IGCSE Ecology and The Environment

Following the Cambridge IGCSE™ Biology Syllabus, our students will learn all about ecology and the environment. In a world where the safety and security of our planet is in jeopardy, we think it’s more crucial than ever for future generations to understand the mechanisms behind the delicate balance of nature, and how we can work to protect it.

George Monbiot was quoted as saying, "progress is measured by the speed at which we destroy the conditions that sustain life." Unfortunately, that has been true of previous generations. The hope is that with education and conscious living, our future generations can work to reverse the damage that has already been caused and pave the way for an eco-friendlier tomorrow. During the year, students will learn about organisms and their environment.

Energy Flow We begin with energy and the principal source of energy for biological systems comes from the sun. It’s a beautiful concept for students to understand that we are so alike the plants and animals that surround us in many ways. One of them is how and where we get our energy from. ME Teachers will guide students through the flow of energy. We look at energy in living organisms that comes from sunlight energy, as well as chemical energy. We then look at the ways that this energy is eventually transferred to the environment.

Food Chains and Food Webs Our energy source is not limited to the sun alone. The curriculum deals with food chains and food webs. As human beings, this portion of the course is a great lesson in our power as well as our responsibility. We should all be aware that although there are food sources that are a lot lower than us on the food chain, they are not lowly. Every life matters and if we are given energy from an animal’s meat, that animal should be shown gratitude and respect for serving its place in the cycle of life. To understand these concepts, students are taught how food chains work, including the transfer of energy from one organism to the next and how that energy is transferred between organisms in a food chain by ingestion. They are asked to construct their own simple food chains to demonstrate their understanding of the subject. They are also asked to identify producers, primary consumers, secondary consumers, tertiary consumers and quaternary consumers as the trophic levels in food webs, food chains, pyramids of numbers and pyramids of biomass. We discuss the idea of Trophic levels. According to the Oxford dictionary, trophic levels are defined as "each of several hierarchical levels in an ecosystem, consisting of organisms sharing the same function in the food chain and the same nutritional relationship to the primary sources of energy." Basically, a step in the food chain of an ecosystem. The organisms of a chain are classified into these levels, based on how they eat. Level 1: The producers- green plants.

Level 2: Second-level organisms—the herbivores, or plant eaters consume the producers.

Level 3: Primary carnivores, or meat eaters, eat the herbivores

Level 4: Secondary carnivores eat the primary carnivores. Many organisms can exist on several trophic levels. For example, some carnivores are also herbivores and vice versa. Then they are classified as omnivores. In this course, students dive deep into the mechanisms behind food chains and food webs (food web is a network of interconnected food chains). We discuss how producers make their own organic nutrients, usually using energy from sunlight, through photosynthesis. We delved into photosynthesis in more detail in a previous blog post which can be found here. Consumers are organisms that get their energy by feeding on other organisms. Consumers may be classed as primary, secondary and tertiary according to their position in a food chain. We look at the feeding behaviours of herbivores and carnivores but students are often surprised to learn about another category: Decomposers. A decomposer is an organism that gets its energy from dead or waste organic material. An example of this would be some fungi or bacteria. An important part of this module is where teachers take students through the discussion of what impact humans have through over-harvesting of food species and through introducing foreign species to a habitat.

Nutrient Cycles In this portion of the module, students are taught all about the carbon cycle, limited to photosynthesis, respiration, feeding, decomposition, fossilisation and combustion. We discuss the effects of the combustion of fossil fuels and the cutting down of forests on the carbon dioxide concentrations in the atmosphere. We also look at the water cycle and how this affects our existence. The water cycle deals with evaporation, transpiration, condensation and precipitation. Students learn about the nitrogen cycle in terms of: – decomposition of plant and animal protein to ammonium ions – nitrification – nitrogen fixation by lightning and bacteria – absorption of nitrate ions by plants – production of amino acids and proteins – feeding and digestion of proteins – deamination – denitrification. They also look at the roles of microorganisms in the nitrogen cycle, limited to decomposition, nitrification, nitrogen fixation and denitrification.

Population Size Populations are a group of organisms of one species, living in the same area, at the same time. The coursework takes students through the factors affecting the rate of population growth for a population of an organism, in particular their food supply, predation and disease. Since humanity is the most problematic population in existence, we also talk about the increase in human population size over the past 250 years and its social and environmental implications. Students will be asked to interpret graphs and diagrams of human population growth.

In Conclusion Most students really enjoy this course because it enriches their world! It is crucial that we understand our role in this great big world including the interdependence between people and nature that is vital for food production, maintaining clean air and water, and sustaining biodiversity in a changing climate. To learn more about our approach to education, or to talk to one of our admissions consultants about reserving a spot for your child, contact us at info@meeducationhk.com.

Reference: https://www.cambridgeinternational.org/Images/414443-2020-2021-syllabus.pdf Section 19.


"Ethan has been with ME Education for six months. Since then, he has seen significant growth not only academically but in other areas as well. With one-on-one private lessons, his teacher Mr Thomas is able to give Ethan enough attention and advice during class. Ethan enjoys having lessons with Mr Thomas because of the atmosphere in ME!"

Ethan Tsang


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