Intro to Ecology

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Objective

Students will be able to name and describe the different levels of ecological organization and the functional roles of the three broad niches (producers, consumers, and decomposers).

Big Idea

One of the most important aspects of understanding the environment is understanding ecology, or the relationships between organisms and their environment.

Introduction

This lesson covers a basic introduction to ecology, including the levels of ecological organization, the concept of a niche, and the three broadest niches (producers, consumers, and decomposers).  

 

The lesson essentially consists of two parts:

1. A pre-class textbook reading and homework assignment focused on close reading techniques, critical-thinking questions, and content vocabulary development.

2. An in class presentation that provides supplementary examples to review the concepts and vocabulary from the chapter along with a class discussion seeking to draw students into more critical examination of the topic at hand and assist in their ability to connect the concepts to their personal experiences. 

The textbook reading comes from Environmental Science: Your World, Your Turn by Jay Withgott.

If you do not have that particular textbook, I would recommend finding a similar chapter or chapters and modifying the lesson accordingly.  

Alternately, the powerpoint attached to the Direct Instruction section covers most of the same concepts and vocabulary as the chapter.  If you have a shorter class period, you may want to skip the reading assignment and assign the discussion questions as homework.  You could then hold the class discussion on the following day.       

In my case, I assign the textbook reading on the meeting previous to this lesson.  In that way, students will have already covered the concepts on their own and the powerpoint presentation will be less of a lecture and more of an opportunity for students to ask questions and clarify their understanding. 

 

Please note that the textbook assignment is printed multiple times on the same page to reduce paper use.  I usually have a TA use the paper cutter to make strips.

 

Connection to Standard:

In this lesson, students will prepare for class by reading and determining the central idea of a text, establish familiarity with relevant scientific vocabulary, and then draw evidence from the text to support arguments and opinions presented as part of their participation in a group discussion.  

 

Direct Instruction

30 minutes

Like I mentioned above, I assign the textbook reading as a homework assignment to be completed upon arrival to this class period.  The powerpoint presentation is then more of a review and an opportunity for students to ask questions.  

 Wondering WHY I use lectures as a pedagogical strategy?  Watch this video.

Wondering HOW I use the Powerpoint to differentiate instruction? Watch this video.

Wondering why I choose to have a reading assignment AND a lecture on the same content?  Read this rationale.

Wondering how you might use this lesson's resources if you don't plan on presenting a lecture? Read this reflection.

 

When class begins, I ask students to get their homework out and first give them about 10 minutes to discuss the critical thinking questions with their group members.  During this time, I walk around and put a stamp on completed homework and answer any questions that students bring up.  If students bring up a good question or insightful comment, I ask them to please remember to bring that up in the larger class discussion to follow the presentation.  

Affording this time before the presentation allows students to "field test" their answers with a smaller group, increasing their confidence to participate in the larger discussion.  Also, because the discussion is graded by groups, it allows the ideas of individual members to influence the thinking of their peers which may lead to greater insights or even new questions.  Finally, while I walk around, I listen to the nature of student discussions and get a better sense of what kinds of questions may be floating around the room, allowing me to emphasize certain aspects of the lesson or offer more detailed examples to scaffold the instruction.

After I have stamped all the homework assignments, I distribute the note sheet that accompanies the presentation.  As I've mentioned in previous lessons, offering students a note sheet provides a readymade study guide for later and allows students to focus on their thoughts and the concepts being discussed as opposed to focusing all of their attention on copying down copies amounts of notes.   

 

Please Note: I find it important to do more thorough checks for understanding during this presentation on a few points:  

1. Like a matryoshka doll, it's important for students to understand that the levels of ecological organization fit within one another.  That is, the biosphere contains many different ecosystems.  An ecosystem contains abiotic, non-living environmental factors as well as a community of interacting organisms.  Communities are made up of populations of different species.  Finally, populations are made up of many separate individual organisms.  

 

2. Even though we will eventually discuss the concept of niches in much greater detail in the lesson on competition and niches, I try to make sure at this point that students understand the 3 major ecological niches of producers, consumers, and decomposers.  Of these, I stress that producers and decomposers are arguably the most important because producers take non-living matter from the environment and produce organic matter (in which they store energy from sunlight).  Decomposers are equally important because they return finite matter to the non-living environment by decomposing organic compounds in dead tissue and waste products, essentially recycling the non-living matter to be used again by producers.  I then mention that consumers could therefore be considered "middlemen" in that, fundamentally speaking, ecosystems could persist without them (lichen are a good example of this).  This is an oversimplification of course, but an interesting point for students to grasp large, fundamental niches before investigating the more complex nuances of actual interspecies relationships in a functioning ecosystem.   Again, the niches and competition lesson goes into greater detail regarding the ways that consumers can play fundamental roles in ecosystems (such as keystone species or pollinators).

Discussion

30 minutes

Following the presentation, I let students know that we will wrap up by having a class discussion to review the concepts of the lesson.  Again, depending on your class length, it may be preferable to have this follow-up discussion on the following day.  

The discussion protocol for this lesson:

  1. all groups are required to participate in the discussion and will receive a “participation” grade for the day

  2. groups with more than one member that participate will receive a higher participation grade

  3. groups that participate more frequently will receive a higher grade

 

These criteria make the group collectively responsible for their grade and accountable to each other. If no one in the group participates, the group as a whole will receive a failing grade.  If only one member of the group participates, regardless of how often, the group can’t receive any grade higher than a C.  

 

To keep track of participation, I begin by making a map of the class with the group tables labeled by group name.  Since there are four students at each table, as a student from a particular group participates, I make a tally mark in the position of that student in their group.  In this way, I can tally how often the group participates, which members are participating, and how often.  To determine "average" participation, I add up all tally marks and divide by the number of groups, rounding down.  I then use this rubric to determine their participation grades.

 

If you'd prefer to not give a grade for participation in discussions, see this reflection where I discuss the conditions that arose that allowed me to not to grade for participation but still have meaningful discussions with broad participation.

See this discussion guide for specific strategies for this discussion, but I would bring your attention to a key point from the guide that may affect how you lead the discussion:

On the question of why environmental scientists choose the individual rather than the cell as the basic level of study, I hope that students come to the understanding that ecologists start at the level of individuals and go up from there (to populations, communities, and ecosystems) because of the kinds of questions they ask. 

For example, the question of how prey populations are affected when a predator species’ population falls doesn’t really require an environmental scientist to investigate the question at the cellular level.  It would be sufficient to look at population numbers and, perhaps, observe any physical and behavioral changes in individuals of the prey species.

Another point to make clear here, though, is that this focus on higher levels of organization doesn’t preclude studying lower levels of organization.  For example, if the predator species’ population is due to a disease carried by a parasite, then the ecological relationship inherent in that symbiotic relationship may compel an environmental scientist to study how the parasite affects the predator on a cellular level to better understand the entire scope of the phenomenon.