Chapter 1 Outline

1.1 Introduction to Environmental Biology

1.2 What is Science?

1.3 Types of Scientific Inquiry

1.4 Basic and Applied Science

1.5 Case Study 1: Using the Scientific Method to Study the Hole in the Ozone Layer

1.6 Sustainability

1.7 Case Study 2: Sustainability and the Vikings of Greenland

Learning Outcomes

After studying chapter 1, each student should be able to:

• 1.1 Understand what Environmental Biology is and why it is important
• 1.2 Understand the process of scientific inquiry
• 1.3 Compare inductive reasoning with deductive reasoning, and the importance of testing hypotheses in science
• 1.4 Describe the different goals of basic science and applied science
• 1.5 Understand how the scientific method is used in a real-world application
• 1.6 Define sustainability and understand its importance
• 1.7 Understand what the result may be of living in a non-sustainable manner

1.1 Introduction to Environmental Biology

Environmental Biology is the interdisciplinary study of the interaction of living and nonliving parts of the environment, with special focus on the impact of humans on the environment. The need for the sustainable, equitable, and ethical use of the earth’s resources by a growing global population requires us not only to understand how human behaviors affect the environment, but also the scientific principles that govern interactions between the living and nonliving components of the environment. Our future depends on our ability to understand and evaluate evidence-based arguments about the environmental consequences of human actions and technologies, and to make informed decisions based on those arguments.

From global climate change to habitat loss driven by human population growth and development, the earth is becoming a different planet right before our eyes. The global scale and rate of environmental change are beyond anything in recorded human history. Our challenge is to acquire an improved understanding of the earth’s complex environmental systems. These biological and physical systems are characterized by interactions within and among their natural and human components.  Environmental Biology can link what is happening locally to global events, short-term phenomena to long-term phenomena, and lastly, individual behavior to collective action. The complexity of environmental challenges demands that we all participate in finding and implementing solutions leading to long-term environmental sustainability.

1.2 What is Science?

Like other natural sciences, environmental biology is a science that gathers knowledge about the natural world. The methods of science include careful observation, record keeping, logical and mathematical reasoning, experimentation, and submitting conclusions to the scrutiny of others. Science also requires considerable imagination and creativity – a well-designed experiment is commonly described as elegant or beautiful. Some types of science are dedicated to practical applications (applied science), such as the prevention of disease. Other types of science are largely motivated by curiosity about the natural world (basic science). Whatever its goal, there is no doubt that science has transformed human existence and will continue to do so.

Environmental science is a science, but what exactly is science? What does the study of the environment share with other scientific disciplines? Science (from the Latin scientia, meaning “knowledge”) can be defined as a process of gaining knowledge about the natural world.

The history of the past 500 years demonstrates that science is a very powerful way of gaining knowledge about the world; it is largely responsible for the technological revolutions that have taken place during this time. There are areas of knowledge, however, that the methods of science cannot be applied to. These include such things as morality, aesthetics, politics, or spirituality, often described as “the arts”. Science cannot investigate these areas because they exist outside the realm of the material world and cannot be observed and measured.

The scientific method is a method of research with defined steps that include experiments and careful observation. The steps of the scientific method will be examined in detail later, but one of the most important aspects of this method is the testing of hypotheses.

A hypothesis is a proposed explanation for a given natural phenomenon, which can be tested. Hypotheses, or tentative explanations, are different from scientific theories. In everyday language, the word “theory” is often used to mean a personal opinion or statement with little evidence to support it. But in science a theory is a much stronger, evidenced based concept!

A scientific theory  is a widely-accepted, thoroughly tested and confirmed explanation for a set of observations or phenomena. Scientific theory is the foundation of scientific knowledge. In addition, in many scientific disciplines there are scientific laws, often expressed in mathematical formulas, which describe how elements of nature will behave under certain specific conditions, but they do not offer explanations for why they occur.

Natural Sciences

What would you expect to see in a museum of natural sciences? Frogs? Plants? Dinosaur skeletons? Exhibits about how the brain functions? A planetarium? Gems and minerals? Or maybe all of the above? Science includes such diverse fields as astronomy, computer science, psychology, biology, and mathematics. However, the fields of science related to the physical world and its phenomena and processes are considered natural sciences. These areas of natural science include primarily the disciplines of physics, geology, biology, and chemistry. Environmental biology is a cross-disciplinary natural science because it relies on the areas of science noted above, along with ways the these sciences interact with politics, human social behavior, literature, law, history, and many other areas of the arts.

1.3 Types of Scientific Inquiry

One thing is common to all forms of science: an ultimate goal to know. Curiosity and inquiry are the driving forces for the development of science. Scientists seek to understand the world and the way it operates. Two methods of logical thinking are used: inductive reasoning and deductive reasoning (Figure 1).

Inductive reasoning is a form of logical thinking that uses related observations to arrive at a general conclusion. This type of reasoning is common in descriptive science. A life scientist such as a biologist makes observations and records them. These data can be qualitative (descriptive)

or quantitative (consisting of numbers)

.

From many observations, the scientist can infer conclusions (inductions) based on evidence. Inductive reasoning involves formulating generalizations inferred from careful observation and the analysis of a large amount of data. Environmental studies are often conducted this way.

For example, sea turtle nesting numbers are recorded year after year along with other environmental factors, such as ocean pollution and changes to their beach nesting habitats. Decreases in sea turtle nesting numbers are often correlated with and attributed to these changes in their environment.

Deductive reasoning is a form of logical thinking that uses a general principle or law to forecast specific results. Deductive reasoning  is the type of logic used in hypothesis-based science. In deductive reasoning, the pattern of thinking moves in the opposite direction as compared to inductive reasoning.  From general principles, a scientist can extrapolate and predict the specific results that would be valid as long as the general principles are valid.

For example, a prediction would be that if the climate is becoming warmer in a region, the distribution of plants and animals should change. Comparisons have been made between distributions in the past and the present, and the many changes that have been found are consistent with a warming climate. Finding the change in distribution is evidence that the climate change conclusion is a valid one.

Both types of logical thinking are related to the two main pathways of scientific study: descriptive science and hypothesis-based science.

Descriptive (or discovery) science aims to observe, explore, and discover.

Hypothesis-based science begins with a specific question or problem and a potential answer or solution that can be tested.

The boundary between these two forms of study can be blurred, because most scientific endeavors combine both approaches. Observations lead to questions, questions lead to forming a hypothesis as a possible answer to those questions, and then the hypothesis is tested.

Figure 1. Scientists use two types of reasoning, inductive and deductive reasoning, to advance scientific knowledge. As is the case in this example, the conclusion from inductive reasoning can often become the premise for deductive reasoning. (Source: “Two Types of Reasoning” by OpenStax is licensed under CC BY 4.0)

Hypothesis Testing

Environmental scientists study the living world by posing questions about it and seeking science-based responses. This approach is common to other sciences as well and is often referred to as the scientific method (Figure 2).

Figure 2. The scientific method consists of a series of well-defined steps. If a hypothesis is not supported by experimental data, one can propose a new hypothesis. (Source: “The Scientific Method” by OpenStax is licensed under CC BY 4.0)

The scientific process typically starts with an observation (often a problem to be solved) that leads to a question.

Let’s think about a simple problem that starts with an observation and apply the scientific method to solve the problem: One Monday morning, a student arrives at class and quickly discovers that the classroom is too warm. Based on the observation of the warm temperature of the classroom, the student can ask the question: “Why is the classroom so warm?”

Recall that a hypothesis is a suggested explanation that can be tested. To solve a problem, several hypotheses may be proposed. For example, one hypothesis might be, “The classroom is warm because no one turned on the air conditioning.” A second hypothesis might be, “The classroom is warm because there is a power failure, and so the air conditioning doesn’t work.”

Once a hypothesis has been selected, a prediction may be made. A prediction is similar to a hypothesis but is typically written as an “If . . . then . . . ” statement. For example, the prediction for the first hypothesis might be, “If the student turns on the air conditioning, then the classroom will no longer be too warm.” The prediction for the second hypothesis may be “If the power is restored, then the air conditioning will come on.” See Figure 3 for a visual representation of how an observation, question, hypothesis, and prediction are related.

Figure 3. Observations lead to questions, which lead to hypotheses. Hypotheses lead to predictions. (Source: “Hypothesis vs. Prediction” by Lauren Roberts is licensed under CC BY 4.0)

A hypothesis must be testable to ensure that it is valid. For example, a hypothesis that depends on what a bear thinks is not testable, because it can never be known what a bear thinks. It should also be falsifiable,  meaning that it can be disproven by experimental results. An example of an unfalsifiable hypothesis is “Botticelli’s Birth of Venus is beautiful”, because there is no way to test this statement scientifically.

To test a hypothesis, a researcher will conduct one or more experiments designed to eliminate one or more of the hypotheses. Note that a hypothesis can be disproven, or eliminated, but it can never be proven. If an experiment fails to disprove a hypothesis, then it is said that the data support the hypothesis, but this is not to say that in the future a better explanation will not be found, or a more carefully designed experiment will falsify the hypothesis.

Each experiment will have one or more variables and one or more controls. Experimental variables are any part of the experiment that can vary or change during the experiment. Experimental variables are further classified as independent or dependent variables:

The independent variable is also known as the manipulated variable. It is the variable that is being tested.

The dependent variable is what is measured and recorded to determine how the independent variable affected the experiment. It may be helpful to think of the dependent variable as the data that is collected throughout the experiment.

The independent and dependent variables show a cause and effect relationship with the independent variable being the “cause” and the dependent variable being the “effect”. In the warm classroom example, the temperature of the classroom is the effect (dependent variable) and the broken air conditioner or power outage are the hypothesized causes (independent variables).

Although the following video on the nature of Science, called “What is Science?”  is not licensed to be embedded to watch in this ebook, follow the link to the author’s copywrited video (What is Science, by MonkeySee) to view this short video:

https://youtu.be/hDQ8ggroeE4

Experiments typically have two groups – an experimental group and a control group. The experimental group contains test subjects that receive the treatment of the independent variable.

The control group contains test subjects that are as similar as possible to the test subjects in the experimental group, but they do not receive the treatment of the independent variable. The control group is often also referred to as the “placebo” group. It is important to have two groups for comparison, to see if the independent variable really did cause a change in the dependent variable or not. It may be helpful to consider the control group as the comparison group or the baseline group. All of the variables that are kept constant between the experimental group and the control group, which should ideally include all variables except for the independent variable and the dependent variable are called the controlled variables. If the controlled variables are not kept consistent between the experimental and control groups, then it is impossible to determine whether the independent variable or some other variable caused an effect on the dependent variable.

Look for the key components of an experiment in the example that follows:

Jasmin noticed that the pond near her house had become green and murky over time Figure 4. She hypothesized that this might be caused by excess phosphate (a nutrient) leaking into the pond and causing an overgrowth of algae, and she designed an experiment to test her hypothesis. She filled ten artificial ponds with water and added phosphate to half of the ponds each week, while the other half were treated by adding a mineral that is not used by algae. The independent variable in this experiment is the presence or absence of the nutrient (phosphate). To make sure she only tested the results of this one independent variable, Jasmin made sure she controlled all other variables. For example, each pond received the same amount of water and was exposed to the same amount of sunlight. The control group was the set of five ponds that received a placebo (the mineral not used by algae) instead of the phosphate. The dependent variable (data) is the amount of algae that grows in each pond. If the ponds with phosphate have more algal growth, then the data support Jazmin’s hypothesis. If they do not have more algae growth, then she can reject her hypothesis and perhaps develop a new one. Be aware that rejecting one hypothesis does not determine whether or not other hypotheses can be accepted; it simply eliminates one hypothesis that is not valid. Using the scientific method, the hypotheses that are inconsistent with experimental data are rejected. From Jasmin’s experiments, she concluded that it was indeed excess phosphate that caused the rapid growth of algae in her pond.

Figure 4. Ponds that are exposed to high levels of the nutrient phosphate may become overgrown with algae, a process called eutrophication. (Source: “Potomac green water” by Alexandr Trubetosky is licensed under CC BY 3.0)

In practice, the scientific method is not as rigid and structured as it might at first appear. Sometimes an experiment leads to conclusions that favor a change in approach; often, an experiment brings entirely new scientific questions to the puzzle. Many times, science does not operate in a linear fashion; instead, scientists continually draw inferences and make generalizations, finding patterns as their research proceeds. Scientific reasoning is more complex than the scientific method alone suggests.

1.4 Basic and Applied Science

Is it valuable to pursue science for the sake of simply gaining knowledge, or does scientific knowledge only have worth if we can apply it to solving a specific problem or bettering our lives? This question focuses on the differences between the two types of science: basic science and applied science.

Basic science or “pure” science seeks to expand knowledge regardless of the short-term application of that knowledge. It is not focused on developing a product or a service of immediate public or commercial value. The immediate goal of basic science is to gain knowledge and understanding. But even this type of science can sometimes reveal information that has practical applications.

Applied science, in contrast, aims to use science to solve real-world problems, such as improving crop yield, finding a cure for a particular disease, or saving species that are threatened with extinction. In addition, applied science is used to make new products, such as a cell phone you might own. One way to remember the areas of applied science is to note the two p’s in “applied” – for solving problems or creating products. Unlike basic science, applied science tends to approach well defined challenges. But even in applied research, new insights may be gained that are not necessarily applied.

Some individuals may perceive applied science as “useful” and basic science as “useless.” A question these people might pose to a scientist advocating knowledge acquisition would be, “What for?” A careful look at the history of science, however, reveals that basic knowledge has resulted in many remarkable applications of great value. Many scientists think that a basic understanding of science is necessary before an application is developed; therefore, applied science often relies on the results generated through basic science. Other scientists think that it is time to move on from basic science and instead to find solutions to actual problems. Both approaches are valid. It is true that there are problems that demand immediate attention; however, few solutions would be found without the help of the knowledge generated through basic science.

One example of how basic and applied science can work together to solve practical problems occurred after the discovery of DNA structure (basic science) led to an understanding of the molecular mechanisms governing DNA replication. Strands of DNA, unique in every human, are found in our cells, where they provide the instructions necessary for life. During DNA replication, new copies of DNA are made, shortly before a cell divides to form new cells. Understanding the mechanisms of DNA replication (through basic science) enabled scientists to develop laboratory techniques that are now used to identify genetic diseases (applied science),  pinpoint individuals who were at a crime scene (applied science), and determine paternity (applied science). Without the basic science that lead to an understanding of DNA structure, applied science in this field would not exist.

Scientific Work is Transparent & Open to Critique

Whether scientific research is basic science or applied science, scientists must share their findings for other researchers to expand and build upon their discoveries. For this reason, an important aspect of a scientist’s work is disseminating results and communicating with peers. Scientists can share results by presenting them at a scientific meeting or conference, but this approach can reach only the limited few who are present. Instead, most scientists present their results in peer-reviewed articles that are published in scientific journals. Peer-reviewed articles are scientific papers that are reviewed, usually anonymously, by a scientist’s colleagues or peers. These colleagues are qualified individuals, often experts in the same research area, who judge whether or not the scientist’s work is suitable for publication. The process of peer review helps to ensure that the research described in a scientific paper or grant proposal is original, significant, logical, ethical, and thorough. Scientists publish their work so other scientists can reproduce their experiments under similar or different conditions to expand on the findings.

As you review scientific information, whether in an academic setting or as part of your day-to-day life, it is important to think about the credibility of that information. You might ask yourself: has this scientific information been through the rigorous process of peer review? Are the conclusions based on available data and accepted by the larger scientific community? Scientists are inherently skeptical, especially if conclusions are not supported by evidence (and you should be too).

1.5 Case Study 1:

Using the Scientific Method to Study the Hole in the Ozone Layer

Since 1957, data on the composition of the atmosphere has been gathered by scientists at the McMurdo Research Station in Antarctica. Dr. Joe Farman, a British researcher at the station, observed something very odd about his readings of ozone levels in the stratosphere between 1975-1984. The ozone layer over Antarctica had thinned dramatically in those years, to the point where there was a seasonal “hole” in the ozone layer over Antarctica as large as the continental United States (Figure 5)!

Ozone (O₃) is a dangerous pollutant at the earth’s surface, damaging the respiratory tract and stinging the eyes of humans who come in contact with this gas. However, about 15 km (9 miles) up in the stratosphere a layer of ozone helps to absorb incoming ultraviolet radiation, protecting life on earth from most of these damaging sun rays.

Figure 5. Satellite imagery of the hole in the ozone layer over Antarctica; low levels of ozone appear purple in this image (Source: “Hole in the Ozone Layer over Antarctica” by NASA is in the Public Domain, CC0)

Dr. Farman and colleagues analyzed their data to determine whether their hypothesis about ozone thinning was supported. They published their results as a scientific paper in the well-respected journal Nature in 1985. In this paper they described the loss of some of the ozone layer over parts of the southern hemisphere; the total loss of which could have devastating consequences for life on earth. A NASA report released in the same year confirmed that the ozone layer was diminishing by as much as 33%. Scientists and others from around the globe wondered what had caused this potentially life-threatening loss of ozone in the stratosphere.

Multiple hypotheses were generated, mostly dealing with various human-caused changes in the atmosphere, especially common forms of air pollution. But it was a second set of data that steered future hypotheses: The amount of chlorofluorocarbons (CFCs) in the stratosphere had greatly increased. CFCs are chemicals that were used in refrigeration, aerosol spray bottles, and packaging since the 1930s, and were thought of as harmless. But when scientists tested the effect of CFCs on ozone, they found that one CFC molecule could act as a catalyst for the breakdown of thousands of ozone molecules!

These experiments, along with many other experiments and observations, supported the hypothesis that CFCs were the cause of the destruction of the ozone layer. The scientists presented their evidence at an international meeting in Montreal, Canada convened to decide how to solve the ozone problem. Representatives from 196 countries created and signed the Montreal Protocol in 1987, setting up a plan to phase out the production and use of all forms of CFCs.

Because ozone rises slowly from the earth’s surface, the destruction of the ozone layer intensified for another nine years, reaching its lowest level in 2006. Fortunately, because far fewer CFCs were being released after the treaty, ozone began to show a recovery in 2010, and ozone levels have been increasing every year since then. Scientists estimate that O₃ concentration in the ozone layer will be back up to pre-1980 levels by the year 2068.

The scientific process that led to the discovery of this ozone thinning problem shows how science can work to support or refute hypotheses and theories, so that corrective action can be taken to solve serious environmental problems. In a similar way, the scientific evidence from around the globe in support of human-driven global warming has brought the nations of the earth together to try to solve this new problem, which is already having devastating effects. Although the science is clear, political beliefs have prevented the United States from fully engaging with the global community to find ways to battle this new threat to our planet.

Watch the following video for more information on the discovery of the CFC caused Ozone Hole over Antarctica:

 

1.6 Sustainability

Sustainability is a key concept in relation to the environment, since it refers to the human use of environmental resources in such a way that the resources are not depleted and the environment is not damaged. In other words, actions that are sustainable can be performed far into the future without compromising life as we know it today. Sustainable practices can meet present day needs, while maintaining the ability to meet the needs of future generations. When resources are used faster than they are replenished, societies and the economic underpinning they depend on are not sustainable, and will eventually fail. Everything that humans use comes from the natural environment, so the wise use of resources allows for healthy and fulfilling living today and into the future.

Ideas related to sustainability can be applied to everyday life, as one uses energy, eats meals, and makes household decisions. Or these ideas can be applied to almost any endeavor of our modern world, from business and agricultural practices to political decisions. To be sustainable, groups and individuals must always ask the question, “Can this be done now and far into the future?”

Sustainability is being discussed more often today because of the highly visible effects of climate change, such as the loss of Arctic ice and the increase in forest fires. It turns out that burning huge amounts of fossil fuels for the last 100+ years has released so much carbon dioxide into the atmosphere that the sun’s heat is being retained in our atmosphere at a greater rate. So burning fossil fuels is not a sustainable practice, causing concerned citizens across our globe to seek alternate forms of energy that do not pump tons of carbon dioxide into the air each day. Renewable fuel sources such as the sun and wind can provide energy today and for decades to come without harming the environment in the same way that fossil fuels have.

The field of sustainability requires input from scientific and non-scientific disciplines. Science can serve to study the impacts of activities on the environment and develop technology to help solve unsustainable practices. The fields of business, political science, psychology, sociology, and more are also needed to change policy, cultural mindsets, and take action.

1.7 Case Study 2:

Sustainability and the Vikings of Greenland

A human community that is sustainable can continue to live in a similar way for generations to come by not using up resources faster than they can be replaced. In addition, societies that live sustainably do not disrupt or damage the local ecosystems in a way that cannot be restored.

The Viking community that settled in Greenland (Figure 6) is a classic example of unsustainable living that led to its eventual demise. The Vikings migrated from Iceland in the year 985 and eventually settled in two areas along the western and southern coasts of Greenland.

Figure 6. The image above shows the landscape of current-day Greenland. (Source: Attribution: “Naajaat_panorama_200.7-08-09_2_cropped_USM_downsampled.jpg” by Herbythyme is licensed under CC BY-SA 3.0)

The Vikings built homes that had thick walls using local grasses for insulation. They needed over 10 acres of grass to insulate just one home. In addition, the Vikings cut trees for firewood, building materials, and other uses. When they arrived, the fjords they settled next to were lined with groves of birch trees and the nearby hills had grasses and small willows. But trees and grass grew very slowly on Greenland, since the warmer growing season was short, and the winters were long and extremely cold. Therefore, the plants the Vikings harvested were not being replaced in a timely manner. To make matters worse, the Vikings brought a variety of grazing animals, first cattle and later goats and sheep, and these denuded the remaining plant life, leading to erosion and poor soil conditions. Blowing sand covered areas that had once been fertile fields. Lastly, the Viking population was increasing at a time when less and less food and other natural resources were available.

By the early 1400s, the people of these Viking settlements had either left the island or died of starvation. A cooling climate during this time period may have made conditions in these settlements even worse. These Viking communities are described as unsustainable because their way of life destroyed the land and local ecosystems that were needed for long term survival.

In contrast to the Vikings, the native Inuit people have survived on Greenland for many centuries. Their lifestyle is sustainable because their way of life did not destroy the land or animal resources that they depended on for food and clothing. They fished and hunted seals and other animals of the land and sea. But they were nomadic, moving on to areas where a certain resource was in abundance, allowing the animals they harvested to replenish their numbers in their absence. The Inuits also lived in small communities, with relatively stable population numbers, decreasing their impact on the earth.

Scientists and others have speculated about whether the Vikings could have changed their way of life to one that was more sustainable. For example, the waters off of Greenland were rich in fish and sea mammals, yet these food items never became a significant part of their diet. Could the Vikings have changed their lifestyle in such a way that they lived off of the abundant sea life instead of continuing to farm their damaged fields?

We as a global community face some of these questions about sustainability today. We are using up resources at a much faster rate than they can be replaced. Fossil fuels such as coal and oil took millions of years to form, yet we are burning these up fairly quickly. One product of this burning, carbon dioxide, is causing more of the sun’s heat to be retained in the atmosphere, warming the entire globe. This is causing major changes to the world climate, which can lead to the loss of key ecosystems across the earth. Can we humans change from an unsustainable to a sustainable lifestyle? Can we break from our dependence on fossil fuels (e.g., by using much more solar and wind energy and reducing overall consumption) and slow or reverse climate change? These questions about sustainability face us today and become more critical with each passing year.

 

Attribution

Content in this chapter includes original work created by Lauren Roberts, Paul Bosch, and Sean Whitcomb as well as from the following sources, with some modifications:

Concepts of Biology by OpenStax is licensed under CC BY 4.0. Modified from original by Matthew R. Fisher.

“Essentials of Environmental Science” by Kamala Doršner is licensed under CC BY 4.0.

The Earth, Humans, and the Environment by Alexandra Geddes is licensed under CC BY 4.0. Modified from original by Matthew R. Fisher.