BIOL1060 Lab 1: The Scientific Method

Please copy this page into your word processing software to make a template. Submit this with your responses and images in the template to the appropriate dropbox in the Canvas.

No materials are needed for this lab. 

Part 1: Experimental Design

We begin our exploration of environmental science with a general investigation regarding the nature of science. The scientific method is a practical and theoretical concept that both guides the process of science and ensures integrity in the process and reporting of scientific findings. You have read about the scientific method and now it is time to put that learning into practice. In this first exercise, you will design a botany experiment. You do not have to do this experiment that you design so be creative and thorough in your explanation. Repeat- this is not about doing an experiment. This is about designing an experiment to identify all the components of a research study and the process of science. 

Read through this entire activity before you begin. You need to add your own responses where you see an .

The process of science begins with observations about the natural world.

→ Make and record an observation about plants:

These observations generate questions about how the natural phenomenon works.

→ Write at least three questions you have about your observations:

A hypothesis is a statement of inquiry. Turn one question into a hypothesis. Usually a scientific hypothesis relates to variables to each other. Therefore, the first step is to identify to two variables relevant to your inquiry. The independent variable is usually an abiotic (non-living) condition like water availability, temperature, light, oxygen availability, etc. The dependent variable is usually the biotic factor. In this case, it is a plant or a community of plants you want to investigate. The dependent variable is called dependent because it varies depending on the independent variable.

→ Identify two variables:

→ Independent variable:

→ Dependent variable:

Now write a hypothesis that relates these two variables. Your hypothesis could express a directional relationship. For example: The pea plants will grow taller with more light. The hypothesis could simply state that there is a potential relationship. For example: Light affects plant growth.

→ Your hypothesis:

Part of the scientific process is neutrality and the elimination of bias. Scientists should never set out to prove a hypothesis correct. Instead, scientists write null hypotheses that seek to investigate the opposite of what is expected. For the example above: There is no relationship between light and plant growth. This would be the null hypothesis for both hypothesis examples above.

→ Your null hypothesis:

After the hypotheses are developed, the scientist must design a study in order to measure the phenomenon in question. The key to designing an experiment is to try to control all the variables that are not the two variables under investigation. So, for example, if you wanted to explore a relationship between plant growth and light, you would design an experiment in which the plants received exactly the same amount of water and nutrients in the same experimental setting. You would use the same seeds, soil, and containers in which to grow the plants. These are the basic parameters of an “experiment.”

It is also very common in botanical research to study a plant or plant community in its natural environment. These are called observational studies. In an observational study, you still compare variables, but you might look at two plant communities of the same species, one growing next to a river and the other growing in an upland setting. Or maybe you would compare plants growing in the botanic garden to plants growing in a natural setting. Maybe you would compare plants growing in Colorado and plants growing in Montana (different latitudes). Even still, maybe you would compare plants growing in the same state, but at different elevations.

Before you start to design your experiment, do a literature search for the species you would like to investigate and read the methods sections of a few papers.

→ Write the citations for at least two journal articles here and summarize the methodology used.

→ Citation 1:

→ Methods summary:

→ Citation 2:

→ Methods summary:

Now that you have some background information about the plant or plant community you would like to about every variable you can think of that might influence the outcome of the experiment. Write at least 200 words.

→ Experimental design:

Part 2: Botanical Clues

Morphology is the study of how organisms look. Morph- means “form” and -ology means “the study of.” Before technology informed our understanding of genetics, all we had for evidence was what we could see. 

Example: Plants

The morphology of plants gives you clues about where the plants grow, how much water they need, and what pollinators visit them. In this investigation, we will consider some common plant designs and consider the purpose of this form. A common phrase in biology is form and function. In this activity, we are using the form to learn about function.

Plant Roots

There are two primary plant root structures- Fibrous roots and tap roots. Fibrous roots are shallow and have vast surface area. Tap roots are thick and penetrate the soil to great depths.

line drawing of fibrous and tap roots

Photo credit: http://garden.org/courseweb/course1/week1/images/c1w1-f.gif

Consider how roots facilitate water uptake. Make an argument for how each root structure works to gather water for the plant.

Postulate in what environment plants with each type of root might live. Write at least 100 words to describe each.

→ Fibrous roots:

→ Tap roots:

Plant stems

There are two groups of flowering plants (angiosperms)-  monocots and dicots. These plant groups have several differing characteristics.

Monocots Dicots
Embryo with single cotyledon Embryo with two cotyledons
Pollen with single furrow or pore Pollen with three furrows or pores
Flower parts in multiples of three Flower parts in multiples of four or five
Major leaf veins are parallel Major leaf veins reticulated
Stem vascular bundles scattered Stem vascular bundles in a ring
Roots are adventitious Roots develop from a radicle
Secondary growth absent Secondary growth often present

Table taken from: Regents of the University of California. 2006. Monocots versus Dicots: The Two Classes of Flowering Plants. http://www.ucmp.berkeley.edu/glossary/gloss8/monocotdicot.html

diagram of plant parts

Photo credit: https:/ /www2.estrellamountain.edu/faculty/farabee/biobk/planthabit.gif

Generally speaking, monocots are grasses and dicots are flowers. Think about the orientation of a grass blade as compared to the orientation of a flower leaf, referred to as broadleaves.

→ Is a grass blade parallel to the vertical plane or the horizontal plane?

→ Is a broadleaf parallel to the vertical plane or the horizontal plane?

→ What does this orientation imply with regard to sunlight capture?

→ Now think about the overall surface area of a grass blade versus a broadleaf? Which has more surface area?

→ Now thinking about broad leaves exclusively, in shadier conditions, are the leaves bigger or smaller?

→ Finally thinking about all these characteristics together, make some inferences about how and when monocots and dicots capture sunlight. Write at least 100 words.

Plant longevity

Among all plants, there are three strategies for survival based on longevity. Annual plants live for just one year. Biennial plants live for two years. Perennial plants live for several years, and in the case of woody plants like trees and shrubs, they may live for many decades or longer. Plants have two major reproductive pathways. Plants produces seeds through sexual reproduction and self-pollination. These seeds produce offspring that are independent from the parent plant. They may be genetically unique (sexual reproduction) or genetically identical (self-pollination). Plants also reproduce through vegetative means. They can increase in basal area over time, ie just get bigger. Any part of the vegetative spread can be separated via anthropogenic means (eg. dividing) and survive independently. Plants can spread vegetatively by sending aboveground stems (stolons) with new offspring that take root when they come in contact with soil. A common example of a stoloniferous plant is a strawberry, or an indoor spider plant, or any variety of mat-forming grasses including Kentucky bluegrass, the predominant species in a turf lawn.  They can also send underground stems (rhizomes) the expand laterally and send up new shoots. Both rhizotomous and stoloniferous plants appear to be separated from the parent plant, but they are still connected the mother plant. That being said, both can survive independent of the parent plant once established. An aspen tree is a classic example of a rhizomotous plant. Aspens connected by a common root system are thought to be the largest organism in the world.

spider plant showing stolon

Caption: spider plants have stolons.

Photo credit: https://upload.wikimedia.org/wikipedia/commons/9/96/Spider_plant_stolon2.jpg

rhizome line drawing

Photo credit: http://ipm.ucanr.edu/TOOLS/TURF/IMAGES/KEYIMAGES/rhizome_1.jpg

Caption: Aspen trees have rhizomes. You can tell which aspens constitute one organism because their leaves tend to change at the same time and to the same color in the fall.

aspens in fall

Photo credit: https://upload.wikimedia.org/wikipedia/commons/9/9e/FallPando02.jpg

Thinking about survival strategies and longevity limitations, answer the following questions.

→ Necessarily, what is the only reproductive pathway that an annual plant could employ? Why?

→ What reproductive pathways can be used by perennial plants? Which do you think is the most advantageous? What drawbacks exist for all the reproductive pathways?

Now thinking about environmental stresses, postulate why particular longevity and reproductive strategies might be more advantageous in specific ecosystems.

→ Describe at least two example ecosystems (at least, the moisture, light, temperature) and defend why particular strategies work or aer challenged (or both!) in those environments. Write at least 200 words.

Conclusion

In this lab we have put our thinking caps on in several ways. Although we do not engage in hands on experimentation, we consider the process of science to prepare for this hands on work. We also think about the form and function of plants. This will facilitate our ability to interpret the results of our future experimentation as well as begin to properly diagnose the ecological relationships plants have with each other and their environments.

→ Write 100+ words of reflection about your learning experience in this lab (free-write):

Do yourself a favor- Now read the next lab: Lab 2: Introduction to Microscopes, Cell Structure and Function and if you are really ambitious, you will go right ahead a read (and participate!) in the next discussion. Knowing what you have to do and how you will be assessed is your first step to success. 🙂