TMJC Climate Change Notes

Page 1 of 51 Tampines Meridian Junior College JC2 H2/9744 Biology 2024 Extension Topic (B) 15. Climate Change – Causes and Impacts on Animals and Plants SYLLABUS OVERVIEW No. Overarching Idea Topics 1 Core Idea 1 The Cell and Biomolecules of Life Cell – The Basic Unit of Life 2 Biomolecules of Life and Cellular Transport 3 Core Idea 2 Genetics and Inheritance Genetics and Inheritance (I) – The Cell Cycle 4 Genetics and Inheritance (II) – DNA Replication and Gene Expression 5 Genetics and Inheritance (III) – DNA Mutations and their Consequences 6 Genetics and Inheritance (IV) – Organisation of Genome & Control of Gene Expression in Eukaryotes [Includes Core Idea 1D: Stem Cells] 7 Genetics and Inheritance (V) – Molecular Techniques in DNA Analysis 8 Genetics and Inheritance (VI) – Organisation and Inheritance of Viral Genomes 9 Genetics and Inheritance (VII) – Organisation of Genome & Control of Gene Expression in Prokaryotes 10 Core Idea 3 Energy and Equilibrium Transformation of Energy – Photosynthesis and Cellular Respiration 11 Core Idea 2 Genetics and Inheritance Genetics and Inheritance (VIII) - Inheritance 12 Core Idea 3 Energy and Equilibrium Communication and Equilibrium in Multicellular Organisms 13 Core Idea 4 Biological Evolution Biological Evolution 14 Extension Topic A Infectious Diseases Immunity and Infectious Diseases 15 Extension Topic B Impact of Climate Change on Animals & Plants Climate Change – Causes and Impacts on Animals and Plants Note: Self-read sections 1-3

Page 2 of 51 What’s the Big Picture? This topic explores the impact of climate change and three main areas of concern: 1. The need for a safe and sufficient food supply; 2. The threat of how infectious diseases are changing; and 3. The maintenance of ecosystems as reservoirs for bio-resources like medicine and food. The following questions should help students frame their learning: • How can our way of life influence climate change? • Why is there an urgent need to ameliorate climate change through an understanding and application of the sciences? Climate change, which is attributed to an increase in the emission of greenhouse gases, has great impact on the human population. By the year 2050, climate change is expected to cause the extinction of approximately at least one quarter of all species on land. In the oceans, species such as corals, which are sensitive to warming temperatures, are also at great risk. Many species have evolved to survive within specific temperature ranges and cannot adapt to the new temperatures. In addition, the survival of a species is threatened when the species it depends on for food cannot adapt. The Intergovernmental Panel on Climate Change (IPCC) has predicted that by 2100, the Earth’s surface will rise by up to 6°C on average. The effects of this temperature rise on species and ecosystems will be catastrophic. Currently, the following effects of global warming are evident: the melting of glaciers; the bleaching and dying of coral reefs; extreme storms, droughts, and heat waves; and major shifts in the timing of organism s’ biological cycles. Climate change is affecting the global ecology and ecosystem, e.g. loss of biodiversity and impact on food webs. The study of biological processes is important in understanding and taking appropriate action, e.g. the observation that many species are becoming smaller in size can be explained by fundamental ecological and metabolic principles. There are also consequences for both crop plants and protein sources, e.g. fish that are important for human nutrition. As a small, low-lying city-state with one of the world's most open economies, Singapore is vulnerable to the harmful effects of climate change, such as rising sea levels and the increased frequency of rainfall. Trends in our local weather records are consistent with the global observations of climate change. The weather has become increasingly hot. Since the 1970s, Singapore has experienced an average warming rate of 0.25°C per decade. The sea level has also risen. Tide gauge data in the Singapore Straits shows that the mean sea level has increased by about 3 mm per year over the last 15 years. More instances of short, intense rainfall have also been recorded within the last few years. Extreme weather events can lead to changes in rainfall patterns, resulting in more intense rainfall or drier periods. Flood, haze and water management will be of greater importance to Singapore. In addition, an increase in the frequency of extreme weather events may lead to unstable global food prices and disruptions to business supply chains, which will affect our food imports and business activities in Singapore. Disruption of ecosystems and loss of biodiversity have major impacts on the emergence, transmission, and spread of many human infectious diseases. For example, deforestation reduces the diversity of forest mosquitoes, which are the vectors for dengue. The species that survive and become dominant, for reasons that are not well understood, almost always transmit dengue better than the species that had been most abundant in the intact forests. Deforestation can also result in loss of habitat and food for species that serve as reservoirs for human disease. The resultant disturbance can bring the reservoir species into closer contact with humans, facilitating the spread of the disease to humans. An example is the original outbreak of Nipah virus infections in Malaysia. Mosquitoes kill more people through the life-threatening diseases they spread than any other predators. Furthermore, mosquito-borne infectious diseases affect millions of people and debilitated people cannot work or support themselves. Climate change has influenced how mosquito-borne diseases have spread in the world through the effects on the diseases’ vectors. Being in a region where two of the main mosquito -borne diseases (dengue and malaria) are endemic, an understanding of the intertwined processes of how vectors respond to climate change and how climate change affects the spread of these diseases will be important to Singapore.

Page 3 of 51 LEARNING OUTCOMES Extension Topic B: Impact of Climate Change on Animals and Plants Candidates should be able to: a) identify and explain the human activities over the last few centuries that have contributed to climate change through increased emission of greenhouse gases (limited to CO2 and methane) including burning of fossil fuels linked to increasing energy usage, clearing of fore sts and food choices (increasing consumption of meat). b) explain the effects of climate change as a result of greenhouse emissions, including the melting of polar ice caps, rising sea levels, stress on fresh water supplies, heat waves and heavy rains, death of coral reefs, migration of fishes and insects, release of greenhouse gases in frozen organic matter. c) explain how climate change affects plant distribution (vertical and latitude) and plant adaptations, including morphology and physiology. d) discuss the consequences to the global food supply of increased environmental stress resulting from climate change, including the effects on plants and animals of increased temperature and more extreme weather conditions. e) explain how temperature changes impact insects, including increased temperature leading to increased metabolism and the narrow temperature tolerance of insects. f) outline the life-cycle of Aedes aegypti as an example of a typical mosquito vector. g) outline the development of the viral dengue disease in humans, including host -pathogen interactions, human susceptibility to the virus, pathogen virulence, transmission and drug resistance h) explain how global warming affects the spread of mosquito -borne infectious diseases, including malaria and dengue, beyond the tropics. i) discu