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Download Energy flow in an ecosystem Energy Flow in Ecosystems Trophic
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Ecosystems Energy Flow in Ecosystems Energy flow in an ecosystem What is the ultimate source of energy? What processes transfer this energy into living organisms? Are there some relevant mathematical relationships? Are there any exceptions to this source of energy? • The ultimate source of energy is the sun! • Plants, algae, and some bacteria turn light energy into food energy through the process of photosynthesis. Can you think about what the parts of the word photosynthesis might mean? • This energy is available to animals… – when they eat plants – when they eat other animals. Ecosystems Ecosystems Trophic (Nutrition) Levels of an Ecosystem Large carnivores Amount of Biomass in an Ecosystem Large carnivores 0.1% Small carnivores Herbivores Herbivores 10% Plants Small carnivores 1% Plants 100% Ecosystems Ecosystems Producers and consumers Can you figure out these definitions? • Producers: organisms that make their own food, such as a plants and algae. • Consumers: organisms that get food by eating other organisms. • • • • The Greek word troph means nutrition or growth. The Greek word auto means self. The Greek word hetero means many or mixed. What do you think is meant by autotroph? – An organism that can make its own nutrition. These organisms are generally plants or algae. • What do you think is meant by heterotroph? – An organism that relies on many other organisms or a variety of other organisms for nutrition. Ecosystems Energy Pyramid Ecosystems Deep-Ocean Ecosystems: (Don’t use the Sun for energy) How many lions? • Deep ocean ecosystems exist in total darkness. • No photosynthesis takes place. • Geothermal vents in the ocean floor emit nutrients and energy for tube worms. • Tube worms coexist with bacteria that let them produce food without sunlight. Ecosystems Decomposers • Decomposers get food from dead organisms. • They are essential components of nutrient cycles. • They return nutrients to the soil. • Examples: bacteria and fungi. Ecosystems Photosynthesis • Roots absorb water from the soil, and veins carry it to the leaves. • Carbon dioxide enters through tiny openings in the leaves. • Sunlight supplies the energy to make the sugar. Chloroplasts in the leaves trap light energy and perform the photosynthesis reaction. How many giraffes? 1000 producers Ecosystems Photosynthesis • Producers use light energy to make food (sugar) from carbon dioxide (CO2) and water (H2O). Ecosystems Photosynthesis General Reaction 6CO2+ 6 H2O + Energy C6H12O6+ 6O2 REACTANTS PRODUCTS Ecosystems RESPIRATION • Harvesting of the chemical energy stored in food (glucose) • Takes place in the mitochondria of cells. Ecosystems Ecosystems General Reaction of Cellular Respiration C6H12O6 + Glucose 6CO2 + Carbon Dioxide Ecosystems 6O2 Oxygen 6H2O + Energy Water CO2 – O2 Cycle Photosynthesis vs. Respiration • Photosynthesis is more or less the opposite of respiration. • In photosynthesis, sugars are formed, oxygen is released, and carbon dioxide is used up. • In respiration, sugars and oxygen are both used up, and carbon dioxide is released. O2 chloroplast CO2 mitochondria Ecosystems Definitions: Niche and Habitat • Habitat : the place where an organism lives. Energy Transfer • Niche: an organism’s way of life within its habitat. Food Chains Food Webs Trophic Levels • The niche an organism fills in its habitat is partially described by what it eats – and what eats it! Ecosystems Food Chains • A sequence in which energy is transferred from one organism to another as each organism eats another Ecosystems Food Web • A food web is a network of interconnecting food chains. • A food web presents a more realistic view of an ecosystem than does a food chain. Ecosystems The Cycling of Materials Water Cycle Carbon Cycle Nitrogen Cycle Ecosystems Water Cycle • All living things need water to survive. • Water evaporates into the atmosphere from surface water and from water that evaporates from land and from plants. • Water returns to the earth as precipitation. Ecosystems Water Cycle Ecosystems Ecosystems Carbon Cycle • Respiration puts carbon into the atmosphere. • Photosynthesis takes carbon out of the atmosphere. Ecosystems Nitrogen Cycle • All organisms need nitrogen (N2) to make protein. • Only the nitrogen fixing bacteria can “fix” atmospheric nitrogen • All other organisms are dependent on these N2 fixing bacteria. Ecosystems Nitrogen Cycle
