearth for rap music in the 1970s. Geographers study how cultures develop in hearths and diffuse-or spread-to other places. Geographers also study taboos, behaviors heavily discouraged by a culture. For example, many cultures have taboos against eating certain foods, such as pork or insects. What is considered taboo changes over time. In the United States, marriages between Protestants and Catholics were once taboo, but they are not widely opposed now. Traditional, Folk, and Indigenous Cultures With the beginning of the Industrial Revolution in the late 18th century, modern transportation and communication connected people as never before and led to extensive cultural mixing, especially as cities have grown. The world prior to this time was very different; however, remnants of the past are still evident in our modern cultures. Traditional, folk, and indigenous cultures share some important characteristics and are often grouped together, but they do have some subtle differences. Traditional Culture Recently, the meanings of traditional, folk, and indigenous culture have begun to merge, causing geographers to debate when each should be used. Increasingly, the term traditional culture is used to encompass all three cultural designations. All three types share the function of passing down long-held beliefs, values, and practices and are generally resistant to rapid changes in their culture. Folk Culture The beliefs and practices of small, homogenous groups of people, often living in rural areas that are relatively isolated and slow to change, are known as folk cultures. Like all cultures, they demonstrate the diverse ways that people have adapted to a physical environment. For example, people around the world learned to make shelters out of available resources, whether 3.1: INTRODUCTION TO CULTURE 133 it was snow or mud bricks or wood. However, people used similar resources such as wood differently. In Scandinavia, people used trees to build cabins. In the American Midwest, people processed trees into boards, built a frame, and attached the boards to it. Many traits of folk culture continue today. Corn was first grown in Mexico around 10,000 years ago, and it is still grown there today. While many elements of folk culture exist side by side with modern culture, there are people whose societies have changed little, if at all, from long ago. These people practice traditional cultures, those which have not been affected by modern technology or influences. They often live in remote regions, such as some small tribes in the Amazon rainforest, and have scant knowledge of the outside world. As the lines continue blurring between cultural designations, the Amish of Pennsylvania are often referenced as both folk and traditional culture. Indigenous Culture When members of an ethnic group reside in their ancestral lands, and typically possess unique cultural traits, such as speaking their own exclusive language, they are considered an indigenous culture. Some indigenous peoples have been displaced from their native lands, but still practice their indigenous culture. Native Americans in the United States, such as the Navajo, have kept indigenous cultural practices. First Nations of Canada, such as the Inuit, have also retained their indigenous culture. Globalization and Popular Culture As a result of the Industrial Revolution, improvements in transportation and communication have shortened the time required for movement, trade, or other forms of interaction between two places. This development, known as space-time compression (see Topics 1.4 and 3.6), has accelerated culture change around the world. In 1817, a freight shipment from Cincinnati needed 52 days to reach New York City. By 1850, because of canals and railroads, it took half that long. And by 1852, it took only 7 days. Today, an airplane flight takes only a few hours, and digital information takes seconds or less. Similar change has occurred on the global scale. People travel freely across the world in a matter of hours, and communication has advanced to a point where people share information instantaneously across the globe. The increased global interaction has had a profound impact on cultures, from spreading English across the world to instant sharing of news, events and music. Globalization specifically refers to the increased integration of the world economy since the 1970s. The process of intensified interaction among peoples, governments, and companies of different countries around the globe has had profound impacts on culture. The culture of the United States is intertwined with globalization. Through the influence of its corporations, Hollywood movies, and government, the United States exerts widespread influence in other countries. But other countries also shape American culture. For example, in 2019, the National Basketball Association included players from 38 countries or territories. When cultural traits- such as clothing, music, movies, and types of 134 HUMAN GEOGRAPHY: AP. EDITION businesses-spread quickly over a large area and are adopted by various groups, they become part of popular culture. Elements of popular culture often begin in urban areas and diffuse quickly through globalization processes such as the media and Internet. These elements can quickly be adopted worldwide, making them part of global culture. People around the world follow European soccer, Indian Bollywood movies, and Japanese animation known as anime. With people in many nations wearing similar clothes, listening to similar music, and eating similar food, popular cultural traits often promote uniformity in beliefs, values, and the cultural landscape across many places The cultural landscape, also known as the built environment (see Topic 3.2), is the modification of the environment by a group and is a visible reflection of that group's cultural beliefs and values. Traditional Culture to Popular Culture Popular culture emphasizes trying what is new rather than preserving what is traditional. Many people, especially older generations or those who follow a folk culture, openly resist the adoption of popular cultural traits. They do this by preserving traditional languages, religions, values, and foods. While older generations often resist the adoption of popular culture, they seldom are successful in keeping their traditional cultures from changing, especially among the young people of their society. One clash between popular and traditional culture is occurring in Brazil. As the population expands to the interior of the rain forest, many indigenous cultures, like the Yanamamo tribe, have more contact with outside groups. Remaining isolated by the forest is becoming increasingly difficult as many young people from the indigenous cultures become exposed to popular culture and begin to integrate into the larger Brazilian society. As the young people leave their communities, they are more likely to accept popular culture at the expense of their indigenous cultural heritage, which threatens the very existence of their folk culture. Traditional culture typically exhibits horizontal diversity, meaning each traditional culture has its own customs and language that makes it distinct from other culture groups. Yet, people people within each group are usually homogeneous, or very similar to each other. By contrast, popular culture typically exhibits vertical diversity, meaning that modern urban societies are usually heterogeneous, or exhibiting differences, within the society and usually contain numerous multiethnic neighborhoods. However, on a global scale popular cultures are relatively similar with the same type of malls, shops, fast food, and clothing. Urban global culture centers are not identical, yet, global cities often do not have as much horizontal diversity across space as folk cultures. 3.1: INTRODUCTION TO CULTURE 135 COMPARING TRADITIONAL AND POPULAR CULTURE Trait Traditional Culture Popular or Global Culture Society • Rural and isolated location • Urban and connected location • Homogeneous and • Diverse and multiethnic indigenous population population • Most people speak an • Many people speak a global indigenous or ethnic local language such as English or language Arabic • Horizontal diversity • Vertical diversity Social • Emphasis on community and • Emphasis on individualism and Structure conformity making choices • Families live close to each • Dispersed families other • Weakly defined gender roles • Well-defined gender roles Diffusion • Relatively slow and limited • Relatively rapid and extensive • Primarily through relocation • Often hierarchical • Oral traditions and stories • Social media and mass media Buildings and • Materials produced locally, • Materials produced in distant Housing such as stone or grass factories, such as steel or glass • Built by community or owner • Built by a business • Similar style for community • Variety of architectural styles • Different between cultures • Similar between cities • Traditional architecture • Postmodern / contemporary architecture Food • Locally produced • Often imported • Choices limited by tradition • Wide range of choice • Prepared by the family or • Purchased in restaurants community Spatial Focus • Local and regional • National and global Artifacts, Mentifacts, and Sociofacts Whether a cultural attribute is considered traditional, folk, indigenous, or popular in nature, it is valuable to differentiate between elements of culture that can be seen and those that can not. There are artifacts that comprise the material culture, which consists of tangible things, or those that can be experienced by the senses. Art, clothing, food, music, sports, and housing types are all tangible elements of culture. Another element of the study of artifacts is understanding the techniques to use or build a specific artifact. Artifacts can be unique to a particular culture, or can be shared. For example, people of all cultures need to communicate through language, yet there are many groups that possess languages unique to their culture. The ability to read, write and understand the English language is an artifact of importance for much of popular global culture. 136 HUMAN GEOGRAPHY: AP" EDITION Mentifacts comprise a group's nonmaterial culture and consist ofintangible concepts, or those not having a physical presence. Beliefs, values, practices, and aesthetics (pleasing in appearance) determine what a cultural group views as acceptable and desirable. Mentifacts can also be unique or shared. People of many cultures possess an belief in one or many deities, and often the deities are unique to that culture. The belief in a god is a mentifact-the religious building or symbols are artifacts. Cultural groups also possess sociofacts, which are the ways people organize their society and relate to one another. Taken altogether, people tend to see the whole of their culture as greater than the sum of its individual parts. Sociofacts are embodied through families, governments, sports teams, religious organizations, education systems, and other social constructs. As with artifacts and mentifacts, sociofacts may also be unique or similar to other societies. Families are the foundations of most societies, yet what constitutes the structure of a family may vary widely between cultural groups. For example, Western cultures tend to view the nuclear family, consisting of the parents and their children as the basic family unit. By contrast, in many Western African cultures the norm is the extended family, consisting of several generations and other family members such as cousins living under one roof.Health 11/12 Review for Final Exam Core Concepts - Mental and Emotional Health, Substance Abuse Prevention, Safety and Violence Prevention, Family Life and Human Sexuality, Disease Prevention and Control, Healthy Eating Health Education Skills - goal setting, decision making, accessing information/resources, analyzing influences, communication, self-management, advocacy DIMENSIONS of Wellness - social, spiritual, emotional/mental, environmental, financial, intellectual, multicultural, occupational, physical, sexual RISK factors - anything that increases the risk of disease, injury, or illness. PROTECTIVE factors - anything that decreases the risk of disease, injury, or illness. INTERNAL health factors - health factors that can be either hereditary and genetic or acquired elements -- include smoking and personal diet or eating habits. Example – a genetic predisposition to an illness. EXTERNAL health factors - health factors that are part of the direct outer environment, the geographical location, micro-organisms, socio-economic elements that could affect an individual's health. Example – being unable to afford mental health services. Unit 1- Managing Personal and Community Wellness Explain Maslow’s Hierarchy of Needs in your own words using the image provided. Explain how each Social Determinant of Health may impact a person’s health. Levels of Disease Prevention • PRIMARY The goal is to avoid conditions altogether. • SECONDARY The goal is early detection. • TERTIARY The goal is to minimize the damage (manage). Define the following terms. Fads/Trends Sleep hygiene Driver safety Unit 2- Investigating Social Ecological Factors on Well-Being Socio-Ecological Model – The SEM examines how health behaviors form based on characteristics of individuals, communities, nations and levels in between. Each level overlaps with other levels signifying how the best public health strategies are those that encompass and target a wide range of perspectives. Interpersonal (personal) health vs. intrapersonal (relationship) health Health INEQUITY - systemic, ingrained and unjust barriers that prevent segments of the population from having the opportunity of health leading to health disparity. IMPLICIT BIAS - a form of bias that occurs automatically and unintentionally, that nevertheless affects judgments, decisions, and behaviors. Research has shown implicit bias can contribute to unequal access to quality healthcare, negative patient-provider relationships and interactions; and create mistrust in the healthcare system and practitioners among patients. This can contribute to health disparities. Health DISPARITY - represents a difference in health between populations. It is often used to describe disease burden and other negative health outcomes socially disadvantaged groups may face. Health EQUITY - The opposite of health inequity. It describes a system that supports a high standard of health and healthcare for all people. Racism - Beliefs, attitudes, institutional arrangements, and acts that tend to denigrate individuals or groups because of phenotypic characteristics or ethnic group affiliation. DISCRIMINATION - An unjust differential treatment of a person or a group. PRIVILEGE- The unearned access to resources and social power that are only available to some because of their membership within certain social groups. OPPRESSION is the act of taking away choices from others and can be defined as a system that maintains advantage and disadvantage based on social identities and that acts on multiple levels from interpersonal to institutional and societal. (internalized, interpersonal, institutional, structural) Systematic Oppression - Intentional disadvantage of groups of people based on their identity while advantaging members of dominant group (race, gender, sexual orientation, language, size, ability, etc.). Intersectionality - The complex, cumulative way in which the effects of multiple forms of discrimination (such as racism, sexism, and classism) combine, overlap, or intersect especially in the experiences of marginalized individuals or groups Unit 3- Accessing Resources and Communicating to Support Mental and Emotional Health What is anger? What is anxiety? What is stress? STRESSORS are the things that cause stress. Stressors can be internal and external. A stressor may be a one-time or short-term occurrence, or it can happen repeatedly over a long time. INTERNAL Stressors - are made by your belief system and the way you evaluate yourself. Examples include pessimistic attitude, negative self-talk, deep need to be perfect, low self-esteem or body image, unhealthy standards for self. EXTERNAL Stressors - are stressful things that happen in your surroundings and/or in your environment. Examples include busy schedules, work problems, family issues, financial trouble, social problems, injury, unforeseen circumstances. Socio-economic issues are also a part of external stressors such as poverty, violence, and racism. Define the following mental health conditions. Depression Eating disorders NSSI Non-suicidal self-injury Grief/Loss Suicide prevention A.C.T. • ACKNOWLEDGE- Tell them in a caring way that you recognize that they are having a problem • CARE- You can show you care by actively listening - put away anything else you are doing, make eye contact, sit down, ask questions. • TELL-(call 988 for additional help and support) - Tell them it is important that they speak with a trusted adult. Help them figure out who this may be and offer to go with your friend. A social norm is an unwritten, informal rule meant to guide behavior among the of society. It distinguishes between acceptable and unacceptable, good and bad, and so on. Social norms can influence a person with emotional or mental health disorders, access to care and stigmatize their situation. STIGMA- a mark of disgrace associated with a particular circumstance, quality, or person. • Self-stigma - This describes the internalized stigma that people with mental health conditions feel about themselves. • Public stigma - This refers to the negative attitudes around mental health from people in society. • Institutional stigma - This is a type of systemic stigma that arises from corporations, governments, and other institutions. Unit 4- Evaluating Risks of Substance Use and Abuse Harm Reduction - a set of practical strategies and ideas aimed at reducing negative consequences associated with drug use. Explain how each level of the Social Ecological Model is impacted by addiction. Individual Relationship Community Society SEM Level Contributing/Risk Factors to substance use Preventative/Protective Factors for substance use Individual Interpersonal/Relationship Community Society Unit 5- Analyzing Influences to Examine Ways to Increase Safety and Reduce Violence HATE CRIME - a crime, usually violent, motivated by prejudice or intolerance toward an individual’s national origin, ethnicity, color, religion, gender, gender identity, sexual orientation, or disability. Explain how the media influences violence in society. The Pyramid of Hate Explain the escalation of hate using the Pyramid of Hate visual. List several hate crime motivators. Example: age HEALTHY Relationship Signs - comfortable pace, trust, honesty, independence, respect, equality, kindness, taking responsibility, healthy conflict, fun UNHEALTHY Relationship Signs - intensity, possessiveness, manipulation, isolation, sabotage, belittling, guilting, volatility, deflecting responsibility, betrayal Sexual Assault is a sexual behavior WITHOUT consent. Human trafficking - the recruitment, harboring, transportation, provision, or obtaining of a person for labor or services, using force, fraud, or coercion for the purpose of subjection to involuntary servitude, peonage, debt bondage, or slavery. Sex trafficking - commercial sex act induced by force, fraud, or coercion, or in which the person induced to perform such an act has not attained 18 years of age. Trafficking happens using… • Force - using violence to control someone. • Fraud - using lies to control someone. • Coercion - using threats to control someone. Unit 6- Family Life and Human Sexuality Agency - A belief about yourself and the extent to which you can act on that belief. • The ability to choose freely one’s own narrative. • To embrace the idea that I am the cause (or agent) of my own thoughts and actions. • Personal agency is a personal responsibility for who we are, what we experience, what we do about that experience, and how we shape our world to give us more of the experiences we want. SEXUAL Agency • The ability to choose your own interests and desires vs. what we see in the media or others’ perceptions • The ability to identify, communicate, and negotiate one’s sexual needs • The ability to initiate behaviors that allow for the satisfaction of those needs Sexually Explicit Material - photographs, videos, films, magazines, and books whose primary themes, topics, or depictions involve sexuality that may cause sexual arousal. Sexual scripts - thoughts, patterns, or behavior that a person has about themselves in a romantic or sexual context. It is how people picture themselves or want to project themselves in front of others. Reproductive Rights of Teens - In Maryland, teens have the right to an abortion, keep their child, obtain and use birth control, paternity tests, adoption, give up custody of their child within 10 days of birth (Safe Haven Law). • REPRODUCTIVE RIGHTS- legal rights and the freedom of the individual to control decisions regarding contraception, abortion, sterilization and childbirth. • SAFE HAVEN LAW- a distressed parent who is unable or unwilling to care for their infant can safely give up custody of their baby, no questions asked. CONSENT is an agreement between participants to engage in sexual activity. • It is clearly and freely communicated, verbal, and affirmative. Consent CANNOT be given if… • A person is underage, one or both partners is intoxicated or incapacitated by drugs or alcohol, one partner is asleep or unconscious, one partner feels pressured, threatened or intimidated, or one partner holds a position of power or authority over the other. Unit 7- Advocating for Enhanced Nutrition, Food Systems, and Health Outcomes Dietary Guidelines for Americans Guideline 1: Follow a Healthy Dietary Pattern at Every Life Stage Guideline 2: Customize and Enjoy Food and Beverage Choices to Reflect Personal Preferences, Cultural Traditions, and Budgetary Considerations Guideline 3: Focus on Meeting Food Group Needs with Nutrient-Dense Foods and Beverages, and Stay Within Calorie Limits Guideline 4: Limit Foods and Beverages Higher in Added Sugars, Saturated Fat, and Sodium, and Limit Alcoholic Beverages FOOD DESERT- a neighborhood where there is little or limited access to healthy and affordable food such as fruits, vegetables, whole grains, low-fat milk and other foods that make up the full range of a healthy diet. FOOD INSEQURITY lack of access to a sufficient amount of food because of limited funds. More than 49 million American households are considered food insecure and are vulnerable to poor health as a result. PROCCESED FOODS- any raw agricultural commodities that have been washed, cleaned, milled, cut, chopped, heated, pasteurized, blanched, cooked, canned, frozen, dried, dehydrated, mixed or packaged — anything done to them that alters their natural state.Physical Science Unit 2 ReviewHere’s a **quiz on Lesson 1: Introduction to Analog Communication (Unit 8)** based on your file 👇 --- # 🧠 **Quiz – Lesson 1 (Analog Communication)** **Marks:** 20 --- ## ✍️ **Part 1: Choose the correct answer (8 marks)** 1. A signal is: a) A device b) A physical quantity that carries information c) A type of wire d) A computer 2. A continuous signal is defined over: a) Discrete values b) Infinite real values c) Only integers d) Binary values 3. Digital signals have: a) Infinite values b) Two values (0 and 1) c) Random values d) Analog values 4. Sampling is used to: a) Increase noise b) Convert analog to digital c) Amplify signals d) Reduce bandwidth 5. A deterministic signal: a) Cannot be predicted b) Has known values c) Is always random d) Has no pattern 6. Even signal satisfies: a) x(t) = -x(-t) b) x(t) = x(-t) c) x(t) = 0 d) x(t) ≠ x(-t) 7. Periodic signal repeats after: a) Time T b) Infinite time c) No time d) Random time 8. A system is: a) A signal only b) Input only c) Takes input and gives output d) A wire --- ## ✍️ **Part 2: Complete (6 marks)** 1. A signal can be represented as __________. 2. Continuous signals are defined over __________ values. 3. Digital signals take values like __________ and __________. 4. A random signal cannot be __________ easily. 5. Odd signal satisfies __________. 6. A periodic signal repeats every __________. --- ## ✍️ **Part 3: True or False (6 marks)** 1. Analog signals are continuous. ( ) 2. Digital signals can take infinite values. ( ) 3. Sampling converts analog to digital signal. ( ) 4. Deterministic signals are predictable. ( ) 5. Odd signals pass through origin. ( ) 6. Aperiodic signals repeat over time. ( ) --- ## 🎯 **Bonus Question (Optional)** Give one example of: * Analog signal * Digital signal -Make a test, with answers best on the following: Conduct an investigation to provide evidence that living things are made of cells; either one cell or many different numbers and types of cells. Supporting Content LS1.A: Structure and Function • All living things are made up of cells, which is the smallest unit that can be said to be alive. An organism may consist of one single cell (unicellular) or many different numbers and types of cells (multicellular). (MS-LS-1.1) Further Explanation: Emphasis is on developing evidence that living things are made of cells, distinguishing between living and non-living things, and understanding that living things may be made of one cell or many and varied cells. In multicellular organisms, the body is a system of multiple interacting subsystems. These subsystems are groups of cells that work together to form tissues and organs that are specialized for particular body functions. (MS-LS-1.3) Further Explanation: Emphasis is on the conceptual understanding that cells form tissues and tissues form organs specialized for particular body functions. Examples could include the interaction of subsystems within a system and the normal functioning of those systems. Organisms reproduce, either sexually or asexually, and transfer their genetic information to their offspring. (MS-LS-1.4) • Living things share certain characteristics. (These include response to environment, reproduction, energy use, growth and development, life cycles, made of cells, etc.) (MS-LS1.4) Further Explanation: Examples should include both biotic and abiotic items, and should be defended using accepted characteristics of life. Plants, algae (including phytoplankton), and many microorganisms use the energy from light to make sugars (food) from carbon dioxide from the atmosphere and water through the process of photosynthesis, which also releases oxygen. These sugars can be used immediately or stored for growth or later use. (MS-LS-1.5) Further Explanation: Emphasis is on tracing movement of matter and flow of energy. Supporting Content LS1.C: Organization for Matter and Energy Flow in Organisms • Within individual organisms, food moves through a series of chemical reactions (cellular respiration) in which it is broken down and rearranged to form new molecules, to support growth, or to release energy. (MS-LS-1.6) Further Explanation: Emphasis is on describing that molecules are broken apart and put back together and that in this process, energy is released and on understanding that the elements in the products are the same as the elements in the reactants. Organisms, and populations of organisms, are dependent on their environmental interactions both with other living things and with nonliving factors. (MS-LS-2.1) • In any ecosystem, organisms and populations with similar requirements for food, water, oxygen, or other resources may compete with each other for limited resources, access to which consequently constrains their growth and reproduction. (MS-LS-2.1) • Growth of organisms and population increases are limited by access to resources. (MS-LS-2.1) Further Explanation: Emphasis is on cause and effect relationships between resources and growth of individual organisms and the numbers of organisms in ecosystems during periods of abundant and scarce resources. Similarly, predatory interactions may reduce the number of organisms or eliminate whole populations of organisms. Mutually beneficial interactions, in contrast, may become so interdependent that each organism requires the other for survival. Although the species involved in these competitive, predatory, and mutually beneficial interactions vary across ecosystems, the patterns of interactions of organisms with their environments, both living and nonliving, are shared. (MS-LS-2.2) Further Explanation: Emphasis is on predicting consistent patterns of interactions in different ecosystems in terms of the relationships among and between organisms and abiotic components of ecosystems. Examples of types of interactions could include competitive, predatory, and mutually beneficial. Food webs are models that demonstrate how matter and energy is transferred between producers, consumers, and decomposers as the three groups interact within an ecosystem. Transfers of matter into and out of the physical environment occur at every level. Decomposers recycle nutrients from dead plant or animal matter back to the soil in terrestrial environments or to the water in aquatic environments. The atoms that make up the organisms in an ecosystem are cycled repeatedly between the living and nonliving parts of the ecosystem. (MS-LS-2.3) Further Explanation: Emphasis is on describing the conservation of matter and flow of energy into and out of various ecosystems, and on defining the boundaries of the system. Ecosystems are dynamic in nature; their characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all its populations. (MSLS-2.5) Further Explanation: Emphasis is on recognizing patterns in data and making warranted inferences about changes in populations, and on evaluating empirical evidence supporting arguments about changes to ecosystems. Biodiversity describes the variety of species found in Earth’s terrestrial and oceanic ecosystems. The completeness or integrity of an ecosystem’s biodiversity is often used as a measure of its health. (MS-LS-2.6) Supporting Content LS4.D: Biodiversity • Changes in biodiversity can influence humans’ resources, such as food, energy, and medicines, as well as ecosystem services that humans rely on—for example, water purification and recycling. (MS-LS-2.6) Supporting Content ETS1.B: Developing Possible Solutions • There are systematic processes for evaluating solutions with respect to how well they meet the criteria and constraints of a problem. (MS-LS-2.6) Further Explanation: Examples of ecosystem services could include water purification, nutrient recycling, and prevention of soil erosion. Examples of design solution constraints could include scientific, economic, and social considerations. Genes are located in the chromosomes of cells, with each chromosome pair containing two variants of each of many distinct genes. Each distinct gene chiefly controls the production of specific proteins, which in turn affects the traits of the individual. Structural changes to genes (mutations) can result in changes to proteins, which can affect the structures and functions of the organism and thereby change traits. (MS-LS-3.1) Supporting Content LS3.B: Variation of Traits • In addition to variations that arise from sexual reproduction, genetic information can be altered because of mutations. Though rare, mutations may result in significant changes to the structure and function of proteins. Changes can be beneficial, harmful, or neutral to the organism. (MS-LS-3.1) Further Explanation: Emphasis is on conceptual understanding that changes in genetic material may result in making different proteins. Organisms reproduce, either sexually or asexually, and transfer their genetic information to their offspring. (MS-LS-3.2) Supporting Content LS3.A: Inheritance of Traits • Variations of inherited traits between parent and offspring arise from genetic differences that result from the subset of chromosomes (and therefore genes) inherited. (MS-LS-3.2) Supporting Content LS3.B: Variation of Traits • In sexually reproducing organisms, each parent contributes half of the genes acquired (at random) by the offspring. Individuals have two of each chromosome and hence two alleles of each gene, one acquired from each parent. These versions may be identical or may differ from each other. (MS-LS-3.2) Further Explanation: Emphasis is on using models such as simple Punnett squares and pedigrees, diagrams, and simulations to describe the cause and effect relationship of gene transmission from parent(s) to offspring and resulting genetic variation. The collection of fossils and their placement in chronological order is known as the fossil record and documents the change of many life forms throughout the history of the Earth. Anatomical similarities and differences between various organisms living today and between living and once living organisms in the fossil record enable the classification of living things. (MS-LS-4.1, MS-LS-4.2) Further Explanation: Emphasis is on finding patterns of changes in the level of complexity of anatomical structures in organisms and the chronological order of fossil appearance in the rock layers. The collection of fossils and their placement in chronological order is known as the fossil record and documents the change of many life forms throughout the history of the Earth. Anatomical similarities and differences between various organisms living today and between living and once living organisms in the fossil record enable the classification of living things. (MS-LS-4.1, MS-LS-4.2) Further Explanation: Emphasis is on explanations of the relationships among organisms in terms of similarity or differences of the gross appearance of anatomical structures. Scientific genus and species level names indicate a degree of relationship. (MS-LS-4.3) Further Explanation: Emphasis is on inferring general patterns of relatedness among structures of different organisms by comparing diagrams, pictures, specimens, or fossils. Natural selection leads to the predominance of certain traits in a population, and the suppression of others. (MS-LS-4.4) Further Explanation: Emphasis is on using concepts of natural selection, including overproduction of offspring, passage of time, variation in a population, selection of favorable traits, and heritability of traits. In artificial selection, humans have the capacity to influence certain characteristics of organisms by selective breeding. One can choose desired parental traits determined by genes, which are then passed to offspring. (MS-LS-4.5) Further Explanation: Emphasis is on identifying and communicating information from reliable sources about the influence of humans on genetic outcomes in artificial selection (such as genetic modification, animal husbandry, gene therapy), and on the influence these technologies have on society as well as the technologies leading to these scientific discoveries. Adaptation by natural selection acting over generations is one important process by which species change over time in response to changes in environmental conditions. Traits that support successful survival and reproduction in the new environment become more common; those that do not become less common. Thus, the distribution of traits in a population changes. (MS-LS-4.6) Further Explanation: Emphasis is on using mathematical models, probability statements, and proportional reasoning to support explanations of trends in changes to populations over time. Examples could include Peppered Moth population changes before and after the industrial revolution. Land warfare is a complex domain that involves the application of military power on the ground to achieve political and strategic objectives. Modern military doctrine, such as that used by the U.S. Army and the Indian Army, categorizes these elements into Combat Power and the Principles of War. 1. The 8 Elements of Combat Power Combat power is the total means of destructive, constructive, and information capabilities that a military unit can apply. It is typically broken down into eight key elements: ElementDescriptionLeadershipThe "multiplier" of all other elements. It provides purpose, direction, and motivation to soldiers.InformationEnables commanders to make informed decisions and creates opportunities to achieve results.Mission CommandThe system used to integrate the other elements. It focuses on decentralized execution based on the commander's intent.Movement & ManeuverThe movement of forces to gain a positional advantage over the enemy to deliver lethal or non-lethal effects.IntelligenceThe understanding of the enemy, terrain, weather, and civil considerations.FiresThe use of weapon systems (artillery, mortars, air support) to create specific lethal or non-lethal effects.SustainmentThe logistics required to maintain operations, including ammunition, fuel, food, and medical support.ProtectionThe preservation of the force so that the commander can apply maximum combat power.2. The Principles of War These are the enduring "rules of thumb" that guide how land forces are employed strategically and tactically: Objective: Direct every operation toward a clearly defined and attainable goal. Offensive: Seize, retain, and exploit the initiative. You cannot win by defending alone. Mass: Concentrate the effects of combat power at the most advantageous place and time. Economy of Force: Allocate the minimum essential combat power to secondary efforts so you can "mass" elsewhere. Maneuver: Place the enemy in a position of disadvantage through flexible movement. Unity of Command: Ensure all forces operate under a single responsible commander toward a common objective. Security: Prevent the enemy from gaining an unexpected advantage. Surprise: Strike the enemy at a time, place, or in a manner for which they are unprepared. Simplicity: Prepare clear, uncomplicated plans to minimize confusion in the "fog of war." 3. The Modern Legal Framework Land warfare is also governed by the Law of Land Warfare (International Humanitarian Law), which rests on four pillars: Military Necessity: Actions must be necessary to achieve a legitimate military goal. Distinction: Forces must distinguish between combatants and non-combatants (civilians). Proportionality: The anticipated harm to civilians must not be excessive in relation to the concrete military advantage gained. Unnecessary Suffering: Weapons and methods must not cause gratuitous or superfluous injury. Note: Contemporary land warfare is increasingly "Multi-Domain," meaning land forces must now integrate with cyber, space, and electronic warfare to be effective. , While land warfare uses many tools, the two primary "philosophies" of how to win a war are Attrition and Maneuver. Most modern conflicts are a spectrum of both, but understanding the pure form of each helps explain military strategy. 1. Attrition Warfare: The "Sledgehammer" Attrition warfare is a strategy where one side attempts to win by wearing down the enemy to the point of collapse through continuous losses in personnel, equipment, and supplies. Core Logic: "I have more than you." It assumes that if you can destroy the enemy’s resources faster than they can replace them, you will eventually win. Focus: Firepower and mass. Success is measured by "body counts," equipment destroyed, and the steady seizing of terrain. Command Style: Usually centralized and methodical. It requires strict synchronization of massive resources (artillery, logistics, manpower). Historical Example: The Battle of Verdun (WWI). German Chief of Staff Erich von Falkenhayn famously stated his goal was to "bleed France white" by forcing them to defend a position they could not afford to lose, regardless of the cost in lives. 2. Maneuver Warfare: The "Scalpel" Maneuver warfare seeks to shatter the enemy’s moral and physical cohesion—their ability to act as a unified force—rather than simply destroying every soldier. Core Logic: "I am faster and more unpredictable than you." It aims to create a state of chaos where the enemy's leadership can no longer make effective decisions. Focus: Speed, surprise, and dislocation (forcing the enemy to be in the wrong place at the wrong time). The OODA Loop: Developed by Col. John Boyd, this is the heart of maneuver theory. It stands for Observe, Orient, Decide, Act. The goal is to cycle through these steps faster than the enemy, essentially "getting inside" their decision-making process until they collapse from confusion. Historical Example: The 1940 Invasion of France (Blitzkrieg). Instead of fighting a line-by-line battle of attrition, German forces used speed and concentrated armor to bypass strongpoints, cut communication lines, and cause a total systemic collapse of the French military in weeks. 3. Key Differences at a Glance FeatureAttrition WarfareManeuver WarfareObjectivePhysical destruction of the enemy army.Functional/Psychological collapse of the enemy.TargetThe enemy's strength (mass).The enemy's weakness (vulnerability).Primary ToolMassed Firepower.Movement and Tempo.Command"Command Push" (Top-down, rigid)."Recon Pull" (Decentralized, flexible).Success MetricExchange ratios (Kill counts).Disruption and loss of enemy control.4. The Modern Synthesis: "Schwerpunkt" In practice, no army is purely "maneuver" or "attrition." To maneuver successfully, you often need a period of attrition to punch a hole in the enemy's line. A critical concept here is the Schwerpunkt (Center of Gravity/Focus of Effort). A commander identifies the single most important place to strike and concentrates all available "elements of power" there. While the rest of the front might look like attrition, the Schwerpunkt is where the maneuver happens to achieve a breakthrough. Modern Reality: In high-intensity conflicts today (like the war in Ukraine), we see a "return to attrition" because modern sensors (drones, satellites) make it very difficult to achieve the surprise needed for pure maneuver warfare. When you can see everything, it's hard to be "unexpected." The advantage of direct method is that the teacher can control the class and fit in a lot of activity into a short class period. This leaves plenty of opportunities for the students to hone their skills, especially new ones. On the other hand, because the class is centered around the teacher, some students may not receive proper feedback, and creativity is limited. Also, the lesser talented athletes often tend to get lost in the shuffle while the great athletes shine. However, there are now a multitude of various teaching strategies that can be employed in addition to that method. Ex: Announcements, Module/Unit introductions, Descriptions/modeling of assignments and learning activities, Written or video lectures, Demonstration videos, Presentations, Discussions moderated by instructors, Interactive tutorials. Indirect Method The Indirect Teaching Style allows students to be involved in their own learning through experience and other peer’s knowledge. Students can use critical thinking to expand their learning capabilities by seeing what others may be doing correct and adjusting this to their own knowledge. The Indirect approach is the opposite of what the direct style suggests, but they are both strictly related, meaning you can’t have one without the other. Direct teaching: The instructor stands in front of the class or group and lectures or advises. Indirect teaching: The instructor assumes a more passive role and guides the student interactions. Movement exploration: Incorporates the use of equipment that involves movement. Movement Exploration The movement exploration class is founded on developing a strong, positive association to physical activity. Classes are aimed at developing movement skills and foundational strength through fun and engaging activities. The activities are age appropriate and include games, challenges, and exploration that positively challenge children’s competency while improving their physical capabilities. Skills such as the ability to climb, hold animal shapes, gymnastic style activities, and the introduction to athletic motor skill competencies are the foundations to youth training. This class provides the introduction to strength training to give children the opportunity to learn the skills required to safely and confidently engage in resistance training. Cooperative Skills Cooperative activities teach students to work together for their group's common good. By participating in these activities, students can learn the skills of listening, discussing, thinking as a group, group decision making, and sacrificing individual wants for the common good. There are two primary objectives guiding the teaching of cooperative activities. First, cooperative activities allow students to apply a variety of fundamental motor skills in a unique setting. Students are typically asked to perform motor skills in a specific way, such as “skip in general space” or “balance on one foot and one elbow.” Cooperative activities ask students to perform different activities such as skip with their hands on the shoulders of someone in front of them, walk with big steps while placing their feet on small spots, or walk across an area blindfolded while someone directs their moves. Due to the uniqueness of such experiences, students often find cooperative activities exciting and motivating. Second, cooperative activities are a wonderful medium for teaching social and emotional learning (SEL). SEL offers students an opportunity to understand and manage their emotions. In addition, such activities offer an opportunity to show empathy for others and develop positive relationships. Cooperative activities demand that all students play a role in completing the task or solving the movement problem. Every student, regardless of ability level, is important and contributes to group goals. 9 traits a PE teacher often needs Here are nine essential traits of an effective PE teacher: 1. Athletic ability Athletic ability is an essential trait for a PE teacher because they're often showing kids how to perform exercises. To demonstrate proper form and encourage the kids to continue their fitness education, it's important they can perform the exercises themselves. Having experience with fitness training can enhance a PE teacher's lesson planning because they're familiar with how each exercise affects a person's body. Athletic ability can also refer to an aptitude for sports and games. PE teachers can instruct students on how to play these games or lead after-school activities involving them, like soccer or basketball. An aptitude for sports and games can help a PE teacher encourage students to participate in the activities during class. If the PE teacher enjoys physical activity, they may make the lessons more enjoyable for the student. 2. Teaching ability A PE teacher is a member of a school faculty, so it's essential they have the teaching ability that allows them to communicate lessons to students. There are various skills involved in teaching, including the technical capabilities associated with each professional's particular field. Learning these skills can help PE teacher plan their lessons effectively and connect with their students, meaning they can encourage students to practice fitness skills in optimal ways for their health. Here are some important teaching skills for PE teachers: Having an engaging classroom presence Real-world learning Project building Lesson planning Technology 3. Interpersonal skills PE coaches are part of faculty teams, so working alongside other teachers is an essential part of their job. They often collaborate with a student's general education teacher to address any behavioral issues that arise. They can also team up with other classes to plan activities for students, like field days and special field trips. Communicating with peers can ensure these interactions remain productive and create opportunities for more fulfilling lessons. Teachers can also model emotional skills for their students by displaying positive social interactions. Interpersonal skills can also help PE teachers interact with students and their families. If a student can make a student feel comfortable expressing their needs and preferences, they can often perform physical exercises or play games to the best of their individual capacities. Understanding how to soothe nerves and support students' emotional needs are important examples of interpersonal skills. When interacting with family members, you may use some of these same techniques to communicate effectively and best uplift students. 4. Written and verbal communication Both verbal and written communication is important for PE teachers because they often communicate with students, families and various personnel on a day-to-day basis. For example, a PE teacher uses their communication skills in a lesson plan to describe any student assignments or expectations accurately. They may also write instructions in a document, then explain them in a classroom lecture. They also use communication skills to share their lesson plans with other PE teachers during conferences or classroom development exercises. Many teachers continue to learn their trade even after working as a teacher for many years. They may share tips with each other or special lessons they've developed if they feel another teacher may benefit from it. Creating a community can help PE teachers continue to expand their teaching methodology and receive feedback on their lessons. 5. Patience and adaptability Working with children can require patience and adaptability because they're encountering many new concepts at the same time and learning how to regulate their emotions. As a result, it's important to treat them with patience and care while they're in your class so they can feel comfortable and feel motivated to complete assignments. As children become teenagers, they may require patience and adaptability to account for their changing bodies and attention spans. Like any job where you perform tasks in real-time, certain circumstances may occur that require you to adapt lesson plans. For example, if the weather turns from sunshine to rain on a day you planned for students to run a mile outside, you may need to adapt the lesson plan so they can practice endurance sports inside a gymnasium instead. 6. Organization PE teachers can use organization skills to improve their lesson planning sessions. For example, they can keep their plans in one place, and determine which parts of a semester or quarter to introduce new concepts. Throughout the year, these objectives may change because of unforeseen setbacks, but organizational skills can help PE teachers control the trajectory of their class curriculum. PE teachers can also use organizational skills to maintain their classroom space. Physical education frequently requires balls, equipment and tools to play games that may be on a lesson plan. They also organize equipment and decide where to store it within their classroom or storage space. 7. Creativity Creativity can help a PE teacher develop fun ways to introduce new material to their students or reinforce previous lessons. They can teach new games or devise interesting ideas to change the rules of a game to help keep students engaged. To find inspiration for their lesson plans, they can turn to personal hobbies or media aspects they enjoy, like movie scenes, songs or dances. A varied lesson plan can foster more engagement among students who prefer action- based learning activities, rather than lectures. 8. Focus Focus is an essential trait of a PE teacher because students often require their full attention during class, especially if they're learning a complicated physical task. You can focus your lesson plans around specific elements of physical education you believe are essential for students of a certain age group or skill level. If students require mentorship, you can also focus on each student's needs to supply them with a steady support system. Focusing on your students can help guide your career purpose. It can give you a core value system that informs your lesson plans and mentorship activities. This passion for your student's well-being can also help you become an advocate for each student in your class. You can also help organize funding for different field trips or establish after-school activities to support their interests. 9. Enthusiasm for teaching sports and fitness Enthusiasm is essential for a PE teacher. Many physical education activities require high energy and may suit someone who enjoys teaching them to others. Being an effective PE teacher also requires an enthusiasm for working with kids and making a positive impact on their lives.CHARACTERISTICS OF LIFE The world is filled with familiar objects, such as tables, rocks, plants, pets, and automobiles. Which of these objects are living or were once living? What are the criteria for assigning something to the living world or the nonliving world? Biologists have established that living things share seven characteristics of life. These characteristics are organization and the presence of one or more cells, response to a stimulus (plural, stimuli), homeostasis, metabolism, growth and development, reproduction, and change through time. Organization and Cells Organization is the high degree of order within an organism’s internal and external parts and in its interactions with the living world. For example, compare an owl to a rock. The rock has a spe- cific shape, but that shape is usually irregular. Furthermore, differ- ent rocks, even rocks of the same type, are likely to have different shapes and sizes. In contrast, the owl is an amazingly organized individual, as shown in Figure 1-2. Owls of the same species have the same body parts arranged in nearly the same way and interact with the environment in the same way. Copyright © by Holt, Rinehart and Winston. All rights reserved. ORGANISM (Barn Owl) ORGAN (Owl’s Ear) TISSUE (Nervous Tissue Within the Ear) CELL (Nerve Cell) Every living organism has a level of organization. The different levels of organization for a complex multicellular organism, such as an owl, are shown in the figure below. FIGURE 1-2 THE SCIENCE OF LIFE 7 All living organisms, whether made up of one cell or many cells, have some degree of organization. A cell is the smallest unit that can perform all life’s processes. Some organisms, such as bacteria, are made up of one cell and are called unicellular (YOON-uh-SEL-yoo-luhr) organisms. Other organisms, such as humans or trees, are made up of multiple cells and are called multicellular (MUHL-ti-SEL-yoo-luhr) organisms. Complex multicellular organisms have the level of orga- nization shown in Figure 1-2. In the highest level, the organism is made up of organ systems, or groups of specialized parts that carry out a certain function in the organism. For example, an owl’s ner- vous system is made up of a brain, sense organs, nerve cells, and other parts that sense and respond to the owl’s surroundings. Organ systems are made up of organs. Organs are structures that carry out specialized jobs within an organ system. An owl’s ear is an organ that allows the owl to hear. All organs are made up of tissues. Tissues are groups of cells that have similar abilities and that allow the organ to function. For example, nervous tissue in the ear allows the ear to detect sound. Tissues are made up of cells. A cell must be covered by a membrane, contain all genetic information necessary for replication, and be able to carry out all cell functions. Within each cell are organelles. Organelles are tiny structures that carry out functions necessary for the cell to stay alive. Organelles contain biological molecules, the chemical compounds that provide physical structure and that bring about movement, energy use, and other cellular functions. All biological molecules are made up of atoms. Atoms are the simplest particle of an ele- ment that retains all the properties of a certain element. Response to Stimuli Another characteristic of life is that an organism can respond to a stimulus—a physical or chemical change in the internal or external environment. For example, an owl dilates its pupils to keep the level of light entering the eye constant. Organisms must be able to respond and react to changes in their environment to stay alive. ORGANELLE (Mitochondrion) BIOLOGICAL MOLECULE (Phospholipid) ATOM (Oxygen) cell from the Latin, cella meaning “small room,” or “hut” Word Roots and Origins www.scilinks.org Topic: Characteristics of Life Keyword: HM60257 mb06se_bios01.qxd 5/18/07 10:37 AM Page 7 8 CHAPTER 1 Homeostasis All living things, from single cells to entire organisms, have mecha- nisms that allow them to maintain stable internal conditions. Without these mechanisms, organisms can die. For example, a cell’s water content is closely controlled by the taking in or releas- ing of water. A cell that takes in too much water will rupture and die. A cell that doesn’t get enough water will also shrivel and die. Homeostasis (HOH-mee-OH-STAY-sis) is the maintenance of a stable level of internal conditions even though environmental conditions are constantly changing. Organisms have regulatory systems that maintain internal conditions, such as temperature, water content, and uptake of nutrients by the cell. In fact, multi- cellular organisms usually have more than one way of maintain- ing important aspects of their internal environment. For example, an owl’s temperature is maintained at about 40°C (104°F). To keep a constant temperature, an owl’s cells burn fuel to produce body heat. In addition, an owl’s feathers can fluff up in cold weather. In this way, they trap an insulating layer of air next to the bird’s body to maintain its body temperature. Metabolism Living organisms use energy to power all the life processes, such as repair, movement, and growth. This energy use depends on metabolism (muh-TAB-uh-LIZ-uhm). Metabolism is the sum of all the chemical reactions that take in and transform energy and materials from the environment. For example, plants, algae, and some bacteria use the sun’s energy to generate sugar molecules during a process called photosynthesis. Some organisms depend on obtaining food energy from other organisms. For instance, an owl’s metabolism allows the owl to extract and modify the chemi- cals trapped in its nightly prey and use them as energy to fuel activities and growth. Growth and Development All living things grow and increase in size. Some nonliving things, such as crystals or icicles, grow by accumulating more of the same material of which they are made. In contrast, the growth of living things results from the division and enlargement of cells. Cell division is the formation of two new cells from an existing cell, as shown in Figure 1-3. In unicellular organisms, the primary change that occurs following cell division is cell enlargement. In multi- cellular life, however, organisms mature through cell division, cell enlargement, and development. Development is the process by which an organism becomes a mature adult. Development involves cell division and cell differen- tiation, or specialization. As a result of development, an adult organism is composed of many cells specialized for different func- tions, such as carrying oxygen in the blood or hearing. In fact, the human body is composed of trillions of specialized cells, all of which originated from a single cell, the fertilized egg. This unicellular organism, Escherichia coli, inhabits the human intestines. E. coli reproduces by means of cell division, during which the original cell splits into two identical offspring cells. FIGURE 1-3 Observing Homeostasis Materials 500 mL beakers (3), wax pen, tap water, thermometer, ice, hot water, goldfish, small dip net, watch or clock with a second hand Procedure 1. Use a wax pen to label three 500 mL beakers as follows: 27°C (80°F), 20°C (68°F), 10°C (50°F). Put 250 mL of tap water in each beaker. Use hot water or ice to adjust the tem- perature of the water in each beaker to match the temperature on the label. 2. Put the goldfish in the beaker of 27°C water. Record the number of times the gills move in 1 minute. 3. Move the goldfish to the beaker of 20°C water. Repeat observations. Move the goldfish to the beaker of 10°C. Repeat observations. Analysis What happens to the rate at which gills move when the temp- erature changes? Why? How do gills help fish maintain homeostasis? Quick Lab mb06se_bios01.qxd 5/18/07 10:37 AM Page 8 THE SCIENCE OF LIFE 9 Reproduction All organisms produce new organisms like themselves in a process called reproduction. Reproduction, unlike other characteristics, is not essential to the survival of an individual organism. However, because no organism lives forever, reproduction is essential for the continuation of a species. Glass frogs, as shown in Figure 1-4, lay many eggs in their lifetime. However, only a few of the frogs’ off- spring reach adulthood and successfully reproduce. During reproduction, organisms transmit hereditary informa- tion to their offspring. Hereditary information is encoded in a large molecule called deoxyribonucleic acid, or DNA. A short segment of DNA that contains the instructions for a single trait of an organism is called a gene. DNA is like a large library. It contains all the books—genes—that the cell will ever need for making all the struc- tures and chemicals necessary for life. Hereditary information is transferred to offspring during two kinds of reproduction. In sexual reproduction, hereditary information recombines from two organisms of the same species. The resulting offspring are similar but not identical to their parents. For example, a male frog’s sperm can fertilize a female’s egg and form a single fer- tilized egg cell. The fertilized egg then develops into a new frog. In asexual reproduction, hereditary information from different organisms is not combined; thus the original organism and the new organism are genetically the same. A bacterium, for example, reproduces asexually when it splits into two identical cells. Change Through Time Although individual organisms experience many changes during their lifetime, their basic genetic characteristics do not change. However, populations of living organisms evolve or change through time. The ability of populations of organisms to change over time is important for survival in a changing world. This factor is also impor- tant in explaining the diversity of life-forms we see on Earth today.