1. Adaptive radiation The rapid diversification of a lineage
The factors that drive adaptive radiation
key innovations/mutations/novelty
ecological opportunity

2. Examples of adaptive radiation
Group Key innovation(s)

3. The Cambrian explosion
The fossil record
Ediacaran fauna
Burgess shale
Mya
The molecular evidence
Hemoglobin ‘clock’
Ecological underpinnings
Increased atmospheric oxygen
Predator-prey coevolution
Global warming and rising sea levels following the most extensive glaciations in history

4. What does the molecular clock say about the timing of the Cambrian explosion?
Bruce Runnegar (1982): 900Mya
Wray et al. (1996): Mya
How can these molecular data be reconciled with the fossil data?
What observations or experiments would shed light on the cause of the discrepancy?

5. The (pre?) Cambrian explosion
1200Mya
from Rasmussen et al. (2002) Science

6. What are these?
bandicoot, sugar glider, koala, kangaroo, numbat

7. What are these?

8. What is this?

9. What are these?

10. What are these?

11. What is this?

12. Phylogeny

13. Adaptation

14. Tarweed huggers Larry = Gerry Carr (U Hawaii)
Moe = Robert Robichaux (U AZ)
Curly = Bruce Baldwin (UC Berkeley)

15. Adaptive radiation in real time
Paul Rainey and Mike Travisano (1998) Nature 394:
Adaptive radiation in bacteria (Pseudomonas) grown in liquid culture (microcosm)
Why use bacteria for evolutionary experiments?

16. Adaptive radiation in real time
Two environments:
Homogeneous (shaken, not stirred)
Heterogeneous (unshaken)
Replicate experiments founded with a clonal isolate of the ‘smooth’ morph
Plated onto solid agar media at daily intervals to measure frequency of morphotypes

17. Pseudomonas

18. Pseudomonas

19. Pseudomonas

20. Pseudomonas