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The story of the peppered moth: 1850: 1850: mostly speckled; a few dark 2000: 2000: mostly speckled; a few dark 1900: 1900: mostly dark; a few speckled
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The story of the bacteria: 1st round of antibiotics: most bacteria die 2nd round of some die same antibiotic: some die 3rd round of same antibiotic: very few die
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What do these two stories have in common? Per. 1 Both adapted in the environment Both changed Change in patterns Change under circumstances Something prompts change
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What do these two stories have in common? Per. 3 Both have three rounds Both can be harmful Natural selection Both adapt The strongest survive
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What do these two stories have in common? Per. 4 They adapt They change over a time period The change could be graphed
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What do these two stories have in common? Per. 5 Both are changing in some way Became lesser as time goes on Both go through adaptations and natural selection
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What do these two stories have in common? Per. 6 Both adapting Both are changing because of environment
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What do these two stories have in common? Per. 8 They both change over time They adapt to their surroundings They both have independent and dependent variables They both are alive
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What do these two stories have in common? examples The changed over time Certain types of organisms decreased and then increased The change was observed and recorded Both living organisms Small organisms Change wasn’t obvious
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Given the phenomena of these two stories, what are some questions you could ask? Per 1 What causes this change? Why does the moth matter? Why did the antibiotics take away less and less bacteria?
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Given the phenomena of these two stories, what are some questions you could ask? Per 3 Why does bacteria death rate go down with more antibiotics? Why are peppered moths and bacteria related? What happened to the moths in 1900? Why did the majority go back to being speckled?
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Given the phenomena of these two stories, what are some questions you could ask? Per 4 How do they adapt? Why did they change? What happened to the moth?
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Given the phenomena of these two stories, what are some questions you could ask? Per 5 What causes the moths to lose their speckles? How does the bacteria get an immunity to antibiotics? How do they evolve over time? How do they change?
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Given the phenomena of these two stories, what are some questions you could ask? Per 6 Why are they both adapting? Why do they die off and come back in large numbers? What made them adapt?
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Given the phenomena of these two stories, what are some questions you could ask? Per 8 How long do they live? How do they change? What were the change? After losing their speckles, how do they get them back? What drives the change?
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Given the phenomena of these two stories, what are some questions you could ask? example How did they change? Why did one change faster than the other? What was the cause of the change? What eventually made the bacteria go away? Does their size influence how the change? Why did the antibiotics stop working? What caused the number of dark moths to increase? What caused the speckled moth to come back?
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Driving Question Per 1 What causes things to change?
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Driving Question Per. 3 “Why do things change?”
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Driving Question Why did they change? Per. 4
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Driving Question Per. 5 How do they change?
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Driving Question Per. 6 Why are they both adapting?
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Driving Question Per. 8 How do they change?
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How did they change over time? Driving Question example
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If all offspring of two parent bunnies survive and reproduce, how many bunnies will there be after 4 generations? A. What happens to population sizes over time? WHAT DO WE OBSERVE ABOUT POPULATIONS OF ORGANISMS?
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Another example: How many flies would there be by the end of one summer if all offspring of a mating pair survived and reproduced?
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OBSERVATION #1: Populations of organisms have the potential to grow exponentially. Graph of exponential growth:
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Is this what really happens? Are we overrun by bunnies… or flies… or any single species? What really seems to happen? In other words, what do we observe in real life? A species of fish A species of grass Biomass of population
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Yeast Sheep Paramecium (a protist) What is the pattern? How would you describe what populations really seem to do?
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OBSERVATION #2: Populations of organisms tend to stay relatively stable in size.
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Potential population growth in elephants Elephants are one of the slowest breeders on the planet. One female will produce 6 young over her 100 year life span. How many elephants could result from one male and one female in 750 years?
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19,000,000 elephants!!!
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With your partner, brainstorm a list of possible reasons why populations stay stable instead of continuing to increase exponentially. Per. 1 1.Hunting 2.Dehydration 3.Lack of resources 4.Climate change 5.Dying 6.Extreme weather 7.Disease
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With your partner, brainstorm a list of possible reasons why populations stay stable instead of continuing to increase exponentially. Per. 3 1.Aging 2.They get eaten 3.Don’t always reproduce 4.Disease/Injury 5.Lack of food 6.Territory 7.Overpopulation 8.Hunted 9.Competition
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With your partner, brainstorm a list of possible reasons why populations stay stable instead of continuing to increase exponentially. Per. 4 1.They die 2.Hunters 3.Not all reproduce 4.Predators 5.Disease 6.Not all offspring survive 7.Food supply 8.Water
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With your partner, brainstorm a list of possible reasons why populations stay stable instead of continuing to increase exponentially. Per. 5 1.They can die off 2.Predators 3.Disease 4.Environmental changes 5.Food/water 6.Famine 7.Meteors
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With your partner, brainstorm a list of possible reasons why populations stay stable instead of continuing to increase exponentially. Per. 6 1.Food chains 2.Predators 3.Starvation 4.Drought 5.Natural Disasters 6.Climate 7.Disease 8.They age
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With your partner, brainstorm a list of possible reasons why populations stay stable instead of continuing to increase exponentially. Per. 8 1.Disease 2.Hunted 3.Drought 4.Lack of resources 5.Starvation 6.Climate 7.They can die
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With your partner, brainstorm a list of possible reasons why populations stay stable instead of continuing to increase exponentially. example 1.Disease 2. predators/ prey Hunters 3. Natural Disasters 4. Not enough water 5. Disruption in the food chain 6. Space 7. Change in climate 8. Food
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What do we call all these things collectively? OBSERVATION #3: Populations are relatively stable in size due to limited resources in the environment. RESOURCES!
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Lets play a game to see what happens when resources are limited!
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1.Even student #’s are DEER, odds are RESOURCES. FOOD WATERSHELTER 2.Signs for resources: FOOD = both hands over belly, WATER = both hands over mouth, SHELTER = make a tent over head. 3.Groups stand with backs to each other. Everyone picks a resource by making the appropriate sign. You must keep displaying your sign the whole time! 4.On teacher’s signal turn and face each other. DEER must find someone showing the same resource on the other side. 5.Each deer can only claim one resource. 6.No changing once you turn around! 7.If a deer finds a resource it can “reproduce”. The resource it caught becomes a deer for the next round. 8.Resources not claimed stay a resource. 9.Deer not able to find their resource die and become a resource for the next round. “OH DEER”
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1. Was it always easy to be a deer in the game? Why or why not? 2. When resources were limited, what did it feel like to be a deer? DISCUSSION:
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INFERENCE #1 Within populations of organisms there is a struggle to survive.
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What do we observe when we compare individuals in a population? OBSERVATION #4 There is variation among organisms in a population. Variation naturally exists.
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Wormeaters
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What is going to happen to: …the wormeater with the disadvantageous variation? Spoony died Didn’t get much food Changed into another wormeater …the wormeater that got the most food? Reproduced Survived Per. 1
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What is going to happen to: …the wormeater with the disadvantageous variation? They die Spoony died Might go extinct …the wormeater that got the most food? Survived Reproduced/had offspring Per. 3
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What is going to happen to: …the wormeater with the disadvantageous variation? No offspring Spoony died …the wormeater that got the most food? Most offspring Survived each generation Per. 4
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What is going to happen to: …the wormeater with the disadvantageous variation? Wormeater die out Spoony usually died …the wormeater that got the most food? He will live/survive reproduce Per. 5
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What is going to happen to: …the wormeater with the disadvantageous variation? It will die. No more offspring Extinction …the wormeater that got the most food? Reproduced It had a surplus Per. 6
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What is going to happen to: …the wormeater with the disadvantageous variation? It will die off. Spoony died in first generation …the wormeater that got the most food? Continued into next generation Survived Per. 8
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What is going to happen to: …the wormeater with the disadvantageous variation? Spoony Die, all spoony die They are not eqiuped for their environment …the wormeater that got the most food? There will be more wormeaters with the forktunis variation over time Going to reproduce Survive longer Reproduce more example
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OBSERVATION #5: Individuals with advantageous variations have a better chance of surviving than those with less advantageous variations. OBSERVATION #6 Survival allows reproduction
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When the surviving wormeaters reproduce what kind of beaks will their offspring most likely have? OBSERVATION #7: Many variations are inherited (in other words, offspring tend to resemble their parents).
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# advantageous What do you predict would happen to the # of individuals with the advantageous variation in the next generation? INFERENCE #2: The # of individuals with advantageous variations will increase in each new generation. The # with disadvantageous traits will decrease. disadvantageous What about the # of individuals with the disadvantageous variations?
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What do you predict will happen to a species over many generations? INFERENCE #3: Over many generations the species changes, i.e. EVOLUTION occurs.
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OVERVIEW of the MODEL OBSERVATION #1 Populations have potential to grow exponentially. OBSERVATION #2 Population sizes remain relatively stable over time. OBSERVATION #3 Stable population sizes are due to limited resources. INFERENCE #1 Within populations there is a struggle to survive. OBSERVATION #4 Within populations there is variation. OBSERVATION #5 Some variations provide a survival advantage. OBSERVATION #6 Individuals who survive can reproduce. OBSERVATION #7 Many variations are heritable. INFERENCE #2 # individuals with advantageous traits increases in each generation. INFERENCE #3 Over many generations, species change. EVOLUTION occurs!
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