Tuesday, February 21, 2012

How populations evolve

Today we brainstormed ideas about some of the evidence that validates the evolutionary view of life.  For part 1 of your homework: look up information on the four key terms on the first page of the packet.  What does a person study if they are in the field of comparative embryology?  What is an example of a homology?  What do homologies tell us about the relationship between species?

Darwin proposed natural selection as a mechanism of evolution, as it turns out there are four parts of evolution.  However, since your book starts with Natural Selection, that's where we will begin.

To see natural selection in action we read a case study about microevolution in a specie of crickets in Hawaii.

Attack of the Mutant Crickets!!!
"Attack of the flesh-eating parasitoid maggots!! Mutant mute crickets run rampant in tropical paradise!! The headlines may sound like a trailer for a cheap horror flick — but in fact, these sensationalist sound bites accurately describe the situation on the Hawaiian island of Kauai. The "flesh-eating parasitoid maggots" are the offspring of the fly, Ormia ochracea, which invaded Hawaii from North America, and the mutant crickets are the flies' would-be victims. The flies follow the chirps of a calling cricket and then deposit a smattering of wriggling maggots onto the cricket's back. The maggots burrow into the cricket, and emerge, much fatter, a week later — killing the cricket in the process. But this fall, biologists Marlene Zuk, John Rotenberry, and Robin Tinghitella announced a breakdown in business-as-usual in this gruesome interaction: in just a few years, the crickets of Kauai have evolved strategy to avoid becoming a maggot's lunch — but the strategy comes at a cost... " Want to read more or see the article with color photos? Click here.

If you did not finish your summary of the case study in class you need to do that for homework as well.  Not sure where to start for you summary, think of how this case study is an example of natural selection.

 Lastly, define the terms/concepts on page six of the packet.  

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