Log in
Biology
2
answers
1
watching
297
views

Design anexperiment to determine the effects of amount of light on thegrowth of tomato plants.
Hypothesis: (Use if...then...statement)
Identify:
- Independent variable ?
- Dependent variable ?
Any pertinent information about the population.
Procedure: Describe set up. List steps.
What is the control? Why is a control needed?
List 3 controlled variables.
Expected Results:
Is your experiment qualitative or quantitative? Explain

Watch
2
answers
1
watching
297
views

For unlimited access to Homework Help, a Homework+ subscription is required.

Unlock all answers

Get 1 free homework help answer.
Already have an account? Log in
Share
Patrina Schowalter
Patrina SchowalterLv2
28 Sep 2019
Already have an account? Log in
Share

Related textbook solutions

Molecular Cell Biology
8 Edition,
Lodish
ISBN: 9781464183393
Biology: Science for Life with Physiology
6 Edition,
Belk
ISBN: 9780134555430
Concepts of Biology
OER Edition,
Openstax
ISBN: 9781938168116
Biology
2nd Edition, 2013
Openstax
ISBN: 9781947172517
Essentials of Biology
5 Edition,
Mader
ISBN: 9781259660269

Related questions

SECTION II. SHORT PARAGRAPH QUESTIONS (25m) Answer each of the following four questions in full sentences. Do not use point form. (9m) The great majority of land plants establish mycorrhizal associations with fungi, in which there is a two-way exchange of nutrients between the plant and the mycorrhizal fungus. Host plants provide mycorrhizal fungi with sugars, while mycorrhizal fungi provide host plants with soil phosphorus. a. Design an experiment to test whether Douglas-fir seedlings grow more quickly in soil containing mycorrhizal fungal spores. Make sure that you state your null and alternate hypotheses, list your dependent and independent variables, describe your experimental setup (including control and experimental treatments), list your controlled variables (explaining how each will be controlled and why), and provide replication. b. Assuming that the results of the experiment support your alternate hypothesis, draw a graph to predict what the resulting data would look like. Don’t forget to label your axes!

dentifying Dependent and Independent Variables

In order to test a hypothesis and prediction, controlled experiments are used. Controlled experiments involve several necessary components. An independent variable is usually manipulated by a researcher but does not change as a result of the experiment. The changes in the dependent variable may be caused by the experiment (and depend upon the independent variable). Graphs that depict the experimental data list the independent variable on the x-axis while the y-axis shows the dependent variable.

A commonly used mnemonic (memory device) to aid in distinguishing the characteristics of the types of variables is DRY MIX.

D = dependent variable (depends on the other)

R = responding variable (one that changes)

Y = y-axis on a graph

M = manipulated variable (one that is changed by the researcher)

I = independent variable

X = x-axis on a graph

The following sentence is a template to write an if/then statement to be used as a prediction:

If the independent variable is changed [increased, decreased, etc.], then the dependent variable will change in this way [increase, decrease, etc.].

Example: If the amount of available light increases, then plant growth will increase.

Discussion Questions:

Use the tools and examples just discussed to answer the questions about the experiment scenario described next.

Jonah and Tessa noticed that some Leopard frogs by a local river had extra limbs. They decided to check various areas along the river to make more observations. They recorded their observations in their field notebooks. Jonah and Tessa performed a simple laboratory experiment with Leopard frog eggs and river water taken at various spots along the river. They noticed that adult frogs developing from eggs in water collected near an industrial park showed more deformities, but the deformities seemed to be different than those seen on frogs in the natural setting by the river.

Write a prediction that would be appropriate for the experiment scenario.

What would be the independent variable in the experiment?

What would be the dependent variable in the experiment?

What steps should Jonah and Tessa take to ensure that the experiment would be controlled?

Why would they perform these experiments in the laboratory and not in the river?

What conclusion should the researchers derive from their data?

What might be some alternative hypotheses for this situation?

What could be a next step for their investigation?

What other information may help them design future experiments?

Experimental Review

Below are five hypothetical experimental designs. Your job as a reviewer is to pick one of the experiments and write a detailed summary of what is wrong with the proposed study.

Your review should use vocabulary words that have been discussed in class and address the following questions.

Is the study feasible? Will it actually be possible to conduct the proposed study in a controlled manner that produces meaningful data? If there is more than one variable changing simultaneously, no controls, or no replication, then the study is unlikely to produce meaningful data. If there is no way to monitor an experiment in the environment, or no way to conduct the experiment in a controlled environment, like a laboratory, then the experiment is unlikely feasible.

Can you tell from the text if the experiment is designed to be conducted by performing treatments, or by analyzing observational data about a species and its habitat?

Is there a testable hypothesis? Is the study set up so that it will be possible to measure the effects in a quantifiable way? What will be measured? Is there a control group and a treatment group? Or, an independent variable like temperature, and a dependent variable like germination time?

Could you graph the results of this experiment? If so, how would you do it? A column chart to show treatments and controls? A scatter plot or a line graph to look at how changes in the independent variable affect the dependent variable?

Create a post on the discussion board by clicking on "Click to Launch" above.

1. Experiments to Review

1. Climate Change Effects on Marine Iguana Mortality

Hypothesis: If the water temperature in the Galapagos Islands changed from being hot (around 77 degrees) to cold (under 70 degrees), then the mortality rate of Marine Iguanas will increase.

Variables: The independent variable is the temperature of the water that the Marine Iguanas live in. The dependent variable is the mortality rate of the Marine Iguanas. The mortality rate of the Marine Iguanas at the average water temperatures of their habitat.

Experimental Treatments: Iguana Group 1 will be water temperatures and marine iguana mortality rates before 1998. Iguana Group 2 will be water temperatures marine iguana mortality rates after 1998

Prediction:By comparting the average water temperatures with the mortality rates every year before the sudden drop in the iguana population and after a trend will be able to be seen. If the water temperature is truly to blame for the mortality rate increase the water temperature will decrease as the population of Iguanas decreases. The control group is intended to show the average number of Iguanas that die due to other causes.

2. Volcanic Ash Impacts Marine Iguana Longevity

Hypothesis: There are several volcanoes between both the Isabela, and Femandina islands which make this the obvious culprit for the extreme rise in mortality in Marine Iguanas.

Variables: The independent variable is the number of volcanic eruptions per year. The dependent variables are the change in pH of the water in the marine iguanas’ habitat, and the mortality rate of the iguanas.

Experimental Treatments: Iguana Group 1 will live on an island with multiple volcanic eruptions each year. Iguana Group 2 will live on an island with no volcanic eruptions.

Prediction: The group of iguanas living on the island with no eruptions will have longer life spans because the pH of the water will not be altered by the large number of volcanic eruptions.

Weekly leaderboard

Home
Homework Help 3,900,000
Biology 460,000
Start filling in the gaps now
Log in