Lesson Plan
Title:  What is it? Using a Dichotomous Key
Subject:  Science
Grade Level:  7
Overview:
TLW be pre and post assessed on knowledge of how to use and how to create a dichotomous key. TLW gain field experience that requires using a dichotomous key before designing their own key. Students will used info gathered in Webquest to design a Kingdoms of Life Brochure. A Webquest and field trip extension are offered but not required. Extensions use Excel to graph student gathered data. Rubrics for assessment are included as well as practice test items.
Approximate Duration:  4 - 6 : 45 minute class periods; Webquest one day
Content Standards:
  • Science as Inquiry
         The students will do science by engaging in partial and full inquiries that are within their developmental capabilities.
  • Life Science
         The students will become aware of the characteristics and life cycles of organisms and understand their relationships to each other and to their environment.
  • Science and the Environment
         In learning environmental science, students will develop an appreciation of the natural environment, learn the importance of environmental quality, and acquire a sense of stewardship. As consumers and citizens, they will be able to recognize how our personal, professional, and political actions affect the natural world.
Benchmarks:
  • SI-M-A5
         developing models and predictions using the relationships between data and explanations;
  • SI-M-A7
         communicating scientific procedures, information, and explanations;
  • SI-M-A8
         utilizing safety procedures during scientific investigations.
  • SI-M-B6
         communicating that scientific investigations can result in new ideas, new methods or procedures, and new technologies;
  • LS-M-C1
         constructing and using classification systems based on the structure of organisms;
  • LS-M-C2
         modeling and interpreting food chains and food webs;
  • LS-M-C3
         investigating major ecosystems and recognizing physical properties and organisms within each;
  • LS-M-C4
         explaining the interaction and interdependence of nonliving and living components within ecosystems.
  • SE-M-A3
         defining the concept of pollutant and describing the effects of various pollutants on ecosystems;
  • SE-M-A4
         understanding that human actions can create risks and consequences in the environment;
  • SE-M-A5
         tracing the flow of energy through an ecosystem and demonstrating a knowledge of the roles of producers, consumers, and decomposers in the ecosystem;
Grade-Level Expectations (GLEs):
    • Science and the Environment
      Grade 7

      39. Analyze the consequences of human activities on ecosystems

      (SE-M-A4)

      40. Construct or draw food webs for various ecosystems

      (SE-M-A5)
    • Populations and Ecosystems

      23. Classify organisms based on structural characteristics, using a dichotomous key

      (LS-M-C1)

      27. Identify the various relationships among plants and animals (e.g., mutualistic, parasitic, producer/consumer)

      (LS-M-C4)
    Interdisciplinary Connections:  
    • English/Language Arts : Standard 1
           Students read, comprehend, and respond to a range of materials, using a variety of strategies for different purposes.
    • English/Language Arts : Standard 2
           Students write competently for a variety of purposes and audiences.
    • English/Language Arts : Standard 3
           Students communicate using standard English grammar, usage, sentence structure, punctuation, capitalization, spelling, and handwriting.
    • English/Language Arts : Standard 4
           Students demonstrate competence in speaking and listening as tools for learning and communicating.
    • Social Studies : Geography: Physical and Cultural Systems
           Students develop a spatial understanding of Earth's surface and the processes that shape it, the connections between people and places, and the relationship between man and his environment.
    Educational Technology Standards:  
    • Demonstrate the operations of a computer (e.g., touch-keyboarding skills, save, organize and back-up files) and other peripheral devices (scanner, digital and video cameras, VCR, laser disc player) at an intermediate level.
    • Use information, media, and technology in a responsible manner which includes following the school's acceptable use policy, adhering to copyright laws, respecting the rights of others, and employing proper etiquette in all forms of communication.
    • Use technology tools (e.g., multimedia authoring, writing tools, digital cameras, drawing tools, web tools) to gather information for problem solving, communication, collaborative writing and publishing to create products for various audiences.
    • Understand Internet concepts (e.g., website, hypertext link, bookmarks, URL addresses) and apply intermediate on-line searching techniques (e.g., employ keyword, phrases, and Boolean Operators).
    • Use telecommunications and online resources efficiently and effectively to collaborate with peers, experts, and others to investigate curriculum-related problems, issues, and information and to develop solutions or products for various audiences.
    Objectives:
    Students will practice using a dichotomous key in the classroom prior to their field study

    Students will collect and identify 8 different tree samples using a dichotomous key and leaf characteristics.

    Students may participate in a field trip extension that will tie in food web, predator/prey and habitat/niche benchmarks. A scavenger hunt, field tree id and pollution scavenger hunt are included in this lesson plan. Data gathered on field trip can be organized into a graph using Microsoft Excel.

    Students will synthesize knowledge they have gained to practice classifying different types of beans and write a 5 sentence paragraph/constructed response to explain how they classified the beans.

    Students will create a dichotomous key to classify 2 assigned objects (beans can be used).

    Students will engage in web based learning using a webquest to explore classification.
    Lesson Materials and Resources:
    Student text for Calcasieu Parish :
    Glencoe/McGraw Hill Life Science Copyright 2002

    Chapter 1 pages 22-29
    Technology Tools and Materials:

    Hardware:
    Computer with printer and internet connections

    Software:
    MS Word, MS Excel

    Websites:
    •Aliens classification
          http://www.doe.state.la.us/lde/uploads/5604.pdf
    •Classifying buttons
          http://www.doe.state.la.us/lde/uploads/2536.pdf
    •Tree identification
          http://oregonstate.edu/trees/dk/
    •Kingdoms background
          http://anthro.palomar.edu/animal/default.htm
    •Archaebacteria & Eubacteria
         www.siri.net/~jgjohnso/monerans.html

         http://co.essortment.com/archaebacteriae_rmkr.htm

         http://tolweb.org/tree?group=Eubacteria&contgroup=Life_on_Earth

     

     

     

     


    Other:
    http://webworldwonders.firn.edu/cameras/keys/sa/tree.html
    http://www.palaeos.com/Kingdoms/kingdoms.htm
    http://www.nbii.gov/issues/biodiversity/species.html
    http://www.borg.com/~lubehawk/kingdms.htm

    Background Information:
    Make sure that students understand that dichotomous keys can be used to identify organisms from all kingdoms of life.

    Here is an article that has great examples of characteristics that might be used to distinguish different species of plants.

    Different groups of plants
    By Ekaterina Zhdanova-Redman

    ________________________________________
    1 Scientists believe that there are more than 300,000 species of plants. The variety of plants on our planet is amazing. Giant sequoia trees are plants just as much as strawberries or tiny mosses. Plantae is the scientific name for the plant kingdom. It consists of many different divisions and groups of plants. Scientists group plants according to their common characteristics.

    2 Scientists group plants by their similar parts, for example, plants' roots. Just think of the huge roots of some trees. Sometimes they can grow through the pavement on walkways. Compare that to the roots of beets or yard grass. They do look very different, don't they?

    3 There are two major kinds of root systems. The root system that looks like one major root--like the one the beet plant has--is called a taproot. A taproot grows down and forms many small secondary roots. Plants with taproot systems use their roots to store food. You can see these plants and roots in many gardens and grocery stores--carrots, beets, radishes, and turnips. Some trees also have taproot systems. Pine trees can grow their taproots as far down as 6 meters (about 20 feet)!

    4 The second major kind of root system is called fibrous roots. They are made up of large numbers of roots that are more or less equal in size. Instead of growing deep down, they usually spread over large areas. Most grasses and some trees, like maple and beech trees, have fibrous root systems.

    5 Even though the roots are different, their functions are the same--to anchor and support the plant, and to absorb, transport, and store water and nutrients. The tissues that roots are made of are the same, too. The outside covering of a root is called epidermis (ep-i-dur-mis).This term is also used for the outer covering of human skin! Epidermis directly contacts the soil and absorbs water and nutrients.

    6 The tissues inside the roots are called xylem (zi-lem) and phloem (flo-em). They are tube-like tissues through which water and nutrients move. Xylem helps to move water and nutrients from the roots to the stems and leaves. Phloem conducts food made in the leaves to all other parts of a plant that need them. Xylem and phloem are separate inside the plant, and they are continuous from the root, stem and leaves.


    7 For our purposes today, we will use the leaves of trees to differentiate the different species
    Lesson Procedures:
    Day One:
    Pretest knowledge of dichotomous keys
    Practice using dichotomous keys
    Strategies:
    Procedure:
    1.Pretest Knowledge. (see attached)
    2. Arrange chairs in a circle.
    Instructor takes off one shoe and places it on the floor in the middle of the circle.
    .
    Dialogue:
    3."There's one of my shoes, so let's have a shoe from some of you". Ask five-ten reliable students to put one of their shoes in the middle of the circle.
    4.Tell the students that they are to divide the shoes into two piles. Tell them the piles don't have to have equal numbers of shoes but, that they all have to agree on some obvious characteristic that will distinguish the shoes in one pile from the shoes in the other pile. After agreement is reached, tell the students a record of the agreement will be kept on the board.
    5.Draw two horizontal lines some distance apart on the chalkboard. Label the lines with the agreed upon characteristics.
    6.Return to the pile of shoes. Tell the students one pile will be pushed aside for the moment but, now they must again divide the pile of shoes into
    two distinct piles. After agreement is reached add this information to the
    ovehead or classroom board sketch.
    7. Continue the procedure of dividing the shoes into two distinct piles and adding the information to the sketch until there is only one shoe with the
    identifying characteristic, at which point the shoe is identified and the owners name is added to the sketch
    8. Divide the second pile of shoes in the same manner as the first pile
    until all the shoes have been identified.
    9. Push all the shoes back together in one pile, adding perhaps a shoe from the distance past or one with characteristics unlike those used in the
    original construction].
    Discuss the meaning of the term dichotomous explaining that the word means "two forks".
    10. Tell the students that dichotomous keys usually appear in a more compact form and that the diagram can be easily converted by adding numbers to each characteristic used. Label the diagram in numerical sequence following the same order the characteristics were agreed upon.
    11. Have the students redeem their shoe by taking it from the pile and placing it on the correct branches of the key which will lead to its'
    correct identification. After all the shoes have been redeemed the shoe added earlier should remain. Ask a student to follow the key until the shoe is identified. Students should discover that a key works only for identification of those items used in its' original construction.
    12. Pass out the practice worksheet(s). Complete the " Using A Dichotomous Key" sheet in class.
    If needed repeat the procedure with the "Some Common Beetles of North America" sheet in class.

    Please note:
    If needed, either before or after the Web quest, the teacher should spend another class period repeating this procedure using a variety of beans. I usually buy a bag of 15 bean soup and put 2-3 beans of each variety into a set of Ziplocs to be uses by cooperative groups. Card stock works well to do the grouping and for students who need even more reinforcement to get to the written step, you can have them glue the beans into place. Then they can work from the glued bean page to develop a written dichotomous key. In our textbook, there is a lab activity on page 27 that sorts and classifies beans according to shape, size, color, texture, etc..

    Day Two: Web quest

    Objective: TLW complete the teacher designed web quest to use technology resources to garner further understanding of classification and dichotomous keys. Information gathered will be
    used to create a "Kingdoms of Life " booklet that can be assessed. Students can use technology skills of cutting and pasting or copying and pasting from the websites into the Classification chart.
    Student journal page and classification chart task page are to be printed out by the student and turned into the teacher for assessment. Rubric is attached. Resources are all embedded in the Web quest.

    Day Three: Practice using Dichotomous keys

    Objective: TLW practice using physical characteristics to classify organisms.

    There are three lessons included to meet individual differences. If your students are catching on and need to be challenged, use the High School lesson
    called Classification of Aliens. If students are weak, use the Buttons Classification and if students are in the middle, use the Tree ID. Microsoft Excel graphs can be created to show class data on two differentiated characteristics to be determined by class. For example:
    1. Aliens (socks and no socks; eyes on stalks and eyes not on stalks, etc...)
    2. Buttons (round and non-round)
    3. Tree Leaves (lobed and non lobed; evergreen and deciduous, etc..)

    Day Four: Design a Dichotomous Key
    Objective: TLW design a dichotomous key that maps out at least 5 different characteristics to distinguish between the two assigned organisms.
    Beans can be used and classified by characteristics like size, shape, color, texture, etc... Students will write characteristics used to differentiate and classify on the chart they design. I like to use cardstock and have students glue beans or leaves onto the chart. Students then write a five sentence constructed response paragraph explaining how they classified their organisms.

    Day Five:
    Students use their chart from the previous day to compose and write 5 steps with 2 choices "a" and "b" at each step for a total of ten statements. Remember, the final two statements serve to identify by Genus and species name, the given specimen.
    Day Six-
    Post test, Closure--class discussion and reflection on Plus/Delta or K-W-L chart.
    Field Trip Extension (see below)
    Assessment Procedures:
    Rubric for Creating a Dichotomous Key

    Rubric for Web quest
    Accommodations/Modifications:

    Follow standard 504 guidelines for your students
              ----- written by Elizabeth Winfrey  

    Reproducible Materials:
    Explorations and Extensions:
    Field trip extension: If possible, have kids visit a campus or nearby botanical garden or public park where they will be asked to identify 4-8 trees using available field guides. Field trip could include a food-web scavenger hunt and a pollution scavenger hunt. To make the field trip data driven have students gather data on two to six specific characteristics like leaves: lobed and non lobed, evergreen and deciduous and have kids create an Excel graph using this data.

    Brain pop movie is great way to reinforce what the student's have learned so far. See reproducible.

    In reproducibles, find the field trip materials:
    1. Food/Energy Web
    2. Tree id
    3. Pollution Scavenger Hunt

    To reinforce:
    Here is a great classification lesson from the state website. The students will love classifying aliens according to physical characteristics. It is considered High School but your students should have no problems.

    http://www.doe.state.la.us/lde/uploads/5604.pdf

    Lesson Development Resources:
    http://www.csdl.tamu.edu/FLORA/tfplab/lab1.htm
    Reflections:
    There were a lot of adjustments I had to make along the way in teaching this series of lessons or Unit, but I think in the long run, your students will have a comprehensive in depth understanding of classification.
    Contact Information:
    Elizabeth Winfrey
    elizabeth.winfrey@cpsb.org
    Oak Park Middle School
    Additional Contacts:
    MarcoPolo Lesson:  No