1. Module 8

1.29. Page 3

Lesson 7: Page 3

Module 8—Populations, Individuals, and Gene Pools

 

Self-Check

 

Succession and Biodiversity

 

You will recall the significance of biodiversity from Biology 20 and from previous lessons in this module. Consider how succession might affect the amount of biodiversity by completing the following questions.

 

Use “Figure 20.21” on page 726 of your textbook to answer the following questions.

 

SC 1. What is the effect of time on biodiversity in a succession? Why does this occur?

 

SC 2. Why is the number of species that can survive at the beginning of the succession so low?

 

SC 3. How many years did it take to complete this succession?

 

SC 4. Which of the following is true of a secondary succession?

  1. The succession starts from bare rock.

  2. The pioneer species could be lichen.

  3. The climax species is the final species.

  4. The succession could occur after a volcanic event.

SC 5. Which of the following is NOT characteristic of succession?

  1. Succession is the orderly replacement of one species by another over time.

  2. Succession occurs when one species changes the environment so that the first species can no longer survive there.

  3. Succession is a natural process in which communities age.

  4. Succession occurs when one species out-competes another species for a specific niche.
Check your work.
Self-Check Answers

 

SC 1. Biodiversity increases rapidly at the beginning of the succession. The slope flattens as the climax community appears. As each species colonizes the area, the accumulation of dead organic matter increases the nutrient- and moisture-holding abilities of the soil and shades seedlings from intense light and heat. Many more species prefer these conditions to the original harsh and barren conditions at the beginning of the succession, so there is more biodiversity.

 

SC 2. This is a primary succession, meaning it is starting from rock. Soil must be made first through the process of freeze-thaw fracturing of rock and accumulation of organic matter from dead pioneer producers. Conditions are harsh and exposed. Until adequate soil is formed, the number of plant species that can survive will be very low.

 

SC 3. approximately 150 years.

 

SC 4. c. The climax species is the final species.

 

SC 5. d. Succession occurs when one species out-competes another species for a specific niche. .

 

Module 8: Lesson 7 Assignment

 

Alberta’s forests are important for much more than pulp and paper or timber industries. Many Canadian forests are part of Canada’s National Parks or are nature preserves that were made to protect wild organisms from human activity. One of the keys to protecting threatened species is to prevent habitat change, including changes caused by forest fires. 

 

Every summer you hear about the forest fire hazard and updates in the news about where forest fires are burning out of control. Although some fires are set by human carelessness, fires caused by lightning storms combined with hot, dry conditions are a normal part of nature that renews soils and begin the cycle of succession again and again. Unfortunately, forest fires break out without warning when those who can control the spread of fire are ill-prepared to fight it. Some districts have adopted a “controlled burn” policy as the answer to this problem. 

 

Retrieve the Module 8: Lesson 7 Assignment you downloaded earlier. Complete Part 2 of the assignment and save a copy to your course folder. Once completed, you may then submit the assignment to your teacher for assessment.

 

Reflect and Connect

 

In Lessons 5 to 7 you have been examining interactions in ecological communities. You have analyzed the types of living relationships and competition within and between species. You have looked at the characteristics and types of succession. Apply your knowledge to the questions on page 730 of your textbook. Your teacher may suggest particular questions for your review.