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Dynamics of Ecosystems Grade 10 Science Glenlawn Collegiate – Ms W

1 | P a g e U n i t N o t e s

Ecosystems Unit

Exercise #1

1. What would happen to an ecosystem if all the decomposers were destroyed?

2. One student argues that humans are producers because they produce their own food by growing crops and raising livestock. Do you agree? Why or why not?

3. Create an Ecosystems Dictionary from the Key Words using the following two pages.



Exercise #2

1. Why is it more energy efficient for humans to eat grains and vegetables rather than meat?

2. Why is sunlight needed to maintain an ecosystem?

3. Draw a food web based on an ecosystem of your choosing. Be sure to include at least two

producers, two primary consumers, one secondary consumer and one tertiary consumer.



Exercise #3

1. Compare and contrast the terms “photosynthesis” and “cellular respiration”. How are they the same?

How are they different?

Summary statement that defines these terms:

2. Write the chemical formula for photosynthesis:

3. Write the chemical formula for cellular respiration:

What do you notice? (compare/contrast #2 and #3.)



4. Use the space provided to draw the Carbon Cycle:



Exercise #4

1. List and describe two “natural events” which affect the carbon cycle:

List and describe two “human activities” which affect the carbon cycle:

2. What do you think are some of the obstacles that stand in the way to reducing human

disruption of the carbon cycle?

3. Some Canadians are not concerned about global warming. How would you respond to someone

who thinks global warming would be great because it would make our winters shorter and not

as cold?



Exercise #5

1. Why is nitrogen important?

2. Why do you think farmers alternate planting clover and alfalfa with their wheat and canola crops? This isn’t in your notes! You have to think this out. (hint: clover and alfalfa are part of the legume family!)

3. Consider algal blooms:

Identify 4 human activities that contribute to algal blooms.

Identify 2 human activities that should not take place in waters in which an algal bloom is occurring. Explain why.



4. Use the image provided and fill in the blanks in the follow questions:

i. What type of bacteria is found at stages B and C? _____________________

ii. The product of the bacteria from question i. that can be found at stage D: ________________

iii. The type of plant-usable nitrogen at stage F is called: _________________

iv. What type of bacteria are found at stage G? ____________________

v. What process is done by the bacteria from question iv.? ____________________



Exercise #6

1. With the use of examples, describe the difference between biodegradable and non-biodegradable substances.

2. Refer back to the Lake Winnipeg food web in Lesson 2 (page 10). Toxins are released into Lake Winnipeg and are absorbed by the algae and passed up the food chain. A) As a person who lives on fish caught in Lake Winnipeg, which fish should you eat? B) Which fish should you avoid? Why?

3. What are some of the possible dangers of eating a lot of fish that contain high levels of mercury?



Exercise #7

1. How does the consumption of mercury affect humans?

2. What are the causes of increased mercury levels in fish found in some of Manitoba’s lakes and rivers?

3. Predict the economic impact of mercury contamination on Manitoba’s fishing and tourism industries.

4. How can you reduce the risk of mercury poisoning to you and others?



Exercise #8 – Carrying Capacity

Many years ago, a fire swept through the boreal forest in an area of northern Manitoba. The trees,

shrubs, and other plants perished in the fire. A team of wildlife biologists decided to study the regrowth

of the forest over time. They chose to focus on the Jack pine population as these trees are some of the

first to grow back after a fire. A graph of the results of their study is shown below.

Questions

1. Why is the number of Jack pines increasing so rapidly in area A of the graph?

2. How do you account for the fluctuations in area C of the graph?

3. What does B represent?



4. What is your estimate of the average growth rate in area C?

5. Describe, in your own words, what is happening to the Jack pine population in the graph.

6. Predict how the graph would change if another forest fire swept through the region.

7. Predict how the graph would change if a forestry company began to log the area.



Exercise #9

1. Limiting Factors Worksheet: Classify each of the statements as DD (density-dependent) or DI (density - independent) and give a reason for your choice.

a. A lion and cheetah attempt to live in the same area and hunt the same food. The more aggressive lion survives; the cheetah does not.

b. Coyotes cross the winter pack ice and enter Newfoundland. The moose population starts to decline.

c. A severe frost wipes our fifty percent of the coffee crop in Brazil.

d. Careless smoking causes a forest fire, which destroys much of the wildlife in a region of northern Manitoba.

e. Due to severe overcrowding in an Asian village, many children do not survive to reach adulthood.

f. Since lynx prey on snowshoe hares, an increase in the hare population causes an increase in the lynx population.



g. A severe flood in the Red River valley causes a decline in the deer population.

h. Large numbers of female lemmings miscarry their young and fail to reproduce.

i. Travelers who visit a crowded African village become infected by parasites.

j. Many fish die due to a change in the winds and the appearance of the El Nino ocean current off the coast of Peru and Chile.

k. Because rabbits in Australia have no natural enemies, their population increases rapidly.

l. Fish on a coral reef stake out their territory and chase away any younger fish that try to live there.

m. The illegal dumping of industrial pollutants into a river causes a massive fish kill.



Exercise #10

1. Concept Overview: Biodiversity (may be handed in for marks)

a. Definition b. List five facts c. Figurative representation d. Create questions e. Create an analogy



Exercise #11

Answer the following questions.

1. How are we affecting our environment?

2. In what ways do we disturb biological cycles?

3. Describe the formation of acid rain.

4. How does acid rain harm ecosystems?

5. List sources of pollution from cities.

6. List sources of pollution from rural areas.

7. What physical effects does pollution have on people?

8. What is being done to reduce pollution?

ecosystems unit - msw-gr10sci.weebly.com€¦ · ecosystems unit exercise #1 1. what would happen...

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