Lesson Notes By Weeks and Term v5 - Grade 7

Lesson Video

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Performance objectives

• Define 'living' and 'non-living' things.
• Identify the basic needs of living organisms.
• Define habitat, population, and community with South African examples.
• Describe an ecosystem and the interactions within it.
• Distinguish between biotic and abiotic factors.

Lesson summary

This week, we begin our exploration of the fascinating world of living organisms and the environments they inhabit. This is a crucial area of study because understanding how living things interact with each other and their surroundings helps us to appreciate the delicate balance of nature and understand the impact of human activities on the environment. In South Africa, where we face challenges like water scarcity, pollution, and biodiversity loss, this knowledge is particularly important. By understanding ecosystems, we can make informed decisions about conservation, sustainable resource management, and protecting our rich natural heritage for future generations.

Lesson notes

What are Living and Non-Living Things? Living things are organisms that exhibit certain characteristics of life, including: Movement: Living things can move, either internally (e.g., blood circulating) or externally (e.g., walking).

Respiration: Living things obtain energy by breaking down food, a process called respiration.

Sensitivity: Living things can detect and respond to changes in their environment (e.g., feeling heat or cold).

Growth: Living things increase in size and complexity over time.

Reproduction: Living things can produce offspring, ensuring the continuation of their species.

Excretion: Living things get rid of waste products.

Nutrition: Living things obtain food for energy and growth. Non-living things lack these characteristics. They do not grow, reproduce, or need food.

Examples: Living: Grass, trees, insects, birds, fish, people, bacteria. For example, a baobab tree grows, reproduces, and needs sunlight.

Non-living: Rocks, soil, water, air, sunlight, sand. A rock simply exists and doesn't need any of the criteria above. Basic Needs of Living Organisms All living organisms require certain basic needs to survive: Water: Essential for all life processes. Water is particularly scarce in arid regions of South Africa like the Karoo, where plants and animals have adapted to survive with very little. In contrast, regions like KwaZulu-Natal have abundant water resources.

Air: Provides oxygen for respiration (breathing). Air is also necessary for plants to perform photosynthesis.

Food: Provides energy and nutrients for growth and repair. Plants make their own food through photosynthesis; animals obtain food by eating other organisms.

Shelter: Protection from predators, harsh weather conditions, and other dangers. The type of shelter varies greatly depending on the organism and its environment; e.g., a bird's nest, a burrow for a meerkat, or the shade of a large tree.

Sunlight: Energy source for plants to make food through photosynthesis. The amount of sunlight affects where certain plants can grow. Habitat, Population, and Community Habitat: The natural home or environment of an animal, plant, or other organism. For example, the habitat of a fish is the water in a river or lake.

Population: A group of individuals of the same species living in the same area at the same time. For example, a population of zebras living in the Kruger National Park.

Community: All the different populations of living organisms that live and interact in the same area. This includes plants, animals, fungi, and microorganisms. For example, the community in a wetland might include reeds, frogs, insects, birds, and fish.

Ecosystems: Living and Non-Living Interactions An ecosystem is a community of living organisms (biotic factors) interacting with each other and with their non-living environment (abiotic factors). It’s a complex web of interactions. Biotic factors are the living components of an ecosystem.

Examples: Plants (e.g., grass, trees, flowers) Animals (e.g., lions, elephants, birds, insects) Fungi (e.g., mushrooms, mold) Bacteria Abiotic factors are the non-living components of an ecosystem.

Examples: Sunlight: Affects temperature and plant growth.

Water: Essential for all life. Its availability influences which organisms can live in a particular area.

Soil: Provides nutrients for plants and a habitat for many organisms.

Air: Provides oxygen for respiration and carbon dioxide for photosynthesis.

Temperature: Affects the rate of biological processes.

Example: A South African Grassland Ecosystem In a grassland ecosystem in South Africa: Biotic: Grasses, zebras, wildebeest, lions, dung beetles, vultures.

Abiotic: Sunlight, water (rainfall), soil, temperature, wind. The grasses use sunlight, water, and soil nutrients to grow (photosynthesis). Zebras and wildebeest eat the grasses. Lions eat the zebras and wildebeest. Dung beetles break down animal waste, returning nutrients to the soil. Vultures scavenge on carcasses. All these biotic factors are influenced by abiotic factors like sunlight and rainfall. If there is a drought (lack of water - abiotic), the grasses may die, affecting the zebras and wildebeest (biotic). This highlights the interconnectedness of all components in an ecosystem. Guided Practice (With Solutions)

Question 1: Classify the following items as living or non-living: rock, rose bush, water, cat, air, mushroom.

Solution: Rock: Non-living Rose bush: Living Water: Non-living Cat: Living Air: Non-living Mushroom: Living

Commentary: This question tests the understanding of the basic characteristics that define living and non-living things. It encourages careful observation and application of the definitions.

Question 2: List three basic needs of a zebra living in the Kruger National Park and explain how each need is met in its environment.

Solution: Water: The zebra needs water to survive. It meets this need by drinking from rivers, watering holes, and dams within the Kruger National Park.