November 18, 2013
Our ecosystem is doing worse than the week before despite the hole that we put in it. We observed that the plant stems are very transparent and brown along with the leaves. There is one stem that is a light green and has two baby leaves sprouting from the middle. We spotted 9 snails, which is the same from last week. One of the elodea is brown and the other one is still green. The water level is the exact same as last week even though we opened the system. The soil looks a little lower. And again, there was no spotted daphnia. The condensation on the top portion was less than last time and there was more condensation on the bottom portion.
- How does the amount of soil put in the beginning affect the health of the overall system (especially the top portion)?
- How does the amount of each organism affect a closed ecosystem?
- How does adding worms to the soil affect the ecosystem?
- How does the amount of sunlight affect a closed ecosystem?
- How does the ecosystem change over a longer period of time (6 months, 1 year, etc)?
Use in future classes:
Using this in an elementary classroom, students can learn about different aspects of ecosystems and the roles of organisms at all grade levels. The degree in which the students analyze the data will vary depending on the grade level. For younger grades it is a great way to learn how to take data and learn from personally observing their own experiments. Also, for younger grades you can use a class ecosystem where you observe as a whole group and record observations. For the younger grades you can focus on one aspect of the ecosystem (water cycle, carbon cycle, etc). For older students, this is a great way to observe the more complex concepts involved within the ecosystem. For a more detailed analysis, students might need to be exposed to some background information - for example food webs and roles of each organism. Before starting this experiment, the teacher should go over how to properly collect data and how to focus on small details. Also, everyday observations can help students collect data on the small changes made on a daily basis.
Results and Future Changes:
We believe that our ecosystem did not have success, especially on the top, is because the amount of soil was too low. We think that the plants did not have enough nutrients due to the low soil levels. We also think that the ecosystem did not receive an adequate amount of sunlight to survive. We would suggest changes for next time to include putting more soil to begin with. We believe that more soil gives the plants more nutrients and there will not be a chance of running out of those nutrients. Comparing our systems to Michele's ecosystem led us to believe this to be true. Michele's ecosystem has a significant amount more of soil compared to ours and hers seems to be much more healthy. Another change we would do would be to put marks on the bottle at the very beginning at the soil and water levels. Doing so would help us better observe how those levels changed throughout the weeks. Also, we would change the amount of sunlight that our ecosystem received. We would place it in more direct sunlight and see the affect that would have.