Transcript Ecology
Chapter 3 Ecology Energy Flow • Ecology is the study of the way living things interact with each other and their physical environment. How does energy flow? •Energy flows in one direction. From sun to the producers to the consumers •Producers (plants)= organisms that make their own food to obtain energy •Consumers( animals)= organisms that consume other organism for energy •Heat Energy (sun) is converted to Chemical Energy (food) through energy flow. •Some energy is lost to heat at each transfer Producers Organisms that use energy from the environment (make their own food) through sunlight or chemicals are called autotrophs or PRODUCERS. •The main source of energy for life on Earth is the SUN. •Organisms use sunlight through photosynthesis. •Photosynthesis is the use of light energy to power chemical reactions that convert carbon dioxide and water into oxygen and carbohydrates like sugar and starch. • On land, plants are the main autotroph. In freshwater ecosystems and the sunlit upper layers of the ocean, algae are the principal autotrophs. Cyanobacteria • Photosynthetic bacteria are the most common and produce much of the earth’s oxygen. • Some autotrophs rely on stored energy found in inorganic chemical compounds instead of the sun. • Since they get their energy from chemicals, they are called chemotrophs and use chemosynthesis to produce carbohydrates. • Chemosynthesis is performed by several types of bacteria. These bacteria can be found in obscure places like: •Volcanic vents on the ocean floor. Hot Springs & Tidal Marshes along the coast. • Organisms that cannot harness energy directly must acquire energy from other organisms and are called consumers or heterotrophs. • There are many different kinds of heterotrophs: Herbivores only eat plants. Prey Carnivores only eat meat Predator Omnivores eat plants & meat Detritivores • Mites, earthworms, snails, and crabs feed on plant and animal remains and other dead matter, called detritus. Decomposers (Saprophytes) break down organic matter. What are some ways we can see how energy is transferred? • • • • • Ecological Food Chains and Webs Ecological Pyramids Energy Pyramids Biomass Pyramids Numbers Pyramids • Energy flows through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers). Food Chain • Series of steps in which organisms transfer energy by eating and being eaten. Food Chain What are the producers in this chain? What are the secondary consumers? Where is the least energy in this chain? What type of feeding organism is the squid? • Food Webs are the feeding relationships among the different organisms in an ecosystem. • Each step in a food chain or food web is a trophic level. Food Chains and Webs •Producers are at the beginning(photosynthetic organisms) •Herbivores (primary consumersget energy only from plants (grasshopper) •Carnivores (secondary/tertiary consumers-feed on other animals (owl) •Omnivore= organism that feeds on both plants and animals •ARROWS INDICATE THE TRANSFER OF ENERGY •The most of the energy is at the producer level. Least is at the top level •Trophic Levels: each step in a food chain or web Ecological Pyramids • A diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web. • Only 10% of the energy available within one trophic level is transferred to organisms at the next trophic level. Ecological Pyramid Energy Pyramid • shows the relative amount of energy at each trophic level •Average energy transfer form one trophic level to the next is 10% Biomass Pyramid Pyramid of Numbers •Shows the total amount of living tissue within trophic level •Shows the relative number of organisms at each trophic level •Highest quantity on the bottom lowest on the top Biomass • The total amount of living tissue within a given trophic level. • A biomass pyramid represents the amount of potential food available for each trophic level in an ecosystem.