Category Archives: evolution

Remembering Darwin on the Sky Harbor Trail

On Darwin Day 2011, the 202nd birthday of Charles Darwin, a group of about 20, students and faculty, members of Tri Beta Biology Club and the Fresno State Nature Club, participated in a celebratory hike along Sky Harbor trail above Lake Millerton just north of Fresno, on the San Joaquin river. It was a glorious day, with the impossibly blue skies typical of this part of the world (although too often obscured by what we pump up into the central valley air these days). Signs of Spring well under way were everywhere: in the songs of the Oak Titmouse and the Towhees, in the drunken bees buzzing about the flowers dotting the lush green slopes everywhere, and in the warm afternoon sun that set everything ablaze with a wonderful light. This was a hike good old Charlie would surely have enjoyed. As it is, my hat is off to you Charlie, on this your day and everyday, for so thoroughly deepening my appreciation of nature’s tangled banks and my own wonderful place within. Thank you. And Happy Birthday, Mr. Darwin.

Posted via email from Darwin’s Bulldogs

Hanging with Mr. Darwin @ Fresno State

As part of Darwin Week at Fresno State, the local chapter of the Tri Beta Biological Honors Society organized Darwin Hour at noon on Feb 9, 2011. Dr. Paul Crosbie of the Biology Dept. dressed up as a youngish Mr. Darwin, circa 1961 to talk about how he came to write his most famous book, and answered questions about what his theory means for us.

[Pictures taken on an iPhone 3Gs, hence the low resolution]

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Hungry for a highly evolved menu? Pull up a chair to the Carnival of Evolution #27

Carnival of Evolution #27 – Feed Your Head Edition

As your server for this evening’s Carnival of Evolution, allow me to introduce the offerings from a line-up of over two dozen chefs!

For your pleasure we have these specials . . . .

1. Chicken’s teeth, whale’s legs, and the tails of humans.

Thus begins a most appetizing (or stomach-turning, depending upon your culinary adventurousness) menu of evolutionary blog writing pulled together by your energetic host Andrew Bernardin, who’s pulled out all the stops for this 27th edition of the Carnival of Evolution. I hope you are hungry. Read your fill, for the next CoE is a whole month away!

Bon appétit!

Posted via email from Darwin’s Bulldogs

Genie Scott on the Evolution of Creationism

[youtube http://www.youtube.com/watch?v=tSTzbJQ6-ag&hl=en&fs=1]

How has creationism changed over the years? How have beliefs–and tactics–changed? What’s the genesis of “intelligent design” and does it truly challenge the foundations of evolutionary biology? Genie Scott discusses the history of creationism and new tactics coming round the bend. From a talk given at North Dakota State University, 2/11/2010.

[youtube http://www.youtube.com/watch?v=mXl8wMI02Po&hl=en&fs=1]

Posted via email from Darwin’s Bulldogs

Repeat after me: Evolution is NOT A LADDER and does not lead to any pinnacles!!!!

ResearchBlogging.orgI am more than a little irritated.

This is not how I normally feel after listening to one of my favorite podcastlets “Our Ocean World” broadcast on the local public radio station most mornings.
As a landlubber biologist, I love learning about the fascinating and often bizarre creatures in the ocean, and therefore really enjoy this brief dose of news from the biggest biome on earth. Especially because it typically comes on when I’m dropping my daughter off at school in the mornings, giving us something wonderful to share.
But today’s segment (which came on just after I dropped the kiddo off – sorry I was unusually early!) on Tuna, titled Big Fish, Big Sea, really pushed some sensitive buttons. It could be that I had just finished grading finals for my Evolution class, and was particularly touchy about evolutionary misinterpretations. But no, this particular gaffe came from a Stanford Professor of Marine Sciences, no less, and is therefore even less acceptable for being broadcast on the radio!! 
Professor Barbara Block, the tuna expert featured in today’s podcast, described these no doubt remarkable fish as being at the top of a bleeping “evolutionary ladder”!! She also said Tuna were “more evolved” than other fish! And that they were on a “pinnacle of evolution”!!!#$*!!!  
More than once! (I checked. I hadn’t misheard).
And here I thought we had buried that damned metaphor of evolution being a ladder for good! Heck, I try to bury it ritually for my students every semester in all of my classes, starting with Intro Bio. Yet it keeps rising, like a zombie, even from the mouths of accomplished biologists!! What’s it going to take to purge this metaphor entirely from our vocabulary, folks?!
And while on the subject, let’s also be clear that no species is “more evolved” than any other. How could they be? If you accept the evidence that we all come from one common ancestor, that the tree of life has one common origin, then every living species has been subjected to the vicissitudes of life on this planet for the same overall length of time, no?! We may have taken different, often surprising and bizarre, twisting branching paths on this journey, but we’ve all (except those branches that went extinct along the way) traveled the same length of time, have we not? How can any one of us, bacterium to tuna, virus to human to dolphins who say thanks for all the fish, then claim to be “more evolved” than any other species?!
Granted there are local peaks and valleys in the fitness landscape for any species, and natural selection may be constantly trying to push us onto the nearest one – but there are no lofty “pinnacles” that we can be proud of conquering! If anything, given the dynamic nature of our world and the new curveballs nature keeps throwing at us, being stuck on any tall pinnacle could lead to the worst sort of evolutionary dead-end. We’re probably far better off wandering around local peaks and remaining capable of even drifting across the fitness landscape. Definitely don’t want to be stuck on any too tall peak, thank you very much! In fact, as my friend Andrew Jones just reminded meall species evolve to extinction!
Although, now that I think about it, perhaps most other species on this planet, our fellow travelers in the evolutionary journey, are hoping that we humans have reached exactly such a pinnacle, and are, even more hopefully, about to fall off our lofty perch for good. Perhaps from these new ecofriendly smokes.
Meanwhile, repeat after me (especially if you are a biologist):
Evolution, in fact, is best described as a TREE:


[youtube http://www.youtube.com/watch?v=H6IrUUDboZo&hl=en&fs=1&hd=1]

And remember, the only thing we are all definitely evolving towards is EXTINCTION!


Thank you!!

Reference:

Andrew R. Jones (2009). The next mass extinction: Human evolution or human eradication? Journal of Cosmology, 2, 316-333

Baba Brinkman raps up Geek Week on the Rachel Maddow show!

Visit msnbc.com for breaking news, world news, and news about the economy

It is so cool to see Baba Brinkman hit the mainstream media now, after wowing so many of us in smaller shows around the world. We were lucky to get him on our campus early in the Darwin Bicentennial year, when he was performing at the Fresno Rogue Festival. Great to see Rachel Maddow putting him on to rap up her first Geek Week!

What next? The Colbert Report, dare one hope? I’d love to see that rap duel, wouldn’t you?

Posted via web from a leaf warbler’s gleanings

Ooze like an amoeba, float like a bird – wish we could still do that when stressed!

Here’s another fun weird science story from NPR, about a creature that might be in the dirt in your own backyard:

20100305 Me 03 by Npr
Download now or listen on posterous

Naegleria-NPR.mp3 (1426 KB)

Naegleria gruberi

Courtesy of Lillian Fritz-Laylan
Naegleria gruberi grows a pair of flagella when under stress. But unlike a sperm tail, it puts these appendages out front, and swims by breast stroke. The organism is stained to emphasize its anatomy.

If you prefer to read the story rather than listen to it aloud, here’s the transcript via npr.org.

ResearchBlogging.org

While that behavioral and morphological flexibility is remarkable enough in something we might, from our lofty hominid perch, consider rather “primitive” and “simple”, what graduate student Lillian Fritz-Laylan and colleagues found in its genome is perhaps even more surprising. Whle the NPR story focuses on the physical transformation of the organism, cool as that is, the full story is much richer and has far more significance for our own origins from a common eukaryotic ancestor. As they describe in their paper in the current issue of Cell, Naegleria gruberi turns out to have almost 16000 protein-coding genes, which is over two-thirds of what you and I have! A single celled organism with that many genes – no wonder it can transform itself so radically.

Here’s an image from the paper illustrating that transformation, which takes a mere 90 minutes or so (far cooler special effects at half the duration of Avatar, if you ask me!):

Figure 1: Schematic of Naegleria Amoeba and Flagellate Forms. Naegleria amoebae move along a surface with a large blunt pseudopod. Changing direction (arrows) follows the eruption of a new, usually anterior, pseudopod. Naegleria maintains fluid balance using a contractile vacuole. The nucleus contains a large nucleolus. The cytoplasm has many mitochondria and food vacuoles that are excluded from pseudopods. Flagellates also contain canonical basal bodies and flagella (insets). Basal bodies are connected to the nuclear envelope via a single striated rootlet. 

Is it just me, or does that upper image, of the amoeboid form, remind you of someone? And… I just realized… that someone also has two apparent flagellae at the top of his head, which unfurl during times of stress!! What better proof do you want of our shared ancestry with Naegleria, eh? No? Oh, what – you mean citing widely published and viewed cartoons is not good enough evidence for you (even though that is a standard of evidence good enough for a third of the good people of Texas)? You want all the boring science-y stuff instead? Well, go read the paper then, which the journal Cell has graciously made freely available!

The paper (luckily for you) turns out to be far from boring. It is indeed quite fascinating because, apart from presenting the complete genome sequence of this remarkable free-living protist, Fritz-Laylan et al also describe several genetic modules for aerobic and anaerobic metabolism (for these guys can do both), amoeboid motility, and a number of other structural and functional necessities of the ecologically diverse lifestyles common to their clade. Further, comparisons with genomes of other protists allow them to predict which genes might have been present in the genome of the common ancestor to all eukaryotes. As the first representative of a fifth (out of 6) major clade of eukaryotes whose genomes have been sequenced thus far, Naegleria holds great promise of generating fresh insights into the early evolution and diversificatiion of eukaryotes. While their lineage diverged from the one we hail from about, oh, a billion or so years ago, understanding their genome brings us closer to understanding and reconstructing the genome of our shared ancestors, those early free-living eukaryotes that gave rise to us both. For it turns out that they contain over 4000 protein families that are similar to ones we have, and therefore were likely found in that common ancestor! That ancestor was presumably also quite versatile and equipped with a set of flexible modules to deal with the diverse environments of that time. And that remarkable flexibility probably underlies the extraordinary diversity of organisms that subsequently evolved from that ancestor. How fascinating and wonderful is that! (Even if some of us later lost the ability to transform ourselves and float away when under stress!)

Let me end with a video where the lead authors talk about what Nargleria‘s genome can tell us about our own ancestry:
[youtube http://www.youtube.com/watch?v=g3II26RCL6w&hl=en&fs=1]


Reference:

Fritz-Laylin, L., Prochnik, S., Ginger, M., Dacks, J., Carpenter, M., Field, M., Kuo, A., Paredez, A., Chapman, J., & Pham, J. (2010). The Genome of Naegleria gruberi Illuminates Early Eukaryotic Versatility Cell, 140 (5), 631-642 DOI: 10.1016/j.cell.2010.01.032

My blog’s strange phylogenetic origin in the Carnival of Evolution #20!

Skeptic Wonder has one of the more creative analytical takes on hosting a blog carnival I’ve ever seen – an actually phylogeny of the blog posts included in the carnival, based on sequence alignment of each blog post’s URL! I’m not sure about some of the results, however… check out where my post on the challenges of teaching evolution ended up in the above tree! How on earth did I end up paraphylizing (if that’s a word) Bjørn Østman’s blog?!

But, never mind that, this 20th edition of the Carnival of Evolution has plenty of good stuff to read, so head on over there in your spare moments. And pardon my tardiness in bringing this to your attention.

Posted via web from a leaf warbler’s gleanings