Biology 12

460 MHR • Unit 5 Population Dynamics

SECTION REVIEW

1. Describe the similarities and differences you
   would expect to see between biogeochemical cycles
   that occur in aquatic ecosystems (such as a pond)
   and those that occur in terrestrial ecosystems (such
   as a grassland).


2. What are the essential differences between
   the biogeochemical cycles for elements like nitrogen
   or oxygen and for elements like phosphorous or
   calcium?


3. Draw a flowchart that illustrates the carbon
   biogeochemical cycle.


4. Explain why oil and coal are often referred to as
   fossil fuels.


5. Describe the role of nitrification in supplying
   essential nutrients to the species found at higher
   levels in a food web.


6. Explain the similarities and differences between
   terrestrial and aquatic ecosystems with respect to
   carbon cycling.


7. Describe the role of bacteria in terrestrial
   biogeochemical cycles.


8. Make a diagram that illustrates each phase of
   the hydrologic cycle. Identify the biotic and abiotic
   elements of the cycle depicted in your diagram.


9. Identify the types of green plants that play a
   critical role in the perpetuation of the nitrogen cycle.


10. Speculate about the possible impact of global
    warming on the carbon cycle in the northern boreal
    forest, which is one of Canada’s more predominant
    biomes.


11. Some concerns now exist about the purity of
    fruits and vegetables that are labelled organic. Some
    academics suggest that it is not possible to grow
    food that is completely free of pesticides, fertilizers,
    and other commercial additives that are commonly
    used by today’s highly industrialized agricultural
    operations. Discuss these concerns within the
    context of your knowledge of how biotic and abiotic
    factors interact in natural ecosystems.


12. In Earth’s northern hemisphere, the amount of
    carbon dioxide in the atmosphere is less during the
    summer than during the rest of the year. Examine the
    carbon cycle and suggest why this is so. (Note: there
    is more land area in the northern than the southern
    hemisphere, and therefore more vegetation).


13. Design an investigation to compare the ecological
    efficiency of a small terrestrial ecosystem (such as a
    small terrarium) with an aquatic ecosystem (such as a
    small aquarium). Specifically, you may want to address
    the following generalization: aquatic ecosystems are
    more efficient than terrestrial ecosystems because the
    bodies of aquatic producers are made up of a smaller
    percentage of indigestible material than the bodies of
    terrestrial producers.

LTER projects are used to study ecosystems for long

periods of time to fully understand the movement and

time required for nutrients to complete certain cycles.

Are LTER projects being undertaken in your country?

What impact might changed biogeochemical cycles have

on humans?

UNIT ISSUE PREP

I

K/U

MC

MC

K/U

C

K/U

K/U

K/U

K/U

C

K/U

K/U

As you continue to prepare for the Biology Course

Challenge, consider the ecological principles presented in

this chapter. These principles offer many opportunities for

selecting an issue to analyze from various perspectives.

For example, look again at the carbon cycle presented in

Figure 13.27 on page 453. This figure shows the effects of

carbon on the following (keep in mind that there are also

effects on living things you cannot see, such as insects

and bacteria):

• plants • animals


• atmosphere • land surfaces


• industries

COURSE CHALLENGE