Food Webs & Energy Transfers

Energy Flow All living things are made of matter & need energy Matter and energy move through the natural world Matter is recycled over and over again, but energy is CONVERTED This conversion is important to all life on Earth pg. 482 Photosynthesis Chemosynthesis Hydrothermal Vents

Acquatic plants -> insects -> bluegill -> bass -> humans Food Chains Energy is transferred from one organism to another through eating producers or other consumers Consumers: organism that obtains energy by eating other organisms Producers: organism that makes its own food (plants) Decomposers: organisms that obtain energy for life when the break down organic material Identifying Discussing the Connection and relationship among them* A food chain is a simple model to show how the energy (as food) passes from one organism to another - arrows indicate the direction of the energy flow - usually only 3-4 links - at each transfer energy is lost as thermal energy (1st link has more than last link) Acquatic plants -> insects -> bluegill -> bass -> humans

Visualizing the Food Chain Some Practice Let’s take a look at pg. 537

How do organisms “relate” to each other? Predation- describes a biological interaction where a predator (an organism that is hunting) feeds on its prey (the organism that is attacked) Parasitism- A parasitic relationship is one in which one organism, the parasite, lives off of another organism, the host, harming it and possibly causing death. The parasite lives on or in the body of the host. Commensalism- is a class of relationship between two organisms where one organism benefits but the other is neutral (there is no harm or benefit). Mutualism- is a relationship in which both animals benefit

Recap Commensalism - there is no harm or benefit Mutualism- where both organisms benefit Competition- where both organisms are harmed Parasitism- one organism benefits and the other one is harmed. Symbiosis

Food Webs Food chains are very simple and don’t really give us an entire picture of how energy flows A food web is a series of overlapping food chains Provides a more complete model Shows how organisms are part of many food chains Compare & Contrast: when compared to a food chain, a food web provides a more complete model of the feeding relationships in a community

Real Life: How do changes in Atlantic food webs affect populations? Identifying the Problem Worldwide, the hunting of most baleen whales has been illegal since 1986. It is hoped that the baleen whale population will increase. How will an increase in the whale population affect the food web illustrated below? Solving the Problem 1- Populations of sharks and krill eating fish increased as whale populations decreased. Explain why. 2- What might happen if the number of baleen whales increases but the number of krill does not? How do changes in Atlantic food webs affect populations? The food webs in the icy Atlantic Ocean are based on phytoplankton, which are microscopic algae that float near the water's surface. The algae are eaten by tiny, shrimplike krill, which are consumed by baleen whales, squid, and fish. How would changes in any of these populations affect the other populations?

Energy Pyramid * The amount of energy is reduced as the energy travels through each link of a food chain (from animal to animal) An Energy Pyramid shows the available energy at each feeding level

Energy Pyramid Explained The bottom of the pyramid (producers) is the largest and first feeding level – it contains the most energy As you move up the pyramid less energy is transferred and it is less efficient Each level becomes smaller and smaller

Food Chain & Energy Web - RECAP GIZMO: Food Chain LAB