Section A3 : Biotic System : Ecosystem, Vegetation & Soils

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Section A3 : Biotic System : Ecosystem & Vegetation & Soils

Paper I :

Paper II :

03#3: TRF : climate ® soil fertility + veg. productivity + importance of maintaining floral diversity + ways to reduce biodiversity loss

97#3 : TD : rainfall pattern + vegetation adaptation + comparison of NPP with TRF

96#4 : Ecosystem : physical, chemical and biological processes + human impact + measures

95#3 : TRF & TD ecosystem : compare and contrast components and interaction

94#3 : TD : vegetation adaptation + man’s impact

93#3 : Tundra : environmental constraints on plants and animals

92#4 : TD : vegetation adaptation (survival, structural forms + spatial characteristics)

91#3 : Tundra : spatial variation in vegetation

89#3 : TRF → TD : vegetation gradient + human impact on vegetation.

88#3 : TRF : reasons of luxuriant vegetation + unfavourable factors for farming + impact

Past Exam Paper :

03#3 Topical rainforests have some of the world’s most luxuriant vegetation and yet some of the world’s least fertile soil.

Discuss the different influences of climatic inputs on soil fertility and vegetation productivity in the tropical rainforest ecosystem. Explain the importance of maintaining floral diversity in the system and suggest ways to reduce the rate of biodiversity loss.

97#3 Describe and explain the pattern of rainfall in tropical deserts. In what ways do desert plants adapt to the desert environment ? Discuss the primary productivity of a desert ecosystem in comparison with other ecosystems in the tropics.

96#4 An ecosystem is a structural and functional unit involving the interplay of various physical, chemical and biological processes.

Discuss this statement with reference to a biome with which you are familiar. Explain how the ecosystem can be modified by human beings and suggest measures to alleviate the problems arising from human impact.

95#3 Compare and contrast the tropical rain forest and tropical desert ecosystems in terms of the components and the interactions among them. Illustrate your answer with examples.

94#3 Describe and explain the adaptation of vegetation to the climatic conditions in tropical arid areas. How and in what ways might man change the ecological balance in such areas ?

93#3 Assess the effects of physical and ecological constraints on plants and animals lives with reference to the harsh environmental conditions in tundra landscapes.

92#4 Survival of plants in arid zones is heavily dependent on avoiding desiccation.

Using examples of plants at the local scale, describe and explain how avoidance of desiccation affects the survival, structural forms and spatial characteristics of desert vegetation in the tropics.

91#3 Account for the spatial variations in vegetation characteristics in the tundra biome at the global scale.

89#3 Describe and explain the changes in vegetation along the climatic gradient from tropical rain forest areas to tropical desert areas. How has the impact of man changed the vegetation pattern you have described ?

88#3 “ In terms of the amount of biomass, natural vegetation is very luxuriant in tropical rain forests, but the natural conditions for developing farming in tropical rain forests are not so favourable.” Explain this statement. With reference to a tropical rain forest area of your choice, evaluate the impact on the natural ecosystem of any one attempt to develop agricultural in that area.

Section A3 : Biotic System : Soils

Paper I :

Paper II :

02#3 : environmental gradient of climatic and soil conditions from the equator to the temperate lat.

01#3 : salinization + relative importance of physical and human factors

00#3 : Soils in TD + human & physical factors → soil degradation + ass. measures

99#1 : 5 soil formers + climate : less influential

98#2 : laterization and salinization + compare biotic and climatic conditions + man → saline soil

96#1 : weathering + soil formation

95#2 : podzolization + gleying

92#3 : Tundra : spatial variation of soil + role of vegetation in soil formation

90#3 : soil formation processes + conditions hinder soil formation, i.e. factors

02#3 The changes of biomes, in which communities and environmental systems interact, are related to environmental gradients.

Discuss the environmental gradients of climatic and soil conditions from the Equator to the temperate latitudes. Using one specific biome as an example, illustrate how human activities may disturb the ecological balance of the community.

01#3 Salinization is a common soil process in arid regions, but it is now also found in semi-arid regions.

Describe and explain the process of salinization. Evaluate the relative importance of physical and human factors in contributing to this soil process in semi-arid regions.

00#3 Describe the characteristics of soils in the tropical desert region. How do human and physical factors interact to trigger soil degradation at the desert margin ? To what extent is soil conservation effective in slowing down the degradation process ?

99#1 Of the soil formation factors, namely climate, topography, parent materials, organisms and time, climate is perhaps the most important.

Explain the statement. Under what circumstances may climate be less influential in soil formation ?

98#2 The characteristics of soil are the results of the interaction of environmental sub-systems.

With reference to laterization and salinization and contrast the soil development process with respect to their climatic and biotic conditions in a natural setting. Discuss with examples how people who fail to manage the soil have led to an increase in producing saline soil.

96#1 Weathering is often regarded as a prerequisite of soil formation. Explain the role of weathering in the formation of soils in the humid tropics. Evaluate the importance of other factors in the formation of these soils. Illustrate your answer with examples.

95#2 Podzolization and gleying are two distinctive soil forming processes under different environment conditions. With the aids of diagrams, describe the major characteristics of the two processes. Compare the ways in which climatic and other environmental factors interact to produce the two processes.

92#3 Describe and explain the spatial variations of soil properties in the tundra ecosystem. To what extent is vegetation a factor of soil formation in this ecosystem.

90#3 Explain the processes which organize soil into horizons, and illustrate your answer with examples of soil from different environments. Account for the conditions where soil horizons are unlikely to be present.