Example+Mini-presentation

Example: Transcript of a KANW radio program “Biocast” by UNM faculty member Bruce Hofkin

**EAST IS EAST, AND WEST IS WEST**

"Ring Species" are one of those things many biologists figure should exist, but nobody's been able to find. In theory a ring species starts out on the edge of some geographic obstacle such as a lakeshore. At an original location, the animals or plants in question breed freely with each other. But over time, they begin to spread out in opposite directions along the edge of the obstacle, say along the north and south shores of the lake. As they do so different selection pressures on opposite sides of the lake result in different evolutionary pathways for the two pioneering populations.

The result is organisms on either side of the barrier become more and more different. Finally, when they once again meet on the far side, they no longer give each other the time of day. Interbreeding no longer occurs, and Voila! Two species where there was once only one.

Well, finally, after nothing but theory for sixty years or so, Darren Irwin of the University of Lund in Sweden, has actually laid his mitts on a genuine ring species-a type of warbler that's spread around a high plateau in Tibet.

The little birds, known formally as Phylloscopus tiochiloides, live around the plateau, but stay away from the frigid highlands in the middle. On the south side, everyone's one big happy family. But as the birds spread east and west, their songs begin to change. By the time they meet on the northern edge of the plateau, the eastern birds don't speak the same language as those from the west, and interbreeding drops to zilch.

DNA evidence too, suggests that the birds traveling up opposite sides of the plateau want nothing to do with each other. And since no babies are born to parents from opposite sides of the tracks, a prime requirement for separate species is met. And never the twain will meet.


 * Factors, features of a successful mini-presentation - I look for these in completing the evaluation **


 * Information – the facts
 * Entertainment - making the facts enjoyable –easy to take
 * Context – why the facts are important in the context of the class and our discussions
 * Citation – where did the facts come from


 * Other factors **
 * Clarity
 * Brevity
 * Enthusiasm
 * Audience awareness