ENVS 260 Envi, Sust and Science

A researcher wants to determine if water runoff from farm fields sprayed with herbicides affects the hatching success of frog eggs in nearby ponds. What experiment could the researcher conduct to address her question?

1) Observation: "I've seen that frog eggs in ponds that receive runoff from farm fields sprayed with herbicides hatch at lower ratesthan those unaffected ponds." 2) Hypothesis: "The hatching success of frog eggs is affected by exposure to herbicides." 3) Prediction: "If frog eggs are exposed to elevated levels of herbicides the hatching success of the eggs will decrease." 4) Test: In the laboratory, raise frogs in pond water with varying concentrations of herbicide, and measure hatching successrates. 5) Result: Analysis of experiment data concludes that herbicide levels affect hatching rates.

Which of the following is true in the Florida Keys?

Ecologists are concerned that worm snails will colonize the artificial reefs.

Which of the following choices embodies the concepts of the 3 P's in environmental sustainability?

Environmental, social, and economic -DIRTT measures its success by the triple bottom line: planet (environmental), people (social), and profit (economic).

Next, let's examine how a nation's environmental ethics and its economic strength may or may not relate to its willingness and/or ability to deal with environmental issues. In this part, you'll examine the relationship between two variables: one that aims to quantify a nation's economic strength, and one that aims to quantify a nation's effectivness at dealing with environmental issues. Environmental ethics play into the latter variable. A nation's gross domestic product (GDP) can be used as a measure of its economic strength. Per capita GDP is a measure of a nation's economic strength divided by the number of people in that nation. A high per capita GDP indicates a strong economy. The Environmental Performance Index (EPI) provides a way to quantify how effective a nation is at dealing with its environmental problems in two broad policy areas: protection of human health from environmental harm and protection of ecosystems. For instance, a nation with a high EPI score would provide ready access to clean drinking water, and do a good job of protecting natural biomes. The graphs below represent possible relationships between these two variables. Drag each description to the appropriate graph.

Graph 1: No relationship: As GDP per capita increases, there is no change in EPI score Graph 2: A positive non-linear correlation: As GDP per capite increases, the EPi score increases at a decelerating rate Graph 3: A negative correlation: As GDP per capita increases, the EPi score decreases Graph 4: A unimodal correlation: As GDP per capita increases, the EPI score increases then decreases

A population's life history consists of its schedule of reproduction and survival, including age at first reproduction, number of offspring, frequency of reproduction, and amount of parental care. In birds, clutch size (the number of eggs per brood) is an important life history trait, and variation in clutch size is the subject of extensive ecological research. Eastern bluebirds are small songbirds that are widespread across eastern North America. Bluebirds nest in natural tree cavities such as abandoned woodpecker holes or in nest boxes provided by bird lovers. Eastern bluebird females usually lay two or three clutches of 3-6 eggs each per breeding season, which is in the spring. Late-season clutches are typically smaller than early-season clutches. Clutch size also displays a geographical gradient -- larger clutches are laid at higher latitudes. What accounts for these seasonal and geographic differences in clutch size? One hypothesis -- the egg-viability hypothesis -- proposes that the variation in clutch size results from reduced viability of eggs in warm temperatures. Observations that led scientists to develop this hypothesis include: Birds typically lay one egg a day until the clutch is complete. At that time, they begin incubating all the eggs together, resulting in an equal pace of development. As long as the surrounding temperature is below 24-26°C (75.2-78.8°F) , the temperature that triggers development, the earlier-laid eggs "keep." However, when eggs are exposed for an extended period to a temperature range between the trigger temperature and the optimum incubation temperature, 36-39°C (96.8-102.2°F), development goes awry. What prediction(s) can researchers make based on the egg-viability hypothesis?

- The probability of hatching failure will be lower at higher latitudes. - The probability of hatching failure will be higher in large clutches. - The probability of hatching failure will be higher later in the spring season. The egg-viability hypothesis suggests that hatching failure is more likely when environmental temperatures are warmer. This is because eggs "keep" at cooler temperatures. However, when temperatures reach values high enough to trigger development but lower than optimum incubation temperatures, eggs develop abnormally.

Imagine that you are walking along a gravel road in Indiana in springtime. The trees are starting to bloom, and you can hear the sound of a distant tractor. But something is missing. You used to hear warblers, blue birds, and cardinals this time of year, but now it is eerily silent.In the mid-1950s, many people in the United States experienced this silent spring and noticed fewer birds and insects around farms. One of those people was author and scientist Rachel Carson. She recognized a general decline in the biodiversity of agriculture-associated ecosystems. She reasoned that agricultural pesticides might have something to do with it.After making these observations, Rachel Carson wrote the book Silent Spring, which suggested that one unintended side effect of agricultural pesticide use was a decline in bird populations. Her book led to further research into a connection between the chemical DDT, which was commonly found in pesticides at that time, and bird population declines.Part A - Scientific method:While Rachel Carson was writing Silent Spring, a picture of how DDT influences bird populations was emerging. Scientists hypothesized that DDT was causing the observed decline in fish-eating bird populations. The assumptions and connections underlying this hypothesis were complex. In this activity, you will reconstruct those connections.Drag each description to the appropriate step in the figure below.

1. Farmers use DDT on their crops to kill insect pests 2. DDT enters nearby waterways via runoff 3. Small aquatic invertebrates absorb the DDR 4. Fish eat the DDT- contaminated invertebrates 5. Birds eat the DDT- contaminated fish 6. Birds with DDT in their bodies lay eggs with DDT and weak shells 7. Few baby birds hatch, and the population declines

Does a higher per capita GDP correlate to a higher EPI? Or does a country's per capita GDP have nothing to do with its EPI?Choose the graph that best represents your hypothesis about how a nation's EPI score is related to its per capita GDP.

A positive, non-linear correlation: as GDP per capita increases, the EPI score increases at a decelerating rate

Environmental ethics studies the moral relationship of humans to the environment and its nonhuman contents. Systems of environmental ethics vary regarding who or what has value. Within a nation, there is often a prevailing system of ethics that is dominant or shared by many individuals. The prevailing attitudes in a nation can change over time, and a nation's situation may influence the importance it places on environmental concerns. Three classes of environmental ethics are: anthropocentric ethics, biocentric ethics, and ecocentric ethics. Sort each action to the class of environmental ethics it most closely represents.

Anthropocentric ethics: - In Mauritania, agricultural water use is reduced to help maintain the drinking water supply. - In Venezuela, some farmers are replacing rainforests with farmland. Biocentric ethics: - In Colombia, a species of mushroom is listed as endangered because there is only one small population remaining. - In Australia, testing on rabbits in a lab is halted because of animal rights concerns. Ecocentric ethics: - In Saudi Arabia, some people purchase hybrid vehicles with good fuel efficiency to help minimize their carbon footprint. - In Mongolia, some land managers are learning about fire management to preserve their grassland landscapes and maintain ecosystem function. Here we categorized environmental actions in a very simple way. In reality, a nation's environmental ethics can be more complicated. For instance, in the early history of the United States, the prevailing environmental ethic was largely anthropocentric. However, as the United States became more developed, people's ethics have shifted toward being increasingly ecocentric. As people have become more ecocentric, they are placing increasing value and importance on the environment. More developed nations tend to be more ecocentric. Keep in mind, though, that many actions that appear largely ecocentric on the surface can also benefit people. How do you think a nation's ethics and economy influence their willingness and/or ability to deal with environmental concerns?

Based on the hypothesis that DDT was causing a decline in fish-eating bird populations in the United States, a group of scientists predicted that the amount of DDT in bird eggs was correlated with the thickness of the egg shells. For their experiment, they planned to visit a number of fish-eating bird populations and take 1 egg from 70 nests. In the laboratory, they would open the eggs to measure the concentration of chemicals such as DDT. They would also measure the thickness of the egg shells.The researchers had to decide which species of birds they would use in their study. Choosing the proper study organisms is very important because the species must be appropriate for the experiment, and practical to work with.Imagine that it is 1960, and the scientists have asked you to help them select the species of bird for use in their research. They have narrowed their options down to 6 species. Drag a check mark to species that would be good to use in the study; there may be more than one. Drag an X to species that would not be good for the study.

Check mark: Osprey Brown Pelican Everything else is X -Osprey and brown pelicans were both good candidates for testing the prediction that DDT in eggs was correlated with egg shell thickness. These species were not endangered, and they ate fish that could be contaminated with DDT from agriculture. Furthermore, these species were available within the United States, so they would be easier and less costly to work with. A team of researchers led by Lawrence Blus chose to use brown pelicans to test their prediction. They took 1 egg from 70 different brown pelican nests in California, South Carolina, and Florida. Then they compared the chemical composition of the eggs to the egg shell thickness.

Drag the labels of group 1 to the graph below to indicate what data researchers should plot on the x- and y- axes. Then select the graph line that would support their hypothesis.

Graph sloping up to right X-axis: female plumage ornamentation Y-axis: Clutch size Researchers hypothesized that small three-egg clutches showed relatively high rates of hatching failure because small clutches are usually laid by lower-quality females. Lower-quality females might produce lower-quality eggs or be less skilled at incubating their eggs. To test this hypothesis, researchers would need to collect data on female quality and clutch size. In the case of bluebirds, plumage ornamentation is known to correlate with female quality. A positive correlation between plumage ornamentation and clutch size (graph line sloping up to the right) would support the researchers' hypothesis. The egg-viability hypothesis appears to explain many of the observed patterns in Eastern bluebird clutch size. However, other factors, such as female quality, may also be important.

In the case of DDT, some researchers and industry leaders were concerned that chemicals other than (or in addition to) DDT could be causing egg shell thinning. Blus and his colleagues also looked for a relationship between egg shell thinning and DDE (a breakdown product of DDT), PCBs, dieldrin, and mercury. This is an example of how scientists can simultaneously test multiple predictions and/or hypotheses. Blus and his team analyzed their data using regressions. A regression is used to compare two continuous variables, for example, a person's height vs. foot length. In a regression, the slope measures how much the y value changes as a function of the x value. In this study, if the slope is very steep, that means that a small amount of chemical is causing a great change in egg shell thickness. The graph shows an adaptation of Blus's results. Notice that next to each line in the graph is a p-value. A p-value is a statistical measure of how likely it is that a relationship is due to random chance. For example, a p-value of 0.05 means that there is a probability of 0.05 (5%) that the results could be due to random chance. If there is a greater than 5% chance the results are due to chance, you cannot trust that a relationship between the variables really exists. In other words, even if you see a dramatic slope, if the p-value is greater than 0.05, you must treat the result as non-significant and conclude that there is not a relationship between the variables. Rank the chemicals according to how much they influence egg shell thickness.

Least DDT dieldrin mercury PCBs DDE Greatest -As you can see, multiple chemicals influence egg shell thickness. You can tell that DDE had the greatest impact on egg shell thickness because it's the significant line with the steepest downward slope. Surprisingly, DDT was not significantly related to egg shell thickness. However, the use of DDT was still influencing bird populations because DDT degrades to DDE.Blus and his team revised their hypothesis to add the step of DDT degrading to DDE and ultimately causing bird populations to decline. If they had tested for only one chemical, they would have missed that link. It was studies like this that supported Rachel Carson's book Silent Spring. The book made the public aware of the negative impact of pesticide use on wildlife. Silent Spring was published in 1962 and was influential in the environmental movement of the 1960s. In 1970, the United States government created the Environmental Protection Agency (EPA). The EPA's mission includes regulation of pesticide use. In 1972, the agricultural use of DDT was banned, and bird populations started to recover.

You create an artificial habitat for worm snails in a lab for further study. Which of the following will you need to provide as a food source?

Microorganisms

Which of the following represents a biotic component of a hardwood forest in Pennsylvania?

Mushrooms under some leaves -Mushrooms are living organisms and are a biotic component of an ecosystem.

Which of the following best illustrates the open nature of ecosystems?

Nitrogen is transported from fertilized agricultural fields into streams and, eventually, into the ocean. -This is a perfect example of inputs and outputs of matter (nutrients in this case) that influence ecosystem functions across different ecosystems.

The graph below shows how EPI changes with GDP based on worldwide data. If you chose the positive non-linear correlation, you were correct. Next to the graph is a map showing per capita GDP of nations around the world. Rank the nations from lowest predicted EPI to highest predicted EPI based on their per capita GDP.

Ranked from lowest to highest predicted EPI: Mauritania Mongolia Colombia Venezuela Saudi Arabia Australia -Here is how these nations' data points appear on the graph. There is also a data point for the United States for comparison. A country that falls above the line is exceeding expectations based on its per capita GDP. A country that falls below the line is underperforming. -In countries with very low per capita GDP, simply meeting people's basic needs may be difficult, and therefore environmental issues may not be of high priority. People there may tend to have more anthropocentric values. Even when people in low GDP nations are biocentric or ecocentric, it may simply be difficult for these nations to accomplish "environmentally friendly" actions.

Which of the following is likely the best place to find adult worm snails?

Stuck on an oil rig.

Which of the following best illustrates sustainability?

Using solar panels on rooftops to generate electricity -This practice follows the definition of sustainability as defined in the text: Sustainability means meeting the needs of the present in an equitable and fair fashion without compromising the ability of future generations to meet their own needs.

Which of the following best illustrates an example of ecosystem integrity?

Within two years after the devastating Yellowstone National Park wildfires of 1988, the burnt forest floor was covered in new grasses, flowers, and young trees, which took advantage of the open regions and enriched soil. -After wildfires that do not represent an ecosystem disaster, an ecosystem can undergo a process of change and recovery, as observed with plants spreading into the open regions of the park.

How are worm snails different from most other snails?

Worm snails are stationary, most other snails are mobile.

A review process is in place to make sure that no _____ has skewed the results of an experiment.

bias

Graph C shows that the probability of hatching failure is highest for ______ clutch sizes. The data ______ Prediction #3.

both the largest and the smallest, do not support

A scientific experiment often involves both a treatment and a _______, which are alike except for the variable that the experiment is designed to test.

control

A _______ is a quantitative relationship between variables.

correlation

Graph B shows that the probability of hatching failure ______ at higher latitudes. The data ______ Prediction #1.

decreases, support

A ____ is a testable statement that proposes an explanation for a set of observations. It leads to predictions that can be tested by an experiment.

hypothesis

Graph A shows that the probability of hatching failure _______ later in the season. The data _______ Prediction #2.

increases, support

Researchers were unable to test Prediction #4. This is because it was too difficult for volunteers to collect data on which eggs were ______

laid earliest

Drag the positive or negative feedback loop on the left to each process on the right. A dog pants as it lies in the hot summer sun, releasing excess body heat to the environment and lowering its body temperature to its stable state

negative

Drag the positive or negative feedback loop on the left to each process on the right. When blood sugar levels rise after eating a meal, the pancreas releases the hormone insulin, stimulating cells to take up sugar from the blood. When blood sugar levels drop, the pancreas releases another hormone to stop sugar uptake by cells.

negative

Drag the positive or negative feedback loop on the left to each process on the right. A bull on the edge of a herd of cattle panics when it hears a loud noise and begins to run. Five nearby cattle sense the panic and also begin to run. This causes another 15 cattle to panic. Eventually, all 100 cattle in the herd panic and stampede.

positive

Drag the positive or negative feedback loop on the left to each process on the right. A snowball rolling down a hill accumulates snow and becomes larger, which increases its speed, causing it to increase its size and speed even more.

positive

Drag the positive or negative feedback loop on the left to each process on the right. Increasing air temperatures from global warming speed up the melting of glaciers, exposing darker rocks underneath the ice. The dark surfaces absorb more sunlight, causing further increases in temperature and accelerated glacier melting.

positive

Drag the positive or negative feedback loop on the left to each process on the right. You invest $1,000 in a savings account and reinvest the 5% interest you earn. The interest makes the amount of money in the account larger, so it earns even more interest. After 20 years, the account contains more than $2,600 and is still growing

positive

A _____ describes specific results that can be expected if a hypothesis is true

prediction

Scientists use a general process known as the ______ to ask and answer questions about natural phenomena.

scientific method

Which of the following do worm snails use to excrete their slime?

tentacles

A ______ is broader in scope than a hypothesis, is supported by a large body of evidence, and generates many new hypotheses.

theory

A _____ is a factor that is either manipulated or measured in an experiment.

variable