1. Copyright Notice! This PowerPoint slide set is copyrighted by Ross Koning and is thereby preserved for all to use from plantphys.info for as long as that website is available. Images lacking photo credits are mine and, as long as you are engaged in non-profit educational missions, you have my permission to use my images and slides in your teaching. However, please notice that some of the images in these slides have an associated URL photo credit to provide you with the location of their original source within internet cyberspace. Those images may have separate copyright protection. If you are seeking permission for use of those images, you need to consult the original sources for such permission; they are NOT mine to give you permission.

2. Figure 25.15 Medium ground finch (Geospiza fortis) Daphne Major

3. Darwin’s Four Postulates Evolution is a logical outcome of four postulates… –populations have natural variation –the organism’s features are heritable –more offspring are produced than can survive –some individuals produce more offspring because of the environment Modern biologists condense Darwin’s four steps into two statements: Evolution by natural selection occurs when: 1. Heritable variation leads to 2. Differential reproductive success

4. Figure 25.16 Weigh and measure all birds in the population before and after the drought. 1976: Before drought N  751 (all birds on island) Beak characteristics changed in response to a drought. No changes in beak characteristics occurred in response to a drought. Average 1978: After drought N  90 (survivors) Number of finches Average beak depth in the population increased Beak depth (mm) Natural selection occurred. The characteristics of the population have changed. Did natural selection on ground finches occur when the environment changed?

5. Figure 25.16-1 Did natural selection on ground finches occur when the environment changed? No changes in beak characteristics occurred in response to a drought. Beak characteristics changed in response to a drought.

6. Figure 25.16-2 Weigh and measure all birds in the population before and after the drought. Did natural selection on ground finches occur when the environment changed? Beak characteristics changed in response to a drought. No changes in beak characteristics occurred in response to a drought.

7. Figure 25.16 Weigh and measure all birds in the population before and after the drought. 1976: Before drought N  751 (all birds on island) Beak characteristics changed in response to a drought. No changes in beak characteristics occurred in response to a drought. Average 1978: After drought N  90 (survivors) Number of finches Average beak depth in the population increased Beak depth (mm) Natural selection occurred. The characteristics of the population have changed. Did natural selection on ground finches occur when the environment changed? ?

8. Figure 25.16 Weigh and measure all birds in the population before and after the drought. 1976: Before drought N  751 (all birds on island) Beak characteristics changed in response to a drought. No changes in beak characteristics occurred in response to a drought. Average 1978: After drought N  90 (survivors) Number of finches Average beak depth in the population increased Beak depth (mm) Natural selection occurred. The characteristics of the population have changed. Did natural selection on ground finches occur when the environment changed? What statistical value is a measure of population variation? clicker!

9. Figure 25.16-4 1976: Before drought N  751 (all birds on island) Average 1978: After drought N  90 (survivors) Number of finches Average beak depth in the population increased Beak depth (mm) Natural selection occurred. The characteristics of the population have changed. is natural variation evident? did the drought select individuals of better fitness for increased reproduction?

10. Darwin’s Four Postulates Evolution is a logical outcome of four postulates… –populations have natural variation –the organism’s features are heritable –more offspring are produced than can survive –some individuals produce more offspring because of the environment Modern biologists condense Darwin’s four steps into two statements: Evolution by natural selection occurs when: 1. Heritable variation leads to 2. Differential reproductive success

11. Figure 25.18 Geospiza fortis Shallow adult beak Geospiza magnirostris Deep adult beak Lower Bmp4 expression (dark area) in embryo’s beak 2 mm Higher Bmp4 expression (dark area) in embryo’s beak Bmp4 is a gene whose expression is shown by in situ hybridization:

12. Figure 25.19 Bacteria Archaea Flowering plants Mosses Tapeworms Vertebrates Fungi The branches on the tree represent the relatedness of populations. All of the species have evolved from a common ancestor. None is “higher” than any other Last universal common ancestor (LUCA) Which dimension shows the progression of time?