evolution
grrlscientist | August 6, 2008tags: researchblogging.org, premature hair graying, autosomal dominant trait, genetics, horses, hair color, syntaxin-17, melanocortin-1 receptor, cis-acting regulatory mutation, melanoma, evolution
This horse is in the process of losing its pigment.
It will end up being all white by the time it is eight years old.
Image: Horse Wallpaper [larger view].
Even though I have always been a fan of black horses, my heart did leap at the sight of the noble Shadowfax racing towards Gandalf in response to his call in the Lord of the Rings. White horses have symbolized purity throughout most ages…
zooillogix | August 6, 2008Fascinating video from the PBS special, Dogs that Changed the World, on the changes that took place when foxes were bred for tameness in the former Soviet Union. This was originally posted on Greg Laden's Blog but I had to repost it here.
pharyngula | August 5, 2008Last week, we watched Evolve: Eyes on the History Channel; tonight, shall we watch the next episode, Evolve: Guts, together? Tune in shortly!
A disgusting beginning: competitive eaters? Bleh. It's a basic introduction to mammalian digestive physiology — I can tell we're going to get lots of Big Vertebrate biology again.
They show a cool machine called Cloaca that simulates human digestion, with vats containing chemicals to act as the various chambers. They don't bother to explain why this machine was built, but it is kind of weirdly interesting.
Once again, they openly say that the…
grrlscientist | August 5, 2008tags: researchblogging.org, begging calls, brood parasitism, coevolution, learning, social shaping, ornithology, Horsfield's Bronze-Cuckoo, Chalcites basalis, Chrysococcyx basalis
Horsfield's Bronze-Cuckoo, Chalcites (Chrysococcyx) basalis,
Capertee Valley, NSW, Australia, September 2003.
Image: Aviceda [larger view].
Brood parasites are birds, fish or insects that deceive unrelated animals of the same species or different species to care for their offspring. By doing so, the parasitic parent is relieved of the energetic demands of constructing a nest and raising its young to…
pharyngula | August 5, 2008Tonight, at 9 Central/10 Eastern, it's time for the second episode in the History Channel's series on evolution: Evolve - Guts.
It doesn't just take willpower to survive. It takes guts--in the form of a digestive system that turns food into fuel. Look closely at the role guts have played in shaping some of Earth's most successful animals: tyrannosaurs, snakes, cows, humans and others. Take a 575-million year journey that begins with the planet's first multi-cellular organisms and ends at our dinner tables. Watch as live-action natural history sequences, CGI, epic docudrama, and experimental…
evolvingthoughts | August 4, 2008
Just lately there's been a flurry of papers on speciation that I haven't had time to digest properly. Several of them seem to support "sympatric" or localised speciation based on selection for local resources with reproductive isolation a side effect of divergent selection. So here they are below the fold with abstracts and my comments...
Evolution of reproductive isolation in plants
Heredity advance online publication 23 July 2008; doi: 10.1038/hdy.2008.69
A Widmer, C Lexer and S Cozzolino
Reproductive isolation is essential for the process of speciation and much has been learned in…
evolvingthoughts | August 4, 2008
My Sciblings Bora, John, Brian and Benjamin have asked what the value of the history of science is to scientists. Below the fold is my apologia for writing a stonking great history of a scientific concept (species, in case the sidebar wasn't enough hint), in which I defend the worth of intellectual history to historians. Maybe it will add something to this debate. It is from the preface to my book. I hope the history of science is worthwhile, but it is interesting that the people who most wanted my book to be published are scientists working in the field on which I am writing, so I think it…
evolvingthoughts | August 3, 2008
A blog post by the incredibly multilingual John Wilkins (who knew he spoke French, Portuguese and Spanish? OK, it's by proxy, but it's nearly as good as actually speaking it) is now available in Spanish. Gee but he looks like he knows whereof he speaks... Thanks to Eduardo Zugasti for the choice and translation.
Second, and more important, is a paper in Nature by Nobel Laureate Paul Nurse. Entitled "Life, Logic and Information" it is yet another claim that information technology is the best way to conceptualise biology, in particular biological systems. I am fully in agreement with…
jlynch | August 3, 2008PZ has a post up discussing some abject stupidity over at WorldNetDaily. Sign #1 of stupidity is that the WND columnist (a lawyer, no less) refers to "Origins [sic] of Species" as being Darwin's 1859 work which legitimized "a pagan, anti-God worldview rooted in fascism, socialism and eugenics and to propagate these diabolical ideas throughout the world." PZ notes:
What logically follows from Darwin's theory is that fit individuals are those that survive and have offspring. There is no presumption that there is only one possible strategy to accomplish that survival: if we maintain a state that…
grrlscientist | August 3, 2008tags: Birdbooker Report, bird books, natural history books, ecology books
"One cannot have too many good bird books"
--Ralph Hoffmann, Birds of the Pacific States (1927).
Here's this week's issue of the Birdbooker Report by Ian "Birdbooker" Paulsen, which lists ecology, environment, natural history and bird books that are (or will soon be) available for purchase.
FEATURED TITLE:
De Roy, Tui, Mark Jones and Julian Fitter. Albatross: Their World, Their Ways. Due out: Sept. 2008. Firefly Books. Hardbound: 240 pages. Price: $49.95 U.S. [Amazon: $32.97]. SUMMARY: A well-illustrated account on…
jrosenhouse | August 1, 2008A few posts back I engaged a discussion about Richard Dawkins' metaphor of “Cimbing Mount Improbable” for the proces by which evolution by natural selection crafts complex structures from simpler precursors. Since I did not have his book in front of me at the time, I was working from memory.
As it happens, earlier today I was browsing through The God Delusion and I came across a description of the metaphor which, I am pleased to say, expresses precisely the view I attributed to Dawkins. You will find this on pages 121-122:
In Climbing Mount Improbable, I expressed the point in a parable…
grrlscientist | August 1, 2008tags: researchblogging.org, evolution, speciation, ring species, phylogeography, landscape genetics, crimson rosella, Platycercus elegans, parrots, birds, Australia
Crimson Rosella, Platycercus elegans.
Image: Australian Broadcasting Corporation.
One of the challenges facing those who believe that evolution cannot create new species is explaining the problem of "ring species." Ring species are a group of geographically connected populations that can interbreed with nearby populations, but cannot breed with those populations that exist at each end of the cline (figure A). These populations…
clock | July 31, 2008Broca's Area, 1865:
This doesn't sound too out there to us now, but at the time it caused a lot of controversy. The problems wasn't the localization to the inferior frontal lobe, it was Broca's claim that it was the LEFT inferior frontal lobe. This didn't sit well with a lot of scientists at the time. It was pretty accepted that, when you had two sides or halves of an organ, the both acted in the same way. Both kidneys do the same thing, both sides of your lungs, and both of your ovaries or testes. Your legs and arms will do essentially the same thing, though due to handedness (or…
pharyngula | July 31, 2008
Ontogenetic allometry in the fang in the front-fanged Causus rhombeatus (Viperidae) displaces the fang along the upper jaw. Scale bars, 1 mm. We note the change in relative size of the upper jaw subregions: i, anterior; ii, fang; iii, posterior. d.a.o., days after oviposition.
I keep saying this to everyone: if you want to understand the origin of novel morphological features in multicellular organisms, you have to look at their development. "Everything is the way it is because of how it got that way," as D'Arcy Thompson said, so comprehending the ontogeny of form is absolutely critical to…
gregladen | July 30, 2008 Sabertooth Cat, Megantereon nihowanensisl There are two kinds of "true cats." Cat experts call one type feline or "modern" partly because they are the ones that did not go extinct. If you have a pet cat, it's a modern/feine cat. This also includes the lions, tigers, leopards, etc. The other kind are called "sabercats" because this group includes the saber tooth. It is generally believed but not at all certain that these two groups of cats are different phylogenetic lineages (but that is an oversimplification).
It has been suggested for some time that the bite force mechanics for at…
evolvingthoughts | July 30, 2008
For a while now, and in particular since I read Robert Bannister's Social Darwinism and then actually read Herbert Spencer's own work, I have been unable to reconcile the mythology about social Darwinism with the actual writings of Spencer himself. Supposedly the founder of the justification for robber baron capitalism, Spencer actually proposes feminism, liberal protection of the poor and weak, and other ideas that are more redolent of Mill than Malthus (who is also the subject of similar demonisation, as Flew showed). Now someone has affirmed my unease: Damon Root, writing in Reason…
pharyngula | July 29, 2008The warm-up act for this program was a dinosaur program called "Jurassic Fight Club", which was loaded with CGI and lots of gratuitous razzle-dazzle — but I thought it was a hoot. It also had enthusiasatic scientists talking about how they figured out what had happened (although it does bug me that they treated some speculative stuff in the narrative as if it were factual). Most of the show was taken up with glitzy animations, but it was balanced with at least some discussion of the process of science, so I'll give it a thumbs up.
Now to settle in for the story of the evolution of eyes…
Oooh…
gregladen | July 29, 2008Did Past Climate Changes Promote Speciation in the Amazon?
Any time you've got a whopping big river like the Amazon (or a mountain chain like the Andes, or an ocean, or whatever), you've gotta figure that it will be a biogeographical barrier. Depending on the kind of organisms, big rivers, high mountains, oceans, forests, deserts, and so on can provide a habitat or a barrier, and when there is a barrier, populations may end up splitting across that barrier and diverging to become novel species.
The role of the big tropical rivers such as the Amazon and the Congo, and the role of rain…
evolvingthoughts | July 29, 2008
Electron cryotomographic reconstruction of a C.
merolae cell. n = nucleus; c = chloroplast; p =
peroxisome; er = endoplasmic reticulum. Source
Elio Schaechter has a typically informative and informed post on the smallest eukaryotes, a kind of algae called picoeukaryotes. These guys make up half the biomass of all marine phages. Only known for about five or six years...
edyong | July 28, 2008
Simon Kirby and Hannah Cornish are watching evolution take place within the confines of their laboratory. But they are studying neither bodies nor genes; their interest lies in languages, and how they change over time.
Regardless of school lessons and textbooks, most of the features of the languages we speak are learned by listening to the words of native speakers. Their sentences convey their thoughts, but they also hint at the structure of the language they are spoken in. That allows people who are learning a new language to infer something about its structure by listening to the way its…