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Integrated Programme Sec 2 SBGE, LSS Biology Module Topic 3.1 Introduction to Ecology A. Introduction B. Habitats and Biomes C. Habitats and Physical Factors a. Air b. Water c. Temperature d. Light e. Minerals f. pH D. Understanding the Ecosystem E. Man’s Impact on the Environment F. Importance of Nature Conservation Ecology Notes Prepared by Mrs Cheryl Siah A. Introduction a. Study of Ecology i. Interactions of living organisms with other living organisms (biotic environment) ii. Interactions of living organisms with physical environment (abiotic environment) iii. Adaptations of living organisms for better survival b. Population i. Group e.g. of organisms of the same species living in a particular habitat Arctic fox in Arctic Tundra Arctic willow in Arctic Tundra Orang utan in rainforests Cinchona tree in rainforests Arctic Fox Arctic Willow c. Community i. All the populations of organisms living and interacting with one another in a particular habitat that make up a community ii. E.g. orang utans, cinchona trees, hornbills and tembusus form a community in a rainforest populations live interdependently any change in one population affects the other populations Rainforest Community Ecology Notes Prepared by Mrs Cheryl Siah B. Habitats and Biomes a. Habitats i. Place where organism lives in ii. E.g. arctic tundra icy cold environment throughout the year northern hemisphere b. Biomes of the World i. Fresh Water Biomes Low salt (less than 1%) Supply of drinking water 1. Ponds and lakes a. Upper littoral zone Warm, well-lit and shallow Floating plants and larvae found here Grazing snails, fish, amphibians, clams and crustaceans, ducks, turtles and snakes b. Limnetic zone well lit Planktons and freshwater fish c. Deeper profundal zone Little light and cold Organisms here eat dead organic matter 2. Streams and rivers a. Single direction water flow b. Clear, cool and high oxygen content 3. Wetlands a. b. c. d. e. Standing water areas which support aquatic plants Moist and humid Hydrophytes found here Highest biodiversity Amphibians, reptiles and birds ii. Marine Biome 1. Oceans a. Largest body of water b. Great diversity of living organisms c. Very large effect on global climate 2. Intertidal zone a. Earth meets land, waves come in and out b. Very few algae and plants c. Predatory crustaceans, crabs, worms, clams and shorebirds 3. Pelagic Zone a. b. c. d. Ecology Notes Prepared by Mrs Cheryl Siah Open ocean Generally cold Floating seaweeds found here Many species of fish, some mammals (whales and dolphins) 4. Benthic zone a. b. c. d. Temperature decreases as depth increases Bottom – sand, silt and dead organisms Dark – not much plants except some seaweed Nutrient rich – hence bacteria, sea anemone, sea stars and warms, sponges and fishes found here 5. Abyssal zone a. b. c. d. e. Very cold Very dark High pressure Hydrothermic vents Chemosynthetic bacteria found here 6. Coral Reefs a. Warm shallow water b. Nutrient poor water c. Found as barriers around continents e.g. Great Barrier Reef in Australia d. Fringing islands and atolls e. Dominant fauna – corals Made up of animal polyps and algae Algae can photosynthesise Animal polyps can “capture” planktons f. Fish, micro-organisms, invertebrates, sea stars, sea urchins and octopi are found here 7. Estuaries a. Freshwater streams and rivers merge with ocean b. Varied salt concentration in water c. Algae, seaweeds, mangrove plants and marsh grasses found here d. Waterfowl, crabs, shrimps and oysters are found here (more reading – http://www.ucmp.berkeley.edu/exhibits/biomes/index.php) iii. Forests (in particular Tropical Rainforests) a. Warm and wet b. Rapid decomposition c. Very diverse in species – half of the world’s 10 million species found in the tropical rainforests! d. e.g. Amazon iv. Deserts (in particular Hot and Dry Deserts) a. Very hot day b. Very cold night c. Only short bursts of very little rainfall in between long periods of rainless days d. Plants are ground hugging shrubs and short woody trees i. Leaves are very reduced – needle like ii. Stems are green and photosynthetic iii. Stomata only open at night prevent excessive water loss e. Animals are active only at night f. Animals may practice aestivation g. Lowering of metabolism h. e.g. Sahara Ecology Notes Prepared by Mrs Cheryl Siah v. Grassland (in particular Savanna Grassland) a. b. c. d. e. Hot and wet Rainfall separated by long periods of drought Violent thunderstorm followed by strong drying winds Loose soil with high drainage of water Consists of the most number of species among the different types of grassland f. Abundance of grass interspersed with lone trees/shrubs g. Frequent fire h. Deep roots of grass not damaged by fires i. Roots with starch reserves for new growth ii. When rain comes, vigorous growth of grass iii. food available, animals reproduce i. Fires that kill insects create a “feast” for small animals vi. Tundra (in particular Arctic Tundra) a. b. c. d. e. f. g. h. i. Coldest biome Treeless Frost covered plain Very little rainfall Poor nutrients Short season of growth and reproduction Energy and nutrients mainly in dead organic materials Low shrubs, sedges, reindeer mosses, liverworts, and grasses crustose and foliose lichen i. mammals with long thick layer of hair and blubber for insulation ii. animals can hibernate iii. migratory birds No reptiles and amphibians (unable to regulate internal temperature) Tundra Environment Ecology Notes Prepared by Mrs Cheryl Siah C. Habitats and Physical Environment (Abiotic Environment) a. Air i. Quality of air 1. Presence/absence of pollutants ii. Content of oxygen 1. most organisms are aerobic 2. cannot survive in low oxygen environment unless specially adapted e.g. mangrove trees with pneumataphores lungfish living in African Mudflats b. Water i. Availability of water 1. Dependant on rainfall 2. Some plant specially adapted for little rainfall e.g. xerophytes 3. Some plants adapted for wet environment e.g. hydrophytes ii. Quality of water 1. Presence / absence of pollutants 2. Clarity of water (affects amount of sunlight penetrating water) c. Temperature i. Affects metabolism and physiological activities 1. Activities controlled by enzyme a. Enzymes are temperature sensitive b. Beyond optimal temperature, enzymes are denature d. Light Intensity i. Affects growth of plants ii. In dim light Plants develop adaptation to get more light Plants need to adapt to block off excessive light to block out excessive heat too iii. In excessive light e. pH i. ii. iii. iv. measures acidity and alkalinity of solution in relation to soil water or water bodies affects types of organisms living in environment decrease in alkalinity can be caused by photosynthesis that removes carbon dioxide from water v. increase in alkalinity can be caused by respiration rather than photosynthesis as carbon dioxide is removed f. Minerals i. Availability of minerals in soil or water ii. water with high concentration of salt/minerals (e.g. salt water) can cause living organisms to lose water iii. living organisms need to have special adaptations to prevent water loss iv. freshwater organisms have tendency to gain water Ecology Notes Prepared by Mrs Cheryl Siah v. living organisms need to have special adaptations to prevent excessive entry of water vi. brackish water mix of salt water and fresh water changes in salt concentration is high (large fluctuations) D. Understanding the Ecosystem a. living organisms (biotic) b. non-living (abiotic) environment c. Interaction of biotic and abiotic environment i. Ecological equilibrium means a biological balance in the relationships between the biotic and abiotic factors ii. Selective addition or removal of organisms affect the equilibrium and affects all other populations 1. External introduction of species can affect native species (naturally found in a particular habitat) E.g. cane toads brought in to control beetles which were destroying sugarcane crops harm native wildlife by eating the small animals and poison predators which try to eat them 2. More examples: http://www.environment.gov.au/biodiversity/invasive/ferals/index.html iii. Problems Related to Introduced species 1. No natural predators a. Can multiply out of control b. Introduced species can predate on native species c. Introduced species spread diseases to native species d. Introduced species can destroy the habitats of native species e. Introduced species can compete with native species for food, water and shelter Ecology Notes Prepared by Mrs Cheryl Siah E. Man’s Impact on the Environment a. Human activities have continually depleting the earth’s natural environment e.g. fossil fuels b. Ecological equilibrium can be upset c. Damages can be long lasting d. Deforestation i. Felling of trees in the forest for 1. Industrialization 2. Fuel 3. Farming 4. Making paper ii. Results in: 1. Loss of habitats for the living organisms 2. Soil erosion a. Lack of canopy coverage to cushion impact of rain b. Lack of roots to hold the soil c. Top soil gets washed away 3. Flooding a. Eroded soil enter rivers b. Blocking of water flow c. Water level rises and floods over 4. Climate changes a. Water evaporates very fast when there is no canopy coverage b. Area becomes very dry and warm i. Less rainfall e. Uncontrolled fishing practices i. Over fishing leads to declining fish/marine life populations 1. Due to destructive fishing methods 2. Fish populations do not replace fast enough Extinction f. Pollution i. Contribution of substances that damage the environment ii. Water Pollution 1. Untreated sewage 2. Pesticides washed into water 3. Eutrophication a. Washing of fertislisers into water i. Profuse growth of algae which blocks sunlight ii. Submerged algae and plants die iii. Bacteria multiply rapidly and compete for oxygen death of aquatic species iii. Bioaccumulation 1. Accumulation of poisonous chemicals through the food chain and concentration of chemicals in top of food chain. Ecology Notes Prepared by Mrs Cheryl Siah F. Importance of Nature Conservation a. Many undiscovered species that can be beneficial to mankind (half of the world’s 10 million species found in the tropical rainforests!) i. Harvesting of useful drugs 1. Potential cure of many illnesses/diseases 2. E.g quinine extracted from bark of Cinchona – antimalarial drug ii. Economically important species 1. Sources of raw materials for industries a. e.g. rattan for furniture b. e.g. fibres from cotton to make cloth 2. food (http://www.integratedconservationresearch.org/ICRIFiles/RainforestProducts.htm) b. Prevent species from reaching threatened or extinction status i. Maintain stable and balanced ecosystem ii. Prevent disruption of natural cycles (KIV) c. Prevent global warming d. Maintain a large gene pool i. Favourable genes in living organisms can be harvested to improve other living organisms 1. Improve agricultural produce 2. Make living organisms and man more resistant to diseases e. Conservation of marine life i. Source of food f. Maintain natural resources for outdoor recreational activities g. Conservation of rainforest i. Source of fresh drinking water supply ii. 1/5 of world’s supply moves though the Amazon Basin! Ecology Notes Prepared by Mrs Cheryl Siah