Ecology (Final) PDF Notes

Topic: Ecology Ecology—the scientific study of interactions between different organisms and between organisms and their environment or surroundings The term ‘Ecology’ was coined by Ernst Haeckel (1866) Biotic—living factors that influence an ecosystem Abiotic—non-livin...

Topic: Ecology Ecology—the scientific study of interactions between different organisms and between organisms and their environment or surroundings The term ‘Ecology’ was coined by Ernst Haeckel (1866) Biotic—living factors that influence an ecosystem Abiotic—non-living factors that influence an ecosystem  Producers A. Sunlight is the main energy source for life on earth B. Also called autotrophs C. Use light or chemical energy to make food 1. Plants 2. plant-like protists (algae) 3. Bacteria D. Photosynthesis—use light energy to convert carbon dioxide and water into oxygen and carbohydrates Light Energy (Remember: 6CO2 + 6H2O 6O2 + C6H12O6) E. Chemosynthesis—performed by bacteria, use chemical energy to produce carbohydrates  Consumers A. Organisms that rely on other organisms for their energy and food supply B. Also called heterotrophs Herbivores—obtain energy by eating only plants Carnivores—eat only animals Omnivores—eat both plants and animals Decomposers—breaks down dead organic matter  Feeding Interactions A. Energy flows through an ecosystem in one direction— from the sun or inorganic compounds to autotrophs (producers) and then to heterotrophs (consumers)  Species Species - group of organisms so similar to another that they can breed and produce fertile offspring  Population Population – same species and live in same area  Community Communities – different populations that live together in a defined area  Ecosystem An ecosystem is a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life. Ecosystems contain biotic or living, parts, as well as abiotic factors, or nonliving parts. The term ‘Ecosystem’ was coined by A G Tansley (1935)  Biome Biome – a group of ecosystems that have the same climate and similar dominant communities. B. Food Chain—series of steps in which organisms transfer energy by eating and being eaten 1. Arrows go in the direction of how energy is transferred 2. Start with producer and end with top consumer or carnivore Ex: grass cricket frog raccoon Examples of Consumers C. Food Web—network of food chains within an ecosystem Hawks Weasels Raccoons Mice Grass Which of the organisms above is the producer? Grass Which of the organisms above is the top consumer? Hawks D. Trophic Levels—each step in a food chain or food web 1. Level 1—Producers (autotrophs) 2. Level 2—Primary Consumers (herbivores) 3. Level 3—Secondary Consumers (carnivores or omnivores) 4. Level 4—Tertiary Consumers (carnivore—usually top carnivore)  Hawks Food Webs Weasels Raccoons Mice Grass IV. Ecological Pyramids A. Diagram that shows the relative amount of energy or organisms contained within each trophic level of a food chain or web B. Energy Pyramid shows relative amount of energy available at each trophic level 1. Organisms in a trophic level use the available energy for life processes (such as growth, photosynthesis, cellular respiration, metabolism, etc.)and release some energy as heat Remember: Every chemical process that happens in your body releases heat as a byproduct (ex: burning calories). 2. Rule of 10—only about 10% of the available energy within a trophic level is transferred to the next higher trophic level C. Biomass Pyramid—represents the amount of living organic matter at each trophic level  0.1% 1% 10% 100% Energy Pyramid Biomass Pyramid Energy and Biomass Pyramid (together) Represents amount of energy available at each level as well as amount of living tissue— both decrease with each increasing trophic level Biomagnification or biological magnification is the process of accumulation of certain chemicals in living organisms to a concentration higher than that occurring in the inorganic, non-living environment Heavy metals Ex: mercury Pesticides Ex: DDT (dichlorodiphenyltrichloroethane) Causes of Biomagnification: Agriculture The agricultural pesticides, insecticides, fertilizers and fungicides are very toxic and are released into the soil, rivers, lakes, and seas. Organic Contaminants Manures and biosolids are processed industrially and contain contaminants like pharmaceuticals and personal care products. Industrial Activities The industries and factories release toxic substances that are released into the soil, lakes, oceans, and rivers. Mining Activities in ocean Mining activities are carried out in the deep sea to extract metal like zinc, aluminium, cobalt, silver and gold. The mining process generates a large amount of selenium and sulphide, which deposits in water and destroys the oceans and coastal regions. Topic: Ecosystem  Ecosystem : An ecosystem is a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life. Ecosystems contain biotic or living, parts, as well as abiotic factors, or nonliving parts. The term ‘Ecosystem’ was coined by A G Tansley (1935) Lentic: Standing Water Lotic: Running Water Aspects of ecosystem Structural: Composition, Biomass, Number, Sp. Energy flow: Energy flow, Production, Respiration  Different Terminologies of ecosystem Primary productivity is the process by which organisms make their own food from inorganic sources. The majority of primary producers are terrestrial plants and microbial life, such as algae. Gross productivity is the overall rate of energy capture. Net primary productivity (NPP) refers to the rate of the accumulation of energy in the form of biomass. It excludes energy lost in the metabolic processes. Secondary productivity is the rate of biomass formation or energy fixation by heterotrophic organisms, such as grazers and decomposers. Pond Ecosystem Forest Ecosystem Grassland Ecosystem