Skippers and Crescents and Blues, Oh My!

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This week at the Market, we talked all about butterflies and the many types of butterflies that you can find in Minnesota. Did you know that there are about 146 species of butterflies in Minnesota and the most of them survive the winter here just like us! Market-goers were able to meet some of these Minnesota natives butterflies and try to identify them. We had Pearl crescents, Cabbage whites, and Eastern tailed blues.

We also talked a lot about how butterflies make different patterns on their wings. Did you know that they are actually made from lots of tiny overlapping scales on the butterflies’ wings. In fact, the other name for butterflies and moths collectively is “Lepidoptera”, which means “scaly wings”.

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We then talked about why butterflies have different wing patterns: to scare predators, to hide from predators, or to tell predators that they don’t taste good. Then junior market scientists were invited to color their own butterfly wings and there were a lot of great creative patterns!

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We also talked about how butterflies have a very specific life-cycle. They start as eggs, hatch and grow as caterpillars, turn into a pupae in a chrysalis, and then emerge as the adult butterflies that we all see. Market-goers could play a guessing game to match the caterpillar with its adult and junior market scientists could make their own caterpillars to match the butterfly that they drew.

Lastly, Market-goers could learn about the very special butterflies in Minnesota that are currently at risk, like the highly endangered Poweshiek skipperling. Did you know that 15 species of butterflies are listed as Endangered, Threatened, or Special Concern by the State of Minnesota? Ten of these species depend on our disappearing native prairies. These Minnesotans are facing many challenges due to loss of habitat and other potential problems. We also learned about what places like the Minnesota Zoo and Monarch Joint Venture are doing to try and save these animals and ways that we all help butterfly populations in Minnesota!

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Dynamic Earth at the Market

by Kevin Theissen

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Our planet is a dynamic, ever-changing system and this past Saturday at the market we explored the fascinating science of geology with a team of students and faculty from the University of St. Thomas.   Geologists use physical models to understand the natural behavior of streams like our local Mississippi River. The models provide insight on major processes such as erosion, transport, and deposition–and the sometimes hazardous consequences which include flooding and landslides. Visitors got hands-on experience investigating the interactions between water flow and landscape with a table-top stream table. They created hills, dams, slopes, and stream channels and experimented with changes in the rate of streamflow. Visitors learned that the “sediment” for our stream table was an unexpected material—recycled toilet seats!

 

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The Earth’s large crustal plates move at the rate that our fingernails grow and accordingly lead to much slower changes than rivers. Given hundreds of millions of years, however, those slow changes mean dramatic differences.   Visitors observed marine fossils of organisms known as brachiopods, bryozoans, and crinoids representing a shallow tropical sea that once covered the Twin Cities and much of southeastern Minnesota during a period of geologic time known as the Ordivician, more than 450 million years ago. Reconstructions of plate movements suggest that Minnesota was likely centered on the equator during this time.

 

Visitors also donned 3-D glasses to get dramatic views of a variety of important plate tectonic settings where plates converge, spread apart, and slide past each other.   Perhaps the best example of this is the Pacific ‘Ring of Fire’ which includes deep-sea trenches, mid-ocean ridges, and several large mountain chains.

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Junior scientists topped all of this off by decorating their own pet rocks!

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Pollen and Plant Development

By Claire Milsted

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Almost all of our food comes directly or indirectly from flowering plants (angiosperms); many plants without conspicuous flowers, such as corn, fall into this category. Angiosperms release specialized cells known as pollen to carry half of their genetic information to other plants for reproduction (though many angiosperms also pollinate themselves). This Saturday’s Market Science session at Midtown Farmer’s Market focused on pollen and plant development. Even though the farmer’s market was unexpectedly rained out before 11am, many visitors were able to participate in one or more activities designed to trace plant development from a flower to pollen to seed.

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A bumblebee visits a rhododendron in Saint Paul. Bumblebees are important pollinators.

In many species, this pollen must be carried by animal pollinators. About 35% of the global food supply comes from plants that require animal pollinators. Our first activity was a guessing game that asked visitors to guess how various flowering plants are pollinated. Most visitors knew about the importance of bees, but some were surprised to learn about other important vectors of pollination. For example, corn is wind-pollinated, while the Blue Agave Cactus is pollinated by the Mexican Long-nosed Bat.

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A Mexican long-nosed bat prepares to pollinate a Blue Agave Cactus. Image via nwf.org

Visitors were also offered the chance to examine various flowers both with the naked eye and with a dissection microscope. Visitors examined lilies and tomatoes, which have simple flowers with several pollen-containing anthers surrounding a pollen-receiving stigma. There were also compound flowers, with a single flower-head made of several small flowers. The compound flowers on display were chrysanthemums, the invasive species Queen Anne’s Lace, and daisies. Daisies are members of the Asteraceae family, which have flower heads that look like a single flower surrounded by petals, in fact each of the small bumps on the head are an individual disk flowers; the structures that look like petals are in fact ray flowers.

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A member of the Asteraceae grows in Saint Paul

Visitors were also able to look at pollen from daylilies and tomatoes under a compound microscope. Daylily pollen was much larger and had a different shape. Finally, visitors were invited to dissect soaked beans and examine them under a dissection microscope. Volunteers explained the various components of a bean seed–its protective coat, two cotyledons which store energy for the growing plant, and a small embryo with two visible embryonic leaves (epicotyls). Hopefully these activities exploring flowers, pollinators, pollen, and seeds gave visitors a clearer view of the developmental and reproductive processes that play an important role in our gardens and on our farms.

 

Ethnobotany: Using plants for food and medicine

By Stephanie Erlandson

This Saturday (July 9) we got to strengthen our connection to plants by examining more closely what we eat, and how some common plants can be used for medicine.

We eat plants all the time, but we rarely take a closer look at what’s inside.  By dissecting plants, we can look at their seeds, their ovaries (yes, plants have ovaries!) and figure out if a specific plant part is a fruit, a leaf, a stem, or a root.  We can also learn more about how plants are related to each other.  For example, the African horned melon (kiwano) is actually closely related to the pumpkins, squash, and watermelons that are more common here in Minnesota.

There were a variety of plants available for dissection, and a map showing the origins of many different agricultural plants from around the world.  Many of the plants that we rely on for food are actually not native to Minnesota (e.g. wheat, oats, watermelon, peas, almonds, coffee).

Visitors were also asked to vote for their favorite berry, and many were shocked to learn that cucumbers are a type of berry, but raspberries and strawberries are not! After voting, visitors learned that a true berry is a fruit that is fleshy, has many seeds on the inside, and grows from only one ovary on a single flower.

Finally, we had some examples of medicinal plants (ephedra, spearmint, horsetail, ginkgo) to view, and we talked about which medicines they provide.  For example, pseudoephed came from the ephedra plant and aspirin came from willow bark.  Willow bark contains salicylic acid, which is a precursor to aspirin.  What plants did the medicines in your cabinet come from?

There are many more medicinal plants around the world that are still unknown to science, and the process of discovering them is still ongoing.  For example, a new chemical was recently extracted from the sweet wormwood plant, and it was found to be very effective at treating malaria.  The scientist to discover the drug, Tu Youyou, was awarded the Nobel Prize in 2015.

Hopefully this market science day will help encourage people to take a closer look at the plants around them, and appreciate everything that they do for us!

Pollinators: the BUZZ about Bees

by Morgan Carr Markell

This past Saturday (June 11th) we got to teach market visitors about bees and their important relationship with flowering plants.

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By gathering food from many flowers, bees provide pollination services. They carry pollen from one flower to another so that the plant can produce more plants and we humans can harvest fruit. We brought pinned bees and wasps along with close-up photos of branched bee hairs with pollen on them to show people why bees are exceptionally good at carrying pollen from one flower to another. Kids also got to make their own pollinators out of pipe cleaners (see photo below) and use them to move artificial pollen (flour) from one artificial flower (cup) to another. It was fun to see all the fuzzy, colorful pollinators that they designed!

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Busy ‘pollinators’ pollinating ‘flowers’.

 

Some kids wanted to make pipe cleaner flowers too so Mohamed, Grace, Jason, and James worked out a method (see flower on the observation hive in the photo below). Also, we discovered that pipe cleaners and pom-poms make great antennae, which bees need to taste pollen/nectar and communicate with each other (see James’ antennae below).

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James wearing his antennae.

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We wanted to give visitors a feel for how diverse bees are. There are over 20,000 species of bees worldwide and over 400 species in Minnesota alone . They have very different lifestyles, living alone or in groups, making nests in stems or underground, and using lots of different methods for carrying pollen back to their young. They also vary tremendously in size (see photo of the pinned bees below).

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We especially wanted to give people concrete steps that they can take to help bees. Lots of people asked about making artificial nests for stem-nesting bees and took our “Plants for Minnesota Bees” handout . A few even came back to show us the bee-friendly plants that they bought at the market!

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We had a bee veil that kids could try on, and beekeeping equipment, including a smoker and hive tool, for them to touch (see photo below). Our biggest draw was the glass-walled observation hive filled with honey bees. Everyone wanted to find the queen! She kept challenging us by moving around and hiding behind workers on the glass. Our thanks go to the nearby vendors that gave us ice for our bees. By 1 pm it was almost 100°F!

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We also had goldenrod and basswood honey for people to taste and compare. Although some people loved the strong, spicy goldenrod taste, most people preferred the basswood honey’s flavor. Honey bees make honey from nectar by concentrating it down to 20% water or less and using enzymes to convert the sucrose sugar in nectar into the glucose and fructose sugars of honey. However, flowers control the specific flavor of the resulting honey by adding their own unique blend of chemicals to their nectar. Yay for biodiversity!

Atoms, Colors, and changes in our Chemical world!

by Joseph Topczewski

This past Saturday (June 4th) we were able to explore Chemistry at Market Science. Our event lived up to its name of “Atoms, Colors, and Changes in Our Chemical World!” and we explored all three in five different activities.

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The first activity was centered on a color change caused by adding dry ice to water that contained a pH indicator. The dissolved CO2 (dry ice is solid CO2) formed carbonic acid and lowered the pH of the water – a reaction that we could see by color change!  This is the same process that occurs when there is an increase in atmospheric CO2, which is a leading cause of ocean acidification.

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The second activity helped us see two other signs of a chemical reaction and also explained some of the ecological effects of ocean acidification. In this activity we mixed clear solutions of Na2CO3 with CaCl2 and caused the precipitation of CaCO3 as a white solid – another sign of a chemical reaction! CaCO3 is the main component of clam shells and coral and these structures are biosynthesized by a similar albeit more complex process. The CaCO3 is not always stable though. As we saw by adding citric acid, the CaCO3 dissolves in acidic solutions and then bubbles form! Bubbles are gas evolution and are a third sign of a chemical reaction. This is essentially the same reaction (sped up) that causes clams and coral to struggle to form shells in an acidified ocean.

Our third activity showed how chemistry can be handy to know about with everyday experiences. The activity focused on cleaning pennies with a little bit of science. While participants struggled to clean their penny in clean water or in soapy water, exposure to some citric acid polished it right up by dissolving the outer layer of copper oxide. See chemistry can be useful.

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The fourth activity asked participants to think about what we are breathing – air. As it turns out air is a gas and gases have special properties. We explored some of those such as the relationship between volume and pressure, moles of gas, and temperature. The last was the most dramatic since we shrunk the balloons in liquid nitrogen and then let them warm up in front of us. While no extra gas was added, they got a lot bigger!

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The last activity was perhaps the most popular – making SLIME! After all slime is cool. Even though the slime was a lot of fun we were also able to explain what the cross linking of polymers can do to its physical properties.

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I think we had a great time at the market having fun with chemistry. I hope everyone can enjoy some chemistry this week and we hope to be back again!

Fungi with a Fun Guy: Feasts, Famines, and the Fungus Among Us!

by Lauren Jackson

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Following one billion challenging years of preparation, we thought that the Midtown Farmers Market would be the optimal venue to unveil (part of) the story of fungi. In fairness, it took us humans just one week to plan the event, but we were only able to do so because fungi had been helping to shape the world as we know it, including elements of human culture, for such a long time. If you were able to join us for our Market Science event, you may have heard some or all of the following fungal synopsis…

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Imagine Earth one billion years ago: the oceans were teeming with microbial life, some of which had evolved to become multicellular; the atmosphere had very little, but slowly increasing levels of, oxygen; and the land masses were barren rock. It is thought that life on land took a dramatic turn as fungi – perhaps as part of lichen-like associations – began to colonize the land and slowly break down rocks. The activity of fungi allowed for some plants to escape their aquatic environments about 500 million years later, and the lives of plants and fungi have remained tightly intertwined since. Fungi have evolved to become the best friends and worst enemies of plants, and nearly everything in-between, over the last 500 million years. And in just the last 12,000 years or so, humans have found innovative ways to exploit fungi, and we are still learning new ways to harness their unique natural abilities.

 

Mycorrhizae (say it with me, my-co-rye-zay), which is Greek for ‘fungus roots,’ are fungi that directly interact with the roots of more than 80% of all plants. These fungi increase the surface area that roots can use to absorb water by ~35-100 times! Importantly, mycorrhizae release enzymes and organic acids that liberate soil nutrients such as phosphorus, and literally pump them into plant roots. The immune systems of plants get a boost from their fungal friends, and they get physical protection from some of the bad actors that may be lurking in the surrounding soil. In exchange for all of this help, plants ship photosynthates (i.e. sugars made from photosynthesis) directly to the fungi to make their lives a little easier. This type of association, where both organisms benefit, is known as a mutualism.

 

At the other end of the spectrum, fungal pathogens cause about 70% of plant diseases, which can range in severity from cosmetic damage to complete mortality. Fungi and fungal-like organisms have been partly to blame for devastating famines including the Irish potato famine of the 1840s and the Bengal famine of 1943. Interestingly, the English were mostly a coffee-drinking nation before the coffee rust disease wiped out their massive coffee plantations in Java and other islands of South Asia just before the turn of the 20th century. Ergot of rye, caused by Claviceps purpurea, was responsible for St. Anthony’s Fire, which is the same fungus that Albert Hofmann famously isolated LSD from in 1938. Trippy stuff, huh?

 

Fungi are also the great recyclers of Earth, doing the heavy lifting to turn dead debris back into soil. You may have seen evidence of this activity in the form of mushrooms or conks growing out of logs and stumps. When you see a mushroom or conk, note that this is just the “fruit” of that fungus, and that most of the fungus is inside of the log releasing enzymes to break down wood into smaller components that they can absorb for food. Ötzi the Iceman was found with two different conks: the tinder conk that he used to make fire; and the birch polypore that he may have used as medicine. Amazingly, some of the same enzymes that fungi use to degrade wood can also be used to clean up contaminants such as diesel fuel, pesticides, dyes, pharmaceutical compounds, explosives and more!

 

Finally, it wouldn’t be fair to talk about fungi at the farmers market without mentioning how we use them for food and beverages. In what may have been two of the most fortuitous mistakes in history, yeast fell into somebody’s dough and somebody else’s juice about 12,000 years ago, giving rise to leavened bread and wine/beer. We have other interesting ways to modify foods with fungi including fermenting soy beans for soy sauce, preserving salami, and changing the flavors of cheeses. Kids (and even some kids at heart) that visited our booth learned how we use a fungus to make blue cheese, and they used blue spores from the cheese to make a living art project!

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Of course, the epitome of fungal cuisine comes in the form of mushrooms. Through trial and error, we have discovered that at least 60 different mushrooms, and probably many more, are edible; and although button mushrooms are delicious, we made sure to encourage everybody who visited us to try other mushrooms that can be purchased or harvested wildly around the Twin Cities. Never eat a mushroom that you find in the wild without absolute certainty that it is what you think it is. It is best to go mushroom hunting with people who are experienced. Have fun with your fungi and try a few of the mushrooms listed below in your next meal!

 

1) Oyster mushrooms; 2) King oyster mushrooms; 3) Shiitake; 4) Enoki; 5) Maitake or hen of the woods; 6) Morels; 7) Chanterelles; 8) Lobster mushrooms; 9) Giant puffballs; 10) Chicken of the woods; 11) Lion’s mane

The Tropics Rule!

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By Christina Smith and Leland Werden

Our May 14th session at the Midtown Farmers Market was focused on diversity in the tropics. It was a fairly cold day (44F and record low for that day in Minneapolis) so we spent time imagining the warm tropics!

Did you know that estimated 50-90% of all the Earth’s plant and animal species in the tropics? Many researchers at the University of Minnesota and elsewhere are working to understand why this is and how this will change with changing climate (https://tropicaldryforest.wordpress.com/). Everyone was excited to see the preserved insects, amphibians, reptiles, and plants from the collections borrowed from the Bell Museum of Natural History and the CBS Conservatory at the University of Minnesota.

 

Fun observations about tropical species:

  • The fastest lizard in the world is from Costa Rica and can run 21 mph
  • 20% of the world’s oxygen is produced by trees in the Amazon rainforest — how would this change with deforestation?
  • Many tropical trees don’t form rings because there are not distinct freeze and thaw cycles in many tropical ecosystems.  

Take a look at this picture, which do you think is not from the tropics?

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Surprise! They all are!
Some of these images look really similar to temperate forests in Minnesota, but the tropics are not only full of dark and dense rainforests, and white sand beaches, like those shown in the movies. The tropics are incredibly diverse, and you can find an incredible amount of species and landscapes there. We love working in the tropics so much because if you look hard enough you can find something new everyday. If you haven’t already make sure to visit, and if you have been, make sure to go again and see something new!

Fun with Fungi!

By: Lotus Lofgren

For most species, it’s not good enough simply to make babies. In order for a species to spread their genes, those offspring need to travel. Nature has evolved some remarkable mechanisms for distributing the next generation to new locations. Most animals can simply transport themselves to a new home. Bacteria can hitch rides on hosts, in soil, or along waterways. Plants spread themselves around using seeds which can fly in the breeze, float downriver, or seduce a multitude of creatures (including us) to do the heavy lifting for them- carrying their fruits to every corner of the globe. It’s just as important to get around if you happen to be a fungus, and like plants, fungi employ some amazing ways to ensure their offspring get to see the world.

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Turn over a mushroom cap and you might find any number of beautiful textures- knife like true gills such as those found in Agaricus bisporus (the common grocery store mushroom), false gills (like those found on Chanterelles, which look like true gills that have melted in the heat), pores (found on many bracket fungi) or teeth (such as those found on hedgehog mushrooms). These structures may look different, but they all serve the same purpose- to house and distribute tiny fungal spores. Spores are the fungal equivalent of seeds, and these varied structures are indicative of the many strategies that fungi employ to get around. We call all these different structures ‘spore bearing surfaces’ and this week at the market, we set out to investigate why mushrooms make them.

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When you slice off a mushroom’s gill section and look at it under a microscope, you will see 4 tiny spores suspended on a structure known as a ‘basidium’ (plural: basidia). The gills support these basidia and hold them at a very specific spacing. The little spores are ejected from the basidia with tremendous velocity, but are halted almost immediately when their small size slams against the viscous air. Then they drop, straight down, in a flight path that clears the adjacent basidia while maximizing the number of spores that can fit in a given area of the gill. After the spores have fallen clear of the cap, they are perfectly positioned to hitch a ride on tiny air currents, which insure they land at the greatest distance possible from the parent mushroom.

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At the market this week, we explored mushroom biology by making gill stamp critters. After taking a look at some diverse examples of fungal spore bearing surfaces under a dissecting microscope, our kid-scientists carefully peeled back the mushroom cap margin to expose the gills and used the gill surface as a stamp. The stamps preserved the important gill spacing of the mushrooms and provided a print to create mushroom critters! Our scientists then glued on googley-eyes, plant materials, fungi and lichens. Like the little mushroom spores traveling far from where they were born, our kid-made art dried in the sun and made its way back to the artists’ homes- with a story to tell about why mushrooms have gills and how some fungal spores travel the world.

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