1. Food Webs & Energy Transfers

2. 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

3. 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

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

5. 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

6. 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

7. 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

8. 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 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?

9. 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

10. 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

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