natural selection
gregladen | June 20, 2008The Evolution 2008 conference started out today with a special program for K-12 teachers (mainly life science teachers) organized by the Minnesota Citizens for Science Education (MNCSE). The opening speaker was Scott Lanyon, director of the Bell Museum of Natural History. (The Bell hosted this event.)
Scott's objective was to outline several areas of evolutionary biology where fundamental changes had occurred over recent years. This was to provide perspective and food for thought for the Life Sciences teachers attending the event, and Scott was very successful in this effort.
In each case…
grrlscientist | June 13, 2008tags: researchblogging.org, evolution, experimental evolution, adaptation, mutation, natural selection, Richard E. Lenski
The common gut bacteria, Escherichia coli, typically known as E. coli.
Image: Dennis Kunkel.
Evolution is a random process -- or is it? I ask this because we all can name examples of convergent evolution where very different organisms arrived at similar solutions to the challenges they are faced with. One such example is the striking morphological similarities between sharks (marine fishes) and dolphins (marine mammals). Thus, based on observations of convergent…
gregladen | April 18, 2008Good question ... what IS in the air?
The simple answer is that the air ... the Earth's atmosphere ... is about 78% nitrogen, 21% oxygen, with a tiny amount of some other gases including water vapor. Then, there's dirt. I want to talk a little about the oxygen, one of the other gases (carbon dioxide to be exact), the water vapor, and the dirt.
Oxygen
The oxygen is one of the most important parts to us because we (and all the other animals) need it to breath. To me, what is most interesting about the oxygen is that in the old days ... before any animals or plants evolved but life…
gregladen | April 6, 2008
Grrrrrrrrrrrrr....
Welcome to the Lucky 13th Edition of The Boneyard ... the Web Carnival about Bones and Stuff.
"The Boneyard is a blog carnival covering all things paleo, from dinosaurs to pollen to hominids and everywhere in between. It's held every two weeks (the 1st and 3rd Saturday of the month), traveling around to a different blog for each installment, connecting some of the best blogging on ancient life."
The previous edition of The Boneyard is here, at Dragon's Tales. The next edition of The Boneyard will be Here at Archaeozoology. If you would like to submit an entry to the next…
gregladen | March 22, 2008A common presumption is that behavior is part of phenotype, and since phenotype arises from genotype (plus/minus Reaction Norm), that there can be a study of "behavioral genetics." This is certainly an overstatement (or oversimplification) for organisms with extensive and/or complex neural systems, such as humans and mice. Neural systems probably evolved (not initially, but eventually) to disassociate behavior with the kind of pre-determined micro-management of behavior that a simple gene-behavior link requires. However, in organisms with neural systems the size of the period at the end of…
gregladen | March 5, 2008Jonathan Wells has launched a nasty attack on PZ Myers and Ian Musgrave on the discredited Discovery Institute web site.
Darwinist bloggers P. Z. Myers and Ian Musgrave hate me. In fact, Myers writes, "My animus for Jonathan Wells knows no bounds."...
The most recent outbursts by Myers and Musgrave were provoked by my February 29 blog on Evolution News & Views, in which I predicted that Darwinists would try to take credit for a recent French discovery regarding antibiotic resistance. And indeed they did.
In the course of claiming credit for Darwinism, Musgrave claims that I completely…
gregladen | February 29, 2008
Photograph of a chicken. Click to see larger version. From PLOS article cited in blog post.
Where and when were chickens domesticated?
From whence the humble chicken? Gallus gallus is a domesticated chicken-like bird (thus, the name "chicken") that originates in southeast Asia. Ever since Darwin we've known that the chicken originated in southeast Asia, although the exact details of which one or more of several possible jungle fowls is the primal form has been debated. The idea that more than one wild species contributed to the early chicken has been on the table for a long time,…
zooillogix | February 28, 2008A fascinating new study published in the Proceedings of the National Academy of Sciences suggests that the impact of human fishing may be reducing the fitness of fish populations overall. It may also explain why your grandfather insists that "the fish don't bite like they used to." The thinking goes like this: bold and aggressive fish tend to eat more, grow faster and ultimately have more baby fish. They also tend to be the ones that chase and bite fishing lures, and in the case of commercial fishing, get caught in gill nets.
Aggressive, fast breeding fish are naturally attracted to huge…
gregladen | February 23, 2008PZ Myers notes that Ken Miller is making a case for the term design in evolutionary biology. Miller simply claims that "design" comes from the usual, expected evolutionary processes (Natural Selection, etc.). PZ is not buying this bill of goods, and neither am I. One way to address this question might be to ask: "What would Darwin do?"
Darwin uses the word quite often in The Voyage (a text I'm closely examining these days) but with only one exception that I found (my search was not perfect) this is typically in connection with cultural things .... the design of a road, for instance. One…
gregladen | February 12, 2008One of the most compelling argument that the story of Noah's Ark is made up is the implausibility of having animals like tigers and lions together with animals like lambs and deer on the same boat for very long. The big carnivores would eventually eat the little cute furry things. The bunnies would be the first to go. But new evidence, shown on the Miracle Pet Show disproves this objection.
So, if it is god's will, or if people just darn try hard enough, anybody and anything can get along with anything and anybody. Put that on an inspirational poster and hang it, I say!
Or is there…
gregladen | February 12, 2008"Disease" is a big word. I'd like to address this question by focusing on the difference, or lack of difference, between a poison, a disease, and a yummy thing to eat. It turns out that they may all be the same. Yet different.
Phenylketonuria (fee-null-keet-o-noo-ria), mercifully also known as "PKU" (pee - kay - you) is a disorder in which the amino acid phenylalanine is not broken down by an enzyme (phenylalanine hydroxylase) and thus accumulates in the body as phenylpyruvic acid.
This is bad because phenylpyruvic acid interferes with normal development of neural tissues.
In western…
gregladen | February 5, 2008Natural Selection is the key creative force in evolution. Natural selection, together with specific histories of populations (species) and adaptations, is responsible for the design of organisms. Most people have some idea of what Natural Selection is. However, it is easy to make conceptual errors when thinking about this important force of nature. One way to improve how we think about a concept like this is to carefully exam its formal definition.
[repost from gregladen.com]
In this post, we will do the following:
Discuss historical and contextual aspects of the term "Natural Selection…
gregladen | February 3, 2008There many ways of dividing up and categorizing Natural Selection. For example, there are the Natural Selection, Sexual Selection and Artificial Selection, and then there is the Modes of Selection (Stabilizing, Directional, and Disruptive) trichotomy.
We sense that these are good because they are "threes" and "three" is a magic number. Here, I'm focusing on the Mode Trichotomy, and asking that we consider that there are not three, but four modes of Natural Selection. This will cause tremors throughout the Evolutionary Theory community because Four is not a magic number, but so be it.
[…
gregladen | January 27, 2008The loss of sight in cave dwelling species is widely known. We presume that since sight in utter darkness has no fitness value, the mutation of a gene critical to the development of the sense of sight is not selected against. Over time, any population living in darkness will eventually experience experience such mutations, and these mutations can reach fixation.
Astyanax mexicanus: Top is the surface, sighted form, bottom is the cave-dwelling, blind form. From the Jeffery Lab.Beyond this, we may hypothesize that a mutation "turning off" sight could be beneficial. By definition, an…
gregladen | January 13, 2008
We are reminded, via Mousie Cat at Evolving in Kansas, that Yesterday (I'm so embarrassed I missed this) was Alfred Russel Wallace's birthday!
Wallace was born in 1823.
We should now clearly recognise the fact, that the wealth and knowledge and culture of the few do not constitute civilization, and do not of themselves advance us towards the "perfect social state." Our vast manufacturing system, our gigantic commerce, our crowded towns and cities, support and continually renew a mass of human misery and crime absolutely greater than has ever existed before. They create and maintain in…
gregladen | January 3, 2008
New research published in Science on the origins of multicellular life reveals an interesting pattern. The Cambrian Explosion may have been samosamo.
What is evolution about? Why are there different species, rather than just one (or a few) highly variable species? Is there a close correspondence between the ecological "spaces" that organisms can fit and the adaptations ... represented by morphology, for instance ... of the species that do exist? Can you imagine a different world where instead of having 10,000 species of birds there is only one bird that is highly adaptable in its…
gregladen | December 16, 2007
Every few years a paper comes out "explaining" short stature in one or more Pygmy groups. Most of the time the new work ads new information and new ideas but fails to be convincing. This is the case with the recent PNAS paper by Migliano et al.
From the abstract:
Every few years a paper comes out "explaining" short stature in one or more Pygmy groups. Most of the time the new work ads new information and new ideas but fails to be convincing. This is the case with the recent PNAS paper by Migliano et al.
From the abstract:
Explanations for the evolution of human pygmies continue to be a…
gregladen | November 29, 2007I have a lot of problems with some of the verbiage he uses. But it is all done with a nice English Accent, so he must be a smart guy...