Eco Assignment 4 – Grade 11

The significance of water masses

1) The biggest reservoir for the water cycle is the ocean. Smaller reservoirs are snow caps, lakes, dams and swamps.
i) Why are they important in the hydrological cycle?
ii) Explain why it is paramount to protect them from degradation.

2) Discuss the role of the oceans in terms of:
i) Climate
ii) World trade
iii) Source of food

3) Mention the ways in which humans negatively impact on the ocean in terms of:
i) Over-exploitation
ii) Pollution (releasing waste products and garbage as well as oil)
iii) Eutrophication (release of excess fertilizers and pesticides via river systems)
iii) Global Warming (excessive carbon dioxide release)

4) Discuss how the clearing of mangrove forests have negatively affected the coastal ecosystems. Refer also to efforts to restore these important ecological ‘buffer’ zones and the positive results it has had.
5) Water is an essential resource for all life on the planet. Due to its salt content, the biggest source of water, the sea, is of limited use to humans. Two-thirds of all freshwater is locked up in ice caps and glaciers. Except for 0.08 of all fresh the world’s water, the rest is unprofitable for use as they are situated in areas prone to floods or too remote to be used easily. The biggest user of this small amount of water available is the agricultural sector using 70%. The rest needs to satisfy the ever increasing demand for sanitation, drinking, manufacturing and leisure.
State the challenge of sufficient water provision we face in South Africa by referring to:
i) The present and future capacity of our main storage dams
ii) The environmental effect that dams and insufficient rainfall has on the perennial state of our rivers
iii) Population growth, industry and agriculture
iv) Water pollution
Ecosystems (biotic and abiotic components)

1) Explain the term ‘self-regulation’ or ‘homeostasis’ in ecosystems by referring to positive and negative feedback (biological control mechanisms).

2) Explain the nutrient cycle by referring to:
i) The process of decomposition
ii) The role of biodiversity in food webs
iii) The transfer of energy

3) Explain how soil is being formed by referring to:
i) Climatic conditions
ii) Mineral processes
iii) Biological processes which includes landscape topography, fauna and flora
iv) Time

4) Explain what soil profiles are by referring to:
i) The main soil horizons (colour and texture) – surface soil, sub-soil and parent rock
ii) General soil Classification (O-A-B-C-R)
iii) Explain how the Australian classification systems is different to the US classification system – in your answer refer to the D horizon
iv) E horizons and P horizons
v) Explain horizon numbering and suffixes ‘c’, ‘e’, ‘h’ and ‘p’ to indicate the presence of mineral concentrations, bleached horizons, accumulation of organic matter, disturbances such as ploughing or tillage

5) The main biomes in the world are freshwater, marine, coniferous, deciduous, ice, mountains, boreal, grasslands, tundra, and rainforests. But humans have fundamentally altered global patterns of biodiversity and ecosystem processes. Because of sustained human interaction with ecosystems through practices such as agriculture and forestry and the creation of settlements, as a result, vegetation forms were altered. predicted by conventional biome systems are rarely observed across most of Earth’s land surface. It now becomes important for us to see in which possible ways we could best maintain the natural component in these ‘irreversible altered biomes’. Discuss how you would do this in the following ‘anthropogenic biomes’.
• Dense settlements
• Villages
• Croplands
• Rangelands
• Forested
Development and Sustainability

During the last number of centauries, the technologies that were applied to sustain the livelihoods of people from the Northern Hemisphere has caused substantial damage to the environment compared to the more environmentally sustainable approaches of the Southern Hemisphere.
i) Discuss the subsequent imbalances that developed in terms of access to goods and services.
ii) Discuss the marginalization that exists in terms of global participation.
iii) From an environmental perspective, discuss the need that exists for a balance between a sustainable practices and development.
a. In terms of industry, stress the dangers of unlimited technological achievement and the advantages of living in line with nature.
b. In terms of agriculture, stress the dangers of a technological approach as opposed to the advantages of living in line with nature.
iv) Discuss the effects that development and industrialization has had on rural populations and on urban populations.
People and their needs: Resource use and management:

1) Distinguish between renewable and non-renewable resources.
i) Why is it important to look after the health of renewable resources?
ii) Why is it critical to preserve non-renewable resources?

2) When it comes to the extraction of raw materials like coal and natural gas, huge pieces of land may be explored. Describe the conflicts that may arise between developers and the local residents as well as the role of government in situations as such.
People and their needs: Energy use and management:

1) Explain the demands that the use of fossil fuel for the purpose of energy is making on the environment.

2) Compare the amount of energy created by fossil fuels with the potential amount of energy that could be created by utilizing:
i) Nuclear resources
ii) Clean energy resources such as wind and solar power

3) Compare the environmental cost caused by Fossil energy resources, nuclear energy resources and clean energy resources. Highlight the various kinds of pollution that results and the need to get rid of resulting waste products.

4) Because of massive air pollution acid rain is on the increase.
i) Explain how it is created and the effects that it has on aquatic and bird life.
ii) Explain the need for international cooperation.

5) Explain why it is necessary to:
i) Conserve our remaining fossil fuel energy resources.
ii) Invest in finding sustainable energy approaches.
Tissues, cells and molecular studies: Introduction to Micro-organisms

1) Review the characteristics of the 5 kingdoms and explain their role in their various ecosystems.

2) Describe the difference between viruses, bacteria, fungi and protists by also pointing to their role in ecosystems / nature.

3) What is a virus and why are viruses important?

4) Describe the difference between plant and animal viruses and the debate amongst each other when an organism is a plant or when it is an animal or when it is both?

5) What are bacteria? Why are they important economically and ecologically?

6) How are bacteria related to disease and how can they be used against disease?
Environmental studies

1) Explain positive and negative feedback and in nature and how it maintains balance in ecosystems.

2) Regarding food pyramids:
i) Distinguish between numbers, biomass and energy food pyramids and give examples when any of the three would be appropriate to be used.
ii) Using food pyramids where humans are included, compare and discuss the results when pesticides are being used. Refer to the effect it has on the natural order.
iii) Rhinos are mega grazers. If they are removed by means of culling, what will the probable results be on that ecosystem? Use a food pyramid to explain.
iii) Describe the effect that water and land pollution has on the food-chain, using a food pyramid
Sustaining/managing our environment

1) Use real-life examples in your neighbourhood. What are the causes and effects of water air and land pollution and
• how it can be prevented
• how it can be controlled
• how it can be reduced
2) Regarding the destruction of natural forests, describe the effects that deforestation has on
a. the habitats of organisms;
b. causing soil erosion;
c. the carbon cycle;
d. the water cycle

3) Discuss the challenge between the need to have land available for food-production and deforestation. Mention possible compromises, e.g harvesting forest products in a sustainable way; replanting what had been removed; encouraging tree-planting in schools and communities.

4) Give ways in which deforestation could be reduced such as the re-use and recycle of wood products such as paper or by using alternative products to fuel fires.

5) The various ways in which we as humans utilize the land has certain impacts on the natural environment. Under the following types of land-use, discuss how it has impacted on the natural world and if there are ways to lessen some of the damaging effects:
• agriculture
• grazing
• mining
• housing
• industries

6) Mainly due to habitat destruction and over-exploitation for the purpose of food production, extinction of species are happening on huge scale currently. Each extinct animal, bird, fish or insect, has played a vital role in supporting a system of interdependent organisms. Explain what the result would be should:
• pollination and seed dispersal agents (insects and birds) become extinct
• succession plant species (such as ferns and mosses) are removed permanently
• plants that ply crucial role in soil fertility (leguminous plants) disappear



Environmental studies; Biodiversity, change and continuity

1) There is more than one way to categorize biomes in South Africa, but for the intents of this exercise we will look at the 7 biome description. Factors that contribute to the type of vegetation found in each region are soil-type and climate (rainfall and temperature). Explain the type of vegetation present in each biome and the type of animal and bird life found in the biome by expanding on reasons:
i) Why the predominant vegetation displays certain characteristics
ii) Why certain animals are better adapted to survive in the particular biome
iii) Discuss the historic influence of the human factor
* Describe the nature of the original landscape
* Discuss the reasons why it had been altered
iv) Describe the threats that the biome faces

If you have access to the internet, you may find the site below useful to collect the information required for the question above.
2) Discuss how various factors can contribute to population fluctuation:
i) External factors: Earthquakes, volcanoes, earth slide, tornadoes, floods, droughts and extreme heat
ii) Internal factors:
• population size (natality; mortality; dispersal (as result of emigration/migration)
• density dependent factors (competition, disease, predation)
iii) Human behaviour: (culling; deforestation; habitat destruction/pollution)

3) Discuss how certain human interventions could help to restore/maintain balance in ecosystems, for example,
• utilizing some resources in planned fashion
• planned culling
• artificial grazing supplied
Social behaviour

Explain how populations survive by exercising certain social behaviours such as, predation, competition, courtship/mating; altruism, territoriality, interaction of successive broods
Managing populations

Significance and value of biodiversity

1) In order for humans to survive, ecosystems need to function well. In this regard  a healthy, well-functioning biodiversity is extremely important. Discuss the various ecosystem services mentioned below:

Provisioning services
• food (including seafood and game), crops, wild foods, and spices
• water
• minerals (including diatomite)
• pharmaceuticals, bio-chemicals, and industrial products
• energy (hydropower, biomass fuels)

Regulating services
• carbon sequestration and climate regulation
• waste decomposition and detoxification
• purification of water and air
• crop pollination
• pest and disease control

Supporting services
• nutrient dispersal and cycling
• seed dispersal
• Primary production

Cultural services
• cultural, intellectual and spiritual inspiration
• recreational experiences (including ecotourism)
• scientific discovery

2) Discuss the threats to biodiversity: Deforestation, disease, agricultural practices, natural disasters, pollution, desertification, alien invasive plants, over-exploitation of resources.
Biodiversity of plants and animals and their conservation

1) Discuss how the White Rhino was brought back from the brink of extinction in the 1970’s. Explain its role in supporting the ecosystem. Mention the strategies that were followed, the challenges encountered and the reasons for its success.

2) Discuss the challenges that exist in the following methods of enforcing environmental legislation.
• permits for fishing and abalone
• banning the fishing of undersized fish
• limiting numbers of fish caught
• permits for cycads
• hunting regulations