Discussion: Number of Isopods in Various Environments
Discussion: Number of Isopods in Various Environments
Discussion: Number of Isopods in Various Environments
answer the following questions on the word documentation feel free to ask when it is not clear.
thank you
Data Analysis & Graphing Online Lab Activity
Objectives
You will:
- use inquiry process skills used by scientists to conduct scientific investigations
- conduct qualitative and quantitative investigations to determine the relationships among variables
- gather and organize empirical data
- draw inferences about your data and explain the limitations of your investigations
Directions
Individually complete the following activity. Be sure to complete all parts of the activity and answer all questions. You may type your answers directly on this document. You must submit your completed document to the turn in link on Blackboard.
This lab activity will require you to analyze and graph data in Excel. You must use the full version of Excel to complete this lab activity. The online version of Excel does not have all of the functions that you will need to use in our course. Towson University provides you with a free version of Excel. Follow the directions in this Lab Activity’s folder on Blackboard to download the full version of Excel if you do not already have it on your computer.
Part I: Background Information – Read the following information.
There are many types of scientific research, but they can be generally grouped into three broad categories, where x and y represent variables:
Descriptive – What is happening with x and y? How can we describe/explain the nature of x and y as we observe it in nature?
Correlational – What is the relationship between x and y? Are changes observed in y somehow related with changes to x?
Experimental – What is the causal relationship between x and y? How does manipulating x affect y?
Descriptive Research
The purpose of descriptive research is to record, analyze, describe,and explain phenomena, usually in its natural setting. Data are gathered primarily throughnaturalistic observation, meaning phenomena/organisms under study are observed in their natural state or habitat. When human or animal subjects are involved, data can also be gathered through surveys, interviews, rating scales, and artifacts that capture a typical or diagnostic aspects of a phenomenon. Scientists conducting descriptive research attempt to describe phenomena rather than assess relationships between/among variables.
This type of research is done when the subjects or phenomenon under study is too complex to be answered with alternative hypotheses or when the phenomenon occurs so rarely that it would make large sample sizes unfeasible. Descriptive research is also useful type when scientists are unable to isolate all variables for experimental tests or when it would be considered unethical to conduct experimental tests, such as withholding necessary resources from animals to sustain life. Some examples of descriptive research include animal and plant inventories, classification of organisms, and studies of animal behavior.
Correlational Research
The purpose of correlational research is to assess the relationships among two or more variables or to correlate relationships among variables. It is important to note that correlation is NOT the same as causation. Like tightly controlled experimental research, correlational research often relies on large sample sizes and systematic data logging. In some cases, experimental variables can be manipulated during the study, while in other cases experimental variables must be examined in situ – in their natural setting. In addition, while correlational research allows for testing of expected relationships among variables, experimental variables are manipulated in the presence of external variables that are not or cannot be completely controlled. As a result, correlational research allows us to make, with some certainty, generalizations, predictions or forecasts about cases with similar variables now or in the future.
Take for instance the relationship between pregnant women’s exposure to the rubella virus and the risk of their babies developing birth defects. It’s impossible and unethical to keep pregnant women in tightly controlled lab conditions during their pregnancies, exposing some women to rubella, while protecting others from it. In reality, women are typically exposed to many pathogens and other harmful substances during their pregnancies. Yet, multiple studies have shown that when women are infected with rubella during early stages of pregnancy, there is a significantly higher chance their babies will be born with physical or intellectual disabilities. Thus, there is a positive correlation between maternal infection with rubella and infant birth defects.
Experimental Research
The purpose of experimental research is to assess the causal impact of one or more manipulations of the experimental (independent) variable on the dependent variable. When humans are not involved, experimental research is often conducted in laboratory settings, where scientists can control as many variables as possible. By holding external variables constant, scientists can conclude with some certainty that changes in y were the direct result of manipulations to x.
Experimental research often relies on large sample sizes and/or long term monitoring to enhance the generalizability (ability to make inferences) across populations, cases, and settings. Data are gathered through comprehensive data logging, meaning all dependent variables are monitored and tracked over time, independent and controlled variables are continually checked. Quantitative data, and subsequently, statistical analysis are emphasized. This does not mean qualitative data are not used. When qualitative data are gathered, they are often transformed into a numerical data set (e.g., white fur = 0; black fur = 1).
There are two types of experimental research that are often cited in the popular media:
- Single-blind study – the subjects or participants in the study do not know to which experimental (or control) group to which they are assigned
- Double-blind study –neither the subjects nor the researchers know to which group, experimental or control, individual participants are assigned. Often a computer algorithm with a randomized number generator is used to assign subjects to experimental groups.
Double-blind studies are considered to be the most reliable because they reduce both subject bias and researcher bias. If a subject had cancer, and voluntarily took part in a study that was testing a new drug that potentially cures cancer, then they would really want that drug to work, even if it didn’t (placebo effect). Likewise, if researchers have been hired by a pharmaceutical company to test a new drug, researchers will be naturally bias towards positive outcomes because it ensures continued funding. Randomized controlled trial is another term that refers to blinding in a study.
Part II:Correlational Study of Human Traits – Follow the directions below to complete this study.
Have you ever noticed that tall people usually have big hands? Do you think that this is true for all humans?
Procedure
Step 1 – Predict
Write a prediction about the relationship between height and hand size:
Step 2 – Plan
Determine how you will systematically measure the hand size and record the height of your participants. Fill in the details belowfor your investigation.
Participants: 6 people total. You must find five additional people to participate in your study.[You do not need to directly interact with the people you choose. You may interact virtually with them.]
Hand size: How will you measure hand size? In the space below, provide a detailed description of how you will measure hand size. Remember to use metric units (cm), and to follow the exactsame steps for each participant.
| Which hand?
highlight one |
Right orLeft |
| Will you measure…
highlight one |
Length or Width |
| How?
Describewhere you will start and stop measuring |
|
Height: Ask each participant for their approximate height.
Remember you must use metric units!
Convert their height to centimeters using the table below.
Follow the same steps for each participant.
|
| Feet Inches | Centimeters |
| 4 feet 0 inches | 121.92 |
| 4 feet 1 inches | 124.46 |
| 4 feet 2 inches | 127.00 |
| 4 feet 3 inches | 129.54 |
| 4 feet 4 inches | 132.08 |
| 4 feet 5 inches | 134.62 |
| 4 feet 6 inches | 137.16 |
| 4 feet 7 inches | 139.70 |
| 4 feet 8 inches | 142.24 |
| 4 feet 9 inches | 144.78 |
| 4 feet 10 inches | 147.32 |
| 4 feet 11 inches | 149.86 |
| 5 feet 0 inches | 152.40 |
| 5 feet 1 inches | 154.94 |
| 5 feet 2 inches | 157.48 |
| 5 feet 3 inches | 160.02 |
Step 3 – Record the Data
Use the table below to record the height and hand size of each participant.
| Participant | Height (cm) | Hand Size (cm) |
| 1 | ||
| 2 | ||
| 3 | ||
| 4 | ||
| 5 | ||
| 6 |
Step 4 – Graph the Data
Use the Excel spreadsheet provided in this Lab Activity’s folder on Blackboardto produce a scatterplotgraphthat displays the correlation between height and hand size. Look near the bottom of the spreadsheet to find the “Height vs Hand Size” sheet, and follow the instructions carefully.
Step 5 – Answer the Analysis Questions
- Compare your graph to the figure below. What does the trend in the graph indicate about the relationship between height and hand size: (strong, weak) positive correlation, (strong, weak) negative correlation, or no relationship?Explain your choice.
- Identify at least 2sources of error in your investigation.Explain how these sources of error could have affected your results.
Part III:Descriptive Study of Niche Utilization of Terrestrial Isopods – Use the information provided below to complete this study.
Terrestrial isopods – sometimes called pillbugs, sowbugs or woodlice – are crustaceans, a class of animals that includes crabs, shrimp, crayfish and amphipods. Unlike most crustaceans, which rely on fresh or salt water in order to breed, terrestrial isopods complete their entire life cycle on land. Terrestrial isopods do not need water in which to lay their eggs because they hold their fertilized eggs in a temporary “pouch” until the eggs hatch as juveniles.
In spite of their ability to tolerate conditions on land, terrestrial isopods still have physiological and anatomical features that reflect their evolution from an aquatic ancestor. These features limitisopods’ utilization of the environment to humid places where desiccation (water loss) is minimal.
It is not surprising to find animals in environments for which they are adapted because they can successfully reproduce and complete their life cycle. After all, we would expect individuals to begin life in areas that are optimal for them. Most animals are mobile and may move through a variety of environmental conditions. You may assume that animals have the instinctive ability to select the best places in the environment. In science, making assumptions, no matter how obvious, are not useful unless objectively investigated. In this exercise, you will observe the ability of terrestrial isopods to utilize appropriate portions of the environment.
Step 1 – Predict
If isopods are exposed to four different “habitats”: (1) sand, (2) soil, (3) sand with a piece of bark, and (4) soil with a piece of bark, write a prediction about which section will have the most isopods. Explain your reasoning for this prediction. Discussion: Number of Isopods in Various Environments
Step 2 – Observe the Isopods
Below is a picture of a group of isopods that were placed in a box containing 4 different habitats: (1) sand, (2) soil, (3) sand with a piece of bark, and (4) soil with a piece of bark. The pieces of bark were turned over just before the picture was taken.
Step 3 – Record your Data
Five other students observed boxes set up in the exact same way; their data is in the table below. Add your data to the table – write the number of isopods found in each of the four sections of the box. Discussion: Number of Isopods in Various Environments
| Student | Sand | Sand + Bark | Soil | Soil + Bark |
| 1 | 1 | 3 | 0 | 6 |
| 2 | 0 | 6 | 1 | 5 |
| 3 | 1 | 1 | 0 | 6 |
| 4 | 0 | 5 | 2 | 4 |
| 5 | 0 | 2 | 0 | 7 |
| YOU |
Step 4 – Analyze and Graph the Data in Excel
Use the Excel spreadsheet provided in this Lab Activity’s folder to produce a bar graph thatdisplays the average number of isopods in each habitat. Look near the bottom of the spreadsheet to find the “Isopod Habitat” sheet and follow the instructions carefully. Discussion: Number of Isopods in Various Environments
Step 5 – Answer the Analysis Questions
- What does the trend in the graph indicate about terrestrial isopods’ habitat preferences?
- Do the results of your investigation support or refute your prediction? Explain your choice. Usedata (numbers) from your graphto support your answer in your explanation .
- Why was it important to include data from 6 students (6 boxes of isopods)? (Why not just use one?)
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