Lesson Notes By Weeks and Term v5 - Grade 10

Lesson Video

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Performance objectives

• Define ecology and its levels of organization.
• Describe the biotic and abiotic components of an ecosystem.
• Identify different types of human impact on the environment.
• Discuss the consequences of human activities on biodiversity.
• Explain the importance of sustainability in South Africa.

Lesson summary

Overview: This week, we embark on a crucial journey into the realm of environmental studies. As South African citizens, we are intrinsically linked to our environment. Our well-being, economy, and cultural heritage are all deeply influenced by the health of our ecosystems. From the availability of clean water in the Drakensberg mountains to the preservation of biodiversity in the Kruger National Park and the impact of mining on local communities, understanding our environmental impact is essential for building a sustainable future. This topic empowers you to become informed and responsible stewards of our natural resources.

Lesson notes

2.1 Ecology and Levels of Organization: Ecology is the scientific study of the interactions between organisms and their environment. It examines how living things interact with each other (biotic factors) and with the non-living components of their surroundings (abiotic factors). Understanding ecological principles is crucial for comprehending the impact of human activities on the environment. Ecological organization is hierarchical, meaning it is structured in levels of increasing complexity: Individual: A single organism (e.g., a single impala).

Population: A group of individuals of the same species living in the same area (e.g., a herd of impalas).

Community: All the populations of different species living and interacting in a given area (e.g., the impalas, zebras, lions, grasses, and trees in a savanna).

Ecosystem: The community of organisms interacting with their physical environment (e.g., the savanna ecosystem, including the soil, water, air, and all the living things).

Biome: A large geographic area characterized by specific climate conditions, animal populations, and plant adaptations (e.g., the savanna biome, the fynbos biome).

Biosphere: The sum of all the ecosystems on Earth; the region of Earth inhabited by living things.

Example: Consider a small dam in a rural area of KwaZulu-Natal.

Individual: A single Tilapia fish.

Population: All the Tilapia fish in the dam.

Community: All the fish (Tilapia, Carp, etc.), aquatic plants (reeds, lilies), insects, and microorganisms living in the dam.

Ecosystem: The dam itself, including the water, sediment, sunlight, and all the living organisms. This includes the chemical composition of the water and surrounding soil.

Biome: If this dam is located within the grassland biome, it represents a smaller ecosystem within that larger biome. 2.2 Ecosystem Components: An ecosystem consists of two main components: Biotic Factors: The living components of the ecosystem, including plants, animals, fungi, and microorganisms. They interact with each other in various ways, such as competition, predation, and symbiosis.

Abiotic Factors: The non-living components of the ecosystem, such as sunlight, water, temperature, soil, and air. These factors influence the distribution and abundance of organisms.

Example: In the Kruger National Park ecosystem: Biotic Factors: Lions, elephants, zebras, acacia trees, grasses, bacteria, fungi.

Abiotic Factors: Sunlight, rainfall, temperature, soil type, availability of water, minerals in the soil, oxygen levels. 2.3 Human Impact on the Environment: Human activities have a significant impact on the environment, often leading to negative consequences.

Some major types of impact include: Pollution: The introduction of harmful substances or contaminants into the environment. This can occur in the air (e.g., from burning fossil fuels), water (e.g., from industrial waste), and soil (e.g., from pesticides). Air pollution in areas like the Highveld due to coal-fired power stations is a significant problem in South Africa.

Deforestation: The clearing of forests for various purposes, such as agriculture, logging, and urbanization. Deforestation leads to habitat loss, soil erosion, and climate change. In South Africa, deforestation is primarily driven by agriculture and informal settlements' need for firewood.

Habitat Destruction: The alteration or elimination of natural habitats, leading to the displacement or extinction of species. This can be caused by urbanization, agriculture, mining, and infrastructure development. The expansion of sugarcane farming in KwaZulu-Natal, for example, has resulted in the destruction of natural grasslands.

Introduction of Alien Species: The introduction of species into areas outside their native range. Alien species can outcompete native species, disrupt ecosystems, and cause economic damage. Examples in South Africa include the water hyacinth, which clogs waterways, and the eucalyptus tree, which uses excessive amounts of water.

Example: Suppose a mining company opens a new coal mine near a small town.

Pollution: Dust and toxic chemicals released during mining contaminate the air and water sources, affecting the health of residents and wildlife.

Deforestation/Habitat Destruction: Large areas of forest or grassland are cleared to make way for the mine, destroying the habitats of many animals and plants.

Consequences: Loss of biodiversity, soil erosion, water contamination, increased respiratory problems in humans. 2.4 Consequences of Human Activities: Human activities have profound consequences for biodiversity and ecosystem stability: Loss of Biodiversity: The decline in the variety of life on Earth. Habitat destruction, pollution, and climate change are major drivers of biodiversity loss. This has an impact on South Africa's unique biomes such as the fynbos.

Ecosystem Instability: The disruption of ecological processes and relationships, leading to imbalances and vulnerabilities.