QUESTIONS FOR DISCUSSION

Qn1:

Explain the following terms: (i) Long day plant. (ii) Day neutral plant. (iii) Critical day plant.

A long day plant grown in short days is transferred to long days. Describe what happens.

It is sometimes said that flowering is brought about by a hormone-like substance formed in the plant in the appropriate day lengths. Describe an experiment that suggests the existence of this substance. KINGS COLLEGE, BUDDO.

Qn2:

a) Plants occupy the most important niches in an ecosystem.

(i) Explain the statement.

(ii) How do plants avail energy to the next trophic level?

b) Explain why trophic levels do not exceed 6.

c) (i) Define succession.

(ii) Describe the process of primary succession leading to a climax community. MT. ST. MARY'S , NAMAGUNGA.

Qn3:

a) Give an account of how a man inside a house perceives a song of a bird in the compound.

b) How is the hearing ability of man different from that of a bat.

c) In what ways is the autonomic nervous system similar to the endocrine system. NABISUNSA GIRLS.

Qn4:

a) Outline the mechanism of contraction of skeletal muscles .

b) what experimental evidences are there to support the mechanisms you have proposed

c) with reference to named examples , state the adaptations developed by various animals for locomotion

i) on dry land

ii) in air. KIBULI S.S.

Qn 5:

i) Give an account of gaseous exchange mechanisms in bony fish.

ii) compare the mechanism of ventilation in man with that in a bony fish .

iii) How is breathing controlled in man? NDEJJE S.S.

Qn6:

(i) Ethology (organisms bahaviour) is an integral part of ecology. Discuss.

(ii) How far can the behaviour of organisms be explained in terms of Reflex Action TRINITY COLLEGE, NABBINGO

Qn7:

a) what do you understand by the following terms

i) photophosphorylation.

ii) Chemosynthesis

iii) Oxidative phosphorylation.

b) Explain how light energy is transformed into chemical energy for dark assimilation.

c) Outline the formation of starch from carbondioxide by green plants.

d) Distinguish between photophosphorylation and oxidative phosphorylation. NAMILYANGO COLLEGE.

Qn8:

a) Describe the pathways and mechanisms of mineral ion and water transport in plants.

b)

(i) What do you understand by primary meristem and secondary meristem. when do they occur in flowering plants?

(ii) Using one example of each describe a series of changes that may occur as one, all differentiates. GAYAZA HIGH SCHOOL.

Qn9:

(a) Describe how you would carry out and record the results of a dihybrid cross(to obtain F1 and F2 generations) in a named organism emphasizing reasons the for various procedures.

(b) Consider an F1 generation of a dihybrid cross . Explain how the results of F2 are dependent on the behaviour of chromosomes during meiosis in the F1. To what extent can the genotype interact with the environment to give phenotypes?

(c) A typical 9:3:3:1 phenotypic ratio is obtained in the F2 of a dihybrid cross. What effects does;

(i) Linkage

(ii) Incomplete dorminance have on this ratio? Explain your answer. MAKERERE COLLEGE SCHOOL.

Qn 10:

The graph below shows the microbial immobilization of carbon in the soil in O1 litter and O2 litter calculated monthly throughout the year . ( adapted from ECOLOGY AND FIELD BIOLOGY by Robert Leo Smith ). Key: carbon pool. carbon immobilized.

GRAPH FOR THE QUESTION

(Sorry the graph could not come not appear. I am still trying to find out how I can include it)

Annual small root input. 100

I 75 50 25

O2 litter 40 20 II 30 15 20

10 5

225 O1 litter Annual litter fall 50 III 175 4 0 30 150 20 10 125 0 J F M A M J J A S O N D TIME (Months).

Questions for No.10:

a)

(i) Describe the trend in the carbon pool and carbon immobilized by micro organisms in the soil from January to December, as shown in graphs II and III. (ii) Relate the trend described in (a) (i) above to the annual small root input as in graph I of carbon into the plants found growing in the soil.

(b) (i) What factors affect the microbial activity in the ecosystem shown above?

(ii) What is the economic importance of the micro organisms found in the ecosystem?

(c) (i) Describe the carbon cycle.

(ii) What are the sources of carbon dioxide to the atmospheric carbon dioxide pool? ST. MARY'S COLLEGE, KISUBI.

Qn11:

(a) Give a summary of Darwin’s reasoning which led him to suggest a hypothesis of evolution by means of Natural selection.

(b) Marsupial are abundant in and around Australia, common in south America and represented by only one species the opossum in U.S.A and found no where else. What kind of evidence best explains cases of this discontinuous distribution of the animals? BUSOGA COLLEGE, MWIRI.

Qn12:

(i) Define the term Alteration of generations.

(ii) What advantages are gained by mosses and ferns in having Alteration of generations in a life cycle?

(iii) Why do you think flowering plants have dispensed with such a life cycle. MUKONO BISHOP’S S.S