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Change since 1609: Settlement Changes Hudson Valley plant communities

Unit Plan: The Hudson Valley: A Social-Ecological SystemLesson: 2 Time: One-two 45-minute class periods Setting: Classroom
6-8, 9-12Hudson River Ecology
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Students will know how the climate of the Hudson Valley has changed over the last 400 years and be able to explain these changes.


1. Students brainstorm about ecosystems in the past

2. Using prepared soil ‘samples’ with fossilized ‘pollen’, students determine the changes in vegetation since European arrival

3. As a class, students reconstruct the history of the Hudson Valley since the arrival of Henry Hudson


  • 6 bags of soil with 14 different types of confetti organized in the manner described below
  • student worksheets
  • tweezers
  • paper plates
  • sample sediment ‘core’ with visibly different soil layers: can be made out of different kinds of soil in a tennis ball container, graduated cylinder, soda bottle, etc. These layers can represent the exact layers from the activity, or it can be used only as a visual to get students thinking about the concept of soil layers.

Preparation: Before class, prepare six bags of soils with the below mentioned types of confetti.. The ratios are approximate.  Feel free to use whatever colors of confetti you have on hand, pieces of paper (hole-punch construction paper or laminated colored paper) or other materials to represent the pollen. You can use visibly different soil types for each ‘layer’ with pollen, but this is not necessary. You can also just tell the students that the soil layers might look alike now, but they look different when scientists collect them.

Once you have prepared the zip-loc bags with the soil and confetti, disperse the bags to your groups of students.  If you can’t make six groups, it would be advisable to give one group two layers (probably the simpler layers, ie combine layer 3 with another layer).  Once students have identified the ‘pollen’ based on the charts they have, they will be able to reconstruct the land use changes in the Hudson Valley over the last 400 years.  You can keep the zip-loc bags with the materials for future use. 

Note: A lesson on the paleoclimate of the Hudson Valley is also available in the first module, and explores sediment layers that are much older.  


Engage: Show students the sediment core and ask: What do you think we can discover about the history of a place using the sediment layers.  Ask: How far into the past can we go? Students will probably think about fossils or the Grand Canyon. Explain that when we collect a sediment core, we are getting a slice of the soil’s layers. There are many differences between layers, including the tiny, fossilized pollen grains found within them. Ask: how can scientists tell what kind of pollen is in a sediment core? Explain that they will become ‘scientists’ to discover the paleoclimate of the Hudson Valley.  Another option is to bring in a flower with pollen.  They could observe the pollen under a microscope.  Remind students of the difference between pollen and spores.


Explore: Distribute the materials to each group of students: one layer (bag with ‘pollen’), tweezers, and a paper plate. Students should sift through their sediment layers and separate out each of the different pollen types. Allow enough time to discover what layer they have and what type of climate may have existed during this period, using the information on their student guide. Once all groups have completed their work, they should compare their results using the class data chart on their worksheet.  This should allow a discussion of the history of climate change in the Valley.


Explain: Since each type of pollen has a distinct shape, scientists can find out what plant produced the pollen.  By discovering what types of plants lived during each time period, scientists can infer what the climate was like during that time, and even how many of each type of plant lived during that period.  They can also draw conclusions about how long it took for different changes to take place-for instance, how long did it take from the last ice age until the appearance of marsh plants?  The speed that plant communities migrate into an area can help scientists understand how plants are currently migrating around the world, and what might happen when the temperatures increase in the future.  Scientists use more recent sediment layers to learn about ecological changes and events such as the incidence of fire, species introductions or local extinctions, and even nuclear weapons testing. Scientists from Lamon-Doherty have collected pollen samples throughout the Hudson River area, and are continuing to collect samples to create a more complete picture.  . “Background Reading About Dr. Peteet” available below under “Lesson Resources” contains more information about this effort.


Extend: Students can investigate other regions of the world to determine the paleoclimate data.  Information can be found at: Climates of the Past ( Students could also be led on a guided walk and discuss what a ‘layer’ at your schoolyard or a nearby woodlot would look like. 


Evaluate: Students should be able to explain how the ecosystem of the Hudson Valley has changed since 1609 and provide evidence to support their answer.  

Lesson Files

Background Reading about Dr. Peteet
Changes Since 1609 Worksheet
Changes Since 1609 Reading

Benchmarks for Science Literacy

1B Scientific Inquiry, 2A Patterns and Relationships, 4B The Earth, 4C Processes that shape the earth, 4G Forces of Nature, 11C Constancy and Change, 12D Communication Skills

NYS Standards

MST 1 - Mathematical analysis, scientific inquiry, and engineering design, MST 4- Physical setting, living environment and nature of science, MST 6- Interconnectedness of mathematics, science, and technology (modeling, systems, scale, change, equilibrium, optimization), MST 7- Problem solving using mathematics, science, and technology (working effectively, process and analyze information, presenting results)
Next Generation Science Standards

Science and Engineering Practices

Developing and using models

Cross Cutting Concepts

Cause and effect

Disciplinary Core Ideas

LS2A: Interdependent Relationships in Ecosystems, ESS3A: Natural Resources
New York State Science Learning Standards

Performance Expectations

MS-LS2-4. Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations., MS-LS4-1. Analyze and interpret data for patterns in the fossil record that document the existence, diversity, extinction, and change of life forms throughout the history of life on Earth under the assumption that natural laws operate today as in the past., MS-ESS1-4. Construct a scientific explanation based on evidence from rock strata for how the geologic time scale is used to organize Earth’s 4.6-billion-year-old history., HS-LS2-2. Use mathematical representations to support and revise explanations based on evidence about factors affecting biodiversity and populations in ecosystems of different scales., HS-LS4-5. Evaluate the evidence supporting claims that changes in environmental conditions may result in: (1) increases in the number of individuals of some species, (2) the emergence of new species over time, and (3) the extinction of other species.

Lesson modified from University Corporation for Atmospheric Research lesson plan,  using data from Lamont-Doherty Earth Observatory, for the Changing Hudson Project, Institute of Ecosystem Studies, 2007. Last edit: January 2013.

Cornelia Harris, Cary Institute

The text is derived from and based on content from Windows to the Universe® ( © 2010, National Earth Science Teachers Association (

This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License (