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1.2: The science of Botany

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    The science that studies plants is called Botany. All natural sciences, including botany, aim to understand how the natural world functions. To be able to do this we need to make observations, run experiments, generate and test hypotheses, record data, and report results. In Western science, people use a series of steps, called the scientific method, that helps to answer a question in an unbiased way.

    It is important to notice that indigenous peoples across the globe have their own knowledge systems that are different from the Western science approach, where “...knowledge for observing, collecting, categorizing, recording, using, disseminating and revising information and concepts that explain how the world works…” (Whyte et al., 2016). Indigenous knowledge often takes place at a much longer time scale with knowledge and observations passed on from generation to generation. The two systems do not need to be isolated and sometimes are used together to answer questions. “Hawaiians like many indigenous people were careful observers of nature. They observed closely, developed possible explanations for what they observed, conducted experiments to either confirm or refine their understanding until they were confident in their understanding. Once their understanding was perfected, they then committed it to memory using such mnemonic devices as the mele (song), oli (chant) or moʻolelo (story) which was then passed on to the next generation. We only have to look at Hawaiian fishponds to realize how many observations, experiments, refinements that must have taken place before they made the immensely huge labor intensive commitment to build a fishpond. One thing we can be sure of, the perfection of the Hawaiian fishpond did not occur in one generation; it was a deliberate process. The western "Scientific Method" operates in much the same way, observations are made, hypotheses presented, experiments conducted to refine the observation, the main difference is that in the west every step is carefully written down and documented.” (Kalei Laimana, pers. communication).

    The Scientific Method

    Botanists and other scientists learn about the natural world by asking questions about it and using a systematic approach, known as the scientific method, to find answers. It might surprise you to learn that even you use this method in your life to solve everyday problems or answer questions that are apparently not related to science. The first step of the scientific method is an observation, which usually leads to a question. Imagine you have some beautiful puakenikeni plants in your garden and you notice their leaves start to turn yellow (Figure \(\PageIndex{1}\)). This is an observation that can lead you to the question: “why are the leaves of my plants turning yellow?” Since you are not a plant expert, you turn to the internet or a member of the family that has a green thumb to try to answer the question and ultimately solve the problem. Scientists follow a similar process; they research information relevant to the question to try to find the answer to it, see if other scientists already tried to answer the question or came across a similar problem and how they solved it.

    Figure \(\PageIndex{1}\): Puakenikeni plant (Fagraea berteroana) with yellowing leaves.

    Going back to our example, after you search the internet for “plant leaves turning yellow” you find several potential reasons for the leaves of your plants turning yellow. Which one is the correct one? After reading more details about some of the causes you decide it must be lack of water, the soil around your plants seems dry so your plants are probably not getting enough water. Now you have a likely answer for your question, or a hypothesis. A hypothesis is a potential explanation for the question that can be tested. Hypotheses usually follow an “if … then” format, that represents the question and the proposed solution. In this case your hypothesis could be: “If I water my puakenikeni plant more often, then the leaves won’t turn yellow.” In our example, there are different reasons that can cause the leaves on your plants to turn yellow, so there are several hypotheses that could be tested, and this is true for most questions in science.

    Take a look at the scientific method flow chart presented in Figure \(\PageIndex{2}\). You can see that we have already followed several of the steps that compose the scientific method in our example: observation, question, and hypothesis/prediction. The following step is to run an experiment to test your hypothesis. Now, how would you test your hypothesis? Sometimes we imagine that scientific experiments are complex and advanced processes that need to be carried out in a super fancy and high-tech facility, but that is not always the case. To a certain extent, we all can run experiments in an easy and accurate way. After determining that your plants have been underwatered, the most logical experiment would be to add more water than normal to your plants to see if this solves the yellowing of the leaves. An experiment can be as simple as that; however, scientists need to be sure of exactly what is affecting the results. In order to do this scientific experiments have one or several experimental variables, which is (are) the part(s) of the experiment that can be changed. In our case the amount of water provided to the plants would be the experimental variable.

    The scientific method consists of a series of well-defined steps._By OpenStax .jpg
    Figure \(\PageIndex{2}\): The scientific method consists of a series of well-defined steps. By OpenStax is licensed under CC-BY 4.0.

    Experiments also need a control group, which is a group that has all the same characteristics as the experimental group (the one in which you are changing the variable), but in which we do not change the variable. By having a control group, we are making sure that the lack of water is the variable (characteristic) that is causing the yellowing of the leaves in your plants and that there is not another reason. In your garden a simple way to test this hypothesis accurately would be to set up an experiment that includes an experimental group and a control group. In the experimental group you are going to have at least one puakenikeni plant that you are going to water more frequently, so the variable you are changing is the water frequency. On the other hand, the control group will be at least one puakenikeni plant to which you will continue to water with the same frequency as you have done until now. You will continue to do this for several weeks, and then you can record your results. If a scientist wanted to run a similar experiment, she/he would probably run it in a greenhouse or nursery, to be able to regulate all other environmental conditions and any other variables, so that nothing else affects the results of the experiment. A scientist would also have several replicas or repetitions of the experiment, to ensure that the results are unbiased. For example, instead of increasing the watering on just one plant, a scientist might have a group of 30 plants that are watered more frequently as the experimental group and a group of 30 plants that are kept in the same watering regime as the control group.

    The next step in the process is to analyze the results. For several weeks you have been watering at least one of your puakenikeni plants more frequently (experimental group) and kept watering at least one puakenikeni plant as before (control group), so it is time to analyze the results of your experiment. You take a good look at the leaves of both plants and to your dismay the leaves of both plants look similarly yellow. At this point you can conclude that it was not the water that was causing the yellowing of the leaves in your plants, therefore your initial hypothesis was incorrect. What do you do next to save your plants? If you look at the flowchart of the scientific method (Figure \(\PageIndex{2}\)), you see that if your hypothesis was not supported by your experiment then you need to try again.

    Do you remember that there were other causes you found on the internet that could be causing the yellowing of the leaves in your plants? Well, you can now test another hypothesis: maybe your plant is suffering from a lack of nutrients in the soil. You need to run a new experiment to test this new hypothesis in a similar way you tested for the water hypothesis. So let’s imagine you add fertilizer to at least one of your puakenikeni plants to increase the nutrients available in the soil (experimental group) and leave at least one puakenikeni plant without fertilizer (control group). After several weeks you analyze the results, and you see that the plant that had fertilizer added now has beautiful green leaves and looks healthy, while your control plant has yellow leaves. Congratulations, you have cracked the case and now you can help your plants live long and healthy lives by adding fertilizer to all of your puakenikeni plants! Normally, an experiment requires replication, so it would require that you had several plants in your control group and several in your experimental group. That’s not always possible if you are doing that in your backyard, but it is important to know that researchers do that to make sure that the results are not the influence of a random variable (for example, the influence of the location of the plant).

    The last step in the scientific method is to report or disseminate the results, which in the scientific community is usually done by publishing a scientific paper or report, doing a public presentation in a scientific meeting, or even publishing an article in a newspaper if the issue is of interest to the community. This last step is important, because it helps to build knowledge and advance science, so that we do not get stuck trying to solve the same issue over and over again. In our example, you could also share the results of your experiment with your family and friends to help somebody facing the same issue.

    Experiments are not the only way to answer a question in science. Sometimes we use descriptive methods when an experimental approach is not feasible. For example, if you wanted to determine how many individuals of an endangered Hawaiian plant are left in the wild in Mount Ka‘ala on O‘ahu, the best approach would be to do a survey or record all the plants of that species in that mountain, instead of running an experiment.

    Basic and applied science

    There are two main types of science: basic and applied. Basic science aims to broaden knowledge; not seeking to find a practical utilization or creating a product, just the spread of knowledge in the subject. An example of basic science would be to record all the different species of plants that are present in Hawai‘i. This does not seem to have any practical application, but we could actually use the knowledge gathered in basic science for applied science. Applied science aims to use science to create a product or solve a real-life problem. For example, if we recorded all the individuals of an endangered Hawaiian plant that are left in the wild in Mount Ka‘ala on O‘ahu, we could use this information to create a conservation plan to save this species from extinction by growing it in the lab and then planting it in the wild to restore native ecosystems. A great example of applied plant science is agriculture, because it uses the plant knowledge to create and improve plant varieties that are adapted to local environments, produce more fruit or yield, or increase resistance to drought. An example is tomato varieties that were developed by University of Hawai‘i plant breeders that were resistant to several tropical diseases. This effort not only helped local food production from 1950-1980s, but helped breeding programs in many countries. The tomato varieties developed here were then used by other research programs to breed other varieties (Teves, 2017).

    Figure \(\PageIndex{3}\): Kalo planting in Waihe‘e, O‘ahu. By DutraElliott is licensed under CC BY-NC-SA 4.0 via Flickr.

    Why is Botany important?

    Botany is a broad science with many different sub-disciplines that encompass different aspects of plant sciences. Some botanists work on biotechnology, like people extracting compounds from plants to create medicines or studying the chemicals produced by different plants to find new uses for them. For example, we use some plant chemicals to treat certain types of cancer. One of these compounds is taxol, which is extracted from the Pacific yew (Taxus brevifolia) and is used to treat ovarian cancer. Botanists in the field of conservation, seek to preserve plant species and restore damaged ecosystems. They can also use biotechnology and grow a whole plant out of a single cell (tissue culture). Other botanists are interested in understanding how plants function (plant physiology), so they focus on studying things like photosynthesis, transportation of nutrients, and the movement of water in plants. Other botanists are more interested in exploring how plants have traditionally been used by people in cultural practices, medicine, or cooking (ethnobotany). Other botanists are interested in studying fossil plants and understanding how plants have evolved over time (paleobotany and plant evolution). These are just a few examples to illustrate the diversity of the botanical field.

    Learning about plants is not only useful for botanists, but to all people. For example, learning about plants can help you grow and maintain healthy plants in your house and garden. In some booming businesses, like natural products and hemp/marijuana products, there is always the need for people with plant knowledge and, in some cases, lab experience, as the extraction of plant compounds can require the use of specific lab techniques. Learning about plants that have traditionally been used in your culture can also help you to connect with your family and community (Figure \(\PageIndex{4}\)).

    Figure \(\PageIndex{4}\): Kalo growing in Waipi‘o Valley on Hawai‘i Island. By DutraElliott is licensed under CC BY-NC-SA 4.0 via Flickr.

    And of course, you cannot pass up the opportunity to answer some of the burning questions that you always had: Why are plants green? What is that smell when I cut grass? How do some plants move? What are those sticky things that attach to my socks? Do carnivorous plants eat human flesh?

    This page titled 1.2: The science of Botany is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Daniela Dutra Elliott & Paula Mejia Velasquez.

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