A Problem Based Learning Unit: Ecosystems

Wow – I can’t believe it has been a full two months since my last post.  While I haven’t been blogging, I have been busy creating instructional materials for my students (and then of course sharing them via my TeachersPayTeachers shop).  My students are just now wrapping up their first unit on ecology and ecosystems. This year, I decided to try “problem based learning” units.  I will admit, I am by no means an expert on this topic.  It is however, in my understanding, a way to improve student engagement and get students operating at higher levels of thinking.  While I provided students with the materials and resources necessary to solve the problem presented, they had to design the solution based on their understanding of the material.  They also had to apply the general ecology concepts they were learning to specific, real-world situations. Since attending the national NSTA conference last year, I have really focused on implementing the NGSS standards (while still meeting my own district’s curricular standards, of course).  This unit was designed to meet the following Next Generation Science Standards: They will be able to: ·      develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem (NGSS MS-LS2-3) ·      construct an argument supported by evidence that changes to components of an ecosystem affect populations in that ecosystem (NGSS MS-LS2-4) ·      evaluate competing design solutions for maintaining biodiversity and ecosystem services (NGSS MS-LS2-5) ·      construct a scientific explanation based on evidence for the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms (NGSS MS-LS1-6) We started off the unit with this question: What happens when something disrupts the ability of an ecosystem to meet the needs of the organisms in it?  Students were also provided with their PBL prompt:

Invasive species are a serious threat to the health of the Great Lakes ecosystems. You have been selected to investigate the impacts on the Lake Erie ecosystem of a specific invasive species – what is currently happening, what we can predict may happen, and the potential outcome if nothing is done to address the problem.  Then, you will identify actions we can take to prevent further damage by the species, such as measures to stop the spread of the species as well as control its current population.  Your plans will also take into account the social and economic considerations of the human population in the Great Lakes region.  You will present your research and action plan in a format of your choosing.  Your options include the creation of a website, the production of video/slideshow documentary, a town hall meeting style presentation, or a traditional report.

Before students could even begin to design solutions to invasive species, they had to understand how healthy ecosystems worked.  We spent a fair amount of time working with basic vocabulary and concepts, such as biotic and abiotic factors, relationships in ecosystems, and food chains and food webs.  Students explored and predicted how changes in biotic and abiotic factors would impact ecosystems in this activity.

And they created food chains and food webs from “field notes” that required them to use vocabulary (preys on, predator to, producer, etc.). I actually used two versions of this — the first was the NSTA activity that inspired this material.  I found in a recent Science Scope issue an activity just like this, where students were presented a chart of “field notes” about a pond ecosystem and had to build a food web from the information provided.  We completed that one together, reviewing which way the arrows point and remembering to include where producers get their energy from and so on.  To assess student mastery of this concept at the end of the unit, students completed the version linked to the left. In addition to these application-type activities, students were assessed through exit tickets and traditional quizzes.  Students took a quiz on general ecology concepts at the end of the first “section” of this unit (the healthy ecosystems stuff), and then we moved on to a look at invasive species and the damage they can do to an ecosystem. I used this great site called Newsela to introduce invasive species.  Newsela is a news website with tons of current event articles that have been rewritten at various grade levels.  When you find an article you want to use, you can adjust the reading level before printing/assigning to students/etc.  The articles are free, and I have used this a TON in my classroom this year.  The only thing I am not a fan of is their quizzes – they are really basic and require very little critical thinking.  The articles themselves though are AWESOME! Anyhoo, I used a news article about lionfish in the Gulf of Mexico to introduce invasive species.  We also read about cane toads in Australia in our Life Science Daybook texts, and we read several other news articles taken from Newsela and our local “Newspapers In Education” section of the Erie Times News.  Students were able to read, discuss, and learn from real life examples of invasive species and the damage they can do.  In addition to lionfish and cane toads, they read about nutria in Maryland, stink bugs in North America, asian carp in the Mississipi River and Great Lakes, tegu lizards in Florida, California king snakes in the Canary Islands, the emerald ash borer in Pennsylvania, and other aquatic invasive species in Lake Erie.  As we worked on the unit’s final essay, brainstorming evidence to scaffold them into constructing these essays independently, it was so exciting to hear them name these species and explain the damage they were doing.  They totally took ownership of these topics, and through various “jigsaw” type activities, became “experts” on these issues. We also did a really fun ecology detective type activity called “The Mystery of the Silent Night: Where Have All The Tree Frogs Gone?” They LOVED this one! Sifting through various clues (everything from diary entries to newspaper articles, advertisements, company memos, etc.), students had to determine the cause(s) of a sudden decline in the tree frog population in the fictional town of Mayberry.  They then had to write a “Claim-Evidence-Reasoning” paragraph to support their explanation, which I assessed with the rubric linked here. The final unit assessment was the Invasive Species Project, which had students researching a Lake Erie invasive species and designing a solution to either prevent its spread or decrease its population.  Students worked in groups, selecting their species randomly through a “drawing” from the top 10 invasive threats to Lake Erie.  They created a “Wanted” poster for their species and then developed a proposal for their solution to present to the class. I have included teacher and student instructions, rubrics, and a research organizer for this project in my TpT store. Students also took a multiple choice test on the unit’s vocabulary and completed an essay assessment in which they answered the unit’s original question.  Because it was the first essay test they have done, we did the planning together.  We broke down the original question (What happens when something disrupts the ability of an ecosystem to meet the needs of the organisms in it?) and developed a structure for student responses.

What happens when something disrupts the ability of an ecosystem to meet the needs of the organisms living in it? Paragraph 1: How does a healthy ecosystem work? Paragraphs 2-4: Give a specific example of a “disruption” to an ecosystem and explain how it affected the ecosystem Paragraph 5: What can humans do to prevent these “disruptions” that throw off the balance in ecosystems? What can humans do to “fix” disruptions that have already occurred?

This unit was definitely a success, and I am constantly impressed with the level of work I get from my students.  They did an awesome job with all of these activities, and it felt really good to finish a clear, cohesive unit and feel like I kind of know what I’m doing! Yay for Year #2!

Closed Ecosystem Challenge

As we have been working our way through a unit on ecology, I have found the tropical aquarium and frog terrarium in my classroom incredibly helpful.  For concepts like populations, communities, the carbon dioxide – oxygen cycle, and nitrogen cycle, students are presented with concrete examples from classroom pets they have observed all year.

To wrap up the unit, I wanted students to consider and observe the two very important cycles to the preservation of life — the carbon dioxide – oxygen cycle and the nitrogen cycle.  To do this, I divided students into groups and asked them to design a closed ecosystem in which the needs of all organisms are met.  You can check out the assignment pack I gave them, as well as some images of their ecosystems below:


Students test their ecosystems for water quality parameters like dissolved oxygen, pH, nitrites, nitrates, and ammonia.

Some students chose to house betta fish in their ecosystems.

Science Unit: Introducing Ecology

Right now, my sixth grade students are working through a unit on ecology.  Our first topic is “Interactions in Ecosystems,” and we are looking at everything from the biotic/abiotic factors that are impacting each other to the various types of ecological relationships between organisms in ecosystems.

My school goes by standards set through the Catholic Diocese.  Some of the standards that this first topic addresses are:

S63.22 Define environment.S63.23 Explain characteristics of his/her environment.S63.1 Describe characteristics of living and non-living things.S63.2 Classify familiar objects as living or non-living.S63.3 State basic needs of living things.

S63.29 Construct food chains/food webs illustrating energy flow in an ecosystem.

S63.30 Define and correctly use the terms: producers, consumers, decomposers.

S63.31 Describe ways in which populations of plants and animals in a community interact with one another and their environment.

S63.24 Give examples of changes in environments.

Additionally, I have been trying to incorporate into my curriculum the Next Generation Science Standards.  The activities in this mini-unit begin to address NGSS MS-LS2  Ecosystems: Interactions, Energy, and Dynamics.  According to NGSS, “Students who demonstrate understanding can analyze and interpret data to provide evidence for the effects of resource availability on organisms and populations of organisms in an ecosystem. MS-LS2-1”  Similarly, this unit’s focus on interactions in an ecosystem, such as competitive, predatory, and mutually beneficial, aligns with MS-LS2-2, “Students who demonstrate understanding can construct an explanation that predicts patterns of interactions among organisms across multiple ecosystems.” Finally, the MS-LS2-3 standard that addresses the flow of energy in ecosystems is considered in this unit.

I begin each class period with a “Warm Up” or “Bellringer.”  Sometimes my Warm Ups review information from the last class, while at other times they preview the information to come.  I also use these questions to assess prior knowledge.  The first Warm Up for this unit asked: What do you need to survive?

Huh, I don’t see a cell phone anywhere on there.

Water, shelter, air, and food – those are our basic needs.  We tied these needs to the idea of a habitat, or where an organism lives.  A habitat must provide these basic needs if we are to live there.

Branching off from this, we started discussing different types of habitats, and then took a closer look at  a few. Each group received a picture, like the ones below, and were asked to make a list of all aspects of the represented environment that interact in the image.



After students shared some of the things they listed, I asked them to sort their lists into living and nonliving things.  We then discussed the terms “biotic” and “abiotic” by first discussing the words “symmetrical” and “asymmetrical.”  Students easily put together that “a” in front of the word indicates it is NOT something, and with that knowledge, they were able to make the connection between biotic and abiotic. 

I followed up this discussion with a similar activity, in which students listed the biotic and abiotic elements of a fish tank.  For this activity, I gave them a drawing, although we also have a tropical aquarium in our classroom that they could use as a resource.  After identifying biotic and abiotic factors, students made predictions about the consequences of various actions.

For example:

  • If the water suddenly dried up, I predict…
  • If the temperature increased, I predict…
  • Without soil, I predict…
  • Without sunlight, I predict…

After this introduction to ecosystems and the elements within them, we moved on to the concept of populations and completed a hands-on population sampling activity to estimate population sizes.  Students enjoyed this very much, and it was a great way to tie in math as well. You can download the papers for the activity at my TeachersPayTeachers store – just click on the image below! Also, you can download the entire plan, for FREE, right here: Mini Unit: Community Interactions!

population sampling science learning activity

Population Sampling Activity