Presentation on theme: "Food Webs Catalyst: Describe evolution in your own words. Solve:"— Presentation transcript:
1Food Webs Catalyst: Describe evolution in your own words. Solve: Shaq is selling candy, M&M’s and Twix. He sold 48 total candy bars. He sells M&M’s for 2 dollars and Twix for 3 dollars and made 124 dollars total. How many of each bar did he sell?Write in complete sentences!Don’t talk during the Catalyst!
2ObjectiveBy the end of today, all SWBAT…Analyze food webs by predicting the impact of the loss or gain of an organism
4How Do Organisms Interact? They eat each other!Key Point #1: A food web shows all the feeding relationships in an ecosystem.
5First, some vocabulary… Producer: another word for autotroph. Makes its own food through photosynthesis.Consumer: another word for heterotroph. Eats other things for energy.Primary consumer: eats producers.Secondary consumer: eats primary consumers.Tertiary consumer: eats secondary consumers.Note that animals can have multiple roles. The cougar is both a secondary and a tertiary consumer.
6Some things to notice…Arrows show how energy flows through the food webThink: they point from one organism INTO the stomach of whatever eats itThe most basic level of the food web is the producer. Where does it get its energy from?Foxes eat snakes.Last transition: Prompt kids… they should be able to come up with their answer on their own. Producers get their energy from the sun.
7Guided Practice (GP) 1The arrow pointing from seed-eating birds to foxes shows that...Foxes eat birdsBirds eat foxesFoxes and birds share foodFoxes and birds compete for the same foodUse ActivExpressions if you have them, otherwise whiteboards/sign language.A
8Guided Practice (GP) 1Although it is not shown in this picture, where does all of this food web’s energy begin?The MoonThe EarthThe SunFertilizerC
9Guided Practice (GP) 1 What is the producer in this food web? Hawks and owlsSquirrelsPlantsSpidersC
10Guided Practice (GP) 1Which of the following is a secondary consumer in this food web?ToadsPlantsMiceSpidersD
11Guided Practice (GP) 1 Which two organisms compete for the same food? Hawks & micePlants & toadsRabbits & spidersFoxes & snakesD
12Which is true?The energy content of the foxes depends on the energy content of the hawksThe energy content of the spiders is transferred to the herbivorous insectsThe energy content of the snakes depends on the energy content of the toadsAll of the above are true
13What If…?Key Point #2: We can use food webs to predict what will happen when we introduce/take away a speciesThree important interactions for you to learn.
14Food Web InteractionsWhat do you think will happen to the rabbits, if all the vegetation is destroyed?If a population loses ALL of its food sources, it will become extinct.Technically extirpated (extirpation = localized extinction), but that isn’t an important nuance for them to learn until college.
15Food Web InteractionsWhat do you think will happen to the cougar, if all of the deer die?If a population loses SOME of its food sources, it will decrease in size.
16Food Web InteractionsWhat do you think will happen to the mice, if all of the foxes are eaten by the cougars?If a population loses its predators, it will increase in size.
17Guided Practice (GP) 2What will happen to the mouse population, if a disease kills all the plants?All will go extinctIncrease in sizeDecrease in sizeReproduce moreA
18Guided Practice (GP) 2Imagine that a bobcat enters the ecosystem. Bobcats eat insectivorous birds. What will happen to the fox population?All will go extinctIncrease in sizeDecrease in sizeMove elsewhereC
19Guided Practice (GP) 2Imagine that a disease kills all of the snakes in the ecosystem. What will happen to predaceous insect population?All will go extinctIncrease in sizeDecrease in sizeStop eating herbivorous insectsB
20Guided Practice (GP) 2What will happen to the squirrel population, if a cow wanders by and eats all the plants?All will go extinctIncrease in sizeDecrease in sizeStart eating toadsA
21Guided Practice (GP) 2What will happen to the rabbit population, if a drought kills all the plants?All will go extinctIncrease in sizeDecrease in sizeEat foxesA
22Guided Practice (GP) 2Imagine that a hunter kills all of the hawks and owls in the ecosystem. What will happen to the seed-eating bird population?All will go extinctIncrease in sizeDecrease in sizeBegin eating spidersB
23Guided Practice (GP) 2Pretend that a falcon enters the ecosystem. Falcons eat toads. What will happen to the snake population?All will go extinctIncrease in sizeDecrease in sizeStop eating toadsC
24Guided Practice (GP) 2Imagine that a population of bears wanders into the ecosystem. Bears eat foxes. What will happen to the squirrel population?All will go extinctIncrease in sizeDecrease in sizeMove elsewhereB
25Independent PracticeMake your own food web. (You don’t actually have to draw each animal, if you don’t want to. You can just write their names.)Your food web must have at least FOUR producers, TWO primary consumers, ONE secondary consumer, and ONE tertiary consumer.Describe two situations in which an organism enters/leaves your food web. Explain what will happen to the other organisms in your food web as a result.Optional, if time permits. Last year, students blazed through this lesson, even though there are a lot of slides/GP questions.
26Key Point Wrap-UpKP#1: A food web shows all the feeding relationships in an ecosystem.KP#2: We can use a food web to predict what will happen when we introduce/take away a speciesIf a population loses ALL of its food sources, it will become extinct.If a population loses SOME of its food sources, it will decrease in size.If a population loses its predators, it will increase in size.
27Exit QuestionsUse the food web at right to answer the questions below.What animal eats the elk?What would happen to the rabbit population, if all the grass were to be burned down in a fire?Imagine that a population of foxes wanders into this food web, and eats all the mice. What will happen to the cricket population?Mountain lionExtinctionIncrease in size