Week 11, Last Observation

Last week, we observed that one of our larger snails appeared dead. However, the large snail is on the side of the bottle, approaching the top in an upward climb. It is clearly moving and alive! There are also 3 baby snails that are apparent. (4 total snails) The very tip of the string is still barely touching the water. The elodea looks about the same. 2/3 of it is very healthy looking and the rest is translucent and brownish. The water quality is good as well, very clear. There is more condensation on the bottom half of the bottle than the top half. The water level is about 1 3/4 cm from the cap. It has progressively gone down, little by little. The top half of the bottle is very foggy on the sides. The soil is still pulling away more from the sides. There is more mold. The plants have not grown more either. The tallest (original) plant has 3 leaves, one brown and 2 green. The second sprout is still 8 cm. The third sprout is about 6 cm (It might have grown about half an inch). Surprisingly, there is much more condensation than we would have expected because we thought that it would dry out. The soil pulling away from the sides plus the string breaking indicated to us that the plants would die. There are now 2 antelary roots growing from the original sprout. We picked up the bottle and observed the very bottom for the first time. The root that has grown through the hole in the cap has not only wrapped itself around the elodea several times, but it has also attempted to plant roots underneath the gravel!

predictions: 

1. Because the string is broken, the soil will dry out, causing the plants to die.

2. The bottom roots touching the gravel will neither continue to grow because they are part of the top plant.

3. The elodea will continue to thrive since the water quality is good.

4. The snails should continue to live for a while because they have a food source (algae?).

Future research:

Instead of planting two different seeds, I would use one type of seed and mark where they were planted.

Using in the classroom:

For younger students (primary grades)- the whole class would observe 1 ecosystem and observe in a whole class discussion so that the teacher can model how to do scientific processes and correct observations. 

For older students, they could observe several ecosystems in groups similar to the way our cohort did. They would create their own observations as well.

Why did the ecosystem turn out the way it did?

-We had clear instructions to follow.

-It was in the same setting the whole time (against the window in the hallway).

-We had about 2 1/2 months to observe the process, making weekly observations.

-Our observations were consistent.

Week 10

The string is now completely disintegrated. This most likely means that the top of the ecosystem will began dying due to the lack of access to the water source. The plants at the top do look very healthy though. The sprouts are 8 cm and 5.5 cm. Half of the top bottle has condensation on it. The tallest plant has 3 healthy leaves and one dead leaf. There is mold on the soil, and the soil is starting to pull away from the sides of the bottle. It has already started drying out. In the bottom of the ecosystem, lots of snails have appeared. Maybe the snails reproduced? However, the 2 main large snails that we have been observing appear to be dead. We have counted 7 baby snails in total. 1 of the big snails is possibly dead. It has stayed in the same position for the past 2 weeks, submerged within the rocks. Half of the elodea appears very healthy, while the other half is brownish and translucent. The roots growing off of the elodea is still touching the bottom rocks. There is condensation on the top of the bottom bottle as well. The elodea is probably that healthiest part of the ecosystem altogether. I would not like our group to volunteer to poke a hole in the bottle. I would like our system to stay closed in order to observe what might happen to the plants and soil.