1. Evolution by natural selection can create adaptation, that tangible sense of “designed for function”

2. But it is also an historical process – only works with existing variation, has a characteristic “makeshift” quality _____________ organs, _____________ genes

3. “Panda’s thumb” The late evolutionary biologist Stephen J. Gould loved to dwell on this historical component of design in nature A favorite example – the “thumb” of the Giant Panda http://www.athro.com/evo/pthumb.html _____bone – radial sesamoid

4. http://www.kamcom.co.nz/kiwi/index.html Kiwi egg Why would such a little bird have such a big egg?

5. Ratites: Ostrich, cassowary, moa (extinct), rhea, emu, kiwi, tinamou http://www.camacdonald.com/birding/Sampler1.htm

6. George C. Williams’ favorite example Williams, G.C. 1992. Natural selection: domains, levels, and challenges. Oxford Press. Vas deferens

7. My favorite example – why is the slime green??

8. Recall that much of the energy in sunlight is in the _____________ portion of the visible spectrum Does plant greenness relate to the use of this energy?

9. Light energy is obtained by the absorption of photons (light “particles”) by PIGMENTS Photosynthetic pigment molecules include Chlorophyll a, b, c Carotenoids Phycobilins

10. Each pigment has its own ______________ SPECTRUM The rate of photosynthesis is also a function of wavelength as a result of the pigments – __________ SPECTRUM

11. So, plants use light in the visible range where most energy is, but there is a ____ in absorption in the green-yellow range. So that’s why plants are green – that light is __________, so it is reflected (so we see it). Ok, but this means lots of energy is ____________________?

12. Maybe – a mistake? Historical accident? Some _____________ (photosynthetic bacteria) have _____________ If plants were fully utilizing sunlight, what color would they be? So, why the slime is green is still a mystery. 2,3 - chlorophyll a,b 4 - phycoerythrobilin 5 – beta-carotene

13. So design by natural selection has a distinctive historical “signature” While many details of organisms in nature seem beautifully, exquisitely adapted for survival, they also need to be given a history - how did it get there? In fact, many details really don’t seem to make much “sense” without that history

14. Extinction – loss of species – speciation _______diversity, extinction ________ it The fossil record documents the existence of many species that _________________

15. http://www.xs4all.nl/~kwanten/http://www.dinofish.com/ Coelacanth Ginkgo Occasionally, a species known first from fossils has been found still existing.

16. Tree of life has many aborted branches http://home.socal.rr.com/wangsong/CaniEvol/CaniEvol.html Canidae – dogs: many more ______ than ______

17. Horses (Equidae)

18. Extinction rates have been ________ over time, with occasional “_____” extinctions 3.4 Despite this, there have been long term _______ in measures of diversity Often _________ is suspected

19. Adaptive Radiation Speciation rates are ______ as well, especially within groups Adaptive radiation – “______” production of descendant species Probably a result of new adaptive “opportunity” 1. 2. 3.

20. Classic island examples _________ finches http://www.rit.edu/~rhrsbi/GalapagosPages/DarwinFinch.html Adaptive radiation

21. Sato et al. 2001

22. ___________ honeycreepers Fleischer et al 1998

23. Hawaiian ____________ California _______

24. Mass extinctions followed by major biotic shifts 1. _________ extinction (250 MYA) 2. __________ extinction (65 MYA) Before -amphibians and ferns After – reptiles and gymnosperms Before – reptiles and gymnosperms After – mammals and angiosperms http://www.dinosaursinart.com/ http://gpc.edu/~pgore/images/mastodon.gif Adaptive radiation

25. Adaptive innovations “Cambrian explosion” – innovation? Large category, most important traits probably qualify (e.g., photosynthesis, nucleus, multicellularity, flowers…) Adaptive radiation By 543 MYA – all extant animal phyla 38 body plans from 3 in 20MY

26. Whales (Cetacea) Since <___MYA Adaptive radiation

27. http://instruct1.cit.cornell.edu/courses/bionb424/students/ckr5/phylogeny.html Whales (Cetacea) Tremendous diversification in a short time Where did they come from?

28. Jean-Renaud Boisserie / UC Berkeley Whales are _________ most closely related to the ___________, in the Artiodactyls, the even-toed ungulates. Horses and rhinos are Perissodactyls, odd-toed ungulates. What are the Archaeocetes? http://evolution.berkeley.edu/evosite/evo101/IID2Understanding2.shtml

29. Archaeocetes http://www.sci.tamucc.edu/~wcrc/cetaceans/extinct/archaeocetes.html Pakicetidae 50 MYA Ambulocetidae 50 MYA Remingtonocetidae 45 MYA Protocetidae

30. Possible transitional whale fossil Basilosaurus 35 MYA Archaeocetes

31. Morphological reconstruction of the Cetacea phylogeny (no DNA for extinct taxa) http://palaeo.gly.bris.ac.uk/Palaeofiles/whales/archaeoceti.htm

32. Whales are a striking example of how evolution can, relatively quickly, result not only in dramatic radiation, but extreme changes in phenotype. Consider: _______ are more closely related to _______ than to _______. What was the “force” that caused this? End Part 2