Biology 105 - Evolution Dr. Theodore Garland, Jr. 1 Dec. 2015:

1. Biology 105 - Evolution Dr. Theodore Garland, Jr. 1 Dec. 2015: Adaptive Radiation & Convergent Evolution Reading is pages 119-120 and 368-369 inBergstrom, C. T., and L. A. Dugatkin. 2012. Evolution. W.W. Norton and Company.

2. Adaptive Radiation

3. Adaptive Radiation = The diversification of members of a single phylogenetic lineage (clade) into a variety of different forms, under the action of natural selection.

4. Adaptive Radiation = Random genetic drift in combination with speciation (from whatever cause) will lead to a proliferation of species with varying morphologies, etc. That does not require diversifying natural selection, so it would not qualify as adaptive radiation.

5. Adaptive Radiation Four Common Causes: Environmental Change Mass Extinctions (see next lecture) Invasion of Island Archipelagoes Key Innovations (a.k.a. General Adaptations)

6. Examples of Adaptive Radiation Mammals Hawaiian Honeycreepers Bromeliads Anolis Lizards Horned Lizards (Phrynosoma) Darwin's (Galapagos) Finches African Rift Valley Cichlid Fishes

7. Reconstruction of Hadrocodium wui, an early Jurassic fossil (about 195 million years old) Approx. 2 grams Paperclip is 32 mm Luo, Z.-X., A. W. Crompton, and A.L. Sun. 2001. A new mammaliaform from the Early Jurassic and evolution of mammalian characteristics. Science 292:1535-1540. Mammals

8. Mammalian Phenotypic Diversity (this phylogeny is not current) "The ~5400 described species of living mammals evolved to occupy diverse ecological niches and include arboreal, fossorial, volant, aquatic, and terrestrial forms - some of which exhibit 100 million-fold differences in body mass" (Meredith et al. 2011 Science 334:521-524)

9. Mammalian Phenotypic Diversity (this phylogeny is not current)

10. A recent time-calibrated phylogeny for mammals (several authors from UCR Department of Biology) "Molecular time trees and diversification analyses suggest important roles for the Cretaceous Terrestrial Revolution and Cretaceous-Paleogene (KPg) mass extinction in opening up ecospace that promoted interordinal and intraordinal diversification, respectively. By contrast, diversification analyses provide no support for the hypothesis concerning the delayed rise of present-day mammals during the Eocene Period." Robert W. Meredith, Jan E. Janecka, John Gatesy, Oliver A. Ryder, Colleen A. Fisher, Emma C. Teeling, Alisha Goodbla, Eduardo Eizirik, Taiz L. L. Simão, Tanja Stadler, Daniel L. Rabosky, Rodney L. Honeycutt, John J. Flynn, Colleen M. Ingram, Cynthia Steiner, Tiffani L. Williams, Terence J. Robinson, Angela Burk-Herrick, Michael Westerman, Nadia A. Ayoub, Mark S. Springer, William J. Murphy. 2011. Impacts of the Cretaceous Terrestrial Revolution and KPg extinction on mammal diversification. Science 334:521-524.

11. Hawaiian Honeycreepers - a diverse group of birds whose uniting features are a unique odor, proximally truncate tongue, and lack of lingual wings (Wagner, 1995). There are three kinds: Drepandini “red birds,” Psittirostrini “finch-billed birds,” Hemignathini “green birds” (Wagner, 1995). They are not separate clades.

12. Hawaiian Honeycreepers

13. Hawaiian Honeycreepers: some older views of their phylogeny

14. Hawaiian Honeycreepers Figure 2. Bayesian Divergence Date Estimates for Hawaiian Honeycreepers from Whole Mitochondrial Genomes Based on Three Island Age Calibration Points [7] Mean ages are shown above each node, with horizontal bars across nodes representing 95% highest probability density intervals. Shaded vertical bars encompass the estimated subaerial to maximal shield-building dates for the recent Hawaiian Islands [1], where the gray bars indicate island ages used as calibrations, and asterisks (*) identify constrained nodes. Lowercase letters identify divergence of a new morphological lineage before formation of Oahu (a), during or after formation of Oahu (b), or before or during formation of Maui Nui (c). Distributions by island are listed to the right of each taxon where closed circles denote historic and/or extant (and sometimes fossil) distributions, and open circles represent fossil distributions with no known historic or extant populations. (1) The extant population occurs on Nihoa Island, but closely related extinct species mainly differing in size occurred on Kauai, Oahu, and Hawaii Islands. (2) The extant population occurs on Laysan Island, but closely related extinct species mainly differing in sizes occurred on Kauai and Hawaii Islands. (3) A closely related species or subspecies occurred on Laysan Island. Photographs are by Jack Jeffrey. Lerner et al. 2011. Current Biology 21:1838-1844.

15. Hawaiian Honeycreepers Our phylogenetic results are consistent either with a single evolutionary loss and subsequent gain of the finchlike morphology and feeding niche or with the persistence of a finch-like lineage with at least two gains of more thin-billed and warbler-like morphologies. In either case, the resolved molecular phylogeny reveals a more complex pattern of morphological evolution than would be expected based on classic papers about the radiation, which proposed phylogenetic patterns that minimized the morphological distance between related taxa. Lerner et al. 2011. Current Biology 21:1838-1844. In other words, parallel or convergent evolution can confound phylogenetic analyses, as you already know!

16. Adaptive Radiation in Bromeliads http://bsi.org/ Bromeliads are members of a plant family known as Bromeliaceae (bro-meh-lee-AH-say-eye). It contains over 2,700 described species in approximately 56 genera. The most well known bromeliad is the pineapple. The family contains a wide range of plants including some very un-pineapple like members such as Spanish Moss (neither Spanish nor a moss). An epiphyte = grows on other plants. Takes nutrition and moisture from the atmosphere = "Air Plant." Other members resemble aloes or yuccas, while still others look like green, leafy grasses.

17. Spanish Moss (Tillandsia usneoides)

18. Adaptive Radiation in Bromeliads

19. "With nearly 400 species, Anolis lizards represent the world's most species-rich amniote genus. This diversity is most striking on Caribbean islands, where anoles have undergone a remarkable adaptive radiation. On many islands, anoles are the most abundant and conspicious vertebrates, making them outstanding subjects for research." http://www.lacertilia.com/research/methods.html

20. Adaptive Radiation in Phrynosoma 13 species;5 are live-bearing P. platyrhinos California P. cornutum Texas P. coronatum California P. douglassi Oregon

21. Squirt blood from eyes as a defense against canid predators Ernest Hodges Family Phrynosomatidae Fringe-toed, Earless, and Zebra-tailed Lizards 10 species Horned Lizards 13 species Spiny & Tree Lizards 98 species Mid - Late Oligocene 30 MYA

22. Horns are a Synapomorphy of Phrynosoma www.digimorph.org

23. and show substantial variation within the clade: www.digimorph.org

24. Parietal Horns Phrynosoma douglasii Phrynosoma mcallii

25. Temporal Horns Phrynosoma douglasii Phrynosoma mcallii

26. Why do the 13 species of Phrynosoma show so much variation in horn size and shape? As discussed in a previous lecture, we know that current natural selection is favoring large horns in at least one species, at present: Young, K. V., E. D. Brodie Jr., E. D. Brodie III. 2004. How the horned lizard got its horns. Science 304:65. But why have some species mostly lost their horns? Have they found other ways to avoid predation? Are large horns costly? (remember beetle example) Why did horns originate in the first place?

27. Adaptive Radiation in Darwin’s Finches 13 or 14 species

28. Adaptive Radiation in Darwin’s Finches

29. Herrel, A., J. Podos, S. K. Huber, and A. P. Hendry. 2005. Evolution of bite force in Darwin’s finches: a key role for head width. Journal of Evolutionary Biology 18:669-675.

30. Another Classic Adaptive Radiation Lakes of the African Rift Valley hold hundreds of species of closely related cichlid fishes.

31. An interesting fact:cichlid females are mouth brooders Barlow, 2000 Fryer and Iles, 1972

32. African Rift Valley Cichlids These closely related species differ in shape, color, and feeding habits. Evolution was very rapid: within the last few million years.

33. One explanation is ecological The fish arebottom nesters. Even though lake water is very clear, nesting at the bottom results in a very short line-of-sight. Barlow, 2000

34. One explanation is ecological M. zebrata Females use male color for choosing mates (i.e., sexual selection occurs). Local “dialects” can develop quickly.

35. A second explanation has to do with skull structure

36. Cichlids have a normal set of teeth

37. Plus a “bonus” set of pharyngeal teeth Pharyngeal "teeth" This may constitute a “key innovation” Barlow, 2000

38. Redundancy is Beneficial …allows one set of teeth to maintain regular function … while theother can adaptto perform new duties. Barlow, 2000

39. Key Innovations: Also known as "general adaptations." A derived characteristic that allows a new way of life. May lead to adaptive radiation. Examples: 1. flight 2. amniotic (cleidoic) egg 3. ability to digest cellulose 4. endothermy

40. But this is hard to test in a rigorous fashion, in part because many putative key innovations are unique evolutionary events. Suppose that a given clade has a putative “key innovation” and is more diverse in terms of numbers of species and/or amount of “morphospace” occupied, as compared with its sister clade. This evidence is not strong, but rather is like what we have when comparing only two species! Could easily just be a coincidence …

41. You could call thisan artificial "adaptive" radiation …

42. Marsupials are another good example of adaptive radiation, and also …

43. Convergent Evolution

44. Convergent Evolution = Evolutionary changes in two or more unrelated organisms that result in the independent development of similar adaptations to similar environmental conditions. (Ancestors were more different than the descendants.)

45. Species a and b are convergent.

46. Convergent similarity (homoplasy) is not uncommon New World cactus Family Cactacea Old World “cactus” Family Euforbicea

47. Convergent similarity (homoplasy) is not uncommon Thylacine (marsupial wolf) Wolf (placental)

48. Marsupials show multiple convergences with placental mammals "Mammals exhibit striking examples of ecomorphological convergence that has led to contentious debates in modern systematics"(Meredith et al. 2011 Science 334:521-524)

49. The same cichlid phenotypes occur in different lakes and taxa

50. Australian Moloch horridus (only 1 species) is convergent with the 13 Phrynosoma Have a “false head” that makes it hard for snakes to swallow P. platyrhinos California P. cornutum Texas And Moloch horns are not underlain by bone. P. coronatum California P. douglassi Oregon