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NATIONAL OPEN UNIVERSITY OF NIGERIA
UNIVERSITY VILLAGE, PLOT 91, CASDASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI, ABUJA.
FACULTY OF SCIENCES
MAY/JUNE 2012 EXAMINATION
COURSE CODE: BIO304
COURSE TITLE: General Ecology
DURATION: 2 Hours
INSTRUCTIONS: Answer any 4 questions
Q1ai. Define the term ecosystem.
ii. List the components of an ecosystem giving two examples of each.
b. Distinguish between the following:
(i) a habitat and a niche
(ii) autotrophs and heterotrophs
(iii) gross primary productivity and net primary productivity
(iv) Density-dependent and density-independent factors of population regulation
Q2ai. What is biogeochemical cycle?
ii. Photosynthetic plants are of gross importance in the ecosystem. Discuss.
iii. What are the primary reservoirs for the chemicals in these cycles?
b. With the aid of a well labeled illustration, describe the carbon cycle
Q3ai. What do you understand by ecological succession?
ii. Humans are considered to be initiators of secondary succession. Discuss.
b. Write a short note on each of the following:
- Nitrogen fixation
- Food Chain
- Pyramid of numbers
- Community
Q4ai. Define a population.
ii. List some ways in which the explosive growth of human population affect the environment.
bi. What can be done to safely maintain nuclear power plants?
ii. Explain how phosphorous cycle differs from other nutrient cycles?
Q5ai. Describe the three types of survivorship curves giving an example of each.
ii. Enumerate some necessary actions to be taken in order to reverse the negative effects of human activities on the environment.
bi. List some special adaptations desert plants and animals have developed.
ii. What are the major factors that influence the formation of terrestrial biomes?
