8.9 Summary

8.9 Summary (ESGBN)

• The biosphere is the sphere in which all ecosystems on Earth exist. It interacts with the atmosphere, lithosphere and hydrosphere.
• Biomes contained within the biosphere are regions with similar climatic and geographic conditions. Broadly, biomes are either aquatic or terrestrial.
• South Africa's major aquatic biomes include freshwater and marine biomes, based on their salt concentrations. Terrestrial biomes of South Africa include Grassland, Savannah, Succulent and Nama Karoo, Forest, Fynbos, Desert and Thicket Biomes. Each is located differently across South Africa and has its own distinctive plant and animal life.
• Ecosystems refer to environments that consist of abiotic factors and biotic factors (organisms) that interact to maintain a balance.
• Abiotic factors including physiographic (slope, altitude and aspect) and edaphic (soil pH, texture, humus content) factors.
• Energy flows through ecosystems from the sun through to producers (plants), primary consumers (typically herbivores), secondary consumers (carnivores), ultimately terminating at decomposers.
• The food chain describes the relationships linking producers, consumers and decomposers. Food pyramids can also be used to represent this relationship. Pyramids of biomass, energy and numbers of organisms can also be used to describe the biotic relationships in ecosystems.
• Nutrient cycles describe the flow of particular nutrients (C, O, N and water) through the ecosystem.
• Ecotourism produces widespread benefits to South Africa, creating jobs, preserving its natural beauty and improving infrastructure. There are ethical considerations involved in ensuring that the ecological and cultural diversity of South Africa's ecosystems is preserved.