Copy of 1 activity resilience of an Ecosystem docx

SBI 3UO
Background Information
Resilience is the ability of an ecosystem to maintain an equilibrium, or balance, despite significant outside
disturbances. Results of studies conducted using experimental plots of plants showed that increased biodiversity in
the experimental plots led to increased resistance to the invasion of nonnative species and decreased the incidence of
disease.
e scientists who reported these results also recorded data about the ability of grassland plants to resist drought
conditions in relation to species diversity. ey measured the change in biomass of the plants from 1986, the year
before the drought began, to 1988, the peak of the drought.
e data collected are shown in the table below. Resistance values closer to zero imply greater resistance to drought.
Total : 14 marks
Number of
Plant Species
Resistance to Drought (change in biomass/year)
0 0.00 2
-1.10 4
-0.80 6
-0.75 8
-0.65 10
-0.50 12
-0.42 14
-0.40 16
-0.40 18
-0.40 20
-0.38 22
-0.38 24
-0.38
Pre-Lab Questions. What is resilience (1 mk)
Resilience is the ability of an ecosystem to maintain an equilibrium, or balance, despite significant outside disturbances. How is resilience related to species diversity within an ecosystem (1 mk)
According to nature.com, biologically diverse communities are also more likely to contain species that confer resilience to that ecosystem meaning that there is a higher chance of anyone of them having traits that enable them to adapt to a changing environment. Why is it important to maintain biodiversity in ecosystems (1mk)
Biodiversity helps maintain viable ecosystems and contributes to medicine and agriculture.

Organize the Data. Make a line graph of the data in the table. Note the values on the y-axis begin with zero and decrease to negative values. (2 mk)
2. Label the axes of your graph and give your graph a descriptive title. (3 mk)
Graph placed in previous question.
Analyze and Interpret. Explain the relationship between resilience and species diversity in the grassland plots used in this experiment. (2 mk)
As the number of species increases, the resilience to drought also increases, meaning the more plant species there are,
there will be a greater chance of survival for the organisms in the ecosystem.

2. Another factor that scientists analyze when determining the stability of an ecosystem is the amount of time it takes for the ecosystem to return to the conditions that existed before the disturbance. Predict which plots returned to the pre-drought conditions more quickly - those with high species diversity or those with low species diversity Explain your reasoning. (3 mk)
I predict that plots with higher species diversity will quickly return to pre-drought conditions quicker than the ones with low species diversity. I say this because with a higher species diversity has higher resistance to drought, therefore the damage caused by the drought will not be drastic, making it easier for the plot to go back to its original conditions.
Conclude and Communicate. How does species diversity a fect the resilience of an ecosystem (1mk)
Having a diversity in species allows ecosystems to survive environmental changes, such as drought, plagues, or disease outbreaks.

Biodiversity and Ecosystem Stability | Learn Science at Scitable https://www.nature.com
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