Now here’s a relationship not many middle school students would stop to consider: bird species diversity and West Nile virus incidence. A press release dated October 6, 2008, indicates researchers at Washington University in St. Louis have collected evidence that shows an inverse relationship between bird species diversity and West Nile virus. Thus, urban and suburban areas are likely to host more cases of West Nile virus than forested or rural areas perhaps. At first, that seems counterintuitive. How can an urban area, presumably low in trees and thus birds, be a more likely host site than a rural one for the bird-harbored West Nile virus?

An understanding of systems — as described by the National Science Education Standards content standard dealing with systems, order and organization — offers insight. In this case an understanding of the systems, order and organization of viral life cycles and transmission modes is needed. First, we understand the disease is caused by a virus. Next, we know a unifying characteristic of viruses is their inability to reproduce outside a hijacked cell. Finally, we note West Nile virus can be transferred from bird to human via the salivary glands of biting mosquitoes.

The next system to consider is the natural history of birds. Their habitat, competition for food and shelter, and their niche are this system’s parameters. This system naturally intersects with the natural history of mosquitoes and the tag-along West Nile virus. Likewise, this system of mosquito and West Nile virus commensalism intersects with the Homo sapiens natural history when the mosquitoes infect humans.

Okay, so we see how systems intersect and impact each other, but what accounts for the inverse relationship these researchers reported?

Most bird species are not good hosts for the virus. However a few are. Those few happen to tolerate urban and suburban conditions well. Those few species include robins and crows, for example. Even if there were 10 species of birds found in a suburban area, you could expect a high incidence of West Nile virus under the following scenario. The raw number of all birds is 1000. Nine hundred are robins. One hundred are split evenly among nine other species. Robins are particularly good West Nile virus hosts.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Students are likely to agree that forested areas would host a greater number of birds and a greater diversity of bird species than urban or suburban areas. Challenge students to explain why. Explain to them that West Nile virus is transmitted from birds to humans through mosquito bites and that the virus can make people sick, sometimes very seriously. Ask them to predict what kind of areas would likely have the highest human incidence of West Nile virus — urban, suburban or rural/forested?  Have them support their prediction with solid logic. Have a student volunteer to verbalize his or her prediction and supporting logic. Then ask other students if they agree or disagree with the prediction and logic (as opposed to agreeing/disagreeing with the student) and why. Encourage respondents to elaborate on their thinking by allowing plenty of wait time.

When all of the students are secure in their stance, and there will likely be two different stances, ask them to brainstorm some methods that should/could be used to test their ideas. What kinds of evidence would they need? How would they go about obtaining it? Again, facilitate some peer review by asking students to evaluate the generated ideas for tests, and to provide methodological improvements where they can. Finally, share with them the methods and findings of these researchers. Are the students surprised? Why or why not? How does the evidence impact arguments for conservation?

The lesson described connects to both the History and Nature of Science and the Science as Inquiry content standards of the National Science Education Standards. In the AAAS’s Project 2061 benchmarks, students in grades 6-8 are expected to acquire knowledge of systems thinking.

Here are additional related resources from the National Science Digital Library Middle School Portal: Structure and function in living systems; The big picture book of viruses; and Zoonotic diseases go global

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.

DEET (short for N,N-diethyl-meta-toluamide) is the most widely used insect repellent in the world for a very good reason – it works really, really well! Just a quick spray on exposed skin keeps mosquitoes, flies, fleas, chiggers, and ticks away. Developed by scientists at the U.S. Department of Agriculture and patented by the U.S. Army in 1946, millions of people worldwide use DEET to ward off vector-borne diseases. First of all, why would researchers study DEET if it works so well? While DEET is an effective repellent, it doesn’t work against all bugs, it’s corrosive to plastics and there are concerns about its effect on human health.

Structural Formula for N, N-diethyl-meta-toluamide (DEET).
Courtesy of Wikipedia - Click on the image for a larger version.

How DEET actually works has puzzled scientists for more than 50 years. Scientists long surmised that DEET masks the smell of the host, or jams or corrupts the insect’s senses, interfering with its ability to locate a host. Mosquitoes and other blood-feeding insects find their hosts by body heat, skin odors, carbon dioxide (breath), or visual stimuli.

Amazingly, within a few months this year, scientists from two different labs have come up with competing explanations of how DEET works. In March of 2008, researchers at Rockefeller University in New York, said that DEET jams odorant receptors in insect nervous systems, in effect masking odors that would ordinarily attract the bugs. According to Dr. Leslie B. Vosshall, a researcher who worked on the project, now that they know that DEET targets OR83b co-receptors, they can quickly screen thousands of other compounds in hope of finding one that is even more effective and has fewer disadvantages.

Are you sure, ask researchers at the University of California, Davis? Mosquitoes flee because of their intense dislike for the smell of the chemical repellent and not because DEET jams their sense of smell. In August 2008, in a paper published in The Proceedings of the National Academy of Sciences, they provide a simpler explanation. Mosquitoes, they say, smell DEET directly and avoid it.

Dr. Vosshall, involved in the earlier study, said that her team stood by its work, and that its findings were based on a variety of experiments. So for now, the jury is still out.

Connecting to the National Science Education Standards

These competing explanations on how DEET works provides a perfect example of one aspect of the nature of science – Scientific Claims are Subject to Peer Review and Replication. Researchers in labs across the world work on answering many of the same questions. The results of their work are published in peer reviewed journals so that researchers around the world can examine their data and logic, identify alternative explanations, and replicate observations and experiments. Peer review is an integral part of genuine scientific enterprise and goes on continuously in all areas of science.

The National Science Education Standards in the History and Nature of Science Content Standard G describes what middle school students should understand about this part of the nature of science, including:

It is normal for scientists to differ with one another about the interpretation of the evidence or theory being considered.

Different scientists might publish conflicting experimental results or might draw different conclusions from the same data.

It is part of scientific inquiry to evaluate the results of scientific investigations, experiments, observations, theoretical models, and the explanations proposed by other scientists.

Although scientists may disagree about explanations of phenomena, about interpretations of data, or about the value of rival theories, they do agree that questioning, response to criticism, and open communication are integral to the process of science.

Additional Resources

Read the entire National Science Education Standards online for free or register to download the free PDF. The content standards are found in Chapter 6.

Science For All Americans Online: The Nature of Science
Science for All Americans consists of a set of recommendations on what understandings and ways of thinking are essential for all citizens in a world shaped by science and technology.

Household Product Database
List of products that contain DEET.

Chemical Technical Summary for Public Health and Public Safety Professionals
The Department of Health and Human Services provides a summary of all medical cases and research done on DEET.

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on the NSDL Middle School Portal science pathway. Email us at msp@msteacher.org.

If you’ve taught plate tectonics at the middle school level, you’re probably quite familiar with the supercontinent Pangaea. But did you know that Pangaea was not the only supercontinent in earth’s history – just the last to date? Millions of years before Pangaea, another supercontinent known as Rodinia united all of earth’s landmass in an unusual configuration. While we tend to think of Pangaea as the “starting point,” earth’s land and ocean basins have been continually shaped throughout geologic time through a supercontinent cycle.

While Pangaea certainly gets more press, Rodinia was the star of a recently published article in the July 11 edition of Science. As summarized in a National Science Foundation News release, John Goodge’s team was collecting geologic specimens in the Transantarctic Mountains when they discovered a single granite boulder atop Nimrod Glacier.

Andrew Barth (L) and Devon Brecke (R), collecting glacial moraine samples in the Miller Range of the Transantarctic Mountains. Photo courtesy of John Goodge, University of Minnesota.

Subsequent chemical and isotopic tests indicated that the boulder was strikingly similar to a belt of igneous rock running through the southwestern United States. These similar chemical and isotopic signatures provided support for the SWEAT (southwest United States East Antarctica) hypothesis, which states that East Antarctica was connected to the southwestern United States approximately one billion years ago, as part of the global supercontinent Rodinia. 

The supercontinent Rodinia as it began to break up approximately 750 million years ago. Click on the image to see a larger version. Image courtesy of http://www.palaeos.com/Proterozoic/Proterozoic.htm.

At the heart of Rodinia was Laurentia, or the precursor to most of North America. Debate exists, however, on whether East Antarctica, Australia, Siberia, or South China fit with the western margin of Laurentia. This geologic discovery provides three lines of evidence in support of an East Antarctica – Laurentia connection.

Researchers theorize that about 600-800 million years ago, a portion of Rodinia broke away, gradually drifting southward to become eastern Antarctica and Australia. This movement just predates the Cambrian explosion, a rapid diversification of life and sudden appearance of complex organisms. Goodge explains that “there are ideas developing about these connections between the geo-tectonic world on the one hand and biology on the other.” It is possible that the shifting and colliding of continents, erosion, and influx of minerals and chemicals into the ocean may have provided nutrients to support a growing diversity of organisms.

Connecting to the National Science Education Standards

As with a discussion of Pangaea or plate tectonics in general, this article provides an opportunity to meet the Earth and Space Science standard’s various concepts. According to the National Science Education Standards, “The idea of systems provides a framework in which students can investigate the four major interacting components of the earth system – geosphere, hydrosphere, atmosphere, and the biosphere. In this holistic approach to studying the planet, physical, chemical, and biological processes act within and among the four components on a wide range of time scales to change continuously earth’s crust, oceans, atmosphere, and living organisms.” The holistic approach described in the NSES is reflected in this study’s use of geologic evidence to explain an important biological phenomenon.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Rather than spark a new lesson, this current event provides an opportunity to revisit a familiar unit on plate tectonics, geologic time, and rocks and minerals. Most teachers include a discussion of Alfred Wegner and the evidence for his theory of plate tectonics, including similar fossilized plants and reptiles found in South America and Africa.

After students understand how Wegner used geologic and fossil evidence to reconstruct Pangaea, present the evidence from this most recent discovery. Ask them to explain how the same type of granite could be found in eastern Antarctica and the southwest United States. Once students conclude that the two continents must have been connected, re-examine a diagram of Pangaea, which shows an African-Antarctic connection, not a North America-Antarctic one. How, then, could these two places have similar rocks?

A reconstruction of the supercontinent Pangaea. Click on the image to see a larger version. Image courtesy of Kieff via Wikimedia.

Referring to geologic time may help at this point. Using a modified time scale, remind students that Pangaea existed approximately 200 million years ago, while earth is approximately 4.6 billion years old. What did earth’s surface look like before Pangaea? Lead students to the conclusion that other supercontinents, like Rodinia, existed well before Pangaea. Introduce the concept of the supercontinent cycle.

This type of discussion naturally progresses to the mechanics and processes driving the cycle: plate movement. The following resources from the Middle School Portal can help you teach about earth’s interior and plate tectonics. It may also be helpful to brush up on concepts related to geologic time, as these processes span millions of years.

Geologic Time: Eons, Eras, and Epochs
http://msteacher.org/epubs/science/science16/science.aspx

Plate Tectonics: Moving Middle School Science
http://msteacher.org/epubs/science/science1/science.aspx

Once students understand plate interactions (rifting, subduction, sea-floor spreading), take a global view. Using a world map, plot the locations of plate divergence and convergence. Challenge students to predict what the next supercontinent will look like. For example, current plate movement indicates that as the Atlantic Ocean basin grows, the Pacific Ocean basin is shrinking. In the future, western North America may be connected to Asia in the earth’s latest supercontinent.

Introducing Rodinia as part of a greater supercontinent cycle presents plate tectonics as a driving force in a long-term pattern of constructive and destructive forces. It provides another opportunity for students to consider the cyclic change: a fundamental principle in science.

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.

A third of reef-building corals around the world are threatened with extinction, according to the first-ever comprehensive global assessment to determine their conservation status. Corals produce reefs in shallow tropical and sub-tropical seas and have been shown to be highly sensitive to changes in their environment. The study findings were published July 11, 2008 by Science Express. 

Built over millions of years, coral reefs are home to more than 25 percent of marine species, making them the most biologically diverse of marine ecosystems.

(Photo Credits: National Oceanic and Atmospheric Administration)

Did you know that –

Healthy coral reefs support commercial and subsistence fisheries as well as jobs and businesses through tourism and recreation?

The coral reef structure buffers shorelines against waves, storms and floods, helping to prevent loss of life, property damage and erosion?

Coral reefs support more species per unit area than any other marine environment, and are living museums that reflect thousands of years of history?

Coral reefs are considered by some scientists to be the medicine cabinets of the 21st century?

Every year, millions of scuba divers, snorkelers and fishermen visit U.S. coral reefs?
(Excerpted from NOAA Coral Reef Conservation Program)

As summarized in the Science Daily article, One-third Of Reef-building Corals Face Extinction, researchers identified the main threats to corals as climate change and localized stresses resulting from destructive fishing, declining water quality from pollution, and the degradation of coastal habitats. Climate change causes rising water temperatures and more intense solar radiation, which lead to coral bleaching and disease often resulting in mass coral mortality.

Shallow water corals have a symbiotic relationship with algae called zooxanthellae, which live in their soft tissues and provide the coral with essential nutrients and energy from photosynthesis and are the reason why corals have such beautiful colors. Coral bleaching is the result of a stress response, such as increased water temperatures, whereby the algae are expelled from the tissues, hence the term “bleaching.” Corals that have been bleached are weaker and more prone to attack from disease. Scientists believe that increased coral disease also is linked to higher sea temperatures and an increase in run-off pollution and sediments from the land.

Researchers predict that ocean acidification will be another serious threat facing coral reefs. As oceans absorb increasing amounts of carbon dioxide from the atmosphere, water acidity increases and pH decreases, severely impacting corals’ ability to build their skeletons that form the foundation of reefs.

The 39 scientists who co-authored this study agree that if rising sea surface temperatures continue to cause increased frequency of bleaching and disease events, many corals may not have enough time to replenish themselves and this could lead to extinctions.

Connecting to the National Science Education Standards

There are many connections between coral reefs and the NSES Life Science strand – biodiversity, life cycle, symbiosis, just to name a few – but for the article highlighted in this post, the grade 5-8 Science in Personal and Social Perspectives strand might be more appropriate. During the middle grades, students should begin to develop a more conceptual understanding of ecological crises such as the cumulative ecological effects of pollution. Other crises occur when an area becomes overpopulated and the environment becomes degraded due to the increased use of resources. One thing to point out – not all reefs are endangered. Students should understand the causes of environmental degradation and resource depletion vary from region to region and from country to country.

I’m sure middle school students are familiar with the term coral reef (most have seen the animated film Finding Nemo) but do they know the location of reefs around the world? Do they know how important they are and what is happening to the many of them? ReefBase: A Global Information System for Coral Reefs provides a map of the world that shows where reefs are found. The map also allows you to see where certain coral reef diseases have been spotted. You can also view the maps year by year. Having a visual representation showing the increased incidence of disease or the reduction of the area that is covered by coral reefs is very powerful. Ask students to think about what would happen if coral reefs become extinct. Why would it matter and to whom?

Here are additional resources from the NSDL Middle School Portal related to coral reefs:

Subscribe to the NOAA Coral Reef monthly newsletter

NOAA Coral Reef Conservation Program

What Are Coral Reefs?

Alien Stingers

Exploring the Environment: Coral Reefs

It is also the International Year of the Reef, so check out those resources.

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.

Need an answer to your students’ question “Why do I need to take science? I’m not going to be a scientist!” On June 1, 2008, Brian Greene, physicist at Columbia University and author, wrote an op ed in the New York Times with your answer. Early in the two page article, he says

When we look at the wealth of opportunities hovering on the horizon — stem cells, genomic sequencing, personalized medicine, longevity research, nanoscience, brain-machine interface, quantum computers, space technology — we realize how crucial it is to cultivate a general public that can engage with scientific issues; . . . These are the standard — and enormously important — reasons many would give in explaining why science matters.

. . . The reason science really matters runs deeper still. Science is a way of life. Science is a perspective. Science is the process that takes us from confusion to understanding in a manner that’s precise, predictive and reliable — a transformation, for those lucky enough to experience it, that is empowering and emotional.

Read this article to its end and get affirmation of the efforts you are making to help your students become positive contributors to society, culture, and government.

A nice follow-up article appeared in the June 3, 2008, Times. This one conveys the experience of the author, Dennis Overbye, as he participated in the World Science Festival in New York City, organized by Brian Greene and his wife. Overbye writes that the event consisted of

. . . 46 shows, debates, demonstrations and parties spread over five days and 22 sites between Harlem and Greenwich Village . . . . Jugglers and philosophers, magicians and biologists, musicians and dancers — a feast one couldn’t hope to sample fairly.

Of course, I cannot fault Dr. Greene and Ms. Day for doing such a good job that I wanted to see much more than space and time permitted. In fact, you cannot help loving them. They are the first couple of New York science. And by their boldness and energy, they seem to have created a new cultural institution.

So keep working toward science literacy in your classrooms with your students and, in combination with the cultural changes scientists like Brian Greene are initiating, change is imminent!

Middle school students are often intrigued by the excitement of exploration and the adventures of explorers, as their enthusiasm for Indiana Jones attests. Space exploration should be no exception. With new images now available from the Mars explorer, Phoenix, teachers can capitalize on student interest in exploration to meet some of the Earth and Space Science content standards of the National Science Education Standards. Comparing the features of Mars to Earth, for example, reinforces concepts of planetary motion and the related concepts of gravity, day, year, and seasons. The effect of the atmosphere as related to the sun’s energy and weather can also be contrasted. And, as the lesson described below indicates, content standards within the History and Nature of science, Science and Technology, and Science as Inquiry are also met.

Probes–unpiloted devices sent to explore space–have been landing on Mars since 1971. (At the probes link, scroll about one third of the way down the page to find the heading “Probes to Mars.”) But the latest probe to land is collecting observations never before collected. The Phoenix mission to Mars has an interesting history documented at this site hosted by the University of Arizona. The site contains access to the multitude of fascinating images being captured by Phoenix as well as articles documenting the mission. It might surprise students that this is not solely a NASA project but a collaborative of NASA, the Jet Propulsion Laboratory, Lockheed Martin and University of Arizona, underscoring the nature of science as a human endeavor building knowledge from multiple sources.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Ask, “Why do explorers do what they do?” Ask students who some of the famous, historic explorers were. Are there any modern day explorers, or is the age of exploration over? Do they mention any space explorers? Ask if anyone knows who John Glenn or Neil Armstrong is. Do explorers always have to be human? Have they heard about Jason, the deep sea robotic explorer? Space exploration is also accomplished often by remote vehicles. Who knows the names of some of those (Galileo, Mariner, Magellan, Pioneer)? As a pre-assessment, consider giving students a few minutes to draw their conception of what a space probe might look like. They should label as many parts as they can and be prepared to orally describe what the parts are and what they are capable of doing. Allow time for student sharing their ideas. During this time, no one is to make judgments about how realistic or accurate their conceptions are. Students can make their own judgments after the lesson and revise their drawing appropriately.

Show them an image of Phoenix or this short, trailer animation by copying and pasting the following URL in your Internet browser: http://phoenix.lpl.arizona.edu/video/edl_teaser_low.mov. For a more detailed simulation of the Phoenix landing shown in real time use this URL: http://phoenix.lpl.arizona.edu/video/edl_hud_english_low.mov. Both are available in either low or high bandwidth. Do students notice any parts equivalent to the parts on their own drawing? Are there parts they omitted?

Ask what motivates scientists to explore Mars. What do they hope to find or think they might find? As a means of reinforcing some methods of science, ask “What would it mean, what can be inferred if such things are found? What types of observations can Phoenix collect?” Note that it is capable of testing the soil for elemental content, in addition to being able to send photographic images. In small groups or as a class, have students generate questions that Phoenix might be able to help answer. Students can also make predictions regarding the kinds of information Phoenix might reveal or the kinds of probes to be designed in the future, their destinations, and their missions. As an extension, students might be directed to peruse the Worldbook article or specific parts thereof.

As a means of reinforcing the nature of science, ask “Can scientists be certain that the inferences they make and the conclusions they draw from the data collected by Phoenix are ‘true’?” Explain. Lead students to understand the concept of certainty and the reliance upon ample empirical evidence from a variety of sources that enable logical inferences and conclusions that are fairly certain. In the absence of ample empirical evidence or variety in data sources, scientists will normally qualify their inferences and conclusions reminding us that the evidence is yet incomplete and thus our current understandings may change when more evidence accumulates.

Here are additional resources from the National Science Digital Library Middle School Portal related to space exploration and Mars: Phoenix Mission to Mars: Final Seven Minutes of Terror; Mission to Mars; and Would Life on Mars be on or Below the Surface?

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.

Many news outlets reported earlier this week that recent rice crop failures could have been avoided. An infestation of the brown plant hopper is the cause for the crop failure. The science knowledge and biotechnology needed to breed resistant rice plants have been in existence for several years. However, funds were not available to mass produce these rice strains and get them into the hands of rice growers. This is one example of crop failure that, when combined with other agricultural woes, is fueling food riots around the world, but especially among the poorest people in the least developed nations.

On May 18, Newyorktimes.com published an article that comprehensively describes how this preventable tragedy happened - World’s Poor Pay Price as Crop Research Is Cut. As with most sociopolitical issues, a combination of circumstances over a long period of time must be considered if one is to accurately account for the current crisis. The article conveys the history of agriculture research, including the Green Revolution of the 1960s and the great advances that emerged then. Ironically that successful movement contributed to the current lack of available funding; as agriculture problems were solved and world food supplies outpaced demand, research money was directed elsewhere.

The article, part of a series on the world’s food production, includes a nice depth and breadth of information concerning agricultural research. Several photos and related links are included.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

The issues described in the news article connect to the History and Nature of Science, Life Science, Science and Technology, and Science in Personal and Social Perspectives content standards of the National Science Education Standards. Here, we narrow our focus to the first two standards. However, this topic - world food supplies as related to agriculture and biotechnology - could easily serve as basis for an interdisciplinary unit in the middle grades.

Do any of the students have experience in growing vegetables? Ask students, what are some of the problems gardeners have to deal with in order to maintain their vegetables? What are some ways to deal with those problems? Help students to include the problem of insect pests in the discussion. Is it reasonable to assume that growers of crops on a large scale also have the same or similar problems? Can growers use the same approaches to deal with their problems that the gardener uses? Why or why not?

Ask students if they can identify one food plant, or crop, that is probably the world’s most common source of food. Consider keeping a list of all ideas and then asking the class to think carefully and critically when they answer these questions: What crop could probably be eliminated from the list, compared to the rest of the list? Why do they believe the food they are choosing to eliminate is probably not the world’s top food crop? You will hope that rice remains on the list!

Ask students to imagine that an insect has infested a large part of the world’s most important food crop. Consider putting the students in small groups in which they predict the consequences of an infestation. You might stipulate that they must have a clear prediction with logical justification for each domain: economy, culture, public health, government, military, and education. Next, ask them to articulate one or two questions that science could investigate in the hope of avoiding the consequences their group identified. For example, Which varieties of rice are most insect resistant? What other food crops can be grown in the areas where rice is currently grown? What nutritional substitutes should/could be distributed to areas where rice is in short supply? Students’ questions will vary widely and all are correct, as long as the questions can be subjected to scientific investigation and seem to point toward a solution to the stated problem.

Share with students the Newyorktimes.com article, showing that such an event - insect infestation of an important crop - has actually happened. Show them the pictures at the story’s web site. Inform them that the knowledge and technology necessary to prevent this disaster already exist. Ask students to speculate then on how this could have happened if people already know how to combat it. Lead them to understand the complexity of the history, funding, cultural values, and competition for funding as contributors to the situation. Finally, confirm and affirm the students’ predictions. They may have heard about food riots for example, in Africa and elsewhere. Ask them what direction they think governments and researchers should go next? Why?

As an extension, you could elaborate on the evolution aspect of the story: the way the bug has evolved through natural selection made possible by use of insecticides.

Here are additional resources from the National Science Digital Library Middle School Portal related to gardening, agriculture and natural selection: Thinking Green? Grow Your Own!; Ag in the Classroom; What Are Seed Banks and How Do They Work? and Dr. Saul’s Biology in Motion.

We Need Your Help
We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).
Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.

Distinguishing between science and science fiction can be a good reinforcement activity for students learning the characteristics of science. Cognitively, middle school students are able to differentiate between fantasy and reality. But because science is not always intuitively obvious, distinguishing science fact from science fiction can be more challenging. Today’s blog encourages you to use pop culture to help students sharpen their conceptual understanding of the nature of science and ethics in science, particularly in archaeology, and to distinguish between science fact and science fiction.

Though your students were not even born when the first Indiana Jones movie was made, they are probably familiar with it thanks to TV, sequels, and theme parks. On May 22 the fourth movie in the series, Indiana Jones and the Kingdom of the Crystal Skull, opens and will appeal to middle school students. On May 13, 2008, ABCnews.go.com published `Indiana Jones’: Real Archaeologists Don’t Have Whips.

The news story highlights how the work of Indiana Jones is unlike the work of real archaeologists. It also points out Indiana Jones’s complete disregard for ethics. He seems to leave a trail of destruction wherever he goes, rarely seeking proper permission from local authorities to conduct his work. Despite the departure from reality, the movies are responsible for increasing interest in archaeology as a college major. Several relevant quotes from archaeologists are included in the article.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Ask students if they have ever heard of Indiana Jones. What does he do? Listen for the ways students characterize him and his work, but do not add judgmental comments at this time. Do they include archaeology or the search for clues to past civilizations in order to inform our understanding of both past and current civilizations? Have students read the news story. Allow them to verbally share their reactions.

Ask, what do archaeologists do? Lead students to understand that archaeologists’ work is based on historical science, using scientific theories of physics, chemistry and biology to uncover clues in artifacts that enable construction of “stories” (hypotheses) of past civilizations.

Ask, where do archaeologists go to look for artifacts? Lead students to understand the archaeologists may have to go to foreign countries where the people may be suspicious of western scientists and protective of their culture and its historical artifacts. How then should the archaeologists go about gaining access and how should they conduct themselves once they do? Help students to understand these are important ethical and legal issues. Care must be taken and the proper authorities consulted before one can proceed to excavate an area. Agreements are made, including what scientists may be allowed to remove; what they may be allowed to do to the artifacts; the kinds of tests they may perform on them; how to restore the area once they complete their dig; and what to do with the artifacts once they have studied them.

Ask, to what extent does Indiana Jones seem to attend to issues of ethics? Why? At this time students can distinguish between science and science fiction, using information provided in the news story. Have them create a chart with two columns, one listing the characteristics of science and one listing the characteristics of Indiana Jones, science fiction. Do some overlap? Why do students think science fiction contains some science fact? Ultimately, students should be able to distinguish science fact from science fiction, identify ethical issue in archaeology, and provide a statement of a caution to science illiterates who plan on seeing the Indiana Jones movie. Use caution yourself. You may want to avoid explicitly promoting student viewing of the movie in order to avoid potential clashes with parents!

The lesson described connects to both the History and Nature of Science and the Science as Inquiry content standards of the National Science Education Standards. Here are five additional resources from the National Science Digital Library Middle School Portal related to the nature of science, ethics and archaeology: Quantum Leaps in the Wrong Direction: Where Real Science Ends…and Pseudoscience Begins; Science Sampler: Reading Science; Ethics Lessons; Teaching Ethics; Why Did the Anasazi Abandon Mesa Verde?

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We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.

Those of us born after World War II have take antibiotics for granted. Strep throat? Ear infection? Acne? Bronchitis? Not a problem. Take the full prescribed antibiotic dose and you are cured. The reality of antibiotic resistant bacteria however, disrupts that scenario. No longer can we always trust in a full recovery from a bacterial infection after completing the antibiotic regimen. Rather than continuing to create new and different antibiotics, the trend in research is to discover the mechanisms of the antibiotic resistance in order to neutralize it.

How Some Bacteria Survive Antibiotics from ScienceDailydescribes how researchers at the University of Illinois, Chicago, studied bacterial action in the presence of erythromycin and related antibiotics. These drugs incapacitate the bacterial protein factories, ribosomes. All cells have ribosomes which are the site of translation in protein synthesis. Erythromycin prevents newly synthesized proteins from detaching from the two subunits of the ribosome, thus preventing the bacteria from thriving. The researchers discovered, however, that these drugs can signal the bacteria to switch a bacterial gene on that enables bacterial release of newly synthesized proteins from the ribosomes. Thus, they effectively resist the drug in a process known as inducible antibiotic expression.

The article quotes one of the researchers

Combining biochemical data with the knowledge of the structure of the ribosome tunnel, we were able to identify some of the key molecular players involved in the induction mechanism. . . .We only researched response to erythromycin-like drugs because the majority of the genetics were already known. There may be other antibiotics and resistance genes in pathogenic bacteria regulated by this same mechanism. This is just the beginning.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

A manifestation of evolution, antibiotic resistance aligns with the Life Science standard of The National Science Education Standards, “Species acquire many of their unique characteristics through biological adaptation, which involves the selection of naturally occurring variations in populations. Biological adaptations include changes in structures, behaviors, or physiology that enhance survival and reproductive success in a particular environment.” Also related is the structure and function section of the standard: prokaryotic cell structure, the ribosome, and protein synthesis.

Ask students if they have ever had an ear infection or strep throat. What did they do about it? Lead them to disclose that they went to the doctor, were prescribed an antibiotic and took it for the full course, often 10 days. Ask if they were cured then, or did anyone suffer a recurrence within the next week or so? If yes, why? Then what did they do? Lead them to articulate the concept of bacterial resistance. Consider showing visuals of a typical animal eukaryotic cell side by side with a bacterial cell. This will highlight the size and structural difference, and enable student comprehension of how bacterial cells can colonize a eukaryotic cell. Showing this image and eliminating the text or modifying it to inform students that the red shows a liver cell, while all the green spots are bacteria cells could do the trick. Make sure they understand the activity of the millions of bacteria cells a) consumes nutrients needed by one’s own healthy cells and b) produces waste that makes one sick.

If you’ve already discussed the characteristics of living things, cell theory and cell structure, lead students to recall the importance of ribosomes to all living cells. Ask, what might happen if the function of the ribosomes were disrupted? Students should reason that protein production would stop and the cell would die for lack of needed proteins. Inform them that this is the way some antibiotics work; they interfere with the bacterial cells’ ribosome function. (Prokaryotic and eukaryotic ribosome structure varies slightly allowing the eukaryotic ribosomes to remain unaffected.) Ask, what if the presence of the antibiotic signaled the bacteria to produce a protein (turn a gene on) that interfered with the drug’s ability to disrupt the ribosome’s work? Allow plenty of wait time for them to think this through logically. They should arrive at the idea of antibiotic resistance, even if they don’t use that phrase.

Allow students to read the first three paragraphs above and follow the links. The protein synthesis link however, is probably too advanced for middle school students and can be eliminated. Have them read the article How Some Bacteria Survive Antibiotics. Assess: what is an antibiotic? How do drugs like erythromycin work? What is inducible antibiotic expression? How might it be helpful to know the mechanisms by which bacteria resist antibiotics? Describe how antibiotic resistance is an example of evolution.

Here are some additional resources from the National Science Digital Library Middle School Portal related to antibiotic resistance and bacteria: Introduction to Bacteria; Microbes: Too Smart for Antibiotics?; Microbes: What They do and how Antibiotics Change Them; Evolution : Online Lessons for Students: Activity 1; and What’s making you sick?

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.

Typically, a middle school life science study of cells explores the ways cells get what they need and get rid of waste, and the cell cycle concept, including how cells reproduce through mitosis. Discussion of cancer at this time is appropriate since cancer cells share the needs of normal cells in terms of obtaining nutrients and getting rid of waste. However, they differ in their cell cycle. Cancer cells lack an interphase–meaning they are in a near constant state of reproducing with little down time in-between divisions. This leads to the formation of a mass of undifferentiated cells, a tumor.

Angiogenesis is the tumor’s ability to construct blood vessels that become the circulatory system for the tumor. Thus, needed oxygen and nutrients are effectively delivered and waste is removed, allowing the tumor to thrive. These blood vessels are also potential blood-letting points, increasing the risks of surgical removal. If angiogenesis is curtailed, the tumor is deprived and fails to thrive reducing potential surgical complications.

On April 19, 2008, ScienceDaily reported that a team of researchers in Australia has identified a master gene responsible for angiogenesis. The gene is named RGS5. The team was able to remove the gene from experimental tumor cells, and this caused angiogenesis to reverse itself! This means that oncologists may have another tool to treat cancers in more targeted ways; ways that do not affect healthy cells, only cancerous cells.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Ask students what cells need to thrive. Their list should be consistent with what all living things need: ability to take in nutrients and get rid of waste, to manufacture needed materials and break down no longer needed materials, and to reproduce. It might be appropriate at this time to show them a schematic of the cell cycle. What are student conceptions of cancer and tumors? Ask if they think cancer cells have different needs than those already discussed? Why or why not?

What is a tumor? How might it differ from or be the same as other organs in the body? A tumor is a mass of undifferentiated cells as opposed to cooperative tissues organized in a functional organ. And it is not part of a functional organ system except in the sense that the tumor’s blood vessels are derived from the healthy organ system’s blood vessels: cells come from other cells.

Lead students to conclude that cancer cells are like other cells with respect to the cell cycle and needs. Then ask, so how is it that cancer cells can grow into a tumor while healthy cells do not? Lead students to the one difference in the cancer cell cycle as compared to healthy cells’ cycle: lack of interphase. The lack of interphase may be attributed to a genetic mutation that fails to produce the needed proteins that signal interphase, or an environmental factor that prevents detection of the interphase signal.

At this point, you have raised student awareness of the nature of cancer cells and tumors. The students are now ready to hypothesize ways to interfere with tumor growth. Solicit and accept all reasonable hypotheses. Ask what if there was a way to control/eliminate a tumor’s ability to construct blood vessels? What do you predict the outcomes might be? Why? What leads you to believe that is a reasonable prediction? Make sure students use known facts about cell structure and function to support their predictions.

Have students read the article: World-first Discovery Could Help Treat Life-threatening Tumors. What other questions come to mind, questions which there are no pat answers to at this time? For example, does RGS5 also control blood vessel formation in healthy tissue and organs? How can it be controlled to impact only tumor blood vessels? What other investigations are needed in order to learn how to use this science knowledge, to apply it to a technological innovation to treat cancer?

The lesson described connects to both the Life Science and the Science as Inquiry content standards of the National Science Education Standards. Here are some additional resources from the National Science Digital Library Middle School Portal related to gene function, cells, and cancer: The Genetic Science Learning Center: The Basics and Beyond; Cell Differentiation; Lessons on Cells, Tissues ,and Organs; and Science sampler: Cancer-Mitosis Run Amok.

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

Let us know what you think and tell us how we can serve you better. We want your feedback on all of the NSDL Middle School Portal science publications. Email us at msp@msteacher.org.