13.3: Segmentation and Targeting
What you’ll learn to do: explain the role of segmentation and targeting in marketing
Segmentation and targeting answer a basic question: Who am I trying to reach? In this section, first we will focus on why segmentation and targeting are so important. Then we will discuss how to conduct segmentation and targeting and use these tools to guide marketing activity.
Learning Objectives
- Explain how segmentation and targeting relate to marketing strategy
- Explain how market research helps marketers validate their target markets
Defining Your Target Market
Whom Are You Trying to Reach?
Suppose you are selling automotive detailing products. Is your target “anyone with money to pay for your product?” Or are you focusing your efforts on a tightly defined market segment of people with an identified need for what you are selling? “Anyone with money” is such a broad audience that it’s difficult to make any impact at all with your marketing efforts or convince very many people that they need your product. If you narrow and carefully define your target market, though, your efforts will be more fruitful because they’re focused on people with a preexisting need or interest in what you offer.
Step 1: Identify the Customer Need You Address
To define your total market, start by stating the needs you will fulfill: Who are your products or services intended for? Who do you want to do business with? What is unique about your product? If you’re selling products used in automotive detailing, your total market consists of vehicle owners—that is, all the people who could potentially buy your product. Your business will help them keep their vehicles clean and shiny.
Step 2: Segment Your Total Market
Next, break down this large market into smaller sections, using a process known as segmentation. You can use a variety of approaches to segment your total market into groups with common wants or needs. In this case, we can segment by vehicle ownership and related behavior. Specific segments might include the following:
- People who restore classic automobiles
- People who drive old clunkers and run them through the car wash occasionally
- People who own “status” cars
- Truck drivers
- Motorcycle owners
Which of these subgroups are likely to be your most productive market segment(s)? You recognize that auto owners who don’t care about keeping their cars clean and shiny probably won’t be very interested in your products. Then there are those who care, but they lack the time and interest to do the work themselves. They take their vehicle to a shop. Others only worry about auto detailing only when it’s time for a trade-in.
You reject these segments as unsuitable for your niche market because they probably don’t care enough about what you offer. After further consideration and research, you decide that your market segment will be automobile owners who have both the time and the interest to do their own detailing work—people who enjoy puttering with their vehicles, who have the time to spend, and who take pride in their vehicle’s appearance.
You need to conduct research to confirm that there are enough potential customers in that group to support your business. You should also do competitive analysis to confirm that what you are offering is not readily available to them elsewhere. With this validation, you move to step three.
Step 3: Profile Your Target Customer Segment(s)
Next, develop profiles of your target customer(s) to get a true picture of the people you’re trying to serve. Describe these potential customers as fully as you can. Who will actually buy your product? What do you know about them? Where do they live and what languages do they speak? How much do they spend on car detailing? Where do they shop? What is their annual income? What kinds of cars do they drive? If you’re selling online, what methods do they prefer for online payment? What type of Web sites do they visit? How do they want their product delivered?
There are many different ways to profile your customers, as shown in the table and graphic, below.
Table \(\PageIndex{1}\). Common Market Segmentation Approaches
| Type of Approach | Segmentation Criteria |
|---|---|
| Geographic | nations, states, regions, cities, neighborhoods, zip codes, etc. |
| Demographic | age, gender, family size, income, occupation, education, religion, ethnicity, and nationality |
| Psychographic | lifestyle, personality, attitudes, and social class |
| Behavioral | user status, purchase occasion, loyalty, readiness to buy |
| Decision maker | decision-making role (purchaser, influencer, etc.) |
Identify your customer profile before you conduct market planning, so that your planning is a good fit for your customers’ behavior, interests, and needs.
Step 4: Research and Validate Your Market Opportunity
Now that you have fully identified your target market, conduct research to verify that there will be enough business in this group to support your company in its growth. This process confirms that the need actually exists and that it’s not just wishful thinking on your part.
Use both primary and secondary sources in your research. You might consult business directories, obtain statistics regarding automobile owners and their car-care practices, or locate newspaper articles and magazine stories written on the subject. You can also conduct your own market research using techniques such as surveys, focus groups, interviews, and so forth.
Your research should also determine the size of the market opportunity in terms of revenue as well as your potential market share.
You can use primary and secondary sources to find out how many potential customers there are in the geographic area you have defined and how many businesses are directly or indirectly competing with you. Your market share will be the number of customers likely to buy from you rather than from your competition.
Having defined and validated your target market, you are now better positioned to develop a marketing plan that will reach your potential customers. Perhaps your sales will take off right away—a great problem to have!
The Importance of Marketing Information and Research
Fresh Customer Insights
Effective marketing starts with a strong knowledge of your customers: the kind of knowledge that gives you unique insights into what they want and how to satisfy them better than the competition. The most reliable source of fresh customer insights is good marketing information . Useful marketing information may come from a variety of sources both inside and outside your organization. Marketing information is generated by a variety of different activities, including marketing research.
Marketing research is a systematic process for identifying marketing opportunities and solving marketing problems, using customer insights that come out of collecting and analyzing marketing information. The mechanics of marketing research must be controlled so that marketers uncover the relevant facts to answer the problem at hand. Control over this fact-finding process is the responsibility of the marketing research director, who must correctly design the research and carefully supervise its execution, to ensure it yields the customer insights the organization needs.
A marketing information system is a combination of people, technologies, and processes for managing marketing information, overseeing market research activities, and using customer insights to guide marketing decisions and broader management and strategy decisions.
Knowledge Is Power Against the Competition
The business environment is increasingly competitive. With something as simple as a Google search, customers have unprecedented opportunities to explore alternatives to what any single company offers. Likewise, companies have ample opportunity to identify, track, and lure customers away from their less-vigilant competitors. A regular infusion of fresh customer insights can make all the difference between keeping customers and losing them. Marketing information and research are essential tools for marketers and the management team as they align strategy with customer wants and needs.
Consider the following examples:
- Before introducing OnStar, the first-ever embedded wireless service in cars, GM used marketing research to understand what types of applications would make consumers most interested in subscribing to the service and how much they would pay for it. Of all the benefits OnStar could offer, the research helped GM prioritize how the initial service would provide value, focusing on driver assistance and security. Research also helped determine OnStar pricing to help the company build a large subscriber base quickly. [1]
- Enterprise systems provider PeopleSoft recruited a diverse set of universities as early-adopter “Beta” partners to provide input as it designed a new student information system for higher education. This marketing research helped PeopleSoft create a versatile system that could support the needs of a variety of colleges and universities, ultimately leading to strong receptivity and market share when the new system became widely available. [2]
- Marketing research to track brand awareness and perceptions helped the World Wildlife Fund (WWF) understand that it had an image problem. Although millions of people recognized and liked the brand, relatively few of them understood what the nonprofit organization actually does for habitat conservation worldwide. Instead, most thought of it as simply the “endangered species” people. With additional research, the organization found that when it communicated effectively about the full scope of its mission, people felt even stronger positive associations, making them more likely to support or affiliate with the nonprofit. [3]
What Should Marketers Investigate Using Marketing Information?
An easy—and truthful—answer to this question is “everything.” There is no aspect of marketing to which information and research do not apply. Every marketing concept and every element involved in the marketing management process can be subjected to a great deal of careful marketing research and inquiry. Some important questions include:
- Who is the customer?
- What problems is the customer trying to solve with a given purchase?
- What does s/he desire in the way of satisfaction?
- How does the customer get information about available choices?
- Where does s/he choose to purchase?
- Why does s/he buy, or not buy?
- When does s/he purchase?
- How does s/he go about seeking satisfaction in the market?
Seeking answers to these questions yields insights into the customer’s needs, perceptions, and behaviors. Another area in which research is critical is profitability. Organizations need to forecast sales and related costs in order to understand how their operations will be profitable. They also need to plan competitive marketing programs that will produce the desired level of sales at an appropriate cost. The analysis of past sales and interpretation of cost information are important in evaluating performance and providing useful facts for future planning. All these activities rely on marketing information and a rigorous marketing research process to produce insights managers can trust and act on.
When to Use Marketing Information and Research
Many marketing decisions are made without consulting marketing information or the use of formal marketing research. For example, a decision maker may feel she already knows enough to make a good decision. The time required to investigate a question or conduct formal marketing research may not be available. In other cases, the cost of obtaining the data is prohibitive, or the desired data cannot be obtained in reliable form. In a few instances, there may be no choice among alternatives and therefore no decision to make because there is little value in spending time and money to study a problem if there is only one possible solution. But in most business situations, marketers and managers must choose among two or more courses of action. This is where fact-finding, marketing information, and research enter to help make the choice.
Marketing information and research address the need for quicker, yet more accurate, decision making by the marketer. These tools put marketers close to their customers to help them understand who they customers are, what they want, and what competitors are doing. When different stakeholders have very different views about a particular marketing-related decision, objective information and research can inform everyone about the issues in question and help the organization come to agreement about the path forward. Good research should help align marketing with the other areas of the business.
Marketers should always be tapping into regular sources of marketing information about their organization and industry in order to monitor what’s happening generally. For example, at any given time marketers should understand how they are doing relative to sales goals and monitor developments in their industry or competitive set.
Beyond this general level of “tuning in,” additional market research projects may also be justified. As a rule, if the research results can save the company more time, money, and/or risk than it costs to conduct the research, it is wise to proceed. If the cost of conducting the research is more than it will contribute to improving a decision, the research should not be carried out. In practice, applying this cost-test principle can be somewhat complex, but it provides useful guidance about when marketing research is worthwhile. Ultimately, successful marketing executives make decisions on the basis of a blend of facts and intuition.
Fact: top performers research customer preferences
In 2010, the management consultancy McKinsey published research about the difference between organizations that produced top-performing products and those that produced under-performing products. The use of marketing research was a striking differentiator:
"More than 80 percent of the top performers said they periodically tested and validated customer preferences during the development process, compared with just 43 percent of bottom performers. They were also twice as likely as the laggards to research what, exactly, customers wanted. [4] "
The study also identified other differences between top and bottom performers, but an underlying theme was the emphasis successful projects and companies placed on understanding their customers and adjusting course when necessary to better address customers’ needs. This research provides more than anecdotal evidence that marketing research and well-applied marketing information can make a substantial contribution to an organization’s success.
The Marketing Research Process
Marketing research is a useful and necessary tool for helping marketers and an organization’s executive leadership make wise decisions. Carrying out marketing research can involve highly specialized skills that go deeper than the information outlined in this module. However, it’s important for any marketer to be familiar with the basic procedures and techniques of marketing research.
It’s very likely that at some point a marketing professional will need to supervise an internal marketing research activity or to work with an outside marketing research firm to conduct a research project. Managers who understand the research function can do a better job of framing the problem and critically appraising the proposals made by research specialists. They are also in a better position to evaluate their findings and recommendations.
Periodically marketers themselves need to find solutions to marketing problems without the assistance of marketing research specialists inside or outside the company. If you are familiar with the basic procedures of marketing research, you can supervise and even conduct a reasonably satisfactory search for the information needed.
Step 1: Identify the Problem
The first step for any marketing research activity is to clearly identify and define the problem you are trying to solve. You start by stating the marketing or business problem you need to address and for which you need additional information to figure out a solution. Next, articulate the objectives for the research: What do you want to understand by the time the research project is completed? What specific information, guidance, or recommendations need to come out of the research in order to make it a worthwhile investment of the organization’s time and money?
It’s important to share the problem definition and research objectives with other team members to get their input and further refine your understanding of the problem and what is needed to solve it. At times, the problem you really need to solve is not the same problem that appears on the surface. Collaborating with other stakeholders helps refine your understanding of the problem, focus your thinking, and prioritize what you hope to learn from the research. Prioritizing your objectives is particularly helpful if you don’t have the time or resources to investigate everything you want.
To flesh out your understanding of the problem, it’s useful to begin brainstorming actual research questions you want to explore. What are the questions you need to answer in order to get to the research outcomes? What is the missing information that marketing research will help you find? The goal at this stage is to generate a set of preliminary, big-picture questions that will frame your research inquiry. You will revisit these research questions later in the process, but when you’re getting started, this exercise helps clarify the scope of the project, whom you need to talk to, what information may already be available, and where to look for the information you don’t yet have.
Marketing research for bookends
Your uncle Dan owns an independent bookstore called Bookends, and it’s not doing very well. (That’s you in the picture.) The store’s sales are down, and the rent is going up. Dan has turned to you for help, since you know a thing or two about marketing.
You need a lot of information if you’re going to help your uncle turn things around, so marketing research is a good idea. You begin by identifying the problem and then work to set down your research objectives and initial research questions:
| Identifying Problems, Objectives, and Questions | |
|---|---|
| Core business problem Dan needs to solve | How to get more people to spend more money at Bookends |
|
Research objectives |
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| Initial research questions | Who are Bookends' current customers? How much do they spend? Why do they come to Bookends? What do they wish Bookends offered? Who isn't coming to Bookends, and why? |
Step 2: Develop a Research Plan
Once you have a problem definition, research objectives, and a preliminary set of research questions, the next step is to develop a research plan. Essential to this plan is identifying precisely what information you need to answer your questions and achieve your objectives. Do you need to understand customer opinions about something? Are you looking for a clearer picture of customer needs and related behaviors? Do you need sales, spending, or revenue data? Do you need information about competitors’ products, or insight about what will make prospective customers notice you? When do need the information, and what’s the time frame for getting it? What budget and resources are available?
Once you have clarified what kind of information you need and the timing and budget for your project, you can develop the research design. This details how you plan to collect and analyze the information you’re after. Some types of information are readily available through secondary research and secondary data sources. Secondary research analyzes information that has already been collected for another purpose by a third party, such as a government agency, an industry association, or another company. Other types of information need to from talking directly to customers about your research questions. This is known as primary research , which collects primary data captured expressly for your research inquiry. Marketing research projects may include secondary research, primary research, or both.
Depending on your objectives and budget, sometimes a small-scale project will be enough to get the insight and direction you need. At other times, in order to reach the level of certainty or detail required, you may need larger-scale research involving participation from hundreds or even thousands of individual consumers. The research plan lays out the information your project will capture—both primary and secondary data—and describes what you will do with it to get the answers you need. (Note: You’ll learn more about data collection methods and when to use them later in this module.)
Your data collection plan goes hand in hand with your analysis plan. Different types of analysis yield different types of results. The analysis plan should match the type of data you are collecting, as well as the outcomes your project is seeking and the resources at your disposal. Simpler research designs tend to require simpler analysis techniques. More complex research designs can yield powerful results, such as understanding causality and trade-offs in customer perceptions. However, these more sophisticated designs can require more time and money to execute effectively, both in terms of data collection and analytical expertise.
The research plan also specifies who will conduct the research activities, including data collection, analysis, interpretation, and reporting on results. At times a singlehanded marketing manager or research specialist runs the entire research project. At other times, a company may contract with a marketing research analyst or consulting firm to conduct the research. In this situation, the marketing manager provides supervisory oversight to ensure the research delivers on expectations.
Finally, the research plan indicates who will interpret the research findings and how the findings will be reported. This part of the research plan should consider the internal audience(s) for the research and what reporting format will be most helpful. Often, senior executives are primary stakeholders, and they’re anxious for marketing research to inform and validate their choices. When this is the case, getting their buy-in on the research plan is recommended to make sure that they are comfortable with the approach and receptive to the potential findings.
A Bookends Research plan
You talk over the results of your problem identification work with Dan. He thinks you’re on the right track and wants to know what’s next. You explain that the next step is to put together a detailed plan for getting answers to the research questions.
Dan is enthusiastic, but he’s also short on money. You realize that such a financial constraint will limit what’s possible, but with Dan’s help you can do something worthwhile. Below is the research plan you sketch out:
| Identifying Data Types, Timing and Budget, Data Collection Methods, Analysis, and Interpretation | |
|---|---|
| Types of data needed | 1) Demographics and attitudes of current Bookends customers; 2) current customers’ spending patterns; 3) metro area demographics (to determine types of people who aren’t coming to the store) |
| Timing & budget | Complete project within 1 month; no out-of-pocket spending |
| Data collection methods | 1) Current customer survey using free online survey tool, 2) store sales data mapped to customer survey results, 3) free U.S. census data on metro-area demographics, 4) 8–10 intercept (“man on the street”) interviews with non-customers |
| Analysis plan | Use Excel or Google Sheets to tabulate data; Marina (statistician cousin) to assist in identifying data patterns that could become market segments |
| Interpretation and reporting | You and Dan will work together to comb through the data and see what insights it produces. You’ll use PowerPoint to create a report that lays out significant results, key findings, and recommendations. |
Step 3: Conduct the Research
Conducting research can be a fun and exciting part of the marketing research process. After struggling with the gaps in your knowledge of market dynamics—which led you to embark on a marketing research project in the first place—now things are about to change. Conducting research begins to generate information that helps answer your urgent marketing questions.
Typically data collection begins by reviewing any existing research and data that provide some information or insight about the problem. As a rule, this is secondary research. Prior research projects, internal data analyses, industry reports, customer-satisfaction survey results, and other information sources may be worthwhile to review. Even though these resources may not answer your research questions fully, they may further illuminate the problem you are trying to solve. Secondary research and data sources are nearly always cheaper than capturing new information on your own. Your marketing research project should benefit from prior work wherever possible.
After getting everything you can from secondary research, it’s time to shift attention to primary research, if this is part of your research plan. Primary research involves asking questions and then listening to and/or observing the behavior of the target audience you are studying. In order to generate reliable, accurate results, it is important to use proper scientific methods for primary research data collection and analysis. This includes identifying the right individuals and number of people to talk to, using carefully worded surveys or interview scripts, and capturing data accurately.
Without proper techniques, you may inadvertently get bad data or discover bias in the responses that distorts the results and points you in the wrong direction. The module on Marketing Research Techniques discusses these issues in further detail, since the procedures for getting reliable data vary by research method.
Getting the data on bookends
Dan is on board with the research plan, and he’s excited to dig into the project. You start with secondary data, getting a dump of Dan’s sales data from the past two years, along with related information: customer name, zip code, frequency of purchase, gender, date of purchase, and discounts/promotions (if any).
You visit the U.S. Census Bureau Web site to download demographic data about your metro area. The data show all zip codes in the area, along with population size, gender breakdown, age ranges, income, and education levels.
The next part of the project is customer-survey data. You work with Dan to put together a short survey about customer attitudes toward Bookends, how often and why they come, where else they spend money on books and entertainment, and why they go other places besides Bookends. Dan comes up with the great idea of offering a 5 percent discount coupon to anyone who completes the survey. Although it eats into his profits, this scheme gets more people to complete the survey and buy books, so it’s worth it.
For a couple of days, you and Dan take turns doing “man on the street” interviews (you interview the guy in the red hat, for instance). You find people who say they’ve never been to Bookends and ask them a few questions about why they haven’t visited the store, where else they buy books and other entertainment, and what might get them interested in visiting Bookends sometime. This is all a lot of work, but for a zero-budget project, it’s coming together pretty well.
Step 4: Analyze and Report Findings
Analyzing the data obtained in a market survey involves transforming the primary and/or secondary data into useful information and insights that answer the research questions. This information is condensed into a format to be used by managers—usually a presentation or detailed report.
Analysis starts with formatting, cleaning, and editing the data to make sure that it’s suitable for whatever analytical techniques are being used. Next, data are tabulated to show what’s happening: What do customers actually think? What’s happening with purchasing or other behaviors? How do revenue figures actually add up? Whatever the research questions, the analysis takes source data and applies analytical techniques to provide a clearer picture of what’s going on. This process may involve simple or sophisticated techniques, depending on the research outcomes required. Common analytical techniques include regression analysis to determine correlations between factors; conjoint analysis to determine trade-offs and priorities; predictive modeling to anticipate patterns and causality; and analysis of unstructured data such as Internet search terms or social media posts to provide context and meaning around what people say and do.
Good analysis is important because the interpretation of research data—the “so what?” factor—depends on it. The analysis combs through data to paint a picture of what’s going on. The interpretation goes further to explain what the research data mean and make recommendations about what managers need to know and do based on the research results. For example, what is the short list of key findings and takeaways that managers should remember from the research? What are the market segments you’ve identified, and which ones should you target? What are the primary reasons your customers choose your competitor’s product over yours, and what does this mean for future improvements to your product?
Individuals with a good working knowledge of the business should be involved in interpreting the data because they are in the best position to identify significant insights and make recommendations from the research findings. Marketing research reports incorporate both analysis and interpretation of data to address the project objectives.
The final report for a marketing research project may be in written form or slide-presentation format, depending on organizational culture and management preferences. Often a slide presentation is the preferred format for initially sharing research results with internal stakeholders. Particularly for large, complex projects, a written report may be a better format for discussing detailed findings and nuances in the data, which managers can study and reference in the future.
analysis and Insights for bookends
Getting the data was a bit of a hassle, but now you’ve got it, and you’re excited to see what it reveals. Your statistician cousin, Marina, turns out to be a whiz with both the sales data and the census data. She identified several demographic profiles in the metro area that looked a lot like lifestyle segments. Then she mapped Bookends’ sales data into those segments to show who is and isn’t visiting Bookends. After matching customer-survey data to the sales data, she broke down the segments further based on their spending levels and reasons they visit Bookends.
Gradually a clearer picture of Bookends’ customers is beginning to emerge: who they are, why they come, why they don’t come, and what role Bookends plays in their lives. Right away, a couple of higher-priority segments—based on their spending levels, proximity, and loyalty to Bookends—stand out. You and your uncle are definitely seeing some possibilities for making the bookstore a more prominent part of their lives. You capture these insights as “recommendations to be considered” while you evaluate the right marketing mix for each of the new segments you’d like to focus on.
Step 5: Take Action
Once the report is complete, the presentation is delivered, and the recommendations are made, the marketing research project is over, right? Wrong.
What comes next is arguably the most important step of all: taking action based on your research results.
If your project has done a good job interpreting the findings and translating them into recommendations for the marketing team and other areas of the business, this step may seem relatively straightforward. When the research results validate a path the organization is already on, the “take action” step can galvanize the team to move further and faster in that same direction.
Things are not so simple when the research results indicate a new direction or a significant shift is advisable. In these cases, it’s worthwhile to spend time helping managers understand the research, explain why it is wise to shift course, and explain how the business will benefit from the new path. As with any important business decision, managers must think deeply about the new approach and carefully map strategies, tactics, and available resources to plan effectively. By making the results available and accessible to managers and their execution teams, the marketing research project can serve as an ongoing guide and touchstone to help the organization plan, execute, and adjust course as it works toward desired goals and outcomes.
It is worth mentioning that many marketing research projects are never translated into management action. Sometimes this is because the report is too technical and difficult to understand. In other cases, the research conclusions fail to provide useful insights or solutions to the problem, or the report writer fails to offer specific suggestions for translating the research findings into management strategy. These pitfalls can be avoided by paying due attention to the research objectives throughout the project and allocating sufficient time and resources to do a good job interpreting research results for those who will need to act on them.
Bookends' new customer campaign
Your research findings and recommendations identified three segments for Bookends to focus on. Based on the demographics, lifestyle, and spending patterns found during your marketing research, you’re able to name them: 1) Bored Empty-Nesters, 2) Busy Families, and 3) Hipster Wannabes. Dan has a decent-sized clientele across all three groups, and they are pretty good spenders when they come in. But until now he hasn’t done much to purposely attract any of them.
With newly identified segments in focus, you and Dan begin brainstorming about a marketing mix to target each group. What types of books and other products would appeal to each one? What activities or events would bring them into the store? Are there promotions or particular messages that would induce them to buy at Bookends instead of Amazon or another bookseller? How will Dan reach and communicate with each group? And what can you do to bring more new customers into the store within these target groups?
Even though Bookends is a real-life project with serious consequences for your uncle Dan, it’s also a fun laboratory where you can test out some of the principles you’re learning in your marketing class. You’re figuring out quickly what it’s like to be a marketer.
Well done, rookie!
- Vincent P. Barabba, Surviving Transformation: Lessons from GM's Surprising Turnaround , pp 46–50, https://books.google.com/books?id=VvbDYad7cLoC&pg ↵
- Proquest, "First We Built, Now We Buy: A Sociological Case Study for Enterprise Systems in Higher Education," pp 292–203
- "The Role of Brand in the Nonprofit Sector: Four Case Studies," pp 1–7
- http://www.mckinsey.com/insights/ope...l_new_products .


29.2.2: Liverworts and Hornworts
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Learning Objectives
- Describe the distinguishing traits of hornworts and liverworts
Liverworts and Hornworts
Liverworts
Liverworts (Hepaticophyta) are viewed as the plants most closely related to the ancestor that moved to land. Liverworts have colonized every terrestrial habitat on earth and diversified to more than 7000 existing species. Liverwort gametophytes (the dominant stage of the life cycle) form lobate green structures. The shape of these leaves are similar to the lobes of the liver; hence, providing the origin of the name given to the phylum. Openings that allow the movement of gases may be observed in liverworts. However, these are not stomata because they do not actively open and close. The plant takes up water over its entire surface and has no cuticle to prevent desiccation.
The liverwort’s life cycle begins with the release of haploid spores from the sporangium that developed on the sporophyte. Spores disseminated by wind or water germinate into flattened thalli gametophytes attached to the substrate by thin, single-celled filaments. Male and female gametangia develop on separate, individual plants. Once released, male gametes swim with the aid of their flagella to the female gametangium (the archegonium), and fertilization ensues. The zygote grows into a small sporophyte still attached to the parent gametophyte and develops spore-producing cells and elaters. The spore-producing cells undergo meiosis to form spores, which disperse (with the help of elaters), giving rise to new gametophytes. Thus, the life cycle of liverworts follows the pattern of alternation of generations.
Liverwort plants can also reproduce asexually by the breaking of branches or the spreading of leaf fragments called gemmae. In this latter type of reproduction, the gemmae (small, intact, complete pieces of plant that are produced in a cup on the surface of the thallus ) are splashed out of the cup by raindrops. The gemmae then land nearby and develop into gametophytes.
Hornworts
The hornworts (Anthocerotophyta) belong to the broad bryophyte group that have colonized a variety of habitats on land, although they are never far from a source of moisture. The short, blue-green gametophyte is the dominant phase of the lifecycle of a hornwort. The narrow, pipe-like sporophyte is the defining characteristic of the group. The sporophytes emerge from the parent gametophyte and continue to grow throughout the life of the plant. Stomata appear in the hornworts and are abundant on the sporophyte. Photosynthetic cells in the thallus contain a single chloroplast. Meristem cells at the base of the plant keep dividing and adding to its height. Many hornworts establish symbiotic relationships with cyanobacteria that fix nitrogen from the environment.
The life cycle of hornworts also follows the general pattern of alternation of generations and has a similar life cycle to liverworts. The gametophytes grow as flat thalli on the soil with embedded gametangia. Flagellated sperm swim to the archegonia and fertilize eggs. However, unlike liverworts, the zygote develops into a long and slender sporophyte that eventually splits open, releasing spores. Additionally, thin cells called pseudoelaters surround the spores and help propel them further in the environment. Unlike the elaters observed in liverworts, the hornwort pseudoelaters are single-celled structures. The haploid spores germinate and produce the next generation of gametophytes. Like liverworts, some hornworts may also produce asexually through fragmentation.
Key Points
- The leaves of liverworts are lobate green structures similar to the lobes of the liver, while hornworts have narrow, pipe-like structures.
- The gametophyte stage is the dominant stage in both liverworts and hornworts; however, liverwort sporophytes do not contain stomata, while hornwort sporophytes do.
- The life cycle of liverworts and hornworts follows alternation of generations: spores germinate into gametophytes, the zygote develops into a sporophyte that releases spores, and then spores produce new gametophytes.
- Liverworts develop short, small sporophytes, whereas hornworts develop long, slender sporophytes.
- To aid in spore dispersal, liverworts utilize elaters, whereas hornworts utilize pseudoelaters.
- Liverworts and hornworts can reproduce asexually through the fragmentation of leaves into gemmae that disperse and develop into gametophytes.
Key Terms
- alternation of generation : the life cycle of plants with a multicellular sporophyte, which is diploid, that alternates with a multicellular gametophyte, which is haploid
- pseudoelater : single-celled structure that aids in spore dispersal
- gemmae : small, intact, complete pieces of plant that are produced in a cup on the surface of the thallus and develop into gametophytes through asexual reproduction


15.22C: Amoebic Meningoencephalitis
- Summarize the route of transmission and effects of infection by Naegleria fowleri
Primary amoebic meningoencephalitis (PAM, or PAME) is a disease of the central nervous system caused by infection from Naegleria fowleri.
Naegleria fowleri is commonly referred to as an amoeba but is actually a unicellular parasitic protist that is ubiquitous in soils and warm, stagnant bodies of freshwater, especially during the summer months. Patients typically have a history of exposure to a natural body of water.
The organism specifically prefers temperatures above 32 °C, as might be found in a tropical climate or in water heated by geothermal activity. The organism is extremely sensitive to chlorine (<0.5 ppm). Exposure to the organism is extremely common due to its wide distribution in nature.
However, thus far the only route for Naegleria fowleri to enter the central nervous system is via deep insufflation of infected water as it attaches itself to the olfactory nerve, which is exposed only at the extreme vertical terminus of the paranasal sinuses.
When this occurs, it then migrates through the cribiform plate and into the olfactory bulbs of the forebrain, where it multiplies itself greatly by feeding on nerve tissue. During this stage, occurring approximately 3–7 days post-infection, the typical symptoms are parosmia, rapidly progressing to anosmia (with resultant ageusia) as the nerve cells of the olfactory bulbs are consumed and replaced with necrotic lesions.
After the organisms have multiplied and largely consumed the olfactory bulbs, the infection rapidly spreads through the mitral cell axons to the rest of the cerebrum, resulting in onset of frank encephalitic symptoms, including cephalgia (headache), nausea, and rigidity of the neck muscles, progressing to vomiting, delirium, seizures, and eventually irreversible coma. Death usually occurs within 14 days of exposure as a result of respiratory failure when the infection spreads to the brain stem, destroying the autonomic nerve cells of the medulla oblongata.
The disease is both exceptionally rare and highly lethal: there have been fewer than 200 confirmed cases in recorded medical history as of 2004, and 300 cases as of 2008, with an in-hospital case fatality rate of ~97% (3% patient survival rate). Its high mortality rate is largely blamed on the unusually non-suggestive symptomology in its early stages, compounded by the necessity of microbial culture of the cerebrospinal fluid to effect a positive diagnosis. The parasite also demonstrates a particularly rapid late-stage propagation through the nerves of the olfactory system to many parts of the brain simultaneously (including the vulnerable medulla).
Michael Beach, a recreational waterborne-illness specialist for the Centers for Disease Control and Prevention, stated in remarks to the Associated Press that the wearing of nose-clips to prevent nasal uptake of contaminated water would be an effective protection against contracting PAM, noting that, “You’d have to have water going way up in your nose to begin with”.
PAM can be effectively treated with antimicrobiotics, if the patient is treated early enough.
Key Points
- Amoebic meningoencephalitis is not actually caused by an ameoba but rather Naegleria fowleri a protist found in warm fresh water.
- Once Naegleria fowleri enters deep into the nasal passage, digesting through the olfactory bulbs it then migrates into the forebrain, where the protists eat neuronal tissue in the brain, leading to death within 14 days from initial exposure.
- The disease is largely asymptomatic until its final stages; often by the time it is diagnosed, it is too late to treat, causing a very high mortality rate.
- Antimicrobial drugs can combat Naegleria fowleri infection if it is treated soon enough. Avoiding the infection by wearing nose plugs when swimming in warm water is a good preventative measure.
Key Terms
- anosmia : Inability to smell; to perceive odors.
- protist : Any of the eukaryotic unicellular organisms including protozoans, slime molds and some algae; historically grouped into the kingdom Protoctista.
- parosmia : A distorted sense of smell, often resulting in phantom, non-existent, and mostly unpleasant, smells.
- ageusia : Partial or complete loss of the sense of taste.


14.5: Notes
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- John Banks & Stuart Cunningham
- University of California Press
1 Guy Standing, The Precariat: The New Dangerous Class (London: Bloomsbury, 2011).
2 Joseph A. Schumpeter, Capitalism, Socialism and Democracy (New York: Routledge, 2006 [1942]).
3 ABS, “8515.0—Digital Game Development Services, Australia, 2006–2007,” last issue April 8, 2008.
4 Ibid.; ABS, “8679.0—Film, Television, and Digital Games, Australia, 2011–2012,” last issue June 18, 2013.
5 Antony Reed, CEO, GDAA, interview with the authors, Melbourne, August 28, 2014.
6 Ibid.
7 Antony Reed, e-mail message to authors, September 30, 2014.
8 Rachel Parker, Stephen Cox, and Paul Thompson, “How Technological Change Affects Power Relations in Global Markets: Remote Developers in the Console and Mobile Games Industry,” Environment and Planning A 46.1 (2014): 168–185.
9 John Vanderhoef and Michael Curtin, “The Crunch Heard Round the World: The Global Era of Digital Game Labor,” in Production Studies: The Sequel! ed. Bridget Conor, Miranda Banks, and Vicki Mayer (New York: Routledge, 2015).
10 Larissa Hjorth, “Games: Mobile, Locative and Social,” in The Media and Communications in Australia , ed. Stuart Cunningham and Sue Turnbull (Crows Nest, NSW: Allen & Unwin, 2014), 281.
11 See John Banks, “The iPhone as Innovation Platform: Reimagining the Videogames Developer,” in Studying Mobile Media: Cultural Technologies, Mobile Communication, and the iPhone , ed. Larissa Hjorth, Jean Burgess, and Ingrid Richardson (New York: Routledge, 2012), 155–172.
12 John Banks and Stuart Cunningham, “Games and Entertainment Software,” in Handbook of the Digital Creative Economy , ed. Ruth Towse and Christian Handke (Cheltenham: Edward Elgar, 2013), 416–427.
13 “Number of Available Apps in the Apple App Store from July 2008 to September 2014,” October 12, 2014, www.statista.com/statistics/268251/number-of-apps-in-the-itunes-app-store-since-2008/; “Most Popular Apple App Store Categories in September 2014, by Share of Available Apps,” October 12, 2014, www.statista.com/topics/1729/app-stores/.
14 Innovation, captured in Schumpeter’s powerful phrase creative destruction, can have extraordinarily two-edged social, economic, and cultural effects. Runaway innovation occurs when change outstrips even its progenitors’ comfort and control. See, e.g., David Lane, “Towards an Agenda for Social Innovation,” European Centre for Living Technology , www.insiteproject.org/wp-content/ uploads/2014/02/Social-Innovation-Manifesto_INSITE.pdf, 2–3.
15 The research on which this chapter draws includes semistructured interviews conducted in Q3 2014 by the authors with sixteen developers from eight development studios, as well as with leaders in the games association and in government program support.
16 Dean Ferguson, interview with John Banks, August 21, 2014.
17 Morgan Jaffit, interview with John Banks, November 27, 2014.
18 Trent Kusters, interview with John Banks, September 24, 2014.
19 For a short history, see Banks, “The iPhone as Innovation Platform.”
20 Wicked Witch CEO Daniel Visser, interview with John Banks, September 23, 2014.
21 “Armello Press Kit,” http://press.armello.com/ .
22 Trent Kusters interview.
23 Ibid.
24 Ibid.
25 Simon Joslin, interview with the authors, August 29, 2014.
26 Ibid.
27 George Fidler, interview with the authors, September 10, 2014.
28 Ibid.
29 The Media, Entertainment & Arts Alliance (MEAA), the largest and most established union and industry advocate for Australia’s creative professionals, has no section for games.
30 Christian McCrea, “Australian Video Games: The Collapse and Reconstruction of an Industry,” in Gaming Globally , ed. Nina Huntemann and Ben Aslinger (Basingstoke: Palgrave Macmillan, 2012), 203–207.
31 Screen Australia, “Australian Interactive Games Fund Industry Consultation: Objectives and Context,” www.screenaustralia.gov.au/gamesoptions/category/Objectives-context.
32 Queensland, the major northern state, and Victoria, the major southern state, have been the twin centers of the Australian industry; the largest state located between them (New South Wales) has had a smaller proportion of the industry.
33 Entertainment and Software Association, “2014 Sales Demographic and Usage Data: Essential Facts about the Computer and Video Game Industry,” ESA (2014), www.theesa.com/wp-content/ uploads/2014/10/ESA_EF_2014.pdf; DataGenetics, “Casual Games Demographics,” www.datagenetics.com/blog/december12010/.
34 IGDA, “Press Release: IGDA Developer Satisfaction Survey Results Are Released,” www.igda.org/news/179158/Press-Release-IGDA-Developer-Satisfaction-Survey-results-are-released.htm.
35 Casey O’Donnell, Developer’s Dilemma: The Secret World of Videogame Creators (Cambridge MA: MIT Press, 2014).
36 Ibid., 28.
37 Ibid., 74.
38 Ibid., 161.
39 Antony Reed, interview with the authors, August 28, 2014.
40 Mark Deuze, Chase Bowen Martin, and Christian Allen, “The Professional Identity of Gameworkers,” Convergence 31 (2007): 336.
41 Casey O’Donnell, “This Is Not a Software Industry,” in The Video Game Industry: Formation, Present State and Future , ed. P. Zackariasson & T.L. Wilson (New York: Routledge, 2012), 17–33.
42 Gina Neff, Venture Labor: Work and the Burden of Risk in Innovative Industries (Cambridge MA: MIT Press, 2012).


5.3: SYMBOLISM AND ICONOGRAPHY
Symbolism refers to the use of specific figural or naturalistic images, or abstracted graphic signs that hold shared meaning within a group. A symbol is an image or sign that is understood by a group to stand for something. The symbol, however, does not have to have a direct connection to its meaning. For example, the letters of the alphabet, which are abstract graphic signs, are understood by those who use them to have individual sounds and meanings. The users have assigned meaning to them, as letters have no meaning in and of themselves. An example of a naturalistic image is a rose, which in most Western civilizations symbolizes love. When one person gives a rose to another, it is a symbol of the love the person feels.
Iconography is the broader study and interpretation of subject matter and pictorial themes in a work of art. This includes implied meanings and symbolism that are used to convey the group’s shared experience and history—its familiar myths and stories. Iconography refers to the symbols used within a work of art and what they mean, or symbolize. For example, in different cultures a snake may stand for evil, temptation, wisdom, rebirth, or the circle of life. A depiction of a snake in a scene with Adam and Eve has specific meanings for those of the Christian faith or others who understand the snake stands for temptation within the context of that subject or story. In Chinese culture, however, a snake represents the power of nature and is said to bring good fortune to those who practice the snake’s restraint and elegance of movement.
5.3.1 Changes in Meaning of Symbols and Iconography
While a symbol might have a common meaning for a certain group, it might be used with variations by or hold a different significance for other groups. Let us use the example of a cross. At its core, a cross is a simple intersection of vertical and horizontal lines that could refer to the meeting of celestial and terrestrial elements or forces or could lend itself to other variations of meaning. The cross most frequently associated with Christianity is the Latin Cross, with the long vertical bar intersected by a shorter horizontal one believed by many to be the form of the cross upon which Jesus Christ, the central figure of the faith, was crucified. (Variants of the Cross: http://wpmedia.vancouversun.com/2010...6.crosses1.png ) But its simplicity of conception lends itself to various other readings, as well, and in pre Christian use it was related to sacred and cosmic beliefs.
Within Christian usage, the cross has taken a great number of different of forms, including the equal-armed Greek Cross, favored by the Byzantine Christians; Celtic crosses, with a circular addition to the crossing; X’s and upside-down crosses associated with specific Christian martyrs , individuals who died for their faith, on such instruments of torture; and many others. In art, we might see them as simple flat graphic works, or decorated in two-dimensional renditions, or as fully developed three-dimensional interpretations, like the numerous grave markers in Irish cemeteries, where they are further embellished with intricate motifs and iconographic depictions of Bible stories. (Figure 5.11)
The Ankh, another cross form, with a looped handle, seems to have been devised by the ancient Egyptians as a symbol of the life-giving power of the Sun. (Figure 5.12) It was one of the numerous pictographic symbols they used both as a separate sign and as part of the hieroglyphic system of writing they developed.
Clearly, many other symbols have various meanings, especially when they are represented as more abstract graphic signs. To read their implications in any particular application will require your considering where it was made and for what specific purposes, as well as how it might have been adopted and turned to different use at that time or later. Sometimes the shifts in meaning may be radical, as in the form of the swastika, an ancient sacred sign used in many different cultures, including India and others throughout Asia, as well as the Near East, and Europe. (Figures 5.13, 5.14, and 5.15) It has historically been a very auspicious sign with implications of good fortune and positive movement, and was therefore adopted for the ground plan for Buddhist stupa worship centers. Of course, in the twentieth century, its appropriation by the Nazi Party as a symbol of the superiority of the Aryan heritage led to very different and now generally negative connotations.
Iconography is often more specific and definitive, with concrete reference to world experiences and, beyond that, to some form of narrative for the group involved. Again, analysis of the pictorial form requires examination of the con- text in which the artwork was created. We can and must look at the underlying narrative, but, as we shall discuss in the next several chapters, the pictorial expressions evolve both independently of the narrative sources and in response to narrative and artistic change.
For example, Christians (more specifically that branch now known as Roman Catholics) debated the “true nature” of the Virgin Mary, the Mother of Jesus Christ. Among the points of debate was whether Mary was bodily in Heaven with her Son or whether she had to wait until the end of time when the whole of mankind would experience bodily resurrection, that is, at the time of the Second Coming and the Last Judgment, when everyone would have their lifetime of deeds assessed for purposes of learning whether they would spend eternity in Heaven or Hell. These Christian ideas are among those a great amount of art has been devoted to over time.
To illustrate, we can look at differences between two works about Mary and her place and role in Heaven that appeared in church relief sculpture during the twelfth and thirteenth centuries. These differing ideas focused on the implied elevation of Mary to a divine status, or to her not being seen as divine herself, in which case, the faithful needed to keep a view of her as being in a more subordinate or secondary status. The questions included consideration of Mary as the “Queen of Heaven,” who might be ruling alongside her son. At Senlis Cathedral (1153-1181) in France, she was depicted as apparently a co-ruler with Christ, but ensuing theological discussion took issue with this possible over-elevation. (Figure 5.16) So, while the renditions of Mary as the celestial queen continued in popularity, they made it clear that she was only considered to be there at the bidding and will of Christ. This can be seen at Chartres Cathedral in France, where she bows her head to Jesus. (North Portal of Notre-Dame Cathedral: https://www.bluffton.edu/~sullivanm/ chartresnorth/cportal.html)
What we see here, again, is that our full analysis of the artworks we encounter needs a complex approach that includes a variety of visual clues and a wide range of research on the contextual details of its creation and use. In contrast to the longstanding assertion that “beauty is in the eye of the beholder,” the appropriate interpretation according to the intended symbolism and/or iconography must take the society, culture, and related circumstances into account to accurately reflect its intended meaning or original meaning for viewers. We will be exploring these ideas in greater detail in the next several chapters.
5.3.2 Symbolism, Iconography, and Visual Literacy
Symbols like the cross or the swastika will only have shared meaning for those who agree upon and affirm a specific interpretation, which can be positive or negative for any particular group of people. This specific meaning in symbols is always going to be the case for viewing of any visual expression, whether in simplified graphic sign form or a more detailed pictorial rendition. Additionally, the viewers must also often have some measure of instruction about how to view a particular work so they can understand its meaning more fully.
Also noteworthy is that members of any group use art as a means of sharing ideas and sentiment, as well as for expressing and teaching ideology. While the didactic uses of art have often been discussed in terms of instruction for the non-literate, we should recognize that the meanings of pictorial content and the tools used to create the picture must be learned as well. The apparent superficial meanings that are evident through unschooled visual examination do not produce the level of comprehension available in a more fully developed illustration of a tenet of a faith, political message, history lesson, or chart or graph of economic trends. So “visual literacy” should be considered a skill related to verbal and reading literacy for any didactic function. Only members of a group who have been led to understand and perceive the underlying principles will know how to “read” an illustrated message.
For example, we can look at the Ritual Vase from Warka (today Iraq) or the Seven Sacraments Altarpiece by Rogier van der Weyden. (The Warka Vase: http:// dieselpunk44.blogspot. com/2013/08/the-warka- vase.html) (Figure 5.17) One could likely identify the basic pictorial content of either work, but further knowledge would be needed to analyze them further. If you were a member of the intended audience, you might have a bit more insight into what each artist had created in pictorial terms, but even the initiated viewer would likely have a limited “reading” of the work.
In the case of the Ritual Vase from Warka , even if you had lived in ancient Sumer and had been a devotee of the goddess Inanna, you would likely need further instruction about how the carvings on the different registers of the vase were arranged to show the cosmological conception of the created world. That is, one starts at the bottom with the primordial earth and waters, moves to the plants and animals above them drawing sustenance so that they could be harvested and herded by the humans, who then offer part of their gleanings to the goddess serving them from the temple as seen in the upper realm of the middle photograph. This design would be further explained as a neatly hierarchical arrangement, in which the levels of the created world were presented in different sizes, according to their relative importance. Additional meanings could be layered upon this cursory explanation with repeated teaching occasions and viewings.
The Seven Sacraments Altarpiece was painted by Rogier van der Weyden in a region and an era of tremendously complicated iconography: Flanders during the Late Gothic/Northern Renaissance period. The presentation here includes detailed pictorial description of each of the seven sacraments that marked the stages and stations of Christian life. This symbolism again developed over time, and often in response to theological writings that informed the artist and the viewer about specific meanings. The written sources are detailed and complex, with the pictorial rendition richly reflecting what the well-instructed Christian would know about these important rituals and their effects.
The larger central panel of the triptych , or three-part, format was used by the artist to emphasize the Crucifixion as the dominant overarching event that is related to each of the sacraments. Additionally, he provided angels with scrolls to identify them as if speaking to the viewer. So, here the messages are both pictorial and inscribed, and the iconography is a complex program that relates all these ritual events to the whole of the Christian life and faith. Truly, the viewer must be an initiate to discern the meanings behind all the symbolism or a scholar to discover them. Nonetheless, even the casual or uninitiated can read much of what is present in the painting and can identify both familiar elements and those that might lead you to further investigation. This is often the task and the path in interpretation of iconography in art.
5.3.3 Symbolism and Iconography in Mythology and Storytelling
From early on, art contained expressions of mythical accounts that people shared about their beliefs and ways of living. From the time of the first great civilizations, for example, in Egypt, the Near East, China, Japan, and India, artwork related to the stories of the people. The degree to which any contemporary written sources confirm these interpretations varies, but that these myths had commonly understood meanings for the people for whom they were made is confirmed by both their frequent appearance and their apparent places in their culture’s artistic traditions, sometimes over centuries. Artistic iconographic traditions therefore show strong relationships to beliefs and practices known from written sources—although written documentation sometimes does not appear until later times.
Because early stories were often passed along through oral tales, we do not always have a literary record of them until later times, even after the ideas had been expressed symbolically in pictorial art. An example of this symbolism may be found in the rich hoard (a collection of objects) known as the Sutton Hoo Ship Burial, found in England and deriving from the early Middle Ages era known as the Migration period (300-700 CE). Although the wooden ship itself has disintegrated, the burial hoard it contained provides details that confirm and broaden our incomplete understating of the adventurous societies of that time and their beliefs about needs for the afterlife. The diverse objects also lend certain insights into the epic tales of such warrior kings as Beowulf, whose story seems to have been a long-standing oral tradition, one perhaps re-told for centuries before being commit- ted to written form. The lavish ornaments, such as this belt buckle and purse cover, give visual testimony to the tales of dragons and heroes like Beowulf through their expressive and intricate patterns and rich materials. (Figures 5.18 and 5.19) The fine metalwork on the purse cover is cloisonné ,which is created by affixing gold or metal strips to the back surface, making compartments, that are filled with powder (in this case, ground garnets) and heated to 1,400-1,600 degrees F.
The art of ancient Greece often showed great concern with the stories of Greek mythology as well. Tales of the gods and warriors abound, including those about great physical or intellectual contest, such as the well-known struggles of Herakles (known as Hercules under the Romans) one of which is seen on this amphora. (Figure 5.20) Such tales were very familiar, and viewers were expected to supply the details of the rest of the story through the parts that were shown. However, the skillful artist can enliven the presentation of the figures with posture, gesture, expression, and such symbolic props as the club and the tripod Herakles holds.
As with literary accounts, the artworks associated with historical and legendary events often include a very wide range of symbols and imagery to help convey ideas. These range from mundane details to grand historical moments, as in the Column of Trajan, nearly 100 feet in height, which commemorates the military campaigns of Roman Emperor Trajan (r. 98-117 CE) against the Dacians (101-102 and 105-106 CE) in 155 scenes. (Figure 5.21) Or as appear in the Bayeux Tapestry, an embroidered cloth 230 feet in length that pictorially recounts the events of the Norman Invasion and Battle of Hastings in 1066. (Figure 5.22) Each of these works shows decisive points in their respective historical events in army operations and in the details of the hard work involved in preparing for battle. (Figures 5.23 and 5.24) In this way, they provide us with glimpses of everyday life in the respective eras alongside specific details about the particular campaigns, the cultures in which they were significant, and the individuals who were key players in the historical events. The details of arms and armor, organized troops and chaotic fighting, building of defensive structures and devices, moments of victory and defeat, and innumerable other items and activities—all are individually and collectively efficient means of recounting the evolution of the events which, in each of these works, is dramatically developed across a long scrolled compositional field that further emphasizes the lengthy narrative each one progressively disclosed.
Like many works of public art of the Roman Imperial era, the column glorifies not only Trajan (the base of the column was designed to contain his ashes) and his deeds, but also the ideas of imperial rule, the role of conquest in expanding the Empire, and the skilled work of Roman soldiers in battlements and tactics. By contrast, the Bayeux Tapestry has more emphasis on the actual tumultuous battle scenes replete with mounted cavalry in chain mail and elaborate helmets but it also includes a great deal more sense of historical con- text: events leading up to the 1066 Battle of Hastings after the death of King Edward the Confessor (r. 1042-1066) and his burial in the newly refurbished Westminster Abbey he had adopted as his royal church. Both of these works also include inscriptions that explicate ideas and events, as well as serve to further present the political messages about the battles presented on the tapestry in a sort of scene-by-scene narrative again, for each, underscoring the relationships between literary and pictorial presentations of ideas.
5.3.4 Exploring Symbolic and Iconographic Motifs
Such items as arms and armor are obvious sorts of symbols that clearly depict their purposes, but much symbolism that we see in other artworks has more veiled and variable meaning. Such simple items as flowers and candles can be used in very complex ways in pictures that carry diverse meanings, thus requiring careful study and even deep research in order to discern their implications in a particular work.
For example, the Merode Altarpiece by Robert Campin (c. 1375-1444, Belgium) depicts the Christian story of the Annunciation to the Virgin Mary by the Angel Gabriel that she will become the Mother of Christ, the son of God. (Figure 5.25) This work is full of symbols that have been widely studied to discern and interpret their messages. The lilies are generally interpreted to symbolize the purity and virginity of Mary in other pictures, though, they might have other meanings, including reference to death, resurrection, birth, motherhood, or other events or conditions. Within this one work, the use of the candle, just extinguished with a trail of smoke, is given several different meanings by diverse viewers and scholars. It might show the moment of acquiescence, when Mary agrees to bear the Christ child, in which God takes human form. It has also been read as a foreshadowing of Christ’s death, of human death in general, and of the fleeting nature of life for all.
In the time and place of the altarpiece’s creation, symbolism in paintings was particularly apt to be rich and varied, offering the viewer/believer a lot to see and to contemplate further. In this way, if the symbols could be read in different ways, they could then provide ongoing stimulus for meditative reflection on the diverse levels of meaning.
For example, the Merode Altarpiece by Robert Campin (c. 1375-1444, Belgium) depicts the Christian story of the Annunciation to the Virgin Mary by the Angel Gabriel that she will become the Mother of Christ, the son of God. (Figure 5.25) This work is full of symbols that have been widely studied to discern and interpret their messages. The lilies are generally interpreted to symbolize the purity and virginity of Mary in other pictures, though, they might have other meanings, including reference to death, resurrection, birth, motherhood, or other events or conditions. Within this one work, the use of the candle, just extinguished with a trail of smoke, is given several different meanings by diverse viewers and scholars. It might show the moment of acquiescence, when Mary agrees to bear the Christ child, in which God takes human form. It has also been read as a foreshadowing of Christ’s death, of human death in general, and of the fleeting nature of life for all.
In the time and place of the altarpiece’s creation, symbolism in paintings was particularly apt to be rich and varied, offering the viewer/believer a lot to see and to contemplate further. In this way, if the symbols could be read in different ways, they could then provide ongoing stimulus for meditative reflection on the diverse levels of meaning.
And some symbolic motifs , distinguishing features or ideas, carry different meaning in one context from what they might in another. Most symbols are not universal, although they often bear related meanings in diverse contexts. For instance, the sort of figure you might identify as an angel, that is, a winged creature with a human-like bodily form, has appeared in the art of many different cultures. They generally represent beings that can travel between the terrestrial and celestial realms, but their more specific roles can vary widely, for good or evil purposes. The Angel Gabriel, just seen in the Merode Altarpiece, was a messenger from God, according to the Christian tradition. This motif was built upon the Jewish tradition of angels sent from God for bringing news or instructions, or intervening as needed. Islamic interpretations, also building on the same traditions, are similar although the figural representation is less common in Muslim artwork.
Prior to such figures, winged creatures known as Nikes were depicted by ancient Greek and Roman artists to show a moment of victory, sometimes, as is the case here, further symbolized by the award of a fillet, a band wrapped around the head, or laurel wreath. (Figure 5.26) These winged figures were sometimes gods or goddesses. The genie figures that adorned palace walls in the ancient Near East, including horses, bulls, lions, and other animals, were also winged to show their superior and sometimes god-like powers or origins. (Figure 5.27) Other examples include the goddess Isis of an- cient Egypt, and the Persian god Ahura Mazda. (Figures 5.28 and 5.29)
Another set of prominent Christian iconographic motifs are the winged symbols which often represent the Four Evangelists in art: Matthew is the winged man or angel; Mark, the winged lion; Luke, a winged ox; and John, an eagle. (Figure 5.30) At the same time they refer to four key events in the life of Christ: the Incarnation, Passion, Resurrection, and Ascension. Interpretations of these evangelist symbols are rooted in the Old Testament Vision of Ezekiel and the New Testament Book of Revelation, as related by the writings of St. Jerome in the fifth century CE. They accrued additional iconographic details over the centuries, with implications of their status as the special creatures who surround the celestial throne of God again, signifying that the wings facilitate movement between the realms traditionally ascribed to a deity , a god or goddess, and divinely related creatures. This use of wings clearly reflects human contemplation of the abilities that birds have to defy gravity and to express artistically the lofty aspirations of the earthbound.
Another frequently used iconographic motif that appears across the ages and across cultures is the halo , usually a circular area of light appearing behind the head of a person or creature. One example is the halo that appears behind the heads of Christ and the symbolic winged creatures in Figure 5.30. Note that Christ’s halo has a cross form embedded in it, and his entire body is surrounded by a circle of light (made up of four arcs) known as an aureole or mandorla . Such devices, in many related forms, indicate a radiance that surrounds certain figures, showing their sanctity, divinity, or divine favor. It indicates their aura of holiness, with implications of their being infused with warmth, inflamed with divinity or with divine love. In some of the Asian versions, notably Hindu or Buddhist, the radiance is literally comprised of flames.
Frequently seen, as well, are such items as crowns, thrones, regalia like scepters, garments like official capes, monks’ robes, or uniforms of all varieties indications of a person’s belonging to a specific group, class, or office that lead the viewer to identify some specific aspect of who the person might be and what role they have in the depiction. The positioning of figures relative to one another should also be read in order to discern meaning, interactions, relative rank, and other implications. The types of garb, accompanying items, and positioning often relate the message to a specific time and place by giving historical and cultural context through details of style or motifs used.
For example, on the stele depicting his victory over the Lullubi, the Akkadian ruler Naram Sin (r. c. 2254-2218 BCE) wears a horned helmet and is much bigger than the men around him. (Figure 5.31) He ascends the mountain as his enemies beg for mercy under the watch of astral deities, and that shows his relationship to them as the source of his power and right to rule. In the Ghent Al- tarpiece by Jan van Eyck (c. 1390-1441, Belgium), we can also see a variety of such motifs: Christ, wearing the papal ti- ara as a crown; Mary, richly dressed and humbly reading; and John the Baptist, in his garment of penitence, and preaching. (Figure 5.32) Adorned with jewels and gold on his clothing, the throne on which he sits, and the crown at his feet, Christ is here being shown as the king of Heaven as well as Earth.
5.3.5 Metaphorical Meanings
The metaphorical meanings of specific artworks also depend upon a certain level of viewer knowledge and insight. A metaphor is a figure of speech in which one thing symbolically stands for another, perhaps unrelated, thing or idea.
In 1550 Chairs Stacked Between Two City Buildings by Doris Salcedo (b. 1958, Columbia) , we see a metaphorical treatment of life change. ( 1550 Chairs Stacked Between Two City Buildings , Doris Salcedo: http://www.mymodernmet.com/profiles/...s-salcedo-1550 chairs-stacked) It is a view of displacement resulting from a 1985 uprising in her Colombian homeland that left many migrants displaced or dead, as well as similar catastrophic events in locales across the globe. The jumbled mass of furniture alludes to the upheaval of lives that are overturned by mass violence and terrorism, often of those already without roots, community, or stable lifestyles. The victims, frequently anonymous and relatively invisible in the site of such a revolt, nonetheless left some hints of their presence in the chaotic remnants of their fleeting existence, in a place where they had established so little sense of their individual identities. Her metaphorical expression gives a probing glimpse of the devastation such events have wrought around the world.


3.2E: Modeling with Exponential Functions (Exercises)
Section 3.2 Exercises
Part 1: Modeling with Exponential functions with a constant percentage rate of change or growth factor.
1. On Monday 20 computers are infected with a computer virus. Each day, the number of infected computers triples.
a. Find an exponential model for the number of infected computers, y, in terms of t, the days since Monday.
b. Predict the number of infected computers in 2 weeks.
2. What is the growth factor b in each of the following situations of exponential growth or decay?
a. A customer's power usage increased by 9% per year
b. The number of subscribers' decreased by 3% per year.
c. The population of a species of from increased by 2.47% per month?
3. For each of the following situations the percentage rate of change per second and initial value at time t = 0 sec. is given. Find an formula for the quantity y as a function of t. Then predict the amount in 12 seconds.
a. The initial amount is 520 ft and is increasing by 4% per second.
b. The initial amount 400 mg and is decreasing by 3% per second.
c. The initial amount is 20 m 3 and is decreasing by 2.41% per second.
4. The populations, P, of six towns, t years after 2010 are given below.
i. \(P=12,000(1.07)^{t} \) ii. \(P=8,000(1.13)^{t} \)
iii. \(P=9,000(0.94)^{t} \) iv. \(P=8,500(1.085)^{t} \)
v. \(P=8,214(0.83)^{t} \) vi. \(P=8,912(0.997)^{t} \)
a. Which towns are increasing in size? Which towns are decreasing in size?
b. Which town is growing the fastest? What is the annual percentage growth rate of that town?
c. Which town is decreasing in size the fastest? What is the annual percentage decay rate of that town?
d. Which town had the largest population in 2010?
5. As of January 2, 2022, the rate of people 70 years or older hospitalized for COVID was 13.32 people per 100,000 people in the US population. At that point in time, the number of people hospitalized was increasing by 3.7% per day . 1 Assume the rate of infection continues to increase at this percentage rate.
a. Find an exponential model for the number of people 70 years or older hospitalized , \(H(t)\) , in terms of t, the days since January 2, 2022.
b. Predict the number of people infected on Jan. 22.
6. As of February 4, 2022, the rate of people 70 years or older hospitalized for COVID was 15.52 people per 100,000 people in the US population. At that point in time, the number of people hospitalized was decreasing by 4.475% per day. 2 Assume the rate of infection continues to decrease at this percentage rate.
a. Find an exponential model for the number of people 70 years or older hospitalized , \(H(t)\) , in terms of t, the days since February 4, 2022.
b. Predict the number of people infected on February 23, 2022.
7. Clovis Community College had 10,464 students in the Fall 2016 - Spring 2017 academic year. At the time, growth was projected to be 8% per years based on state funding projections. 3 Assume the student enrollment continues to increase at this percentage rate.
a. Find an exponential model for the number of students, \(S(t)\) , in terms of the years since the Fall 2016 - Spring 2017 .
b. Predict the number of students at Clovis Community College in the Fall 2026 - Spring 2027 semester.
8. The concentration of fine particulate matter pollution (PM2.5) in California was 13.95 \(\dfrac{\mu g}{m^{3}} \) in 2003. From 2003 to 2011, the concentration decreased by approximately 4.942% per year. 4 Assume the concentration of fine particulate matter pollution continues to decrease at this percentage rate.
a. Find an exponential model for the concentration of fine particulate matter pollution, \(c(t)\) , in terms of the years since 2003.
b. Predict when the concentration of fine particulate matter pollution in 2025.
9. The fox population in a certain region has an annual growth rate of 9% per year. It is estimated that the population in the year 2010 was 23,900. Estimate the fox population in the year 2018.
10. The amount of area covered by blackberry bushes in a park has been growing by 12% each year. It is estimated that the area covered in 2009 was 4,500 square feet. Estimate the area that will be covered in 2020.
11. A vehicle purchased for $32,500 depreciates at a constant rate of 5% each year. Determine the approximate value of the vehicle 12 years after purchase.
12. A business purchases $125,000 of office furniture which depreciates at a constant rate of 12% each year. Find the residual value of the furniture 6 years after purchase.
Part 2: Modeling with exponential functions from data.
In problems 13- 17, find a formula for an exponential function passing through the two points.
13. \(\left(0,\; 6\right),\; (3,\; 750)\)
14. \(\left(0,\; 3\right),\; (2,\; 75)\)
15. \(\left(0,\; 2000\right),\; (2,\; 20)\)
16. \(\left(-1,\dfrac{3}{2} \right),\; \left(3,\; 24\right)\)
17. \(\left(3,\; 1\right),\; (5,\; 4)\)18. A house that was valued at $300,000 in California in January 2018 was valued at $376,000 in January 2021. 5
a. Find an exponential formula for the value of the house, \(v(t)\) t years since January 2018, assuming the value continues at the same percentage rate.
b. Predict the value of the home in January 2025.
c. What was the annual growth rate?
19. A house that was valued at $400,000 in California in January 2019 was valued at $480,000 in January 2022. 6
a. Find an exponential formula for the value of the house, \(v(t)\), t years since January 2019, assuming the value continues to increase at the same percentage rate.
b. Predict the value of the home in January 2025.
c. What was the annual growth rate?
20. A car was valued at $38,000 in the year 2012. The value depreciated to $11,000 by the year 2021. Assume that the car value continues to drop by the same percentage rate.
a. Find an exponential formula for the value of the car, \(v(t)\), t years since 2012.
b. Predict the value of the car in 2025.
21. A car was valued at $24,000 in the year 2006. The value depreciated to $15,000 by the year 2009. Assume that the car value continues to drop by the same percentage rate. What was the value in the year 2014?
22. The population of California was 37,253,956 on April 1, 2010. The population grew to 39,538,233 on April 1, 2020. Assume that the population continues to increase by the same percentage rate. 7
a. Find an exponential formula for the population of California, \(P(t)\), t years since April 1, 2010.
b. Predict the population of California on April 1, 2025.
23. A person drinks alcohol at a party. After her last drink, the alcohol level of her blood soon reaches a maximum of 0.28 milligram per milliliter of blood. 50% of the alcohol remained after 2 hours. Assume the blood level decreases exponentially.
a. Find an exponential formula for the alcohol level in her blood, \(A(t)\), in t hours.
b. If she waits 3 hours, will her blood alcohol level be below the legal limit of 0.08?
_________________________________________________
1,2 The data was reported by the CDC at https://covid.cdc.gov/covid-data-tra...tal-admissions on January 20, 2023.
3 The data was r eported by the Clovis Community College Institutional Research Department at Clovis Community College on August 12, 2018 ( https://www.cloviscollege.edu/about/...-research.html ) .
4 The data was reported by the CDC at https://wonder.cdc.gov on February 24, 2023.
5,6 The data was reported by the U.S. Federal Housing Finance Agency House Price Index Calculator at www.fhfa.gov/DataTools/Tools/Pages/HPI-Calculator.aspx on January 25, 2023.
7 The data was reported by the U.S. Census Bureau at https://www.census.gov/quickfacts/fa...e/CA/PST045222 on January 26, 2023.
- Answer
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1. a. \(y=20(3)^{t} \) b. y = 95,659,380
3. a. \(y=520(1.04)^{t} \) b. \(y=400(0.97)^{t} \) c. \(y=20(0.9759)^{t} \)
5. a. \(H(t) =13.32(1.037)^{t} \) b. 27.55
7. a. \(S(t) = 10,464(1.08)^t\) b. 22,591 students
9. The fox population can be modeled by the function \(y=23,900(1.09)^{t} \). In 2018, there will be 47622 Fox.
11. The vehicle \(V=32,500(0.95)^{t} \). In 12 years, the value will be $17561.70.
13. \(y = 6(5)^x\)
15. \(y = 2000(0.1)^x\)
17. \(y = (\dfrac{1}{8})(2)^x\)
19. a. \(y = 400,000(1.0627)^{t}\) b. 576,000 c. The home value is growing by 6.27%
21. The car will be worth $6,853.
23. a. \(A(t)=0.28(0.7071)^{t}\) b. The blood alcohol level is 0.09899 after 3 hours.


9.3: San Francisco Bay
The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Governments to include the nine counties that border the estuaries: Alameda, Contra Costa, Marin, Napa, San Mateo, Santa Clara, Solano, Sonoma, and San Francisco. The core cities of the Bay Area are San Francisco, San Jose, and Oakland.
Home to approximately 7.76 million people, Northern California's nine-county Bay Area contains many cities, towns, airports, and associated regional, state, and national parks, connected by a complex multimodal transportation network. The Bay Area is known for its natural beauty, progressive politics, world-class universities, technology companies, and affluence. The larger federal classification, the combined statistical area of the region which includes fourteen counties, is the second largest in California (after the Greater Los Angeles area), the fifth largest in the United States, and the 41st-largest urban area in the world. The Bay Area's population is ethnically diverse: roughly three-fifths of the region's residents are Hispanic, Asian, African American, or Pacific Islander (with the other two-fifths being non-Hispanic White American), all of whom have a significant presence throughout the region.
Despite its urban character, the San Francisco Bay is one of California's most ecologically important habitats, providing key ecosystem services such as filtering pollutants and sediments from the rivers and supporting several endangered species. In addition, the Bay is known for its stands of coast redwoods, many of which are protected in state and county parks. The region is additionally known for the complexity of its landforms, the result of millions of years of tectonic plate movements. Because the Bay Area is crossed by six major earthquake faults, the region is particularly exposed to hazards presented by large earthquakes. The climate is temperate and generally very mild and is conducive to outdoor recreational and athletic activities such as hiking, running, and cycling. The Bay Area is host to six professional sports teams and is a cultural center for music, theater, and the arts. It is also host to higher education institutions, including research universities such as Stanford University and the University of California, Berkeley. Home to 101 municipalities and nine counties, governance in the Bay Area involves numerous local and regional jurisdictions, often with broad and overlapping responsibilities. Over time, droughts and wildfires have increased in frequency and become less seasonal and more year-round, further straining the region's water security.
The COVID-19 pandemic resulted in many tach career-based people leaving the area to live elsewhere, while working remotely. In fact, it was suggested by some that over 116,000 people moved within the first year of the Pandemic. One of the effects is empty residences, empty professional buildings, increased property rates, and increase homelessness. As of 2024, data is suggesting that the population decline may be leveling off, but the long-term impacts will be better known after the next Census.
Physical Geography
The Bay Area is in the warm-summer Mediterranean climate zone (Köppen Csb) that is a characteristic of California's coast, featuring mild to cool winters with occasional rainfall, and warm to hot, dry summers It is largely influenced by the cold California Current, which penetrates the natural mountainous barrier along the coast by traveling through various gaps. In terms of precipitation, this means that the Bay Area has pronounced seasons. The winter season, which roughly runs between November and March, is the source of about 82% of annual precipitation in the area. In the South Bay and further inland, while the winter season is cool and mild, the summer season is characterized by warm sunny days, while in San Francisco and areas closer to the Golden Gate strait, the summer season is periodically affected by fog
Due to the Bay Area's diverse topography, the result of the clashing tectonic plates, the region is home to numerous microclimates that lead to pronounced differences in climate and temperature over short distances Within the city of San Francisco, natural and artificial topographical features direct the movement of wind and fog, resulting in startlingly varied climates between city blocks. Along the Golden Gate Strait, oceanic wind and fog from the Pacific Ocean can penetrate the mountain barriers inland into the Bay Area. During the summer, rising hot air in California's interior valleys creates a low-pressure area that draws winds from the North Pacific High through the Golden Gate, which creates the city's characteristic cool winds and fog. The microclimate phenomenon is most pronounced during this time, when fog penetration is at its maximum in areas near the Golden Gate strait, while the South Bay and areas further inland are sunny and dry.
Along the San Francisco Peninsula, gaps in the Santa Cruz Mountains, one south of San Bruno Mountain and another in Crystal Springs, allow marine air into the interior, causing a cooling effect for cities along the Peninsula and even as far south as San Jose. This weather pattern is also the source for delays at San Francisco International Airport. In Marin county north of the Golden Gate strait, two gaps north of Muir Woods bring cold air across the Marin Headlands, with the cooling effect reaching as far north as Santa Rosa. Further inland, the East Bay receives the moderate effects of the ocean, that travels through the Golden Gate strait, and further diffuses that air through the Berkeley Hills, Niles Canyon and the Hayward Pass into the Livermore Valley and Altamont Pass. Here, the resulting breeze is so strong that it is home to one of the world's largest array of wind turbines. Further north, the Carquinez Strait funnels the marine air into the San Joaquin River Delta, causing a cooling effect in Stockton and Sacramento, so that these cities are also cooler than their Central Valley counterparts in the south.
Physical Geology
The Bay Area is well known for the complexity of its landforms that are the result of the forces of plate tectonics acting over millions of years, since the region is in the crux of a meeting point between two plates. Nine out of eleven distinct assemblages of rock types have been identified in a single county, Alameda. Diverse assemblages adjoin in complex arrangements due to offsets along the many faults (both active and stable) in the area. Therefore, many types of rock and soil are found in the region. The oldest rocks are metamorphic rocks that are associated with granite in the Salinian Block west of the San Andreas fault. These metamorphic rocks were formed from protolith of sedimentary rock of sandstones, limestones, and shales in uplifted seabeds. Volcanic deposits also exist in the Bay Area, displaced by the movement of the San Andreas fault, whose movement sliced a subduction plate and allowed magma to briefly flow to the surface
The region has considerable vertical relief in its landscapes, the topography, and geologic history, of the Bay Area can largely be attributed to the compressive forces between the Pacific Plate and the North American plate. The three major ridge structures in the Bay Area, part of the Pacific Coast Range, are all roughly parallel to the major faults. The Santa Cruz Mountains along the San Francisco Peninsula and the Marin Hills in Marin County follow the San Andreas fault, The Berkeley Hills, San Leandro Hills and their southern ridgeline extension through Mission Peak roughly follow the Hayward fault, and the Diablo Range, which includes Mount Diablo and Mount Hamilton and runs along the Calaveras fault.
In total, the Bay Area is traversed by seven major fault systems with hundreds of related faults, all of which are stressed by the relative motion between the Pacific Plate and the North American Plate or by compressive stresses between these plates. The fault systems include the Hayward Fault Zone, Concord-Green Valley Fault, Calaveras Fault, Clayton-Marsh Creek-Greenville Fault, Rodgers Creek Fault, and the San Gregorio Fault. Significant blind thrust faults (faults with near vertical motion and no surface ruptures) are associated with portions of the Santa Cruz Mountains and the northern reaches of the Diablo Range and Mount Diablo. These "hidden" faults, which are not as well known, pose a significant earthquake hazard Among the more well-understood faults, as of 2014, scientists estimate a 72% probability of a magnitude 6.7 earthquake occurring along either the Hayward, Rogers Creek, or San Andreas fault, with an earthquake more likely to occur in the East Bay's Hayward Fault. Two of the largest earthquakes in recent history were the 1906 San Francisco earthquake and the 1989 Loma Prieta earthquake.
Cultural Geography
The earliest archaeological evidence of human settlements in the Bay Area dates to 8000–10,000 BCE (from shell mounds in the Coyote Hills). In 1769, the Bay Area was inhabited by Ohlone people when a Spanish exploration party led by Gaspar de Portolá entered the Bay – the first documented European visit to the Bay Area. After Mexico established independence from Spain in 1821, the region was briefly controlled by the Mexican government until the United States seized the territory in 1846 during the Mexican American War. Soon after, discovery of gold in California attracted a flood of treasure seekers, many using ports in the Bay Area as an entry point. During the early years of California's statehood, state legislative business rotated between three locations in the Bay Area before a permanent state capital was established in Sacramento. A major earthquake leveled the city of San Francisco and environs in 1906, but the region quickly rebuilt in time to host the 1915 Panama-Pacific Exposition. In fact, a lot of the debris from the 1906 earthquake was pushed offshore to help create a man-made extension of the San Francisco Harbor. During World War II, the Bay Area played a major role in America's war effort in the Asiatic-Pacific Theater, with the San Francisco Port of Embarkation, of which Fort Mason was one of fourteen installations and location of the headquarters, acting as a primary embarkation point for American forces. In 1945, the United Nations Charter was signed in San Francisco, establishing the United Nations, and in 1951, the Treaty of San Francisco re-established peaceful relations between Japan and the Allied Powers. Since then, the Bay Area has experienced numerous political, cultural, and artistic movements, developing unique local genres in music and art, and establishing itself as a hotbed of progressive politics. Economically, the post-war Bay Area saw huge growth in the financial and technology industries, creating an economy with a gross domestic product of over $700 billion, and home to the third-highest concentration of Fortune 500 companies in the United States (as of 2018).
According to the 2010 United States Census, the population of the nine-county Bay Area was 7.15 million, with 49.6% male and 50.4% female. The Bay Area cities of Vallejo, Suisun City, Oakland, San Leandro, Fairfield, and Richmond are among the most ethnically diverse cities in the United States.
Non-Hispanic whites form majorities of the population in Marin, Napa, and Sonoma counties. Whites also make up the majority in the eastern regions of the East Bay centered around the Lamorinda and Tri-Valley areas. San Francisco's North Beach district is considered the Little Italy of the city and was once home to a significant Italian-American community. San Francisco, Marin County and the Lamorinda area all have substantial Jewish communities.
The Latino population is spread throughout the Bay Area, but among the nine counties, the greatest number live in Santa Clara County, while Contra Costa County sees the highest growth rate. The largest Hispanic or Latino groups were those of Mexican (17.9%), Salvadoran (1.3%), Guatemalan (0.6%), Puerto Rican (0.6%) and Nicaraguans (0.5%) ancestry. Mexican Americans make up the largest share of Hispanic residents in Napa county, while Central Americans make up the largest share in San Francisco, many of whom live in the Mission District which is home to many residents of Salvadoran and Guatemalan descent.
The Asian-American population in the Bay Area is one of the largest in the United States. Asian-Americans make up the plurality in two major counties in the Bay Area: Santa Clara County and Alameda County. The largest Asian-American groups were those of Chinese (7.9%), Filipino (5.1%), Indian (3.3%), Vietnamese (2.5%), and Japanese (0.9%) heritage. Daly City has the highest proportion of Asian-American residents (58.4%) in a large U.S. city outside of Hawaii Asian Americans also constitute a majority in Cupertino, Fremont, Milpitas, Union City and significant populations in Dublin, Foster City, Hercules, Millbrae, San Ramon, Saratoga, Sunnyvale, and Santa Clara.
Pacific Islanders such as Samoans and Tongans have the largest presence in East Palo Alto, where they constitute over 7% of the population.
The African-American population of San Francisco was formerly substantial, had a thriving jazz scene and was known as "Harlem of the West." While black residents formed one-seventh of the city's population in 1970, today they have mostly moved to parts of the East Bay and North Bay, including Antioch, Fairfield and out of the Bay Area entirely. The South Park neighborhood of Santa Rosa was once home to a primarily black community until the 1980s, when many Latino immigrants settled in the area.
The Bay Area is the wealthiest region in the United States, due, primarily, to the economic power engines of San Jose, San Francisco, and Oakland. The Bay Area city of Pleasanton has the second-highest household income in the country after New Canaan, Connecticut. However, discretionary income is very comparable with the rest of the country, primarily because the higher cost of living offsets the increased income.