Leaf Litter Lab
Pre Lab
Problem
Is biodiversity greater in leaf litter or soil?
Hypothesis
Biodiversity will be greater in the soil because the soil contains more moisture.
Parts of Experiment
Independent Variable - soil, leaves.
Dependent Variable- the amount of biodiversity.
Control Variables - same amount of light, room temperature, same type of alcohol and beaker, same amount of time given under the light.
Control Group - there is no control group.
Experimental Groups - all the soil and leaf litter experiments.
Dependent Variable- the amount of biodiversity.
Control Variables - same amount of light, room temperature, same type of alcohol and beaker, same amount of time given under the light.
Control Group - there is no control group.
Experimental Groups - all the soil and leaf litter experiments.
Materials
- Ziploc Bags 8
- Shovel
- Rake
- Beaker
- Alcohol
- Lamp
- Plastic milk containers
- Cheese cloth
- 8 Petri Dish
- Microscope
- Holding racks
Procedure
- Take Ziploc bags and shovel and go outside.
- Use the shovel to dig up some soil and put it in 2 of the Ziploc bags.
- Use the rake to gather and collect samples of leaves; put the samples in the remaining Ziploc bags. Go back inside.
- Set up 8 stations around the classroom, the lamps should be attached to the bookshelves with the light bulb facing the counter.
- Cut the milk containers into top and bottom halves, only keep the top half.
- Put cheese cloth around the top of each milk container where the cap would usually go. Put each container on a holding rack under the light.
- Pour alcohol into the beakers filling them about half way.
- Pour soil samples into two of the containers and leaf litter into the remaining ones.
- Keep the samples under the light source for 7 days.
- Empty out each beaker into a separate petri dish. You should have eight petri dish.
- Put each petri dish under the microscope and observe the organisms found in the samples.
- Share your results with the class.
Observations
Location: Heritage High School Trail
Type of Community: Woods, forest.
Date of Collection: 2.7.13 Date of Observation: 2.15.13
Time: 12 pm.
Weather Description: Cloudy and slightly windy.
Air Temperature: 41 Degrees Fahrenheit
Soil Temperature: 41 Degrees Fahrenheit
Relative Humidity: 60%
There was only one critter, a tick, found in the soil. There were a lot of different types of critters found in the leaf litter (look at table below). Ticks and beetle mites were most present. Ants were seen on the day when the samples were collected but were not present in either leaf litter or soil samples.
Type of Community: Woods, forest.
Date of Collection: 2.7.13 Date of Observation: 2.15.13
Time: 12 pm.
Weather Description: Cloudy and slightly windy.
Air Temperature: 41 Degrees Fahrenheit
Soil Temperature: 41 Degrees Fahrenheit
Relative Humidity: 60%
There was only one critter, a tick, found in the soil. There were a lot of different types of critters found in the leaf litter (look at table below). Ticks and beetle mites were most present. Ants were seen on the day when the samples were collected but were not present in either leaf litter or soil samples.
Pictures
Data Table and Graphs
Calculations
- Soil had no diversity.
Analysis and Conclusion
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 because of the heat that is being produced thus indicating that the species do not like to be out in the heat and prefer colder environments. Another reason why the organisms move away from the light could be because of the actual light it produces indicating that the critters prefer darker environments along with colder ones.
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 of this leaf litter is high because there are 9 types of different critters present compared to the soil sample that had one type present. Also, most of them have somewhat equal numbers indicating that the richness is even.
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 more than one measurement if he was calculating the biodiversity, especially of a large forest, because the amount of organisms found can depend on a variety of things such as weather, season, and location from where the sample was taken. When measuring the biodiversity of a large forest it would be beneficial to take samples from different locations throughout the forest in order to get the most accurate results. Gathering samples from different parts and locations of the forest helps make sure that each area is included and that the forest is represented as a whole and not just one part of it.
The organisms move away from the light because of the heat that is being produced thus indicating that the species do not like to be out in the heat and prefer colder environments. Another reason why the organisms move away from the light could be because of the actual light it produces indicating that the critters prefer darker environments along with colder ones.
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 of this leaf litter is high because there are 9 types of different critters present compared to the soil sample that had one type present. Also, most of them have somewhat equal numbers indicating that the richness is even.
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 more than one measurement if he was calculating the biodiversity, especially of a large forest, because the amount of organisms found can depend on a variety of things such as weather, season, and location from where the sample was taken. When measuring the biodiversity of a large forest it would be beneficial to take samples from different locations throughout the forest in order to get the most accurate results. Gathering samples from different parts and locations of the forest helps make sure that each area is included and that the forest is represented as a whole and not just one part of it.
General Analysis and Conclusion
Hypothesis Evaluation: The hypothesis turned out to be incorrect because the amount of critters found in the soil was not even close to the amount of critters found in leaf litter. There was only one critter found in the soil sample compared to the 32 critters found in the leaf litter samples combined.
Accuracy of Results: Although the leaf litter was gathered from different locations the soil was not, both soil samples came from one location; therefore, the results of this lab are not completely accurate. This lab could be fixed by making sure that both soil samples do not come from the same location. The area where the soil was gathered was really swampy and muddy which could have been the reason why there were practically no critters found in the soil. Also, it had rained the night before and the morning of the day when the samples were collected making the soil wet, this could also be a reason for why there was only one and not more critters present. In order for this lab to be more accurate the soil samples would need to be collected on a day when the soil is dry and both samples need to come from different locations on the trail.
Application: I have learned from this lab that an ecosystem is a lot more prosperous when it is bio diverse. Biodiversity helps sustain the ecosystem by increasing its productivity and making it less susceptible to any type of disasters. Also, I have learned that biodiversity is beneficial not only to the ecosystem but to everything that is in it including us humans. It provides us with cleaner air, cleaner water, and more abundant resource supply.
Real Life Example: Research shows that biodiversity is being threatened in tropical rain forests due to human activities such as traffic pollution, hunting, logging, and destruction of habitat. Many animals that once used to inhabit the rain forest are now on the endangered species list. The nature trail from where we had collected the leaf and soil samples for this lab is man made; therefore, we can infer that because the ecosystem was disturbed by humans many organisms that lived there could have escaped or died thus confirming our results of finding only one critter in the soil sample.
Armstrong, Dave. "Biodiversity within protected tropical forests threatened." Earth Times. The Earth Times, 26 July 2012. Web. 21 Feb. 2013. <http://www.earthtimes.org/conservation/biodiversity-protected-tropical-forests-threatened/2102/>.
Accuracy of Results: Although the leaf litter was gathered from different locations the soil was not, both soil samples came from one location; therefore, the results of this lab are not completely accurate. This lab could be fixed by making sure that both soil samples do not come from the same location. The area where the soil was gathered was really swampy and muddy which could have been the reason why there were practically no critters found in the soil. Also, it had rained the night before and the morning of the day when the samples were collected making the soil wet, this could also be a reason for why there was only one and not more critters present. In order for this lab to be more accurate the soil samples would need to be collected on a day when the soil is dry and both samples need to come from different locations on the trail.
Application: I have learned from this lab that an ecosystem is a lot more prosperous when it is bio diverse. Biodiversity helps sustain the ecosystem by increasing its productivity and making it less susceptible to any type of disasters. Also, I have learned that biodiversity is beneficial not only to the ecosystem but to everything that is in it including us humans. It provides us with cleaner air, cleaner water, and more abundant resource supply.
Real Life Example: Research shows that biodiversity is being threatened in tropical rain forests due to human activities such as traffic pollution, hunting, logging, and destruction of habitat. Many animals that once used to inhabit the rain forest are now on the endangered species list. The nature trail from where we had collected the leaf and soil samples for this lab is man made; therefore, we can infer that because the ecosystem was disturbed by humans many organisms that lived there could have escaped or died thus confirming our results of finding only one critter in the soil sample.
Armstrong, Dave. "Biodiversity within protected tropical forests threatened." Earth Times. The Earth Times, 26 July 2012. Web. 21 Feb. 2013. <http://www.earthtimes.org/conservation/biodiversity-protected-tropical-forests-threatened/2102/>.