Non Biology major

BIO 1100, Non-Majors Biology 1

Course Learning Outcomes for Unit VIII

1. Evaluate concepts of basic biological sciences. 1.1 Identify various aspects of photosynthesis. 1.2 Categorize plants.

7. Evaluate relationships between living organisms and nonliving factors in ecosystems.

7.1 Compare and contrast sustainable and unsustainable farming practices. 7.2 Evaluate the effects of excess carbon dioxide and the effect on greenhouse gases.

8. Apply lab simulations and activities for further scientific understanding.

8.1 Interpret and record data. 8.2 Examine various effects of transpiration on plants.

Reading Assignment Chapter 5: Life in the Greenhouse: Photosynthesis and Global Warming Chapter 23: Feeding the World: Plant Structure and Growth Chapter 24: Growing a Green Thumb: Plant Physiology

Unit Lesson This unit includes information from Chapters 5, 23, and 24. The materials in these chapters will help you understand the important relationship between plants and the survival of the human race. You will learn what plants need in order to grow and about agricultural practices that provide food to humans. In addition, you will learn about the various plant structures and their functions. You will also learn about the future of agriculture. We know that past and present agricultural practices have caused damage to the environment. How can we reduce this damage, or can we? At least three times a day, we sit down and eat. Do you ever really think about what you eat—not just whether it is good for you, or if it is a vegetable, but what it is made of? In early chapters, we learned that there are two types of cells: prokaryotes and eukaryotes. We learned that eukaryotes are fungi, protists, plants, and animals. We eat a lot of eukaryotic organisms. What do you think makes up most of what you eat? If you are eating a healthy diet, the majority of your food comes from plants. Even if you ate no plants at all, whatever you are eating ate a plant or another organism, which probably ate a plant. What is the point? The point is that plants are important. We have to have food. Is that all we get from plants? Do plants just look nice and provide us with food? In Chapter 5, you will learn about the delicate relationship between plants (through photosynthesis) and humans (through cellular respiration). Plants provide us with the sugars and oxygen that we need in order to synthesize ATP, or energy. Plants are required for our survival. Recently, you have probably heard a lot in the news about the greenhouse effect and global warming. There has been, and currently still is, a debate among scientists, politicians, and other groups of whether or not global warming exists. As productive members of society, you need to develop an understanding of these concepts. In this unit, you will learn about the greenhouse effect and the gases that play an important role in the environment.

UNIT VIII STUDY GUIDE

Photosynthesis and Plant Biology

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Look around where you live. Have you visited an area that you had not been to in a few years? If so, you probably noticed that it looks different. There are probably more buildings, commercial properties, and houses. When development occurs, destruction also occurs. When forests and plants are destroyed, it is really a double-edged sword. When the number of plants is reduced, there are fewer organisms available to absorb carbon dioxide from the atmosphere. Before the plant was cleared or cut, it had absorbed carbon dioxide. What happens to the carbon dioxide that was absorbed? Right, it is released back into the atmosphere. There are fewer plants to absorb the carbon dioxide and more is being released. You would think with the technology that we have, we could figure out a way to reduce atmospheric carbon dioxide. Even if we could, plants are still important. They are so important that we figured out how to grow them thousands of years ago and continue to farm plants today. Agriculture is just a fancy name for farming. We have to have food. Can we provide enough food on a global scale with traditional ways of farming? Do we have the same amount of farmland? With more people and less land, how are we going to feed everyone? All of these questions have transformed the methods that farmers use to grow crops. Are these methods better? Are there costs? Do the costs outweigh the benefits? You may be thinking that this does not apply to you because you are not a farmer; however, you are a consumer. You do eat food. You do live in the environment. This does affect everyone, whether you are a farmer or not. During the first decade of the 2000s there was an extreme drought affecting much of the United States, including the Midwest region (NOAA, 2015). This is an area of our country that produces a lot of corn. Corn is used in many different foods, even when you do not think it is. Just in consumption alone, each person consumes about 1500 pounds of corn per year. That is a lot of corn. Think about this the next time you drink a regular soda (not a diet soda), look at the ingredients list. The first ingredient is probably water and the next ingredient is probably high fructose corn syrup. Basically, you are drinking corn water. Think back to the drought in the Midwest. If we use that much corn and our largest production region was not able to produce any, what will happen to our corn supply? Where will it come from? What will this do to the price of corn? Again, corn is even in soda. Will the cost of soda increase? Farmer or not, we are all affected by crops. We have staple crops that we rely on for various reasons; many are required for our survival. Food is not the only issue when it comes to plants and farming. We know that our population has increased. This means more crops are required. This means more pesticides are being used. What are pesticides doing to our environment? What are they doing to you? A large population of the United States lives along the coastal regions, especially the Gulf Coast along the Gulf of Mexico. When pesticides are used, a lot of the residue ends up as run-off. Where does the pesticide end up? If you have not had a chance, make sure you view the image on page 587 in your textbook. This image shows how pesticide residue is dispersed from the Mississippi River. Why are farmers using so many pesticides? Why are they using more? In early chapters, we learned about evolution. Are some pests resistant to pesticides? Are pest smarter than we are? Of course not. Natural selection allows them to change naturally over time. Think about growing your own garden again. You will probably not be lucky enough to not have any pests. You may decide not to worry about them since you are not trying to sell your products; however, you may decide to use pesticides. If you do not have a garden, you probably have grass in your yard and you want your grass to be beautiful and green. In the south, St Augustine is a popular variety of grass among both residents and chinch bugs. Chinch bugs attach themselves to the grass blade and suck out the fluid. This kills the grass and leaves the grass looking as if someone poured chemicals on it. Chinch bugs reproduce quickly. When organisms reproduce fast, this means there are more chances for mutations. Remember, mutations are random. Some chinch bugs mutate and are immune to chemicals that were once used to treat them. Some chinch bugs are actually even resistant to DDT, a highly effective insecticide once touted as a wonder-chemical until it was discovered to be toxic to humans and subsequently banned (PAN, n.d.). If you spray your yard with the chemical currently being used to treat chinch bugs, it will kill them unless some have mutated. If some have mutated, they will survive. At first, this resistant population is small; however, they now have the resources of your entire yard to themselves. They reproduce quickly. The resistant population is larger. You spray again; however, the chinch bugs are resistant, and it does not affect them. You try something new that scientists just came out with. This kills most of the chinch bugs; however, a few

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mutated and are able to survive. This is known as the “pesticide treadmill.” You (or the farmer) keep running as fast as you can only to stay in one place.

References National Oceanic and Atmospheric Administration. (2015). Drought - June 2015. Retrieved from

https://www.ncdc.noaa.gov/sotc/drought/201506 Pesticide Action Network. (n.d.). The DDT story. Retrieved from http://www.panna.org/issues/persistent-

poisons/the-ddt-story

Suggested Reading Please see the chapter presentation links in Blackboard to download and view Chapter 5, 23, and 24 presentations. This will summarize and reinforce the information from these chapters in your textbook.

Learning Activities (Nongraded) Is It Possible to Plant a Seed Upside Down? Estimated Time to Complete: This activity takes approximately 10 minutes to set up and three to four days to see the results. Introduction: Often, novice gardeners think that seeds that do not grow may have been placed or settled into the ground upside down—that is, with shoots emerging from the seed facing away from the soil surface. Actually, seeds that do not produce seedlings were most likely inviable or were planted too deeply. The emerging shoots and roots are affected in opposite ways by the same hormone, auxin. In response to gravity, auxin accumulates on the lower side (side closest to the pull of gravity) of the embryonic shoot and root. The shoot responds to the auxin by cells elongating. The root senses gravity in the root cap and responds in the opposite way, and cell elongation on the underside of the root is inhibited, causing it to bend down into the soil. Materials:

 Cheesecloth or soft paper towels

 Seeds of various types. Corn, wheat, rye, and beans are examples that work well. Use seeds that have distinct shapes that allow easy distinction of different orientations.

 Foil Procedures:

1. Dampen the cheesecloth or paper towel completely. 2. Arrange seeds in different orientations, snaring them in the cloth or paper to prevent them from

dropping out. Lay another damp cloth over them and enclose the seed (i.e., “sandwich” them in the foil, pressing it tightly closed).

3. Place the seed sandwich upright (not flat) by leaning it against a wall or on a bookshelf. Allow seeds to germinate for three to four days.

4. After three to four days, carefully open the foil packets (do not lose track of which side was up) and examine the germinating seeds inside.

Questions:

1. Did the roots always grow down and shoots always grow up? 2. What was the hormone involved? 3. Why is planting a seed too deep much more likely to reduce germination than planting a seed upside

down?

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Answer Key:

1. Did the roots always grow down and shoots always grow up? Yes. 2. What was the hormone involved? Auxin. 3. Why is planting a seed too deep much more likely to reduce germination than planting a seed upside

down? The roots and shoots can orient themselves correctly if planted upside down. If they are planted too deeply, however, the shoot may not have enough energy reserves to make it out of the soil.

Nongraded Learning Activities are provided to aid students in their course of study. You do not have to submit them. If you have questions, contact your instructor for further guidance and information.