BIOLOGY, ECOLOGY QUESTIONS AND ANSWERS. PHILOSOPHICAL ACADEMIC CENTER.
Ecology QUESTIONS
- Mr,Juma wanted to estimate the number ofgrasshoppers in 5km² grass field near the school compound.
Using a sweep net he captured36 grasshoppers. He used a redfelt pen to mark the thorax of each insect before releasing back into the field. Three days later he made another catch of grasshoppers. He collected 45 grasshoppers of which only 4 had been marked with red mark.
a) Name the above method usedin the population estimation
b) Calculate the population of grasshoppers using the above data
2. What is the significance of the following in the ecosystem?
a)Decomposers’)Pres
3. Birds feed on grasshoppers that feed on grass.
a) Draw a possible food chain from the above information
b) Explain why the biomass of organisms decreases at each preceding trophic level.
4. Define the following terms:-
(i)Autecology (ii)Biomass
5. State two most important factors that favor exponential growth of a population of gazelle in a park.
6. (a) Distinguish between habitat and niche.
(b) Explain why Biomass of producers is greater than that of primary consumers in a balanced ecosystem.
(c) State two advantages of a biological control method over the chemical control method of
pests and parasites.
7. Explain how oil as a pollutant may affect aquatic plants and animals.
ANSWERS.
1. a) Capture –recapture method;
b) Calculate the population of grasshoppers using the above data
FM x SC | = 36 x45; | =405; |
MR | = 4 |
|
2. a) Help to breakdown dead organic matter hence reducing bulk; in the recycling of Nutrients;
b) Regulate the predator – prey population;
3. a) Grass grasshoppers birds;
b) Not all the energy is transferred from one trophic level to another;some is lost as heat, some is used up during metabolism and some is lost when organisms die and decay;
4. Autecology is the study of population / study of members of a specie
Biomass is the quantity of matter of a given type of organisms at a given trophic level; Or the dry weight of an organism;
5. – Availability / adequate food supply ;
– Absence of predations ;
– Absence of disease; (mark the first two pts
6. (a) Habitat – physical location with asset of condition where an organism lives; while niche is the exact place where an organism occupy and its role in the habitat;
(b) Producers have a greater biomass than primary consumers since they start the food chain.
Inter-trophic energy losses occur inform of heat;(c)It’s non-toxic ;It’s organism are specific;
7. Reduce oxygen supply and hence suffocation and death of plants and animals, closs respiratory surfaces (gills and stomata) leading to death;
* END *
PREPARED BY MR JUMA SOSPETER.
APPROVED BY SCIENCE DEPARTMENT PHILOSOPHICAL ACADEMIC.
