Ecology Powerpoint ptbeach生态ptbeach PowerPoint.pptx

Ecology—the scientific study of interactions between different organisms and between organisms and their environment or surroundings 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 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 (Remember: 6CO2 + 6H2O 6O2 + C6H12O6) E. Chemosynthesis—performed by bacteria, use chemical energy to produce carbohydrates Consumers 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) Food Chain—series of steps in which organisms transfer energy by eating and being eaten Arrows go in the direction of how energy is transferred Start with producer and end with top consumer or carnivore C. Food Web—network of food chains within an ecosystem Which of the organisms above is the producer? Which of the organisms above is the top consumer? Grass Hawks 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) Food Webs Ecological Pyramids A. Diagram that shows the relative amount of energy or organisms contained within each trophic level of a food chain or web Energy Pyramid shows relative amount of energy available at each trophic l