Darwinian Snails: What Makes Populations Evolve? 2007

By Vazquez, Jose | The American Biology Teacher, November 2007 | Go to article overview

Darwinian Snails: What Makes Populations Evolve? 2007


Vazquez, Jose, The American Biology Teacher


Darwinian Snails: What Makes Populations Evolve? 2007. Part of EvoBeaker series. Produced by SimBiotic Software, 148 Grandview Ct., Ithaca, NY 14850. (617) 812-0093. Visit www.simbio.com for ordering and pricing information.

This simulation is part of the larger series EvoBeaker, which includes other computer-based activities that look at various aspects of the evolutionary process. Darwinian Snails looks at the underlying principles of natural selection using green crabs preying on periwinkle snails. The instructor and the students are given a set of assumptions and by turning these on and off, the user can then observe whether natural selection has occurred. The program is divided into four activities:

* A model of evolution by natural selection

* The requirements for evolution by natural selection

* Darwin's theory of evolution by natural selection

* The source of variation among individuals

During the first activity students can look at variation in the shell thickness distribution in the snail population as some of them are predated upon. Predictions can then be tested and subsequent observations allow the student to see which snails tend to get eaten and which ones tend to survive. At the end of this activity the evolution of the snails can be compared based on predator type (the student or the crabs).

The second activity deals with the various requirements for natural selection: variation, inheritance, and selection. Shell thickness can be made variable or non-variable, Shell thickness can be made heritable by clicking on the appropriate box. Also, survival can be made selective by clicking on the appropriate parameter. Students can make predictions about population distribution as they work on the activity.

During the third activity students can apply Darwin's theory by describing which conditions in the snail population would or would not allow evolution of a thicker shell. Finally, the role of mutation can be investigated by reproducing the snails with mutation and observing whether there is a limit as to how far predatory crabs can drive shell thickness in the snail population. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

Darwinian Snails: What Makes Populations Evolve? 2007
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.