Sherrie Adduci

Geoscience P.7

October 1, 2010

Understanding Systems Lab

Introduction:

The forest consists of trees, soil, watcher and air, plants and animals. These are

the elements of a forest, but the parts alone do not form a system. A living system,

which has both living and nonliving parts, is called in ecosystem. Some systems change

so slowly they seem as though they do not change at all. Forests may seem that way to

people who merely use them for camping, hunting or fishing. In this lab, systems are

observed and recorded over time to depict their alterations in an atmosphere filled with

natural and artificial lighting, as well as a system with no light at all. As evidenced by

figure 1, two lab tubes hold water, two hold an aquatic plant, two hold one tadpole, and

two hold both aquatic plant and a tadpole. One group of these tubes resided in the light,

while the other stayed in the dark. Elodea is an aquatic plant of a species that include

ornate waterweeds. Tadpoles are aquatic larva of an amphibian, including frogs, toads,

newt and/or salamanders. They breathe through their gills, and lack legs until the later

stages of their development. Through this lab it is discovered how light, or the lack of

light, can affect the organisms in an aquatic ecosystem.

Research Question: How does the lack of light affect an aquatic ecosystem?

Hypothesis: System in the light will survive more, the plant will be fine, tadpoles alone

will die, and both together will be content. System in the dark will suffer, all systems will

die out at similar times.

Materials:

Bromothymal Blue

Tadpoles

Leaves

Tubes

H2O

Procedure:

The first step one must do in order to create their very own ecosystem is to

confine a considerable quantity of tadpoles, water, and plant material from a nearby

pond. In an average sized tank, one must hold the tadpoles with pond water and the

plant material. One must use eight test tubes and there are two different sections

utilized. One section dedicated to remaining in the dark, while the other would reside in

the light. Two test tubes need to be filled with water, this is the controlled variable. Two

test tubes must be filled with both water and a tadpole, and two test tubes must be

filled with water, a tadpole and plant material and two test tubes must be filled with

water and plant material alone. Four test tubes, one with a tadpole, one with water, one

with a tadpole and plants and one with plant, required stoppers placed on top of the

test tubes prior to their placement in the dark atmosphere.

Data Observation:

DATE IN THE DARK IN THE LIGHT

August 23, 2010 Tadpole alone is still alive.

Water (control) – bluish on top, oxygenated

Plant – not photosynthesizing, giving off carbon dioxide.

Tadpole and plant- the tadpole is dead and the water is yellow.

Tadpole is alive Plant and tadpole =

alive, water has a blue coloring.

Plant and water: thicker (photosynthesizing, growing) the water is blue, and the plant is growing new leaves.

Controlled water is bluish.

August 25, 2010 Control has a blue tone. Water and tadpole,

tadpole is alive. Just plant = less plant

material Tadpole and plant -

tadpole is dead, plant is almost dead, floating white substances, fungus too.

Just tadpole – dead, yellowish water

Tadpole and plant – water color is blue, the tadpole is alive.

Just plant – alive, healthy, bluish water.

August 29, 2010 Just tadpole – alive, no food

Tadpole with plant – dead tadpole, plant is dead.

Only plant – yellow,

Just the tadpole – decomposing, yellowish water

Tadpole with plant – blue water, plant is just as big.

plant material looks unhealthy a bit of decomposition.

Just plant – area of plant is not changing much

August 31, 2010 Just tadpole – alive, yellowish

Plant and tadpole – still dead, mold fungus. Less plant material, yellowish white growth

Just plant – mostly dead Controlled – stuff

growing, bacteria, still blue water

Just tadpole – dissolving, broken up into pieces, no longer visible

Tadpole and plant – alive, blue water

Plant only – blue water, plant is alive

September 6, 2010 Just plant – yellow, greenish, quantity of the plant it less

Tadpole and plant – tadpole is dead, plant is decaying

Just tadpole – still alive and active

Just tadpole – dead dissolved

Tadpole and plant- plant material is healthy, tadpole is alive, water is blue

Just plant – water is

blue, greater amount of

plant material

September 14, 2010 Just tadpole – no movement, yellow water

Plant – on to the decomposing mode, dying, yellowish

Plant and tadpole –

tadpole is dead, in four

different pieces

Tadpole and plant – both are alive, water is blue

Just plant – alive, green, blue water (bluer than controlled group)

Just tadpole – tadpole is

disintegrated, the water

is murky

September 27, 2010 Tadpole is dead and the plant is still somewhat alive, it is dying.

Just plant – dead, yellow Just tadpole –

disintegrate in pieces

Just tadpole – all disintegrated but brown material are at the bottom of the test-tube

Tadpole and plant – dead tadpole, plant is alive

Just plant – alive, increased size, blue water.

Figure 1

Conclusion:

In some ways the hypothesis is correct, the system in the light did survive better

than the system in the dark. As predicted, the plant in a test tube alone flourished and

remained alive, while the tadpole in a test tube alone disintegrated at the bottom of the

test tube and died. But, the hypothesis was wrong in predicting that the test tube that

held both the plant and the tadpole, the plant lived and the tadpole did not. There are

no specific alterations I would make if this lab were done again, because the lab is about

a system and what is necessary to keep a system alive. We are testing this, so we don’t

want every system to be alive and perfect in the end, because the flaws help us to

discover the answer to the research question. The lack of light effects an ecosystem

drastically because compared to the system in the light, the system in the dark killed the

tadpole and plant in the same test tube, killed the plant that was alone and destroyed

and killed the tadpole that was alone.