Leaf Litter Lab
Collaborators- The entire class...
Abstract- An experiment was conducted to check the biodiversity of organisms hiding in leaves and dirt. Samples taken from a nearby forest, samples of leaves and dirt were left under a heating lamp for several days; flushing most organisms from their shelter and into a small beaker of alcohol. After several days, the amount and variety of organisms in the beaker was recorded using a microscope. It was observed that the environment where the samples were taken from had relatively high biodiversity with organisms ranging from tiny mites to fairly large beetles.
Problem- What is the biodiversity in the leaf litter and soil of the nearby forest?
Hypothesis- If we count all the organisms living in our samples of leaf litter and soil, we will find that the biodiversity of the leaf litter will be higher than the soil.
Parts of the Experiment- Control group- A sample of soil.
Experimental group- Samples of leaf litter from the nearby forest.
Dependent variable- the amount of organisms in the samples.
Independent variable- Location from where the samples were taken.
Materials- Leaf litter
Soil
Microscope
Alcohol
Berlese Funnel
Source of light
Methods- 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.
4. 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.
5. After a few days, 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.
6. Use the information to calculate the diversity indices for your sample.
Abstract- An experiment was conducted to check the biodiversity of organisms hiding in leaves and dirt. Samples taken from a nearby forest, samples of leaves and dirt were left under a heating lamp for several days; flushing most organisms from their shelter and into a small beaker of alcohol. After several days, the amount and variety of organisms in the beaker was recorded using a microscope. It was observed that the environment where the samples were taken from had relatively high biodiversity with organisms ranging from tiny mites to fairly large beetles.
Problem- What is the biodiversity in the leaf litter and soil of the nearby forest?
Hypothesis- If we count all the organisms living in our samples of leaf litter and soil, we will find that the biodiversity of the leaf litter will be higher than the soil.
Parts of the Experiment- Control group- A sample of soil.
Experimental group- Samples of leaf litter from the nearby forest.
Dependent variable- the amount of organisms in the samples.
Independent variable- Location from where the samples were taken.
Materials- Leaf litter
Soil
Microscope
Alcohol
Berlese Funnel
Source of light
Methods- 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.
4. 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.
5. After a few days, 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.
6. Use the information to calculate the diversity indices for your sample.
Data- As a class, we recorded environmental information and calculated the amount of each organism from all of the samples combined:
Location: Wake Forest
Type of community: Temperate forest
Date: 9/18/13 Time: 7:30 AM-8:10 AM
Weather: Sunny
Temperature: 19 degrees C
Relative humidity: 28%
LEAF LITTER SOIL (control)
Mites 51 aphid 1
Springtail 4 Simpson's Index = 1
Centipede 1 Simpson's Index of Diversity = 0
Aphid 31 Simpson's Reciprocal Index = 1
Japygid 6
Termite 3
Beatle mite 25
Thrips 5
Diplura 1
Psocid 13
Mosquito 1
Spider 1
Simpson’s Index = .22
Simpson’s Index of Diversity = .78
Simpson’s Reciprocal Index = 4.55
Data Analysis- The data shows that the leaf litter was pretty diverse with a Simpson's index of .22, which means it is more diverse the closer it is to 0. Although, species richness was somewhat lacking with simply 12 species hiding in the leaves. The soil, on the other hand,is not diverse whatsoever in diversity or richness as it simply had one organism and species.
Lab questions-
1. What are two reasons the organisms move away from the light down the funnel? What does this indicate about the organisms?
Organisms moved away from the light because of the heat being emitted from the light and are probably not accustomed to it and go deeper to avoid it. Another reason can be that the organisms were following the moisture. As the light dried up the leaves and dirt, the organisms went deeper to remain hydrated.
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.
The biodiversity if high because of the sheer amount of organisms living in the same general ares and it could have possibly been higher because the lab did not account for organisms that could have escaped capture or during the lab.
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 take several samples in different locations to get an accurate looks at the entire biodiversity. It could also be at different times of day or at different temperatures to see different species that come out with different factors. If I had to take samples of a large forest, I would get samples from different locations and check the net biodiversity.
Conclusion- The leaf litter was surprisingly far more diverse than the soil than initially expected. The soil and leaf litter samples were both taken from the same general area and it was expected that the soil and leaf litter would have been close in diversity, but the leaf litter was, in reality, much more diverse. However, there was room for inaccuracy. There could have been more organisms in each sample but could have been skipped over by the tunnel vision provided by the microscope or could have climbed out the top of the funnel and escaped early on in the lab, lowering the number of captured ones. Of course, taking the organisms out of their environment is an inefficient way to measure biodiversity compared to quadrant sampling, which would have helped to eliminate the variables of organisms escaping the funnel and also kept the organisms in their habitat (1).
Citations-
(1) "Quadrant Sampling." Census of Marine Life. Census of Marine Life, n.d. Web. 4 Oct. 2013. <http://www.coml.org /investigating/observing/quadrat_sampling>.
Location: Wake Forest
Type of community: Temperate forest
Date: 9/18/13 Time: 7:30 AM-8:10 AM
Weather: Sunny
Temperature: 19 degrees C
Relative humidity: 28%
LEAF LITTER SOIL (control)
Mites 51 aphid 1
Springtail 4 Simpson's Index = 1
Centipede 1 Simpson's Index of Diversity = 0
Aphid 31 Simpson's Reciprocal Index = 1
Japygid 6
Termite 3
Beatle mite 25
Thrips 5
Diplura 1
Psocid 13
Mosquito 1
Spider 1
Simpson’s Index = .22
Simpson’s Index of Diversity = .78
Simpson’s Reciprocal Index = 4.55
Data Analysis- The data shows that the leaf litter was pretty diverse with a Simpson's index of .22, which means it is more diverse the closer it is to 0. Although, species richness was somewhat lacking with simply 12 species hiding in the leaves. The soil, on the other hand,is not diverse whatsoever in diversity or richness as it simply had one organism and species.
Lab questions-
1. What are two reasons the organisms move away from the light down the funnel? What does this indicate about the organisms?
Organisms moved away from the light because of the heat being emitted from the light and are probably not accustomed to it and go deeper to avoid it. Another reason can be that the organisms were following the moisture. As the light dried up the leaves and dirt, the organisms went deeper to remain hydrated.
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.
The biodiversity if high because of the sheer amount of organisms living in the same general ares and it could have possibly been higher because the lab did not account for organisms that could have escaped capture or during the lab.
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 take several samples in different locations to get an accurate looks at the entire biodiversity. It could also be at different times of day or at different temperatures to see different species that come out with different factors. If I had to take samples of a large forest, I would get samples from different locations and check the net biodiversity.
Conclusion- The leaf litter was surprisingly far more diverse than the soil than initially expected. The soil and leaf litter samples were both taken from the same general area and it was expected that the soil and leaf litter would have been close in diversity, but the leaf litter was, in reality, much more diverse. However, there was room for inaccuracy. There could have been more organisms in each sample but could have been skipped over by the tunnel vision provided by the microscope or could have climbed out the top of the funnel and escaped early on in the lab, lowering the number of captured ones. Of course, taking the organisms out of their environment is an inefficient way to measure biodiversity compared to quadrant sampling, which would have helped to eliminate the variables of organisms escaping the funnel and also kept the organisms in their habitat (1).
Citations-
(1) "Quadrant Sampling." Census of Marine Life. Census of Marine Life, n.d. Web. 4 Oct. 2013. <http://www.coml.org /investigating/observing/quadrat_sampling>.