NATIONAL OPEN UNIVERSITY OF NIGERIA

UNIVERSITY VILLAGE, PLOT 91, CASDASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI, ABUJA.
FACULTY OF SCIENCES
JUNE/JULY 2013 EXAMINATION

COURSE CODE:                                                                              BIO304

COURSE TITLE:                                                                             General Ecology

DURATION:                                                                                     2 Hours

INSTRUCTIONS:                                                                            Answer any 4 questions

Q1ai.    Define the biogeochemical cycles.

   ii.      Humans are considered to be the initiators of secondary succession. Discuss.

Q1bi.   Explain the interaction between the nutrient cycles.

   ii.      Distinguish between the following:

1. Gross primary productivity and net primary productivity
2. Density-dependent and density independent factor of population regulation.

Q2ai.    List the major nutrients in an ecosystem that are cycled and recycled by living organisms.

   ii.      Describe the roles of space and predator-prey interaction on population regulation.

Q2bi.   Outline the main periods of human population increase.

   ii.      What are the harmful effects of decreasing the earth’s ozone layer?

Q3ai.    Define pollution

    ii.     Photosynthetic plants are of gross importance in the ecosystem, Discuss.

Q3bi.   Explain how phosphorous cycle differs from other nutrient cycles?

    ii.     Describe how energy transfer occurs in an ecosystem.

Q4ai.    Name the biomes known for the following:

(a)       wheat production                 (b)       lumbering                  (c)       trapping

(d)       tallest trees in the world.     (e)       Explain the process of the following:

(f)        ammonification                     (g)       nitrification                (h)nitrogen fixation

Q4bi.   Define the term biome.

  ii.       Describe the human population pyramid.

Q5ai.    Define a community

ii.         Compare the tropical rain forest and the savanna in terms of rainfall, animal types, vegetation and burning by   fire

Q5b.    Describe the structure of a community.

Q6ai.    List the important climatic factors that determine the distribution of terrestrial biomes.

   ii.      Describe how the explosive growth of human population affects the environment.

Q6bi.   What did you understand by the term ecological succession?

   ii.      Write short notes on the following:

1. pyramid of biomass
2. pyramid of energy
3. pyramid of numbers