Introduction to Ecology

Ecology Review All organisms need to acquire energy to survive. Autotrophs- “self” “energy” use energy from the sun (Photosynthesis) or chemicals (Chemosynthesis) to make their own food.

Ecology Review Heterotrophs- “different” “energy” eat plants, animals, fungi, protists or bacteria in order to get energy.

Types of Heterotrophs: Carnivore - feeds on animals Herbivore - feeds on plants Omnivore - feeds on both plants and animals Scavenger - feeds on dead animals Decomposer- breaks down and absorbs dead organisms and wastes

A food chain illustrates the flow of energy through an ecosystem. Each organism represents a different Trophic Level.

Food Chain Examples Trophic Levels (Hawk) (Snake) (Mouse) (Cricket) (Plant) (Orca Whale) (Cod Fish) (Minnows) (Zooplankton) (Phytoplankton) Trophic Levels

Trophic Levels The 1st trophic level = Producers Produce their own food (plants) The 2nd trophic level = Primary Consumers Herbivores (eat the producers) The 3rd trophic level = Secondary Consumers Carnivores (eat the herbivores) The 4th trophic level = Tertiary Consumers Carnivores (eat other carnivores)

Trophic Levels in a Trophic Pyramid

Energy Flow in a Trophic Pyramid *With each step UP the Food Pyramid the amount of energy transferred decreases With every passing level, 90% of all energy is used up by the consumer! Only 10% of the producer’s energy actually makes it into the herbivore’s system! Only 10% of the herbivore’s energy actually makes it to the first carnivore in the chain! And so on…

Where does the Energy go??? The energy is lost in many ways: through biological processes and as heat to the environment.

Example of Energy Transfer In order to survive, a 3 pound hawk eats 30 pounds of lizards in a month. In that same month in order to survive, those lizards have to eat 300 pounds of crickets. How many pounds of grass do those crickets have to eat in order to survive? 3000 pounds!

Example of Energy Transfer There are 9000 pounds of grass in one particular habitat. How many pounds of crickets can live here? How many pounds of lizards can live here? How many hawks? (One hawk weighs 3 pounds)

Example of Energy Transfer There are 9000 pounds of grass in one particular habitat. How many pounds of crickets can live here? 900 How many pounds of lizards can live here? 90 How many hawks? (One hawk weighs 3 pounds) 3 hawks (9 pounds)

Food Chain Activity Students should work in groups of 3 to complete the worksheet and play the food chain game. Go to Google Classroom and follow the link. The worksheet is due at the end of class today. http://www.sheppardsoftware.com/content/animals/kidscorner/foodchain/foodchain2.htm

Food Webs A food web is more involved, and describes all of the possible feeding relationships in an ecosystem. Arrows indicate the flow of energy from where energy was stored (prey) to where the energy is going (predator)

Blue Whale Penguin Seal Fish Sea Gull Plankton

Food Web Activity There is ONE BLANK CARD - *What NONliving thing should be drawn? Cut out the cards and arrange them based on their feeding relationships. Glue them on the white paper and connect them with arrows. Add color and details to your food web. Answer the questions on the back. Due at the end of class!

Food Web Analysis Questions Write your names AND your answers on the back of your food web paper… 1. What does the frog depend on indirectly? 2. What would happen to the spider populations if the aphid population went down? 3. If there was a drought and the grass died, how would the food web change? Be specific.