Taylor Wichmanowski LOS ANGELES HIGH SCHOOL OF THE ARTS (LAHSA), LOS ANGELES, CA
High School Science : Unit #6 - Biodiversity : Lesson #1

What is Biodiversity?

Objective: Students will be able to describe multiple types of biodiversity and provide examples to support the notion that biodiversity has many different types of value.
Standards: SL.11-12.1 SL.11-12.1a SL.11-12.1b SL.11-12.1c SL.11-12.1d L.11-12.6 RST.11-12.1 RST.11-12.2
Subject(s): Science
60 minutes
1 Introduction - 0 minutes

This lesson covers the different types of biodiversity and the different ways that biodiversity has value for humans and other organisms.

 

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.  The concepts covered in this chapter that I would look for in a different text are...

  • An overview of biodiversity including species diversity (different species), genetic diversity (different genes and traits within a species), and ecosystem diversity (the different ecosystems in an area)
  • A description of the different ways that biodiversity has value, including
    • ecosystem function
    • medical
    • agricultural
    • recreational
    • intrinsic

 

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. 

 

Connection to Standards:

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. 

2 Warm Up - 15 minutes

As I mention in more detail in the discussion section of this lesson, by this point of the year, much of our discussion of the homework questions actually takes place in warm ups or during the presentation itself, leaving the final discussion as more of a review.  For an overview of all homework/discussion questions, see this lesson's discussion guide.

 

In this case, I begin the class by asking students to discuss the first question from the homework with their groups for a few minutes:

Why does the book say that species diversity is the “easiest to visualize”?  In your explanation, list at least 5 examples of species diversity in your neighborhood.

After students have had time to discuss this question, I ask for their explanations to the first part of the question, regardin why species diversity is easy to visualize.  Essentially I am looking for students to explain that it makes sense to say that species diversity is the easiest because it almost always corresponds to differences in physical form that are visually apparent.  For example, a pigeon is easily distinguishable from a crow, or a pelican, or a flamingo, etc. 

The real meat of this question, though, is for students to think about the species diversity in their own neighborhood (which winds up as the focus of the class’ final project: the biodiversity survey).  If every student has 5 examples and shared them with their groups, there should be an abundance of examples and I therefore just ask students to continue offering examples of different species that they have seen and write them on the board as they are mentioned.

 

For the second question, I also give students about five minutes to discuss with their groups:

Look at the humans around the classroom and give at least 5 examples of genetic diversity.

For this question, it’s easiest to answer if the students take a few minutes with their groups and log all of the obvious differences between the individuals.  As I discuss in this reflection, it's important that you set students up to remain respectful of each others differences as they discuss them.  The idea here is for students to understand that, even with a lot of surface similarities, every individual is unique and a lot of genetic diversity is present in the class. 

As students mention differences between the members of the group, I write them on the board.  However, I don't write down specific difference between students (e.g., Jaime has blonde hair and Robert has Black hair), but rather the category of differences (e.g., hair color, eye color, height, blood type, etc.).

 

Following these two short discussions, I explain that we will be discussing the benefits of these types of diversity in our presentation and then have a student volunteer distribute the notesheet before beginning the direct instruction section of the lesson.

 

 

Diversity? But we're all the same!
Trust and Respect

It can be a bit sensitive to have students in a group point out the differences between them if the differences are based on weight, complexion, height, or any other physical traits that high school students in particular may be self-conscious about.  Still, it’s worthwhile to point out that humans are not identical to each other and if students approach this respectfully, it can be a lot of fun. 

Differences that my students pointed out had to do with hair texture, eye color, height, body type (which they dubbed “metabolism”), and other surface differences. 

However, since the majority of my students are Latina/o, many groups got “stuck” saying things like, “we’re all brown”, “our eyes are all dark”, “our hair is all black”, etc. 

Digging a bit deeper, this question provides an opportunity to review genetics from biology.  You might ask, for example, “are siblings identical?  If not, then how are they different? How do they get these differences from the same parents?”  Students may then answer that siblings can have differences in facial structure, gender, hair color, eye color, etc.  Going beyond the surface differences, you might also talk about traits like being double jointed, types of fingerprint patterns, attached or detached ear lobes, or even blood type.  This might lead students to talk about dominant and recessive traits, and homozygous and heterozygous genotypes, and ultimately (hopefully) to recalling that not all genotypes affect the phenotype and that much of our genetic diversity is actually “hidden” from our eyes. 

The fact that there's more genetic diversity within human ethnic groups than between them is a good lesson to recall when a group of unique individuals are fixated on the idea that they’re all the “same”.

3 Direct Instruction - 60 minutes

Following the quick warm up, I begin the powerpoint presentation for this lesson.

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.  

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.

 

During the presentation, I make sure to continually solicit student involvement by asking for them to provide personal experiences that might relate to the content and encouraging them to ask questions when they arise. 

 

Please Note: Since so much of the homework-based discussion for this lesson takes place either during the warm up or during this presentation, I would point out the following:

For the homework question regarding whether or not California has high ecosystem diversity when compared to other states, this question would probably work best using the state your school is in.   However, the images on slides 17 and 18 allow you to use California as a good comparison to your state.  You might find it useful to add images of your own state (and perhaps others) to the presentation to help students visualize high and low ecosystem diversity. 

As for answering the question: yes, California has amazing ecosystem diversity compared with most states.  For example, we have chaparral, coastal regions, deserts, dunes, alpine mountains, pine forests, the fertile plains of the central valley and more. To compare your state with another, I suggest you draw from students’ own experiences.  This is another good example of an opportunity to have students become more engaged in a discussion by asking them to combine their own prior knowledge and personal experiences with new content to strengthen their learning.

4 Discussion - 15 minutes

By this point in the year, much of the discussion takes place during the lecture itself as I pause to ask students to consider some aspect of the presentation and then share out their perspectives.  In this particular lesson, two of the "discussion" questions are approached in the warm up, and one is tackled during the presentation.  The remaining questions are approached as a review discussion at the end of the class. 

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 all the discussions that take place during the lesson, but I would bring your attention to the following for this final review discussion:

The question regarding the different benefits of biodiversity really just reviews content directly from the presentation, but it’s a good exercise to ask students to rephrase the benefits in their own words and provide an example.  You might want to split up the benefits amongst groups and then have the groups share out to the whole class.  When I do this, I assign each group a benefit of biodiversity and give them about five minutes to come up with their own explanation of biodiversity's value and an illustrative example (with eight groups we ended up with each benefit being tackled by two groups, helping to ensure we heard a diversity of student perspectives on each benefit).  I then write each category (ecosystem function, agriculture, etc.) on the board and then write the student-phrased explanation of each category and also write down the examples that the students offer. 

Basically I'm looking for students to offer the following, hopefully being able to offer their own examples:

    • Ecosystem Function: the different organisms in an ecosystem are the working parts of a system.  Just as a watch doesn’t work when you remove random pieces, nor does an ecosystem function as well when species diversity is reduced.  [e.g., the disappearance or significant population reduction of a “keystone” species can disrupt an entire ecosystem]

    • Agriculture: Many varieties of crops exist because of the genetic diversity of food species [e.g., hundreds of varieties of potato exist in Andean South America], a variety of species increases food options for humans [e.g., potatoes are native to South America but became a staple crop in many other areas of the world], pollinating species are essential to continued crop production [e.g., the loss of honeybees may significantly affect crop yields].

    • Medicine: Many varieties of medicinal compounds come directly from nature, to lose species means losing potential cures for human pathologies [e.g., penicillin came from mold]

    • Tourism and Recreation: Economic development can occur from the preservation and conservation rather than exploitation of natural resources [e.g., Costa Rica and Panama have experienced economic growth from their eco-tourism industries while conserving rainforest]