lecture%204%20natural%20selection%20B

Lecture 4 natura - DISCUSSION SECTION Enrollment closes at 12:30 Friday October 9 You must be enrolled by that time(190 points Starting Monday

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10/8/09 1 DISCUSSION SECTION Enrollment closes at 12:30, Friday October 9 You must be enrolled by that time (190 points) Starting Monday October 12 you must go to your enrolled discussion CLICKER REGISTRATION clicker points count starting Tuesday October 13 you will not get points until you register your clicker correctly online (no retroactive points) Overview – Natural Selection I. Background II. Artificial selection III. Variation IV. Measuring natural selection V. Different modes of selection How does evolution happen? 1. individuals vary 2. individuals with certain traits - greater survival/reproduction (selection) 3. variation is heritable (genetic) 4. result- evolution D. Did the population evolve? We know all these things were true: 1. individuals vary 2. individuals with certain traits - greater survival/reproduction (selection) 3. variation is heritable (genetic) 4. result- evolution Why don’t all finches all have bigger and bigger and bigger bills?
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10/8/09 2 Why don’t all finches all have bigger and bigger and bigger bills? a. Variation was exhausted b. They attained the perfect beak size, thus natural selection ceased c. The environment is constantly changing d. Estimates of heritability were incorrect e. All of the above 1977 - drought 1983 - El Niño – lots of rain Super abundance of small seeds 2003/4 - another drought 1977 drought - red line Changes in average beak size 1970 - 2000 1983 - rain Beaks got smaller
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This note was uploaded on 02/21/2010 for the course BILD BILD3 taught by Professor Henterheather during the Fall '08 term at UCSD.

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Lecture 4 natura - DISCUSSION SECTION Enrollment closes at 12:30 Friday October 9 You must be enrolled by that time(190 points Starting Monday

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