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Introduction

An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment (things like air, water and soil), interacting as a system. Ecosystems are found everywhere on Earth, from the polar ice caps to the tropical rainforests.

Understanding the organisation of ecosystems is essential for GCSE Biology students because it helps to explain how organisms interact with each other and their environment. This knowledge is important for understanding the impact of human activities on the environment and for developing strategies to protect and restore ecosystems.

Main Content

• Key Concepts and Definitions
• Ecosystem: A community of living organisms and their nonliving environment interacting as a system.
• Biotic factors: The living components of an ecosystem, such as plants, animals, and bacteria.
• Abiotic factors: The nonliving components of an ecosystem, such as air, water, and soil.
• Food chain: A linear sequence of organisms through which nutrients and energy pass, starting with a producer organism and ending with a top predator.
• Food web: A more complex network of interconnected food chains.
• Biological Processes and Systems
• Food Chains and Food Webs

Food chains and food webs show how energy and nutrients flow through an ecosystem. Producers (plants and algae) use sunlight to make food, which is then eaten by primary consumers (herbivores), which are then eaten by secondary consumers (carnivores), and so on.

• Ecological Niches

Every species in an ecosystem has a unique ecological niche, which is the role it plays in the ecosystem. This includes the organism's habitat, feeding habits, and interactions with other species.

• Symbiosis

Symbiosis is a close relationship between two different species. There are three main types of symbiosis:

• Mutualism: Both species benefit from the relationship.
• Commensalism: One species benefits from the relationship, while the other is neither harmed nor helped.
• Parasitism: One species benefits from the relationship, while the other is harmed.

Step-by-Step Explanations

• Example of a Food Chain:

Grass → Grasshopper → Frog → Snake → Hawk

• Example of Symbiosis:
• Mutualism: Bees and flowers. Bees get nectar from flowers, and flowers get pollinated by bees.
• Commensalism: Barnacles and whales. Barnacles attach themselves to whales, but the whales are not affected.
• Parasitism: Tapeworms and humans. Tapeworms live in the human intestine and absorb nutrients from the human's food.

Common Mistakes to Avoid

• Confusing food chains and food webs.
• Not understanding the difference between biotic and abiotic factors.
• Oversimplifying the complexity of ecosystems.

Practice Problems

1. Construct a food web for a pond ecosystem.

2. Explain the ecological niche of a lion in a savanna ecosystem.

3. Describe an example of mutualism in an ecosystem.

Conclusion

The organisation of an ecosystem is a complex and fascinating topic. By understanding the key concepts and processes involved, GCSE Biology students can gain a deeper appreciation for the interconnectedness of life on Earth.

• Tips for Exam Success
• Study the key concepts and definitions.
• Understand the different types of food chains and food webs.
• Be able to identify the ecological niche of different species.
• Know the different types of symbiosis.
• Practice solving practice problems.

Links to Practice Resources

• BBC Bitesize GCSE Biology: Ecosystems
• Khan Academy: Food Webs and Ecological Niches
• Edpuzzle: Organisation of Ecosystems