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Mennonite, evolutionary biologist, cat-4 cyclist. Not necessarily in that order.
Denim and Tweed
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Nothing in Biology Makes Sense!
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- August 13, 2009
- 12:10 PM
- 1,232 views
A helpful invasive species?
by Jeremy Yoder in Denim and Tweed
Introduced species can wreak havoc on the ecosystems they invade. But what happens after they've been established for centuries? A new study in the latest Proceedings of the Royal Society suggests that, in one case, an introduced species has actually become an important part of the native ecosystem -- and helps protect native species from another invader [$-a].
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Letnic, M., Koch, F., Gordon, C., Crowther, M., & Dickman, C. (2009) Keystone effects of an alien top-predator stem extinctions of native mammals. Proc. R. Soc. B, 276(1671), 3249-3256. DOI: 10.1098/rspb.2009.0574
Marris, E. (2009) Ecology: Ragamuffin Earth. Nature, 460(7254), 450-3. DOI: 10.1038/460450a
Savolainen, P. (2004) A detailed picture of the origin of the Australian dingo, obtained from the study of mitochondrial DNA. Proc. Nat. Acad. Sci. USA, 101(33), 12387-90. DOI: 10.1073/pnas.0401814101
- July 31, 2009
- 12:10 PM
- 1,081 views
How it does a body good: The selective advantage of drinking milk depends where you drink it
by Jeremy Yoder in Denim and Tweed
I am a super-powered mutant. For a given value of "super-powered" and "mutant," anyway: I am an adult human who can drink milk. This is unusual among mammals, but as those (in retrospect, somewhat creepy) PSAs that used to run during my Saturday morning cartoons said, milk has a variety of nutritional benefits, if you can digest it. Which of these is behind the evolution of adult milk digestion in humans? According to a new paper in this week's PLoS ONE, the benefit you get from drinking milk de........ Read more »
Diamond, J. (2005) Evolutionary biology: Geography and skin colour. Nature, 435(7040), 283-284. DOI: 10.1038/435283a
Gerbault, P., Moret, C., Currat, M., & Sanchez-Mazas, A. (2009) Impact of selection and demography on the diffusion of lactase persistence. PLoS ONE, 4(7). DOI: 10.1371/journal.pone.0006369
Ingram, C., Mulcare, C., Itan, Y., Thomas, M., & Swallow, D. (2008) Lactose digestion and the evolutionary genetics of lactase persistence. Human Genetics, 124(6), 579-91. DOI: 10.1007/s00439-008-0593-6
Swallow, D. (2003) Genetics of lactase persistence and lactose intolerance. Annual Review of Genetics, 37(1), 197-219. DOI: 10.1146/annurev.genet.37.110801.143820
Tishkoff, S., Reed, F., Ranciaro, A., Voight, B., Babbitt, C., Silverman, J., Powell, K., Mortensen, H., Hirbo, J., Osman, M.... (2006) Convergent adaptation of human lactase persistence in Africa and Europe. Nature Genetics, 39(1), 31-40. DOI: 10.1038/ng1946
Wright, S. (1943) Isolation by distance. Genetics, 114-38. info:other/http://www.genetics.org/cgi/reprint/28/2/114
- July 12, 2009
- 12:57 AM
- 910 views
Sonar gives whales the bends
by Jeremy Yoder in Denim and Tweed
The New York Times Magazine has a cover article on human-whale interactions, with special attention to whales' cognitive, communicative, and social abilities. It's pretty neat stuff, and I started reading it with the intention of posting something about it with a title along the lines of "So long, and thanks for all the fish." But, rather than all the whales-as-fellow-sentients stuff, this early aside about the effects of navigational sonar on whales is what actually caught my attention:The resu........ Read more »
Cox, T.M., T.J. Ragen, A.J. Read, E. Vos, R.W. Baird, K. Balcomb, J. Barlow, J. Caldwell, T. Cranford, & L. Crum. (2005) Understanding the impacts of anthropogenic sound on beaked whales. J. Cetacean Res., 7(3), 177-87. DOI: http://www.whalescience.com/SDSU/My Work/CoxEtAl_BeakedWhaleReport2006.pdf
Jepson, P., Arbelo, M., Deaville, R., Patterson, I., Castro, P., Baker, J., Degollada, E., Ross, H., Herráez, P., Pocknell, A.... (2003) Gas-bubble lesions in stranded cetaceans. Nature, 425(6958), 575-576. DOI: 10.1038/425575a
Piantadosi, C., & Thalmann, E. (2004) Pathology: Whales, sonar and decompression sickness. Nature, 428(6984). DOI: 10.1038/nature02527a
- July 11, 2009
- 03:05 AM
- 1,187 views
Correlation and causation: Why are there so many flowering plants?
by Jeremy Yoder in Denim and Tweed
Among the flowering plants, groups with flowers adapted to a narrower range of pollinators -- the more specialized ones, like orchids or mints -- tend to contain more species. Why? The classic hypothesis is that coevolution between plants and their pollinators leads to more pollinator-specialized plants, which are then more likely to become reproductively isolated, and eventually form separate species. However, I've just finished reading a review article that suggests an interesting alternative:........ Read more »
Armbruster, W., & Muchhala, N. (2008) Associations between floral specialization and species diversity: Cause, effect, or correlation?. Evolutionary Ecology, 23(1), 159-79. DOI: 10.1007/s10682-008-9259-z
V. Grant. (1949) Pollination systems as isolating mechanisms in angiosperms. Evolution, 82-97. DOI: http://www.jstor.org/pss/2405454
Johnson, S.D., & Steiner, K.E. (2000) Generalization versus specialization in plant pollination systems. Trends in Ecology , 15(4), 140-3. DOI: 10.1016/S0169-5347(99)01811-X
Sargent, R. (2004) Floral symmetry affects speciation rates in angiosperms. Proc. R. Soc. B, 271(1539), 603-608. DOI: 10.1098/rspb.2003.2644
- July 2, 2009
- 01:34 AM
- 767 views
Evolution 2009: The Evolution meetings were, indeed, blogged
by Jeremy Yoder in Denim and Tweed
So I've been putting off a final post-mortem on the use of online resources in connection with Evolution 2009, but Nature finally shamed me into it with an article specifically about blogging and microblogging at scientific meetings as part of a special section devoted to science journalism.
The Nature piece captures the concerns that came up when I first broached the subject of trying to increase the meetings' online profile, especially the question of unwanted publicity: scientific meetings o........ Read more »
Batts, S., Anthis, N., & Smith, T. (2008) Advancing science through conversations: Bridging the gap between blogs and the academy. PLoS Biology, 6(9). DOI: 10.1371/journal.pbio.0060240
Saunders, N., Beltrão, P., Jensen, L., Jurczak, D., Krause, R., Kuhn, M., & Wu, S. (2009) Microblogging the ISMB: A new approach to conference reporting. PLoS Computational Biology, 5(1). DOI: 10.1371/journal.pcbi.1000263
- June 26, 2009
- 03:05 AM
- 565 views
No room for group selection in disease evolution?
by Jeremy Yoder in Denim and Tweed
Parasites coexisting within a single host have been proposed as one of the best examples of individuals sacrificing their own reproductive fitness for the benefit of a group. A new theory paper in last week's Nature suggests that the apparent effect of "group selection" in this case can be explained by individual-level selection instead [$-a].
Group selection posits that organisms sometimes evolve traits that hurt their individual fitness but benefit their social group. Charles Darwin originall........ Read more »
Cochran G.M., Ewald P.W., & Cochran K.D. (2000) Infectious causation of disease: An evolutionary perspective. Persp. Biol. Medecine, 43(3), 406-48. DOI: 10.1353/pbm.2000.0016
Day, T., & Gandon, S. (2007) Applying population-genetic models in theoretical evolutionary epidemiology. Ecology Letters, 10(10), 876-888. DOI: 10.1111/j.1461-0248.2007.01091.x
Frank, S.A. (1996) Models of parasite virulence. Quarterly Rev. Biol., 71(1), 37-78. DOI: http://www.jstor.org/stable/3037829
Wild, G., Gardner, A., & West, S. (2009) Adaptation and the evolution of parasite virulence in a connected world. Nature, 459(7249), 983-986. DOI: 10.1038/nature08071
Wilson, D., & Wilson, E. (2007) Rethinking the theoretical foundation of sociobiology. Quarterly Rev. Biol., 82(4), 327-48. DOI: 10.1086/522809
- June 21, 2009
- 03:05 AM
- 605 views
For wasps' pheromones, quantity predicts quality
by Jeremy Yoder in Denim and Tweed
Don't tell the people behind Axe body spray, but entomologists have shown that the fertility of male Nasonia vitripennis wasps is predicted by how much sex pheromone they produce [$-a].
How many sperm a male wasp can produce turns out to be a big deal for female Nasonia wasps, because the species is haplodiploid -- fertilized eggs become females, and unfertilized eggs become males. Because females are the only sex that can fly off to lay more eggs, the number of female offspring a wasp produces........ Read more »
Ruther, J., Matschke, M., Garbe, L., & Steiner, S. (2009) Quantity matters: male sex pheromone signals mate quality in the parasitic wasp Nasonia vitripennis. Proc. R. Soc. B. DOI: 10.1098/rspb.2009.0738
- June 16, 2009
- 05:09 AM
- 694 views
Evolution 2009: Day three
by Jeremy Yoder in Denim and Tweed
On the third day of Evolution 2009, things are winding down already. I've been up late saying goodbye to folks leaving tomorrow.
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A bog turtle
Photo by Wall Tea.The most entertaining talk of the day was more about physics than evolution as such: specifically, an analysis of turtle shell architecture. C.T. Stayton discussed work he........ Read more »
Harmon, L., Matthews, B., Des Roches, S., Chase, J., Shurin, J., & Schluter, D. (2009) Evolutionary diversification in stickleback affects ecosystem functioning. Nature, 458(7242), 1167-70. DOI: 10.1038/nature07974
Stayton, C. (2009) Application of thin-plate spline transformations to finite element models, or, how to turn a bog turtle into a spotted turtle to analyze both. Evolution, 63(5), 1348-55. DOI: 10.1111/j.1558-5646.2009.00655.x
- June 15, 2009
- 02:26 AM
- 1,126 views
Evolution 2009: Day two
by Jeremy Yoder in Denim and Tweed
After a late (early) night yesterday, I started my day at the R.A. Fisher Award talk, a presentation of results from "an outstanding Ph.D. dissertation paper published in the journal Evolution." This year's winner turned out to be a paper I remember reading when it was first published, in which Megan Higgie and Mark Blows showed that sexual selection for mate-signaling hydrocarbons in Drosophila serrata is opposed by selection to avoid mating with the closely related D. birchii. Populations of D........ Read more »
Higgie, M., & Blows, M. (2008) The evolution of reproductive character displacement conflicts with how sexual selection operates within a species. Evolution, 62(5), 1192-203. DOI: 10.1111/j.1558-5646.2008.00357.x
- June 14, 2009
- 06:55 AM
- 583 views
Evolution 2009: Day one
by Jeremy Yoder in Denim and Tweed
In this morning's session on species interactions and coevolution, everyone was talking about these videos of snakes attacking snails. Turns out that snail shell chirality (the direction the shell spirals) can determine how easy it is for a snake to attack. Very, very cool. Detailed discussion by John Dennehy is here.
I presented today, and survived another twelve-minute talk. Immediately after I finished describing my preliminary conclusion that coevolution between species only generates evolu........ Read more »
Fox, J., & Vasseur, D. (2008) Character Convergence under Competition for Nutritionally Essential Resources. The American Naturalist, 172(5), 667-80. DOI: 10.1086/591689
- June 11, 2009
- 11:49 PM
- 854 views
When plant siblings play nice, everyone loses
by Jeremy Yoder in Denim and Tweed
A couple years ago, scientists studying the wildflower American searocket, noticed something funny: when grown in the same pot with sibling seeds, searocket plants grew smaller roots than they did when sharing a pot with unrelated plants. It looked as though searocket plants recognized their siblings, and tried not to compete with them.
If this were a widespread phenomenon, it could dramatically change how biologists think about plant's evolution and ecology. Right now, we think that the huge ........ Read more »
Dudley, S., & File, A. (2007) Kin recognition in an annual plant. Biology Letters, 3(4), 435-8. DOI: 10.1098/rsbl.2007.0232
Milla, R., Forero, D., Escudero, A., & Iriondo, J. (2009) Growing with siblings: A common ground for cooperation or for fiercer competition among plants?. Proc. R. Soc. B, 276(1667), 2531-40. DOI: 10.1098/rspb.2009.0369
- June 5, 2009
- 12:48 AM
- 630 views
Familiarity breeds contempt: Mockingbirds recognize and react to repeat intruders
by Jeremy Yoder in Denim and Tweed
Humans are a fact of life for many, many parts of the natural world. This doesn't always have to be a bad thing -- some critters adapt to human-dominated landscapes pretty well. A paper in this week's PNAS, for instance, shows that Northern Mockingbirds nesting on a busy university campus learn to differentiate between uninterested passers-by and people who repeatedly disturb the nest site [$-a].
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Cheptou, P., Carrue, O., Rouifed, S., & Cantarel, A. (2008) Rapid evolution of seed dispersal in an urban environment in the weed Crepis sancta. Proc. Nat. Acad. Sci. USA, 105(10), 3796-9. DOI: 10.1073/pnas.0708446105
Grant, B.S., Owen, D.F., & Clarke, C.A. (1996) Parallel rise and fall of melanic peppered moths in America and Britain. Journal of Heredity, 351-7. DOI: http://jhered.oxfordjournals.org/cgi/content/abstract/87/5/351
Levey, D., Londono, G., Ungvari-Martin, J., Hiersoux, M., Jankowski, J., Poulsen, J., Stracey, C., & Robinson, S. (2009) Urban mockingbirds quickly learn to identify individual humans. Proc. Nat. Acad. Sci. USA, 106(22), 8959-62. DOI: 10.1073/pnas.0811422106
- May 30, 2009
- 11:40 PM
- 771 views
How fast do ecosystems recover from disturbance? It's complicated.
by Jeremy Yoder in Denim and Tweed
In the 21st century, human activity promises to impact the natural world on an unprecedented scale. In order to decide where to focus conservation effort, one thing we need to know is how permanent the damage from a forest clear-cut or a collapsed fishery actually is. A paper in this week's PLoS ONE looks at natural systems' ability to recover after human and natural disturbances, and the authors say the results are hopeful. I'm not so sure.
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Jones, H., & Schmitz, O. (2009) Rapid recovery of damaged ecosystems. PLoS ONE, 4(5). DOI: 10.1371/journal.pone.0005653
- May 29, 2009
- 02:29 PM
- 743 views
In social courtship, it pays to be a good wingman
by Jeremy Yoder in Denim and Tweed
The search for a mate is traditionally a selfish enterprise. After all, the ultimate goal is reproduction, and -- barring any effect of kin selection -- natural selection only cares about how many babies you make, not how many you help to make. This is fundamentally a biological question, though, and if there's a universal rule in biology, it's that nature is good at making exceptions.
One such exception is the wire-tailed manakin. A study in the latest Proceedings of the Royal Society seems to........ Read more »
Prum, R.O. (1994) Phylogenetic analysis of the evolution of alternative social behavior in the manakins (Aves: Pipridae). Evolution, 1657-75. DOI: http://www.jstor.org/stable/2410255
Ryder, T., McDonald, D., Blake, J., Parker, P., & Loiselle, B. (2008) Social networks in the lek-mating wire-tailed manakin (Pipra filicauda). Proc.R. Soc. B, 275(1641), 1367-74. DOI: 10.1098/rspb.2008.0205
Ryder, T., Parker, P., Blake, J., & Loiselle, B. (2009) It takes two to tango: reproductive skew and social correlates of male mating success in a lek-breeding bird. Proc. R. Soc. B, 276(1666), 2377-84. DOI: 10.1098/rspb.2009.0208
- May 24, 2009
- 01:06 AM
- 494 views
When the going gets tough, C. elegans gets sexy
by Jeremy Yoder in Denim and Tweed
The trouble with sex, from an evolutionary perspective, is that it's expensive. Not just in terms of the efforts a sexually-reproducing organism has to go through to secure a mate; every offspring produced by sexual reproduction bears half the genome of each of its parents, compared to an asexual offspring, which bears a complete copy of its only parent's genome. So, in terms of natural selection, an asexual critter gains twice as much reproductive fitness for each offspring it produces -- asexu........ Read more »
Keightley, P., & Otto, S. (2006) Interference among deleterious mutations favours sex and recombination in finite populations. Nature, 443(7107), 89-92. DOI: 10.1038/nature05049
Morran, L., Cappy, B., Anderson, J., & Phillips, P. (2009) Sexual partners for the stressed: Facultative outcrossing in the self-fertilizing nematode Caenohabditis elegans. . Evolution, 63(6), 1473-82. DOI: 10.1111/j.1558-5646.2009.00652.x
- May 21, 2009
- 02:00 AM
- 477 views
Getting away from it all: Why are invasive species invasive?
by Jeremy Yoder in Denim and Tweed
When humans move from place to place, we almost always bring other organisms with us. Sometimes it's intentional -- domestic animals carried along with Polynesian colonists, for instance. Just as often, it's accidental, as with mice stowing away on Viking longships. A lot of these introduced species have done so well in their new habitats that they become invasive, outcompeting natives and disrupting local ecosystem processes. But the species that go crazy-invasive -- the cane toads and the purp........ Read more »
Blumenthal, D., Mitchell, C., Pysek, P., & Jarosik, V. (2009) Synergy between pathogen release and resource availability in plant invasion. Proc.Nat. Acad. Sci. USA, 106(19), 7899-904. DOI: 10.1073/pnas.0812607106
Vellend, M., Harmon, L., Lockwood, J., Mayfield, M., Hughes, A., Wares, J., & Sax, D. (2007) Effects of exotic species on evolutionary diversification. Trends Ecol. , 22(9), 481-8. DOI: 10.1016/j.tree.2007.02.017
- May 17, 2009
- 03:31 PM
- 1,375 views
Seed dispersal by ants: A lousy way to travel, a good way to diversify
by Jeremy Yoder in Denim and Tweed
New in the always open-access PLoS One: turns out that a great way to make new species, if you're a plant, is to have your seeds dispersed by ants. This is because ants aren't very good at seed dispersal.
Seed dispersal by ants, or myrmecochory, works very much like dispersal by fruit-eating birds and mammals: ant-dispersed seeds typically have a fatty attachment, called an elaiosome, that looks tasty to ants. Ants collect elaiosome-bearing seeds, bring them back to their nest, pry off the tast........ Read more »
Beattie, A.J., & Culver, D.C. (1981) The guild of myrmecochores in the herbaceous flora of West Virginia forests. Ecology, 107-15. DOI: http://www.jstor.org/pss/1936674
Giladi, I. (2006) Choosing benefits or partners: a review of the evidence for the evolution of myrmecochory. Oikos, 112(3), 481-92. DOI: 10.1111/j.0030-1299.2006.14258.x
Kozak, K., Weisrock, D., & Larson, A. (2006) Rapid lineage accumulation in a non-adaptive radiation: phylogenetic analysis of diversification rates in eastern North American woodland salamanders (Plethodontidae: Plethodon). Proc. R. Soc. B, 273(1586), 539-46. DOI: 10.1098/rspb.2005.3326
Lengyel, S., Gove, A., Latimer, A., Majer, J., & Dunn, R. (2009) Ants sow the seeds of global diversification in flowering plants. PLoS ONE, 4(5). DOI: 10.1371/journal.pone.0005480
Moyle, R., Filardi, C., Smith, C., & Diamond, J. (2009) Explosive Pleistocene diversification and hemispheric expansion of a "great speciator". Proc. Nat. Acad. Sci. USA, 106(6), 1863-8. DOI: 10.1073/pnas.0809861105
- May 1, 2009
- 12:00 AM
- 1,243 views
Why are there so many weevils? Coevolution, maybe.
by Jeremy Yoder in Denim and Tweed
Asked what attributes of the Creator were manifest in the natural world, the 20th-century biologist J.B.S. Haldane is said to have replied, "an inordinate fondness for beetles." Beetles are, indeed, the most diverse group of animals on earth, accounting for something less than 40 percent out of five to ten million arthropod species, according to one estimate [PDF]. Naturally, evolutionary biologists would like very much to know how there came to be so many beetles* -- and a new paper i........ Read more »
Ehrlich, P.R., & Raven, P.H. (1964) Butterflies and plants: A study in coevolution. Evolution, 586-608. DOI: http://www.jstor.org/stable/2406212
Farrell, B. (1998) "Inordinate Fondness" explained: Why are there so many beetles?. Science, 281(5376), 555-9. DOI: 10.1126/science.281.5376.555
McKenna, D., Sequeira, A., Marvaldi, A., & Farrell, B. (2009) Temporal lags and overlap in the diversification of weevils and flowering plants. PNAS, 106(17), 7083-8. DOI: 10.1073/pnas.0810618106
Ødegaard, F. (2000) How many species of arthropods? Erwin's estimate revised. Biol. J. of the Linn. Soc., 71(4), 583-97. DOI: 10.1111/j.1095-8312.2000.tb01279.x
- April 24, 2009
- 12:31 PM
- 722 views
Female birds stop singing when they move north
by Jeremy Yoder in Denim and Tweed
A study in this week's Proceedings of the Royal Society B suggests that the sexually dimorphic pattern of birdsong we're used to in temperate latitudes -- with males singing elaborately and females usually not -- evolves because female birds stop singing when their species move to more northerly latitudes [$-a]. Why this is, however, remains an open question.
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Price, J., Lanyon, S., & Omland, K. (2009) Losses of female song with changes from tropical to temperate breeding in the New World blackbirds. Proceedings of the Royal Society B: Biological Sciences, 276(1664), 1971-80. DOI: 10.1098/rspb.2008.1626
- April 20, 2009
- 02:04 AM
- 755 views
Un-bear-able (ha) predation creates variable natural selection
by Jeremy Yoder in Denim and Tweed
Natural selection is a fact of life. As Steven Jay Gould put it, it's an "inescapable conclusion" arising from the "undeniable facts" that (1) populations of living things have inheritable variation in many traits; and (2) produce a surplus of offspring. But populations often experience selection from multiple sources, and in conflicting directions. The cover article for this month's issue of Evolution suggests that bears may be creating ongoing selection in wild salmon populations, but the stre........ Read more »
Carlson, S., Hilborn, R., Hendry, A., & Quinn, T. (2007) Predation by bears drives senescence in natural populations of salmon. PLoS ONE, 2(12). DOI: 10.1371/journal.pone.0001286
Carlson, S, Rich, HB, Jr., & Quinn, T. (2009) Does variation in selection imposed by bears drive divergence among populations in the size and shape of sockeye salmon?. Evolution, 63(5), 1244-61. DOI: 10.1111/j.1558-5646.2009.00643.x
Grant, PR, & Grant, BR. (2002) Unpredictable evolution in a 30-Year study of Darwin's finches. Science, 296(5568), 707-11. DOI: 10.1126/science.1070315
Hendry, A. (2000) Rapid evolution of reproductive isolation in the wild: Evidence from introduced salmon. Science, 290(5491), 516-8. DOI: 10.1126/science.290.5491.516
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