Evolutionary Biology
gregladen | February 19, 2008Comparing living chimpanzees to living humans, in reference to the species that gave rise to these two closely related species, is one way to frame questions about the evolution of each species.
Generally, it is useful to address evolutionary questions by comparing two living species with the reconstructed "last common ancestor" (LCA) of those species. All of the similarities and differences between the LCA and the living form, in each lineage, represent evolutionary "stories" (that could even be worked out as hypotheses). Similarities indicate important, long-maintained adaptations, and…
gregladen | February 13, 2008Bats; Signaling in the Rain Forest; Sumatran Tiger Body Parts; Humans in the New World 20,000 years ago.
Bats are funny. Funny strange, not funny ha ha. There are two kinds of bats, microchiroptera and megachiroptera. The micros are smaller, the megas larger, by and large. and the micros have bat-sonar, while the mega's don't The micros tend to eat insects, the megas tend to eat fruit. Micros are more global in their dsitribution, mega's are more tropical.
It is not the case that all of the evidence regarding bat evolution clearly indicates that the common ancestor of both kinds of…
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 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 29, 2008UC Berkeley biologist Sheila Patek gives a wide-ranging talk on the effort to measure the hyperfast movements of peacock mantis shrimp heels using high-speed video cameras recording at 20,000 frames per second. She and her team slowed down the movements of these amazing animals and showed they had the fastest known feeding strike in the animal kingdom. (In 2006, Patek's team announced an even faster animal part: the mandible of the trap-jaw ant.)
gregladen | January 28, 2008The Twin Cities Creation Science Association Home School Science Fair, held each year in February, in Har Mar Mall, Roseville, Minnesota, will occur this year on Saturday & Sunday, February 16 and 17, 2008.
The Application Deadline is January 31st, 2008 ($5.00 entry fee)
You can register after January 31st at the door for only three bucks more!
Here are the entry guidelines:
This fair is open to all Home School students in the greater Twin Cities area.
Each student may enter only one project.
There will be only individual projects, and team projects will not be allowed.
Each exhibit…
gregladen | January 27, 2008This is my reply to a post by Coturnix called The Hopeless Monster? Not so fast!
First, the phylogeny of the discussion.
Olivia Judson wrote this:
The Monster Is Back, and It's Hopeful
Which was responded to here:
Hopeless Monsters--A Guest Post from Dr. Jerry Coyne
That dyad of posts was passed around by Carl Zimmer, who asked for commentary. This is the set of posts of which I'm aware that resulted:
Why wither Goldschmidt?
Nature makes no leaps...
Jerry Coyne smacks down Olivia JudsonCoyne is on the Loom
Macromutations and Punctuated Equilibria
Hopeful Monsters and Hopeful Models
Then, we…
gregladen | January 24, 2008A hopeful monster is a mutant born with a genetically determined and large novel trait (compared to its parents) which confers enhanced fitness on that individual. This enhanced fitness increases the likelihood that the new mutant gene that determines this trait will be passed on and spread throughout the evolving population, so in a single generation a rapid process of speciation is initiated. For example, a fish with a mutation that causes both its eyes to grow on one side of its head could become the flounder of a new generation of flatfish. Well, just for the halibut, it might be fun…
gregladen | January 22, 2008Marine biologist Tierney Thys asks the audience to step into the open ocean, for a visit to the world of the Mola mola, or giant ocean sunfish. Basking, eating jellyfish, and getting massages, this behemoth offers clues to life in the open ocean -- which accounts for 90 percent of the living space on this planet -- and also shows how climate change may be affecting all life.
gregladen | January 22, 2008
The narration is annoying, but it is a good example of fieldwork (with ants)
gregladen | January 21, 2008Is chimpanzee food sharing an example of food for sex?
One of the most important transitions in human evolution may have been the incorporation of regular food sharing into the day to day ecology of our species or our ancestors. Although this has been recognized as potentially significant for some time, it was probably the Africanist archaeologist Glynn Isaac who impressed on the academic community the importance of the origins of food sharing as a key evolutionary moment. At that time, food sharing among apes was thought to be very rare, outside of mother-infant dyads. Further research…
gregladen | January 20, 2008The Bell Museum, in Minneapolis, will sponsor a Valentine's Day Cafe Scientifique that will be especially close to my heart ...
... mainly because it is me doing it.
Evolution, Cuisine and RomanceTuesday, February 19, 7 p.m.Bryant-Lake Bowl, Uptown
Were the opposable thumb, an upright stance and a large brain the most important evolutionary events in human history? According to Anthropologist Greg Laden, these and other traits are only the byproducts of the truly important evolutionary transitions for our species: the rise of romance and the evolution of cuisine. Join Laden for a…
gregladen | January 20, 2008Scientists at The Scripps Research Institute have found that a naturally occurring peptide known for its antibacterial action can also inhibit viral infection.
The study was published in the January 17, 2008 edition of the journal Cell Host & Microbe.
The new study shows that defensins, short antimicrobial peptides that disrupt bacterial membranes and prevent bacterial invasion, use a separate mechanism to ward off adenovirus. Adenovirus is a group of viruses responsible for a number of respiratory diseases as well as infection of the stomach and intestine, eyes, bladder, and skin. While…
gregladen | January 18, 2008There is a discussion on the internet about Junk DNA, that includes a discussion at Sandwalk (Larry Moran's blog) ... I made a comment there about genome size that was responded to by T.R. Gregory. I started to write my response in Larry's Little Box, but realized that it would not fit. So it is here:
Imagine a gene family distributed among all the species in a given taxon. There are several alleles per gene. The gene codes for an enzyme that plays a role in determining cell size. Different combinations of genes/alleles exist to cause cell size to vary such that each species has a…
gregladen | January 16, 2008Traveling from Ecuador to Africa, Jane Goodall takes the audience on an ecological journey, discussing highlights and low points of her experiences in the jungle. She shows how progress is helping research (DNA analysis) and hurting the environment (clear-cutting). And she draws a dozen parallels between primate and human behavior, making the point that we really aren't all that different. Our big advantage, she says, is the ability to communicate with sophisticated spoken language -- yet, sadly, we are abusing this power and destroying the planet. She urges the TED audience to behave…
gregladen | January 16, 2008Well, it is a good thing that I have a thick skin and a good sense of humor, or I would be very put off by Larry Moran and probably T. Ryan Gregory as well.
Apparently, I stepped into an ongoing partially ad hominem debate over "Junk DNA" centering on the work of John Mattick and his research group. In this post, I'd like to provide a clarification of my "position" on Junk DNA, and I'll spend a moment admonishing my colleagues for being dorks.
My offending post is here. This is a report on a recent paper by Mattick and others in which they provide evidence that non coding RNA does…
gregladen | January 15, 2008You know that organisms develop, grow, and function in part because genes code for proteins that form the building blocks of life or that function as working bioactive molecules (like enzymes). You also know that most DNA is junk, only a couple percent actually coding for anything useful. Most importantly, however, you know that everything you know is wrong. Right?
The "Junk DNA" story is largely a myth, as you probably already know. DNA does not have to code for one of the few tens of thousands of proteins or enzymes known for any given animal, for example, to have a function. We know…
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…