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Warmup Get out a sheet of notebook paper and put your name on it. You will use this paper all week for warmups. Answer the following question – What is a dead zone?
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Learning targets to this point
Use a model to describe the interactions in an ecosystem Use a model to describe how water collects in a watershed Explain the features of an estuary Analyze data to explain how humans have impacted dead zones *Use a model to look for patterns in an ecosystem*
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Lesson Concept: How have human activities impacted the Chesapeake Bay ecosystem? Apply concepts from… Pops and ecos Watersheds Estuaries
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Open your notebook to page 33
Quick Write – In what ways do human activities effect the world around us? Try to come up with 3 activities (causes) and the impact on the environment (effects) these activities have. You have 5 minutes.
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What caused dead zones in the Gulf of Mexico?
Excess runoff from fertilizers (farming) Increase nutrients plankton increased died fed bacteria bacteria increased oxygen decreased organisms die or leave the area
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Chesapeake Bay Ecosystem
Affected by dead zones Open your notebook to page 36. At the top of the page copy the following focus question: How do increases in the human population affect the resources available to organisms? Now write your initial thoughts in a complete sentence
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Chesapeake Bay: US Coast Guard
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The Chesapeake Bay Watershed
Chesapeake Bay Watershed: US Department of Agriculture Begin with a map of the Bay and close up images of the rivers from six states and the District of Columbia that feed into the Bay. Note that there are two maps of the same area on the slide. The map on the left shows the geographic area, but the map on the right shows the waterways involved in the watershed. Ask students to share what they remember from the watershed and estuary lessons at the beginning of the unit and ask them to use the map in their discussion.
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Largest estuary in the United States
Share that the Bay is the largest estuary in the United States. Guide students in making connections to their previous estuary lessons. Bay Map: NASA Largest estuary in the United States
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No other American estuary has a higher yield
Fishing Industry of: No other American estuary has a higher yield Blue Crab Oysters Striped Bass Clams Share that no other American estuary has a higher yield of fish and seafood (including blue crab, oysters, clams, and striped bass). Blue Crab: The Children's Museum of Indianapolis Oyster: David Monniaux Striped Bass: Mike Smedley Clam: Aung/Wikipedia
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The Bay is not healthy… Direct students to notice the bright green areas in this small area of The Bay. Those are areas where algae is growing quickly (algal blooms). Ask students what they think cause algal blooms?
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Nutrient Pollution Causes Algal Blooms and Fish Kills
This is a close up of an algal bloom. Students will note the dead fish and this can lead to a discussion about the consequences of algal blooms. But where does nutrient pollution come from? Remind students of their work during the watershed modeling lesson when they “polluted” the watershed with food coloring in order to model runoff. Ask students to share connections between that lesson and what is happening in The Bay. What kinds of sources for water pollution might be affecting Algal Blooms: Jennifer L. Graham/US Geological Survey Nutrient Pollution Causes Algal Blooms and Fish Kills
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What causes the excess nutrients?
Rivers and tributaries are bringing the nutrients to the Chesapeake Bay: Sewage Farming Factory farms discharge 650 million lbs of chicken manure each year Confirm the sources of the runoff for The Bay with students. Factories and farms exist all along the tributaries that lead into The Bay. This carries extra nutrients into the water, leading to algal blooms. Hog Farm Waste: USDA Chickens: SRAP Pigs: Farm Sanctuary
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Nutrients, Algae and Fish Kills
Dead zones appear in the bay where nothing can live Low dissolved oxygen in the water kills fish and other organisms Microbes use the oxygen in the water Detritus is decomposed by microbes, microbe populations boom. Algae die and become detritus (decaying matter) Adding nutrients causes algal blooms In normal ecosystem low nutrient levels keep algae in check Walk through the process by which algal blooms cause dead zones by reading through the graphic. Tell students that algae exists normally in the water, but that increased nutrients causes the algae to reproduce rapidly, resulting in an “algal bloom.” Normally, we might think of the term “nutrients” as being a good thing. But in this case it might have positive effects on one organism (the floating algae) but negative effects on other organisms in the ecosystem. When the algae die it becomes detritus (decaying matter) that is decomposed by microorganisms. The microorganisms (microbes) use oxygen from the water. This causes the dissolved oxygen levels to be low, which means that fish and other organisms can’t survive. This causes a dead zone, or an area where nothing can survive. Dead Fish: US Geological Survey Fish kill caused by nutrient build-up, Nanticoke River, Chesapeake Bay, 1992
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How have humans activities impacted the Chesapeake Bay ecosystem?
Longshoreman Atlantic City: Isabella & Carroll Walker Collection/The Norfolk Public Library
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Open notebook to page 35 Working with your table, discuss the question – how do increases in the human population affect the resources available to organisms? Complete page 35 as a group – you will have 5 minutes
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To Investigate this question you will:
Analyze historic and modern day food webs Chart trends in harvesting and ocean health using real data on the Chesapeake Bay Draw conclusions from your analyses to determine how humans have impacted the Bay Explore the biodiversity loss of the Bay and connect it to local ecosystems
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Analyze historic and modern day food webs
How many of you included a comparison of historic and modern data in your brainstorm on page 25? Think – how nutrient levels have changed over time Why would it be important to know about how the historic levels compare to the levels today?
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Exit Slip – Why would we want to know more about the dead zones in the Chesapeake Bay? We should be able to apply what we learn in Chesapeake Bay to other ecosystems as well, including local ecosystem How could this information be beneficial to us even though we do not live there? If we are able to determine what things humans do that negatively impact an ecosystem, we could avoid doing that in the future.
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Warm-up What is an “algal bloom?”
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Today you will… Analyze a historic food web from the Chesapeake Bay ecosystem before settlers and large-scale fishing was introduced into the area (early 1700s). What do you think was different during this time period? Think back to your focus question – how have human activities impacted the Chesapeake Bay ecosystem?
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Look at the historic food web
Terms to know: Consumer Abundant Rare Producer Detritus Extinct decomposers Strong interaction Weak interaction Tertiary Secondary
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Open your notebook to page 39
Worksheet 1 – Questions for the Bay Before Large Scale Fishing You will be given a colored food web to use. You also have a black and white one on page 37 that you can mark on. You will have minutes to complete this activity. Complete pages 39, 40, 41, 42 Show me your completed work. You will then start worksheet 2
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Question 1 Rare – Jellyfish, worms/amphipods, floating algae, microbes, detritus/decaying matter Everything else is abundant
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Question 2 Most are abundant
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Question 3 Tertiary consumers: eat primary/secondary consumers
Secondary consumers: eat mainly primary consumers Primary consumers: eat producers Producers: make own food, energy from sun Decomposers: consume dead matter *Which organism is a decomposer and primary consumer?
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Question 4 Decomposer and primary consumer
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Question 5 Detritus or decaying matter is not living sonot part of the food web. It is food for decomposers.
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Question 6 Let’s do this together on the board
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Question 7 Float: floating algae
Sea bottom: seafloor algae, grasses, plants
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Question 8 Seafloor bottom plants
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Question 9 Floating algae oyster predatory invertebrates predatory fish seal shark
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Question 10 Detritus decomposers
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Question 11 increase
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Question 12 increase
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Question 13 Microbes increase
Floating algae increase or stay same because zooplankton eat them Floating algae increase detritus increase
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Warmup What was the title of yesterday’s worksheet on page 39 of your notebook? What is the significance of this title?
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Today you will Analyze the Chesapeake Bay food web as it exists today and compare it to the historical data. Now you have the influx of settlers and large-scale fishing. Do you expect to see changes in the modern day food web?
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Let’s look at the current food web
Now open your notebook to page 45 Worksheet 2: Questions for the Bay after large-scale fishing You will have minutes to complete the activity.
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Question 1 Humans
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Question 2 Abundant: bird, jellyfish, worms/amphipods, floating algae, microbes, detritus Extinct: alligators, manatee Rare: Everything else
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Question 2 Alligators, manatees
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Question 3 Rare Abundant: birds, jellyfish, worms/amphipods, floating algae, microbes
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Question 4 No – they were mostly rare in the historic food web
The only one still abundant are birds
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Question 5 More All tertiary consumers affected
So lower trophic levels affected
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Question 6 Let’s do this together on the board
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Question 7 They have the same number of interactions
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Question 8 weaker
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Question 9 The complexity of the ecosystem is reduced – a lot less is going on
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Question 10 Only successful redraw is in the low trophic levels – detritus, microbes, floating algae, worms/amphipods No higher trophic levels included Complexity of ecosystem is lost Humans are added Jellyfish abundant Some species have no connections at all
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Question 11 Similar: most organisms still there, birds are abundant
Different: alligator and manatee extinct, many organisms that were abundant are now rare, jellyfish are abundant, humans added
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Question 12 Few sea turtles, whales to eat them
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Question 13 Humans are hunting them too
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Question 14 Floating algae
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Question 15 High nutrient pollution (fertilizer) in run off from the land caused an increase in algae that live on the surface
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Question 16 Thick layers of floating algae block sunlight from reaching seafloor algae, plants below Without sunlight – seafloor algae and plants cannot grow
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Question 17 Oysters filter water
Remove microbes, floating algae, excess nutrients Humans fished oysters taking away natural filter Now Bay is filled with excess nutrients, microbes, floating algae that would have been consumed by oysters
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Question 18 Must be testable
What effect does the size of the oyster population have on floating algae
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Question 19 Historic and present day data on the number of oysters and level of floating algae in the Bay
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Exit Slip What are the two names given to organisms that make their own food? What are the two names given to organisms that rely on others for food? What is the purpose for detritus?
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Warm-up 9/9/16 What organism was found in the after food web that was not in the historic food web? Which organisms became extinct? What organisms were known as natural filers for the Bay?
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After assessment You have 10 minutes for the test. Turn in your test
Turn in your folder Open your notebook to page 52. Complete pages
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Why are oysters so important to Chesapeake Bay?
Exit Slip Why are oysters so important to Chesapeake Bay?
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Today you will… Analyze data about the populations of oysters and algae over time in the Bay. You will use data to draw conclusions about the effect of overharvesting of oysters on the ecosystem. Remember from the previous two activities that the oyster population went from abundant to rare.
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Open your notebook to page 51
How does the oyster population in the Chesapeake Bay ecosystem affect the floating to sea floor ratio of algae populations? Focus your attention to worksheet 3 – Oyster catch vs nutrient levels in the Chesapeake Bay We will be graphing this data. After graphing, you will move onto the analysis portion found on pages 53-55
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Key ideas to graph The graph has two y-axes each with the same scale (0-8) You can round the numbers on the oyster catch to the nearest 0.5 You can round the numbers on the floating algae to the nearest 0.5 The ratio of floating algae to sea floor algae is an indication of the nutrient levels in the water.
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Think metric ton – a school bus is almost 12 metric tons and a blue whale is 170 metric tons. So in a year when people harvested 500,000 metric tons of oysters, they removed the equivalent of more then 40,000 school buses or 3000 blue whales from the Chesapeake!
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Question 1 Ratio = 1 Same number of floating algae to sea floor algae
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Question 2 Today ratio is 8:1 – 8 times more floating algae than seafloor algae
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Today’s nutrients levels are much worse.
Question 3 Today’s nutrients levels are much worse.
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Question 4 European settlers – cleared land to farm crops and raise cattle putting more nutrients in Bay from run-off
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No, people were not catching many oysters at this time
Question 5 No, people were not catching many oysters at this time
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Question 6 The algae ratio remained at 3 and the oyster landings increased dramatically to 6 x 105 tons
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Increased landings mean decreased oyster population
Question 7 Increased landings mean decreased oyster population
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Question 8 Floating algae increased, seafloor algae decreased when oysters were removed. Loss of oysters (filter feeders) increases nutrient input in Bay
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Question 9 No enough oysters in the Bay to make overfishing worthwhile.
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Question 10 The lower the oyster population, the more floating algae and less seafloor algae present. Question 11 Add oysters to the Bay Solutions to decrease nutrient run-off from watershed.
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Question 11 Add oysters to the Bay Solutions to decrease nutrient run-off from watershed.
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When you are finished Bring me your folder. Bring me your test.
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Warmup Get out a sheet of notebook paper. You will use this all week. Put today’s date. Answer the following questions: An organism that only eats plants ___________ An organism that only eats animals __________ An organism that eats plants and animals _____ Organisms that make their own food (2 answers) Organisms that rely on others for food (2 answers)
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Warmup 9-13-16 Open your notebook flat to page 57-58
What was the ratio of floating algae to seafloor algae in 1981? What is the importance of this number?
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Worksheet 4 page 56 notebook
Question 1 – part 1: Did you predict what happened in the Bay? NO Part 2 – What were two major changes that occurred that you did not expect? Manatees/alligators went extinct Humans were added
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Question 2 Oysters filter the nutrients, microbes, and floating algae in the Bay. High oyster pop = low floating algae pop, high seafloor algae, and few dead zones Low oyster pop = high floating algae, low seafloor algae algal blooms and dead zones
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Question 3 It is the only way to truly see changes from what the original ecosystem looked like. The role of the oysters in keeping the Bay clean was overlooked. Once the complexity was lost, the reality set in.
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Question 4 People have overharvested species in the Bay (whales, sharks, seals, alligators, sea turtles, predatory fish, grazing fish, predatory invertebrates, oysters). Algal blooms loss of seafloor plants, increase of bacteria Jellyfish now abundant Manatees, alligators extinct
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How to cite evidence When humans began large-scale fishing in the Bay, the ecosystem’s food web was dramatically changed. Evidence: Evidence from food webs.
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Nutrient levels have increased dramatically in the Bay in the last 300 years.
Evidence: The ratio of floating algae to sea floor algae has increased over the last 300 years.
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As the oyster population decreased, the floating algae population increased.
Evidence: Evidence from graph
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Humans began impacting the Bay even before oyster harvesting became popular.
Evidence: The floating algae levels were increasing in the 1700’s before the oysters were even harvested. This was the time period when farming was being established in the area and nutrients were being added to the Bay.
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Scientific question – top page 57
How have human activities impacted the Chesapeake Bay ecosystem? Claim: Humans have negatively impacted the Chesapeake Bay ecosystem.
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Background knowledge The bay changed significantly when humans came in the 1750’s. Many organisms became rare.
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Initial Thoughts Humans pollute the Bay.
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Evidence Claim Science Concepts Alligators and manatees went extinct. When humans began large-scale fishing, the ecosystem’s food web was dramatically changed. Food web diagrams In 1700, floating algae to sea floor algae ratio was 1.0 (balanced). In 1981, the ratio was 8:1 – 8 times the amount of floating algae. Nutrient levels have increased dramatically in the Bay in the last 300 years. Data table/graph Between 1883 – 1891, over 1,700,000 metric tons of oysters were removed from the Bay. In 1957, floating algae was 6 times higher than seafloor algae. As the oyster population decreased, the floating algae population increased. Data tables 1750’s settlers began farming, raising cattle, and building homes – oysters were not hunted until late 1800’s(early 1800’s floating algae population increases) Humans began impacting the Bay even before oyster harvesting became popular. Data tables and background information
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Top box page 58 Claim: Humans have negatively impacted the Chesapeake Bay ecosystem.
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Does your claim agree with your initial thinking? Why or why not?
Look at what you wrote on your initial thoughts? Did you think humans would impact the Bay this much?
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Scientific Reasoning The evidence that led to my claim is extinction of manatees and alligators, increase in the floating algae population, evidence that as the oyster population decreased the floating algae population increased, and that when humans came in the 1750’s they effected the Bay. The concepts that relate to the evidence and support my claim are use of data tables, graphs, food web diagrams, and analysis questions. These concepts support my claim because they show a direct correlation between the loss of oysters and the increase of floating algae – human impact.
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Scientific Explanation
My evidence is the following: (copy your four pieces of evidence) Evidence 1 Evidence 2 Evidence 3 Evidence 4
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Evidence: one piece from each section
Food webs: before and after comparisons (think worksheets 1 and 2) Oyster and algae data (pages 51-56) Dead zone lesson (pages 27-29) Worksheet 4 page 56 Scientific Question: How have human activities impacted the Chesapeake Bay ecosystem?
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Graded on… Claim Evidence Science Concepts Scientific reasoning
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Pages 67-68 Text Dependent questions
Must cite the paragraph number/numbers as well as write your answer. You have 20 minutes to work.
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Question 1 Paragraphs Biodiversity describes the variety in the forms and shapes of life in an area. It can refer to the total number of species living in an ecosystem, the diversity of functions that different organisms perform in an ecosystem, or the diversity within a single species
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Question 2 Paragraphs 18
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Question 3 Paragraphs 10, 12, 26, 28, 29
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Question 4 Paragraphs 8, 26, 34
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Question 5 Paragraphs 16, 17
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Question 6 Paragraph 20
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Question 7 Paragraphs 25, 26, 27
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Question 8 Paragraph 20
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Question 9
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Image Credits Chesapeake Bay: US Coast Guard Chesapeake Bay Watershed: US Department of Agriculture Chesapeake Bay Map: NASA Blue Crab: The Children's Museum of Indianapolis Oyster: David Monniaux Striped Bass: Mike Smedley Clam: Aung/Wikipedia Map: NASA Algal Blooms: Jennifer L. Graham/US Geological Survey Dead Fish: US Geological Survey Hog Farm Waste: USDA Chickens: SRAP Pigs: Farm Sanctuary Longshoreman Atlantic City: Isabella & Carroll Walker Collection/The Norfolk Public Library
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