Pre-Lab Questions
1. Why would we want to rate the amount of biodiversity in a location?
We would want to rate the amount of biodiversity in a location in order to determine the health and condition of the location. It would also provide information regarding what types of microorganisms are more prominent in the area and if their numbers are growing or shrinking. Knowing this will help make predictions about future changes in the ecosystem.
2. Examine the charts below and calculate the diversity indices for the three samples.
Sample 1: [10(9)+10(9)+10(9)+10(9)+10(9)] / [50(49)]
90(5) / 50(49) = Simpson's Index: 0.18
Simpson's Index of Diversity: 1 - 0.18 = 0.82
Simpson's Reciprocal Index: 1 / 0.18 = 5.56
Sample 2: [20(19)+20(19)+10(9)+10(9)+2(1)] / [62(61)]
942 / 3782 = Simpson's Index: 0.25
Simpson's Index of Diversity: 1 - 0.75 = 0.25
Simpson's Reciprocal Index: 1 / 0.25 = 4
Sample 3: [100(99)+1(0)+1(0)+1(0)+1(0)] / [104(103)]
9900 / 10712 = Simpson's Index: 0.19
Simpson's Index of Diversity: 1 - 0.92 = 0.08
Simpson's Reciprocal Index: 1 / 0.92 = 1.09
We would want to rate the amount of biodiversity in a location in order to determine the health and condition of the location. It would also provide information regarding what types of microorganisms are more prominent in the area and if their numbers are growing or shrinking. Knowing this will help make predictions about future changes in the ecosystem.
2. Examine the charts below and calculate the diversity indices for the three samples.
Sample 1: [10(9)+10(9)+10(9)+10(9)+10(9)] / [50(49)]
90(5) / 50(49) = Simpson's Index: 0.18
Simpson's Index of Diversity: 1 - 0.18 = 0.82
Simpson's Reciprocal Index: 1 / 0.18 = 5.56
Sample 2: [20(19)+20(19)+10(9)+10(9)+2(1)] / [62(61)]
942 / 3782 = Simpson's Index: 0.25
Simpson's Index of Diversity: 1 - 0.75 = 0.25
Simpson's Reciprocal Index: 1 / 0.25 = 4
Sample 3: [100(99)+1(0)+1(0)+1(0)+1(0)] / [104(103)]
9900 / 10712 = Simpson's Index: 0.19
Simpson's Index of Diversity: 1 - 0.92 = 0.08
Simpson's Reciprocal Index: 1 / 0.92 = 1.09
3. Use the results from the previous question to describe the biodiversity of each sample.
Sample 1 has large species richness and evenness because the Simpson's Index is close to zero. Sample 2 also has large species richness but it is not as even as the species in Sample 1. Sample 3 has very low species richness. Unlike the first two samples, that exhibit both species richness and evenness, Sample 3 had four species that had only one organism each.
Sample 1 has large species richness and evenness because the Simpson's Index is close to zero. Sample 2 also has large species richness but it is not as even as the species in Sample 1. Sample 3 has very low species richness. Unlike the first two samples, that exhibit both species richness and evenness, Sample 3 had four species that had only one organism each.
Problem
What is the biodiversity of leaf litter collected along the bank of Smith Creek?
Hypothesis
Leaf litter collected in a wooded area with high vegetation and plenty of shade will yield a high amount of biodiversity.
Parts of the Experiment
Independent Variables: location of the leaf litter
Dependent Variables: biodiversity of the area
Controlled Variables: light source, time, amount of water, amount of leaves
Control Group: none/organisms not found
Experimental Group: organisms on leaf litter
Dependent Variables: biodiversity of the area
Controlled Variables: light source, time, amount of water, amount of leaves
Control Group: none/organisms not found
Experimental Group: organisms on leaf litter
Materials
- Compound Microscope
- Berless Funnel
- Leaf Litter
- Alcohol
- Source of Light
Procedure
1. Collect a sample of leaf litter. Be sure to collect the entire layer down to the soil.
2. Examine the sample and classify what you see the layer is composed of.
3. Place your sample into the Berlese Funnel under the light source. Place a small beaker of alcohol under the funnel. The hope is that small invertebrates will travel away from the light and fall into your alcohol.
4. The next day, collect your beaker and examine the organisms you have collected under the microscopes. You will need to calculate the number of each species you have, and identify them. Each person may work on a portion of the sample and put your numbers together. Use the Identification pages to name each species.
5. Use the information to calculate the diversity indices for your sample.
2. Examine the sample and classify what you see the layer is composed of.
3. Place your sample into the Berlese Funnel under the light source. Place a small beaker of alcohol under the funnel. The hope is that small invertebrates will travel away from the light and fall into your alcohol.
4. The next day, collect your beaker and examine the organisms you have collected under the microscopes. You will need to calculate the number of each species you have, and identify them. Each person may work on a portion of the sample and put your numbers together. Use the Identification pages to name each species.
5. Use the information to calculate the diversity indices for your sample.
Observations
Location: _Along the bank of Smith Creek_
Type of Community: _Climax, Deciduous forest_
Date: ___February 11, 2013____ Time: ______1:30 am_______
Weather description: ___Overcast____
Air temp: ____17° Celsius _____ Soil temp: ____8.2° Celsius_____
Relative Humidity: ____80%_____
Type of Community: _Climax, Deciduous forest_
Date: ___February 11, 2013____ Time: ______1:30 am_______
Weather description: ___Overcast____
Air temp: ____17° Celsius _____ Soil temp: ____8.2° Celsius_____
Relative Humidity: ____80%_____
Calculations
Simpson’s Index = _[1(0)+2(1)+2(1)+3(2)+1(0)+1(0)] / (10*9) = 0.11__
Simpson’s Index of Diversity = __1 - 0.11 = 0.89__
Simpson’s Reciprocal Index = __1 / 0.11 = 9.09__
Simpson’s Index of Diversity = __1 - 0.11 = 0.89__
Simpson’s Reciprocal Index = __1 / 0.11 = 9.09__
Lab Questions
1. What are two reasons the organisms move away from the light down the funnel? What does this indicate about the organisms?
The organisms move away from the light and down the funnel because they are used to a more dark and shaded environment. The organisms will replicate their known behaviors by evading the light, much like they would dive into soil to escape sunlight. The organisms are conditioned to survive and they move down the funnel to adapt to the changes in their environment. Soil is cool and full of nutrients so when the organisms move down the funnel, they are expecting to find soil to retreat to. This information indicates that organisms will try to survive if moved because of the way they were conditioned to avoid light in their natural environment.
2. Summarize whether you think the biodiversity of this litter is high or low density. If low, try to give some reasons why this might be.
I believe the biodiversity of this leaf litter is moderately high in density. The Simpson's Index os 0.11 which is closer to zero than it is to one, indicating a significant amount of diversity. The leaf litter also exemplifies species evenness because most of the species had similar numbers of organisms.
3. Why would an environmental scientist need to make more than one measurement if he was calculating the biodiversity? How would you take samples of a large forest?
An environmental scientist would need to make more than one measurement in order to calculate biodiversity because there are factors that affect the results found. They would need to account for the different times of the year and the day, as well as the weather on that particular day. It is also important to note the size of the area that the leaf litter is taken from. If I were to take samples of a large forest then I would mark off areas that have been measured in square meters and monitor which marked area the litter came from. I would also collect the litter from the forest on a very sunny day and then on a cloudy or overcast day to account for the impact that the weather has on what organisms would be present.
The organisms move away from the light and down the funnel because they are used to a more dark and shaded environment. The organisms will replicate their known behaviors by evading the light, much like they would dive into soil to escape sunlight. The organisms are conditioned to survive and they move down the funnel to adapt to the changes in their environment. Soil is cool and full of nutrients so when the organisms move down the funnel, they are expecting to find soil to retreat to. This information indicates that organisms will try to survive if moved because of the way they were conditioned to avoid light in their natural environment.
2. Summarize whether you think the biodiversity of this litter is high or low density. If low, try to give some reasons why this might be.
I believe the biodiversity of this leaf litter is moderately high in density. The Simpson's Index os 0.11 which is closer to zero than it is to one, indicating a significant amount of diversity. The leaf litter also exemplifies species evenness because most of the species had similar numbers of organisms.
3. Why would an environmental scientist need to make more than one measurement if he was calculating the biodiversity? How would you take samples of a large forest?
An environmental scientist would need to make more than one measurement in order to calculate biodiversity because there are factors that affect the results found. They would need to account for the different times of the year and the day, as well as the weather on that particular day. It is also important to note the size of the area that the leaf litter is taken from. If I were to take samples of a large forest then I would mark off areas that have been measured in square meters and monitor which marked area the litter came from. I would also collect the litter from the forest on a very sunny day and then on a cloudy or overcast day to account for the impact that the weather has on what organisms would be present.
General Analysis & Conclusions
Evaluation of Hypothesis: According to the results of the leaf litter I collected, my hypothesis is correct. There was a high level of biodiversity in the leaf litter that was retrieved from the floor of the deciduous forest that ran along the bank of Smith Creek. However, it is not determined by the experiment whether the proximity of the litter to a creek or the amount of shade in the area played a role in the amount of species diversity.
Accuracy of Results: The results of the leaf litter diversity may have been more accurate if compared to other samples from the deciduous forest. Even after comparing data, the results may still be inconclusive because some groups collected litter from different areas within the forest. Parts of the forest with different soil or surrounding vegetation may differ in the type of organisms or the biodiversity of all the organsims found. Another possible source of error in the experiment would be the amount of leaf litter collected per group which could be adjusted to achieve more accurate results.
Application: Being able to calculate biodiversity can help expand scientific exploration and understanding as well as lead to economic success. Biodiversity is studied by biologists and other scientists to seek ways that they can reproduce the capabilities of organisms in an environment. Biodiversity calculation can assist in economic growth due to its' role in agriculture and even tourism. Biodiversity is also the key to many medical advances. Biodiversity is important to a lot of background processes and can be essential in predicting changes in the Nitrogen cycle.
Accuracy of Results: The results of the leaf litter diversity may have been more accurate if compared to other samples from the deciduous forest. Even after comparing data, the results may still be inconclusive because some groups collected litter from different areas within the forest. Parts of the forest with different soil or surrounding vegetation may differ in the type of organisms or the biodiversity of all the organsims found. Another possible source of error in the experiment would be the amount of leaf litter collected per group which could be adjusted to achieve more accurate results.
Application: Being able to calculate biodiversity can help expand scientific exploration and understanding as well as lead to economic success. Biodiversity is studied by biologists and other scientists to seek ways that they can reproduce the capabilities of organisms in an environment. Biodiversity calculation can assist in economic growth due to its' role in agriculture and even tourism. Biodiversity is also the key to many medical advances. Biodiversity is important to a lot of background processes and can be essential in predicting changes in the Nitrogen cycle.
Citation: Shah, Anup. "Why Is Biodiversity Important? Who Cares?" - Global Issues. N.p., n.d. Web. 27 Feb. 2013