[thvinstitute13] cadmium at foundry cove: an ecology & evolution story
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Cadmium at Foundry Cove: An Ecology & Evolution Story
Cornelia Harris
Today’s Workshop• Quick overview of the Changing Hudson
Project• What do students know about evolution? • Lesson overview• Share ideas, Questions
Research & Education based on Ecosystem Ecology
Changing Hudson Project: Ecology Curriculum for the High School
Classroom
Changing Hudson Project• Help students understand
how the Hudson River estuary changes over time using local data
• Train educators through weekend, evening and summer workshops
Resources: Visualizations, Readings, Lesson Plans with worksheets & labs
What do students think about how evolution works?
• Work in groups• Sort the answers in order of increasing
sophistication• Fill out the first column of the worksheet: what
characteristics are you using to sort the students’ answers into different levels?
• Write the letter of the student responses in the second column (teacher generated rubric); leave the last column blank for the “answers”
Change in Population Questions
Level 4 for change in a population: NY 12th grader: This occurs because the pesticide wipes out
all of the non-resistant insects thus leaving the resistant insects to breed and reproduce and become a dominate trait in the population.
INTERVIEWER: Okay. How does an insect become resistant? NY 12th grader: It's born with natural variation in genetic
population. If there's a 100 bugs maybe 10 are resistant and then when the whole population is sprayed those 10 are left. So when the population eventually recovers those 10 will be the, will now be the entire 100 or they will be make up a large part of it and if the same pesticide is used over and over again eventually it won't have an effect because the entire population will be resistant to it.
Change in Population Questions
Level 1 for change in a population: CO 7th grader: The increase in resistance is most likely
caused by the evolving animals in the environment of a farm. Lately we have talked about the changes animals and/or organisms use to change and adapt to their environment. These insects highly adapt to avoid the chemicals.
INTERVIEWER: Okay. How do they evolve? CO 7th grader: They evolve by adapting to their
surroundings or doing something to make them – make better use of their surroundings.
INTERVIEWER: Okay. And so – do you know anything about mechanism? So how does – how do they adapt?
CO 7th grader: Probably just by finding different ways to use their surroundings or finding different ways to do something.
Change in Population: InsecticidePr
opor
tion
of A
nsw
ers
Middle School High School0%
10%
20%
30%
40%
50%
60%
70%Level 1 Level 2 Level 3 Level 4
n = 187 n = 160L1-4 = 80% L1-4 = 85%
What do students know and think about how evolution works?
• Understanding adaptation by selection and phenotypic plasticity are both important for predicting effects of disturbances, including climate change and other human impacts, on ecosystems
• When asked why a population may have changed over time, students describe an individual gaining or losing traits based on some environmental cue
• When given enough scaffolding, even young students can understand that there is standing variation in a population and a trait can increase in a population over time through differential reproductive success
• We propose understanding the mechanism of adaptation by selection is not what is limiting students understanding of how individuals and populations change: instead we propose that understanding the nature of phenotypic traits - and thus the existence of standing variation in a population - is their largest hurdle.
• Key problems that plague students: they don’t really understand what a population is, and they don’t think about multiple generations
What makes the Hudson a unique river ecosystem?
What do you already know about the Foundry Cove story?
Cadmium in the Cove
Scientists collecting samples in Foundry Cove
FOUNDRY COVE
SOUTH COVE
NORTH COVE
1.0 km
N
NEW YORK CITY
FOUNDRY COVE
200 km
N
Marathon Battery Factory made nickel-cadmium batteries in Foundry Cove from 1952-1979.
Heavy Metal Pollution between 1952
and 1979, over 112,000 pounds of cadmium was released into Foundry Cove
Foundry Cove became “the most cadmium polluted site in the world”
nickel and cobalt were released in much smaller amounts
How could scientists find out where the cadmium went after it left the Marathon Battery outfall?
= 50,000+ ppm cadmium in sediments of Foundry Cove ppm = parts per million
1975
Marathon Battery Factory
1975Distribution of cadmium in surface sediments in East
Foundry Cove
1983Distribution of cadmium in surface sediments in East
Foundry Cove
What changed?
Marathon Battery
Map activity
Cadmium in sediments of Foundry Cove
What happened to the cadmium between 1979 and 1983?
Where could it have gone?
Sampling at the train trestle, Foundry Cove
Outgoing Tide Incoming
What happens to cadmium that gets
eaten?
Cadmium in
sediments of Foundry
Cove
Major Cadmium Pathways
Transported out by tides
Eaten by organisms
Buried by sediments carried in by tides or freshwater runoff
Redistributed by waterMovements within the cove
Part B of worksheet
ELA connections• CCS ELA Reading Standards 6-12: Cite specific
textual evidence to support analysis of science and technical texts
• CCS ELA Reading Standards 6-12: Determine the central ideas or conclusions of a text; provide an accurate summary of the text distinct from prior knowledge or opinions
Overview of Unit
• Lesson 2: Marathon Battery Factory (dilution activity)
• Lesson 3: Biomagnification (mobile or poster)• Lesson 4: Survivors at Foundry Cove (what
happened to the worms in the toxic mud?)• Lesson 5: Natural Selection• Lesson 6: Evolution & Pollution
What’s so bad about a little cadmium?• At very high levels, causes Itai-Itai (or ouch-ouch)
disease in humans – pain in bones and joints, bones break easily
• Can cause cancer and other health problems
• Entered the human food web via contaminated blue crabs in the Hudson River
• Liver lesions in muskrats in Foundry Cove
Lesson 3
Looking at a Millionth - Activity
100 ppm
1,000 ppm
10,000 ppm
50,000 ppm
How big is 1 ppm?
How big is 250,000?
Lesson 3
30
Survivors at Foundry Cove
How did the worms in Foundry Cove survive when their environment became highly contaminated by toxic cadmium?
Lesson 4
31
Scientific experiments were conducted on Limnodrilus hoffmeisteri worms.
Sampling for worms in Foundry Cove Lesson 4
32
L. hoffmeisteri
cadmium
Lesson 4
33
Foundry Cove South Cove
Very similar environments
Extreme Cd contamination
50,000 ppm
Lower level of Cd contamination
19 ppm
Mud worm dominant mud-dwellers
Lesson 4
34
Are L. hoffmeisteri worms usually resistant to cadmium?
What kind of experiment could be
done to find out? Pause here to discuss your ideas. Then describe and sketch an idea for an
experiment to answer the question. Lesson 4
35
Are all L. hoffmeisteri worms resistant to cadmium?
Control Area Foundry Cove0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Graph A: Numbers of Limnodrilus hoffmeisteri worms surviving sediment exposure after 28 days
Foundry CoveControl Area
Sediment Source
Perc
ent S
urvi
ving
Worms from
Lesson 4
“Adaptation”, Evolutionary adaptation or plasticity?
• A squirrel lines its nest with grasses and leaves because it has suddenly become very cold outside – “adaptation”
• Twin dogs, separated at birth, grow to different sizes because they have access to different types of nutrition– plasticity
• A rabbit grows white fur in the winter – the mechanism is an evo adaptation
• A species of mosquito has been going dormant later each fall – evo adaptation
• Butterfly species in CA are migrating an average of 24 days earlier when compared to 30 years ago– plasticity
37
Resistance to Toxins
• Physiological plasticity:– In individual organisms
– Depends on environmental conditions
– Disappears if returned to a clean environment
• Heritable trait:– In populations of organisms
– Increased through natural selection
– Persists in offspring for at least a few generations Lesson 4
38
Did Foundry Cove worms pass their cadmium resistance to their offspring?
O 20 30 45 65 900
10
20
30
40
50
60
70
80
90
100
Graph B: Limnodrilus hoffmeisteri Survivors
Foundry Cove wormsFoundry Cove offspringSouth Cove worms
Cadmium level in sediment (mg Cd/g of dry sediment)
Perc
enta
ge o
f Sur
vivo
rs
39
Natural Selection at Foundry Cove: Evolution of
Cadmium Resistant Worms
Part 1Of Mice, Bugs, and
Bacteria
Part 2Mud worms
Source: www.smc.edu Source: www.fcps.edu
Lesson 5
40
How did Foundry Cove worms become resistant to cadmium?
Natural Selection
Natural selection of an invisible trait such as cadmium resistance is hard to visualize.
So let’s first look at natural selection of a visible trait such as fur color.
Source: museum2.utep.edu Lesson 5
41
Pocket Mice and Predation
http://www.hhmi.org/biointeractive/evolution/pocket_mouse_predation.html
Source: www.nps.gov
Lesson 5
42
Pocket Mice and Evolution
http://www.hhmi.org/biointeractive/evolution/pocket_mouse_evolution.html
Lesson 5
43
Existing Variation
Variation within a species
e.g. Genetic variation for fur color-multiple alleles for color
Present in a population or species before natural selection occurs
Lesson 5
44
Natural Selection in a Population of Pocket Mice
• Existing genetic variation multiple alleles for fur color
• Heritable fur color is passed from parent to offspring
• Differential succcess dark fur protects mice better than
light fur on lava flow habitat
• Time many generations of mice have lived and passed on
their genesLesson 5
45
Evolution of an Invisible Trait
Now, on to the natural selection of cadmium resistance in Foundry Cove mud worms.
Source: www.spiegel.de
Lesson 5
46
Foundry Cove WormsNatural Selection Process Diagram
Key= Non-resistant worm= Resistant worm
Selection and Growth
Toxic levels of cadmium kill 50% of
the population
First Generationas Young
How many are alive?
What % are resistant?
Lesson 5
47
Foundry Cove WormsNatural Selection Process Diagram
Key= Non-resistant worm= Resistant worm
Selection and Growth
Toxic levels of cadmium kill 50% of
the population
First Generationas Young
First Generationas Adults
How many are alive?
What % are resistant?
How many are alive?
What % are resistant?
Lesson 5
48
Foundry Cove WormsNatural Selection Process Diagram
Key= Non-resistant worm= Resistant worm
ReproductionSurviving adults reproduce, each having one baby
Selection and Growth
Toxic levels of cadmium kill 50% of
the population
First Generationas Young
First Generationas Adults
1st Gen. Survivors & their Young
How many are alive?
What % are resistant?
How many are alive?
What % are resistant?
How many are alive?
What % are resistant?
Lesson 5
49
Foundry Cove WormsNatural Selection Process Diagram
Selection and Growth
Toxic levels of cadmium kill 50% of
population
ReproductionSurviving adults reproduce, each having one baby
Key= Non-resistant worm= Resistant worm
1st Gen. Survivors & Their Young
(Copy)
1st & 2nd Gen. Survivors as Adults
Survivors & theirYoung
ReproductionSurviving adults reproduce, each having one baby
Selection and Growth
Toxic levels of cadmium kill 50% of
the population
First Generationas Young
First Generationas Adults
1st Gen. Survivors & their Young
How many are alive?
What % are resistant?
How many are alive?
What % are resistant?
How many are alive?
What % are resistant?
How many are alive?
What % are resistant?
How many are alive?
What % are resistant?
Copy totals for 1st gen. survivors & young here:
Lesson 5
50
Scientists noticed fewer muskrats in Foundry Cove during the most polluted years.
1. Do you think muskrats evolved resistance to cadmium? Why or why not?
2. What else might cause a reduction in the number of muskrats in the cove?
Source: www.fcps.org
Lesson 5
Lesson 6: Evolution & Pollution
• Tomcod resistance to PCBs in the Hudson River
• Students get a variety of articles to choose from – they select one, read it & critique
52
1. Scientists have discovered a strange fish that lives in a soup of some of industry's worst pollutants.
2. Bottom-feeding fish in the Hudson River have developed a gene that renders them immune to the toxic effects of PCBs, researchers say.
3. An unpretentious little fish that has learned how to thrive in one of the most polluted rivers in North America has scientists wondering if foul water is driving its evolution and, ironically, whether genetic changes that seem to be taking place might jeopardize its ability to survive in cleaner water.
4. IT IS not often that biologists have a chance to watch natural selection in action.
5. Some fish in New York’s Hudson River have become resistant to several of the waterway’s more toxic pollutants.
6th grade 11th-12th grade
CCSS.ELA-Literacy.RI.6.1 Cite textual evidence to support analysis of what the text says explicitly as well as inferences drawn from the text.
CCSS.ELA-Literacy.RI.11-12.1 Cite strong and thorough textual evidence to support analysis of what the text says explicitly as well as inferences drawn from the text, including determining where the text leaves matters uncertain.
CCSS.ELA-Literacy.RI.6.3 Analyze in detail how a key individual, event, or idea is introduced, illustrated, and elaborated in a text (e.g., through examples or anecdotes).
CCSS.ELA-Literacy.RI.11-12.3 Analyze a complex set of ideas or sequence of events and explain how specific individuals, ideas, or events interact and develop over the course of the text.
CCSS.ELA-Literacy.RI.6.5 Analyze how a particular sentence, paragraph, chapter, or section fits into the overall structure of a text and contributes to the development of the ideas.
CCSS.ELA-Literacy.RI.11-12.5 Analyze and evaluate the effectiveness of the structure an author uses in his or her exposition or argument, including whether the structure makes points clear, convincing, and engaging.
CCSS.ELA-Literacy.RI.6.7 Integrate information presented in different media or formats (e.g., visually, quantitatively) as well as in words to develop a coherent understanding of a topic or issue.
CCSS.ELA-Literacy.RI.11-12.7 Integrate and evaluate multiple sources of information presented in different media or formats (e.g., visually, quantitatively) as well as in words in order to address a question or solve a problem.