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Symbiosis and Co-evolution

By Daniel Bisaccio


This unit allows students an opportunity to integrate technology with active research through :
  • investigating a symbiotic relationship in a lab setting,
  • followed by an on-line and CD Rom primary information search,
  • and then create a presentation using technology for our "Symbiosis Symposium".
  • Students are then assessed on:

    1. Knowledge and Content (Symbiosis, Co-Evolution, Technology)

    2. Problem-Solving Skills (Lab & Information Search/ Processing Skills)

    3. Communication Skills (Presentation for Symbiosis Symposium)

    Information for the Student

    Prior to working on this unit, students have completed an in-depth investigation of "what is an ecosystem?" through fieldwork. They examined terrestrial succession and the biotic and abiotic factors that operate within an ecosystem. This unit then allows them to begin to understand how and why species interact within an ecosystem.


    Students are introduced to symbiosis through a short slide presentation highlighting a few types of symbiosis as well as the adaptive value of them. Although following a lecture format, emphasis is placed on asking students probing questions related to the slides they are viewing so that they may begin to construct a working knowledge of the dynamics involved.

    Three examples follow:

    1. Ant Birds follow Army Ants eating fleeing insects while Butterflies follow the Ant Birds feeding on their droppings. Why? Diagram the interspecies relationships presented and give a possible reason for each.

    2. A Sloth has hollow hair which allows a Green Algae to colonize within the hair, while a Tropical Algae Moth lives in the fur. Why? Diagram the relationships presented.

    3. Coral are animals that need a Brown Algae (Zooanthellae) living inside them to survive. Why? Diagram the relationships.

    We then review class results and both define and graphically illustrate symbiosis as:



    Sp. A   Sp. B      SYMBIONT TYPE 
     +        -     PARASITISM/ PREDATION
     +        +           MUTUALISM
     +        0          COMMENSALISM 
     -        -          COMPETITION
     -        0          AMMENSALISM

    Students then investigate a symbiosis through a lab investigation in which they remove the hindgut of a termite and examine it for protists. Background information is given to them so that they may identify the protist species found and determine the type of symbiosis (mutualism) present. Additionally, students are asked to develop a hypothesis for how this symbiotic relationship may have come to be. Class discussion and articles published by biologists are read to locate the answer.

    (* It is worth noting that most students have not had any experience with reading scientific papers and this is a good point to introduce students to "how to" read a scientific paper.)

    Student Assignments

    Students are given the following assignment:

    Choose any species and research an adaptive symbiotic relationship it shares with another species. Why and how did this interspecies relationship develop?

    Our school librarian (Information Specialist) then works with the students on locating primary sources of information as well as processing the information. Students use Booleian Search Strategies in locating information while learning how to cite notations and construct bibliographies. Their search allows them to access and process information in a meaningful context versus learning how to access and process information "as a skill" only. Their search leads them to discovering the power of CD Rom information banks, using ProQuest magazine/ periodicals, Internet information networks, and use of Wilson Disks.

    Once their research has been completed, students then work with our technology teachers on creating a professional presentation using a variety of presentation software. Students opt to use computer generated and projected outlines, videoclips, and simulations for their presentations to support their work. Students not only construct meaningful knowledge, but also develop life long skills as they "symbiotically" integrate technology, information, and science during this unit.

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