March 17, 2016 Bell Work: What is primary succession? Objective: The student will be able to… Describe the flow of energy through ecosystems.

Today in History 1941 The National Gallery of Art opened in Washington, D.C. 1942 Gen. Douglas MacArthur arrived in Australia to become supreme commander of Allied forces in the southwest Pacific theater during World War II.

Movement of Energy Through Ecosystems Anything an organism does in an ecosystem requires energy The flow of energy controls what type of organisms that live in an ecosystem It also controls how many organisms an ecosystem can support.

Primary Energy Source The sun is the ultimate source of energy for all living organisms All organisms depend on the energy the sun emits in one way or another

Primary Energy Source Primary productivity is the rate at which organic material is produced by photosynthetic organisms Primary productivity manages the amount of energy available in an ecosystem

Primary Energy Source Producers are organisms that first capture the energy and make energy-storing molecules. Includes plants, some bacteria, and algae Consumers are the organisms that consume plants and other organisms to obtain the necessary energy to build their molecules.

Quick Review What is the primary source of energy for all living systems? What does the amount of energy produced in an ecosystem depend on? Explain the difference between producers and consumers.

Trophic Levels Trophic Level: one of the steps in a food chain or food pyramid; examples include producers, and primary, secondary, and tertiary consumers Energy moves from one trophic level to another

Trophic Levels

Trophic Levels A food chain is the path of energy through a trophic level in an ecosystem Producers are the first level of a food chain. Use energy from the sun to produce their food Many also absorb key substances from the environment, such as nitrogen, and build them into their molecules

Trophic Levels The second level of the food chain consists of primary consumers Consumers must consume plants or other organisms to obtain energy Primary consumers are herbivores Herbivores are animals that eat plants and other producers Must be able to break down plants’ molecules into usable compounds

Trophic Levels The third level of the food chain consists of secondary consumers Carnivores are animals that eat other animals Example: Wolves, tigers, snakes, most felines Omnivores are animals that eat plants and other animals Example: Bears, humans, Both carnivores and omnivores are secondary consumers Secondary consumers cannot digest cellulose

Trophic Level Detritivores are organisms that obtain their energy from the organic wastes and dead bodies produced at all trophic levels Bacteria and fungi are known as decomposers Decomposers cause decay Decomposition releases nutrients back into the environment Tertiary consumers make up a fourth trophic level in many ecosystems This level is composed of carnivores that eat other carnivores Also called top carnivores

Trophic Levels A food web is a complicated interconnected group of food chains In most ecosystems, energy does not flow in straight path. Organisms feed at several trophic levels.

Energy in Food Chains Potential energy is the energy stored in chemical bonds of leaves. This energy is transferred through the food chain During the transfer of energy in an ecosystem, energy is lost through heat The amount of useful energy available decreases as the energy passes through the ecosystem This limits the number of trophic levels and ecosystem can support

Energy in Food Chains Photosynthesis only captures about 1% of energy available to leaves 10% of energy is transferred to each trophic level Herbivores only get 10% of the potential energy from plants and other organisms. 90% is lost to heat. Carnivores only get 10% of the potential energy from other animals they consumes. 90% is lost as heat. At each trophic level, one tenth (1/10) of the energy is stored than that stored by organisms in the previous trophic level.

Energy in Food Chains The flow of energy through an ecosystem can be illustrated with an energy pyramid Energy pyramid: a diagram in which each trophic level is represented by a block and the blocks are stacked on top of each other with the lowest trophic level being on the bottom. The width of each block is determined by the amount of energy stored in the organism at that trophic level.

Energy in Food Chains Most terrestrial ecosystems involve only three or four trophic levels Four or more trophic levels is very rare Too much energy is lost at each level for an ecosystem to support more than three or four trophic levels The number of individuals may not be an accurate indicator of the amount of energy of that level Depends on the size of the organisms Larger animals use more energy

Energy in Food Chains Biomass is the dry weigh of tissue and other organic matter found in an ecosystem. Each level of an energy pyramid contains only 10% of biomass found in the trophic level below it.

Vocabulary

Ticket Out What is a trophic level?