1 Aim: How does competition affect organisms in nature? Do Now: List three things you compete for in your life.

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4 II. Predator-Prey Relationships A. Predators help control the size of the prey populations 1. Prey populations are kept below their carrying capacity (The max. number an ecosystem can support). Example: NYS Deer.

5 II. Predator-Prey Relationships B. B. Population explosions are common when prey populations are moved into areas that don’t have natural predators. Ex - Rabbits in Australia one dozen rabbits were introduced ,000 rabbits were shot ,000,000 rabbits were shot

6 II. Predator-Prey Relationships C. Prey populations control the size of the predator populations 1. When a predator has one type of food, it depends on how many prey there are. ex. Lynx and Snowshoe hairs

7 II. Predator-Prey Relationships D. Neither predator nor prey influences the other’s population size. 1. This occurs when a predator relies on many different prey species for food. Example: Humans

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9 Objective: Population Size Do Now: Take out your HW to be checked. Take out your HW to be checked. Why is the interaction on the next slide taking place, and predict what will happen next. Why is the interaction on the next slide taking place, and predict what will happen next.

10 Zebra Mussels ed/myContent.cfm?rand=E1D94B3A-F20F EC09DCC69EBE146B

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19 III. Food Chains – show what things eat. A. Parts of the food chain: 1.Producers – make their own food. 2.Herbivores – eat plants only 3.Carnivores –eat animals only 4.Omnivore – eat plants or animals 5.Decomposers – break down dead organisms back to soil.

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21 III. Food Chain B. Food Web – shows overlapping food chain.

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