Leaf Litter Lab Report:
Collaborators: Julianne Rodgers, Logan Shytle, Christina Fillipini, and collaborated with the whole class to obtain the class data.
Introduction:
The purpose of the Leaf Litter Lab was to determine the biodiversity of the leaf litter in the woods behind Heritage High School. To determine the biodiversity, Simpson's Diversity Index is used. Simpson's Diversity Index is a measure of diversity in an area taking into account the richness and evenness. Richness is a measure of the number of different kinds of organisms present in a particular area, such as the number of different species present. The more species present in a sample, the 'richer' the sample. Evenness is a measure of the relative abundance of the different species making up the richness of an area. As species the evenness and richness increases, so does the diversity in the area. In order to separate the small organisms from the leaf litter a Berlese Funnel is used.
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This allows for the organisms to be looked at closely to determine what types are found in the leaf litter and to ultimately determine the biodiversity of the leaf litter. There are three different ways to look at biodiversity with Simpson's Diversity Index. The first is Simpson's Index, which is the number found when the equation (above right) is solved. "D" is equal to Simpson's Index, where n sub one is equal to the number of organisms of a particular species and "N" is equal to the total number of organisms in all the species. For this particular index, the closer "D" is to 0, the more diversity there is. The second is Simpson's Index of Diversity, which is equal to 1-D, however for this index, the greater the value the greater the diversity. The third is Simpson's Reciprocal Index, which is equal to 1/D. For this index, the values can range from 1 up to the number of species. The three different values obtained from the different indices of diversity all represent the same biodiversity.
Knowing the amount of biodiversity in a location is very important. According to greenfacts.org "biodiversity is the foundation of ecosystem services to which human well-being is intimately linked." Meaning that without biodiversity ecosystem services such as pure water, breathable air, fertile soil, etc. would not be possible. It is important to monitor the biodiversity in a location because if the biodiversity becomes to low or non-existent it could cause major problems for all life.
Knowing the amount of biodiversity in a location is very important. According to greenfacts.org "biodiversity is the foundation of ecosystem services to which human well-being is intimately linked." Meaning that without biodiversity ecosystem services such as pure water, breathable air, fertile soil, etc. would not be possible. It is important to monitor the biodiversity in a location because if the biodiversity becomes to low or non-existent it could cause major problems for all life.
Hypothesis:
If a leaf litter sample and a soil sample are collected from the woods behind Heritage High School then we will discover that the biodiversity is higher in the leaf litter because it contains more types of organisms than what would be found in the soil.
Parts of the Experiment:
- Independent Variable: The different kinds of samples (leaf litter v. soil)
- Dependent Variable: The Biodiversity of the different samples
- Control Variables: Temperature, Humidity, the amount of time under the lamp, the location of the lamp
- Experimental Group: Leaf Litter Sample
- Control Group: Soil Sample
Materials:
- Stereoscope/Dissecting Microscope
- Berlese Funnel
- Leaf Litter
- Alcohol
- Small Beaker
- Source of Light (Lamp)
- Pictures/Diagrams of the types of organisms that can be found
Methods:
1. Collect leaf litter from the woods
2. Examine the sample and classify what you see the layer is composed of
3.Place the samples into the Berlese Funnels (this experiment used nine samples and nine funnels) under the light source.
4. Place a small beaker of alcohol under the funnel.
5. After a few days, collect the beaker and examine the organisms in it under the microscope.
6. Calculate the number of each species that is found in the sample, identify them using the pictures and diagrams of the types of organisms.
7. Compile all the groups data and calculate the diversity indices for the total of all the samples.
2. Examine the sample and classify what you see the layer is composed of
3.Place the samples into the Berlese Funnels (this experiment used nine samples and nine funnels) under the light source.
4. Place a small beaker of alcohol under the funnel.
5. After a few days, collect the beaker and examine the organisms in it under the microscope.
6. Calculate the number of each species that is found in the sample, identify them using the pictures and diagrams of the types of organisms.
7. Compile all the groups data and calculate the diversity indices for the total of all the samples.
Data:
Temperature: 34 degrees Fahrenheit
Humidity: 70% |
Leaf Litter:
Simpson's Index (D): .0833 Simpson's Index of Diversity (1-D): .9167 Simpson's Reciprocal Index of Diversity (1/D): 12 Soil: none |
Pictures:
Data Analysis:
The data table above displays the type of species that is found in either the soil sample or the leaf litter sample. The data when analyzed using Simpson's Index, Simpson's Index of Diversity, and Simpson's Reciprocal Index shows that the leaf litter is home to a bio-diverse population. With Simpson's Index, the closer to 0 the value is, the more diverse the population is, as opposed to a value of 1 would mean there is no diversity. The Simpson's Index of the Leaf Litter Sample was .0833, which is close to zero, meaning that the leaf litter has a high level of biodiversity. The Simpson's Index of Diversity displayed the same results in terms of biodiversity. For Simpson's Index of Diversity the closer a value is to one, the higher the diversity and the closer the value is to zero, the lower the diversity. The Simpson's Index of Diversity was .9167 for the Leaf Litter. Simpson's Reciprocal Index is measured having one as the lowest figure and the number of species present, in this case 14, as the highest figure. The Simpson's Reciprocal Index for the Leaf Litter was 12. All of these values show the same thing, that the Leaf Litter contains a diverse amount of organisms as opposed to the soil, where zero organisms were found meaning it has no biodiversity.
The Leaf Litter has a high level of richness, which contributes to its high diversity. The richness of a community is determined by how many different species live in it, the Leaf Litter sample had 14 different species. However, the Leaf Litter sample has a low evenness. The evenness of a community is determined by how many individuals of each species live in it. For example, the Leaf Litter sample has a low level of evenness due to its range in individual organisms within a species. One species, the mite, has 14 individuals in the sample, while other species, the true bug and the ant, only have one individual each in the sample. The evenness is low because of the large range of organisms that live in the community. While both the richness and evenness of a community contribute to the biodiversity of an area, the low level of evenness did not seem to have a large effect on the biodiversity. However, if in fact the evenness level was higher, meaning there was an equal number of individuals per species, the biodiversity would increase.
Since there soil sample was not found to have any organisms in it, the soil does not have any biodiversity, any level of richness, or any level of evenness. The biodiversity of the Leaf Litter sample was greater than the biodiversity of the soil sample.
The Leaf Litter has a high level of richness, which contributes to its high diversity. The richness of a community is determined by how many different species live in it, the Leaf Litter sample had 14 different species. However, the Leaf Litter sample has a low evenness. The evenness of a community is determined by how many individuals of each species live in it. For example, the Leaf Litter sample has a low level of evenness due to its range in individual organisms within a species. One species, the mite, has 14 individuals in the sample, while other species, the true bug and the ant, only have one individual each in the sample. The evenness is low because of the large range of organisms that live in the community. While both the richness and evenness of a community contribute to the biodiversity of an area, the low level of evenness did not seem to have a large effect on the biodiversity. However, if in fact the evenness level was higher, meaning there was an equal number of individuals per species, the biodiversity would increase.
Since there soil sample was not found to have any organisms in it, the soil does not have any biodiversity, any level of richness, or any level of evenness. The biodiversity of the Leaf Litter sample was greater than the biodiversity of the soil sample.
Conclusion:
The data found from completing the Leaf Litter Lab supports the original hypothesis: If a leaf litter sample and a soil sample are collected from the woods behind Heritage High School then we will discover that the biodiversity is higher in the leaf litter because it contains more types of organisms than what would be found in the soil. The biodiversity of the Leaf Litter sample is higher than the biodiversity of the soil sample due to a greater number of species (14) and organisms (64) living in it. The soil sample did not have any organisms in it, thus showing that there was no biodiversity for this specific sample. The biodiversity of this Leaf Litter sample seems to be high. However, the sample of soil it is being compared to does not allow for much of a comparison. Considering that both richness and evenness contribute to biodiversity, the Leaf Litter biodiversity is not as high as it could be. The richness of the Leaf Litter sample was very high because of the 14 different species while the evenness of the sample was low due to the inconsistent number of individuals within each species. The biodiversity of the Leaf Litter sample could have been higher if there was more evenness within the sample. The time of year could have affected the amount of organisms in the samples. For example, this experiment was completed in February, a winter month, whereas if it were completed in a warmer, summer month a different number of organisms and/or species could have been found.
The use of the Berlese Funnel allowed for the organisms to be viewed separately from the leaf litter. According to the Mississippi Entomological Museum, "They work on the principle that insects and other arthropods that normally live in soil and litter will respond negatively to light. Therefore, a light source is used to force the arthropods to move downward, where they will fall into a funnel and then into a container of ethanol." Massey University says that "As the soil dries out from the top down, the dryness stimulates the soil animals to move downward (this behaviour is called positive geotaxis). " Which means that the organisms, or invertebrates, move downward to escape harsh and damaging effects of the sun and to move to cooler, less dry soil where they can live. This shows that the organisms can adapt to the surroundings, they know that if they move deeper into the ground they will find relief from the sun. However, with the Berlese Funnel, when the organisms move farther down they fall into a small beaker of alcohol which kills them and then allows for them to be viewed.
An environmental scientist would need to make more than one measurement if they were calculating the biodiversity. The data above was compiled from nine different groups analyzing samples. The data would become more accurate if more samples were taken and looked at from the same location as well as obtaining samples from locations within the same proximity of the others. The increased number of samples would potentially show an increased number of species , or richness, as well as an increased number of individuals per species, or evenness, which would contribute to a higher level of biodiversity. To take samples of a large forest it would be important to gather multiple samples from different areas of the forest in order to be sure that the most organisms and species could be discovered and found.
Biodiversity is an important factor to monitor and preserve. Biodiversity allows for life on Earth because of its ecological services such as purifying water and air, providing food, allows for species and organisms to adapt, allows for new medical discoveries to occur. Biodiversity can decrease due to natural factors such as climate change, but humans have a large impact on biodiversity as well. Biodiversity decreases due to habitat destruction and overexploitation (nwf.org) If biodiversity is not preserved, life on Earth will not be able to be the same.
The use of the Berlese Funnel allowed for the organisms to be viewed separately from the leaf litter. According to the Mississippi Entomological Museum, "They work on the principle that insects and other arthropods that normally live in soil and litter will respond negatively to light. Therefore, a light source is used to force the arthropods to move downward, where they will fall into a funnel and then into a container of ethanol." Massey University says that "As the soil dries out from the top down, the dryness stimulates the soil animals to move downward (this behaviour is called positive geotaxis). " Which means that the organisms, or invertebrates, move downward to escape harsh and damaging effects of the sun and to move to cooler, less dry soil where they can live. This shows that the organisms can adapt to the surroundings, they know that if they move deeper into the ground they will find relief from the sun. However, with the Berlese Funnel, when the organisms move farther down they fall into a small beaker of alcohol which kills them and then allows for them to be viewed.
An environmental scientist would need to make more than one measurement if they were calculating the biodiversity. The data above was compiled from nine different groups analyzing samples. The data would become more accurate if more samples were taken and looked at from the same location as well as obtaining samples from locations within the same proximity of the others. The increased number of samples would potentially show an increased number of species , or richness, as well as an increased number of individuals per species, or evenness, which would contribute to a higher level of biodiversity. To take samples of a large forest it would be important to gather multiple samples from different areas of the forest in order to be sure that the most organisms and species could be discovered and found.
Biodiversity is an important factor to monitor and preserve. Biodiversity allows for life on Earth because of its ecological services such as purifying water and air, providing food, allows for species and organisms to adapt, allows for new medical discoveries to occur. Biodiversity can decrease due to natural factors such as climate change, but humans have a large impact on biodiversity as well. Biodiversity decreases due to habitat destruction and overexploitation (nwf.org) If biodiversity is not preserved, life on Earth will not be able to be the same.
Citations:
"Biodiversity
& Human Well-being." 1. Biodiversity: What Is It, Where Is It, and
Why Is It Important? GreenFacts Scientific Board, n.d. Web. 28 Feb. 2015.
<http://www.greenfacts.org/en/biodiversity/l-3/1-define-biodiversity.htm>.
"Berlese Funnels - Collecting Methods - Mississippi Entomological Museum Home." Berlese Funnels - Collecting Methods - Mississippi Entomological Museum Home. Mississippi State University, n.d. Web. 28 Feb. 2015. <http://mississippientomologicalmuseum.org.msstate.edu/collecting.preparation.methods/Berlesefunnel.htm#.VPUO1JU5Dug>.
"Soil Bugs - An Illustrated Guide to New Zealand Soil Invertebrates." Soil Bugs - An Illustrated Guide to New Zealand Soil Invertebrates. Massey University, n.d. Web. 01 Mar. 2015. <http://soilbugs.massey.ac.nz/collection_berlese.php>.
"What Is Biodiversity? - National Wildlife Federation." What Is Biodiversity? - National Wildlife Federation. National Wildlife Federation, n.d. Web. 26 Feb. 2015. <http://www.nwf.org/Wildlife/Wildlife-Conservation/Biodiversity.aspx>.
"Berlese Funnels - Collecting Methods - Mississippi Entomological Museum Home." Berlese Funnels - Collecting Methods - Mississippi Entomological Museum Home. Mississippi State University, n.d. Web. 28 Feb. 2015. <http://mississippientomologicalmuseum.org.msstate.edu/collecting.preparation.methods/Berlesefunnel.htm#.VPUO1JU5Dug>.
"Soil Bugs - An Illustrated Guide to New Zealand Soil Invertebrates." Soil Bugs - An Illustrated Guide to New Zealand Soil Invertebrates. Massey University, n.d. Web. 01 Mar. 2015. <http://soilbugs.massey.ac.nz/collection_berlese.php>.
"What Is Biodiversity? - National Wildlife Federation." What Is Biodiversity? - National Wildlife Federation. National Wildlife Federation, n.d. Web. 26 Feb. 2015. <http://www.nwf.org/Wildlife/Wildlife-Conservation/Biodiversity.aspx>.