JWSS Biology Chapter 11 Organisms and the Environment

4E Science Biology Chapter 10 Notes JURONG WEST SECONDARY SCHOOL SECONDARY FOUR – BIOLOGY (6093) Chapter 10: ORGANISMS AND THEIR ENVIRONMENT Learning Outcomes: Candidates should be able to: a) briefly describe the non-cyclical nature of energy flow b) describe the roles of producers, consumers and decomposers in food chains and food webs c) explain how energy losses occur along food chains, and discuss the efficiency of energy transfer between trophic levels d) interpret pyramids of numbers and biomass e) describe how carbon is cycled within an ecosystem and outline the role of forests and oceans as carbon sinks f) describe how human activities, such as deforestation and use of fossil fuels, cause an increase in atmospheric carbon dioxide concentration, leading to global warming g) discuss how human actions can reduce the effects of global warming ENGAGE - Activity 1.1 – The living organisms around us Watch the following video “Dead stuff - The secret ingredient in our food chain.” As you watch the video, think of the following: What is another word for ‘dead stuff’? 21.1 What is Ecology? – The study of the interactions of organisms with one another , as well as with their environment . 1

Prepared by: Ms Pui Li Xian & Ms Domina Ng Commented [PLX1]: https://www.youtube.com/watch?v=KI7u _ pcfAQE Commented [PLX2]: detritus (FYI)

4E Science Biology Chapter 10 Notes Common terminologies in Ecology Definition Term The place where an organism lives. E.g. pond, freshwater stream, forests Habitat A group of organisms of the same species living in a particular habitat Population All the populations or organisms living and interacting with one another in a particular habitat (E.g. Mangroves, Mudskippers, Fiddler crabs, Community Soldier crabs living in a mangrove swamp) A community together with its abiotic environment Ecosystem The study of interactions of organisms with one another, as well as with their environment Ecology 2 Prepared by: Ms Pui Li Xian & Ms Domina Ng

4E Science Biology Chapter 10 Notes Explore sungei buloh! Documentary o n sungei buloh! The Abiotic Environment (FYI) • It consists of physical factors such as o Light intensity o Temperature o Amount of water available o Oxygen content o Salinity of soil and/or water o pH of soil and/or water b) explain the terms producer , consumer and trophic level in the context of food chains and food webs 3 Prepared by: Ms Pui Li Xian & Ms Domina Ng

Commented [PLX3]: https://www.thinglink.com/scene/12939 45209960267779?buttonSource=viewLimits Commented [PLX4]: https://www.thinglink.com/scene/12939 67096413159427?buttonSource=viewLimits Commented [PLX5]: https://youtu.be/E1pp_7-yTN4

4E Science Biology Chapter 10 Notes c) explain how energy losses occur along food chains, and discuss the efficiency of energy transfer between trophic levels The Biotic Environment 4 Prepared by: Ms Pui Li Xian & Ms Domina Ng

4E Science Biology Chapter 10 Notes 1. Producers • Contain chlorophyll which traps and convert light energy into chemical energy . Chemical energy is stored in glucose. • Synthesise glucose from carbon dioxide and water, and they produce oxygen as a by-product during photosynthesis . • Producers affect the lives of other organisms because they provide them with energy and oxygen. • All food chains start with producers . ( first trophic level ) • E.g. green plants and green algae 2. Consumers • Consumers are not able to make their own food. • They obtain energy and nutrients by feeding on other organisms. • Three types: 1. Primary consumers (herbivores): Animals that feed on plants. 2. Secondary consumers (carnivores): Animals that feed on primary consumers. 3. Tertiary consumers (carnivores): Animals that feed on secondary consumers. 3. Decomposers • Obtain energy by breaking down dead organisms, faeces and excretory products • The decomposition process releases inorganic nutrients, such as carbon and nitrogen, for nutrient cycling. • E.g. fungi, bacteria and earthworms. • Note that decomposers are not included in food chains/webs. Think! Do decomposers release ALL of the energy stored in the bodies of dead organisms ? 5 Prepared by: Ms Pui Li Xian & Ms Domina Ng