Life Sciences - Term 4 - Week 9

An ecosystem is a community of living organisms interacting with their physical environment. It includes both biotic factors, such as plants and animals, and abiotic factors, like water, soil, and climate. Ecosystems can be as large as a desert or as small as a puddle, and they are characterized by the flow of energy and the cycling of nutrients.

Biodiversity refers to the variety of life in a particular habitat or ecosystem. It encompasses the diversity of species, genetic variation within those species, and the variety of ecosystems themselves. High biodiversity is crucial for ecosystem resilience, allowing ecosystems to adapt to changes and recover from disturbances.

Consider a simple food chain: grass (producer) → rabbit (primary consumer) → fox (secondary consumer). In this chain, energy flows from the grass to the rabbit and then to the fox. Each level of the food chain represents a trophic level, and energy decreases as it moves up the chain due to energy loss through metabolic processes.

Decomposers, such as fungi and bacteria, play a vital role in ecosystems by breaking down dead organic matter. This process recycles nutrients back into the soil, making them available for producers. For example, when a tree dies, decomposers break it down, enriching the soil and supporting new plant growth.

In groups, students will identify different components of a local ecosystem. They will categorize organisms as producers, consumers, or decomposers and discuss their roles. For instance, students might observe a pond and identify algae (producer), frogs (primary consumer), and snakes (secondary consumer). Each group will present their findings to the class.

Students will choose an ecosystem to research, focusing on its biodiversity. They will create a poster that includes the types of organisms found in that ecosystem, their roles, and the importance of maintaining biodiversity. Students will present their posters to the class, highlighting key findings and discussing threats to their chosen ecosystem.

• A group of similar species
• A community of living organisms and their environment
• A type of food chain
• A single organism

Answer: A community of living organisms and their environment

An ecosystem includes both living organisms and their physical environment, interacting as a system.

• Rabbit
• Grass
• Fox
• Bacteria

Answer: Grass

Producers are organisms that can make their own food through photosynthesis, such as plants like grass.

Answer: Decomposers break down dead organic matter, recycling nutrients back into the soil.

This process is essential for nutrient cycling, allowing new plants to grow and supporting the ecosystem.

• It increases competition among species
• It helps ecosystems recover from disturbances
• It limits the number of species in an ecosystem
• It has no significant impact

Answer: It helps ecosystems recover from disturbances

High biodiversity enhances ecosystem resilience, allowing it to adapt and recover from changes.

Answer: A primary consumer eats producers, while a secondary consumer eats primary consumers.

Primary consumers are herbivores that feed on plants, whereas secondary consumers are carnivores that feed on herbivores.

• Plants
• Animals
• Soil
• Bacteria

Answer: Soil

Soil is an abiotic factor, while plants, animals, and bacteria are biotic factors.