Sunday, July 31, 2011

Attack of the Blobs

Cnidarians are jelly fish. You know what they are: little (or big) pulsing animals you see under the docks down at the water front. That is, if you live near the sea. There are little cnidarians in fresh water but you can't really see them without a microscope.

But the characteristic feature of cnidarians is they live in water. Or, at least, we thought they did.

Turns out that they have a much broader range of form and locale once they hopped on the parasite train. Up to and including forms that look almost indistinguishable from nematode worms.

See here.

Saturday, July 30, 2011

National Debt or OMG are these guys really that stupid?

Really nice James Fallows entry on the National Debt discussion here.

Friday, July 29, 2011

Thursday, July 28, 2011

More on Faux News

James Fallows has a nice catch on the Faux News "take" on the Rupert Murdoch scandals. See here, here and here.

Wednesday, July 27, 2011

Fox News Watch

Just discovered newshounds, a group that watches Faux News. Check them out.

Tuesday, July 26, 2011

Fish Bone Lead

Turns out that fish bone meal can be mixed with soil containing lead. A chemical reaction occurs that turns lead into an indigestible and harmless compound. Who know? See here.

Sunday, July 24, 2011

Thermoregulation: Today's Hot Topic

It's been hot this week so it seems appropriate to talk about it.

Humans are mammals and all mammals exercise some form of internal thermoregulation. The temperature setting might not be exact (marsupials have a somewhat wider temperature variation than placental mammals) but we all keep our temperature within relatively narrow ranges. Remember 98.6? Your dog and cat have a higher temperature.

Humans are vertebrates so we like to lump the animal world as vertebrates versus invertebrates. Sorry about the rest of all animal life on this planet. You're now all lumped together.

Similarly, we like to lump thermoregulatory groups together, too. Endothermy: animals like us that keep our body temperatures close to the same temperature by metabolic or behavioral means. Ectothermy: animals that are completely dependent on external temperature and regulate solely be behavioral means. Sort of a humans versus snake mentality.

Like everything else in biology, it's more complicated than that.

Endothermy at it's most narrow sense is demonstrated pretty well by killer whales, elephants and human beings. Temperature is kept within a very narrow range. An increase in an adult human of 1 degree Fahrenheit is a fever and is accompanied with fair distress. Children have a bit more variation and infants have to be protected from their own defective thermoregalatory systems until the get older.

Mammals have endless mechanisms to control their temperature. Elephant ears (radiators), human sweat (evaporative cooling loss), controlled blood flow to the extremities. Marmots and bears have the additional problem of two settings: one when they are in normal mode wandering around eating and reproducing and hibernation. They have what is called brown fat, a mitochondria rich adipose tissue that can generate a great deal of heat in a short time.

We also have behavioral mechanisms. Sam Ridgeway gave a talk on his work at the university I attended. He was talking about determining heat responses of sea lions. They put the seal lion subject in a room and heated it. When it got hot enough the animal needed to response it did not respond physiologically. It defecated and urinated on itself. Evaporative cooling loss is a wonderful thing.

Which brings us to the most important point of mammalian thermoregulation. It's not how you keep warm; it's how you keep cool. Certainly, retaining heat is a necessary thing. Humans have clothes. Whales have blubber. Rabbits have hair. But being able to shed heat is equally as important. Humans sweat. Heretofore elephant ears. The highly vascularized flippers of sea lions and seals to to shed heat when necessary.

Endothermy, at least as mammals practice it, is costly and complex.

Ectothermy, by contrast, is cheap. The metabolic needs of crocodiles, an ectothermic species, is so small that one big meal might be enough to keep them going for a year. It should come as no surprise that those heat filled environments are filled with ectotherms: amphibians and reptiles. Endotherms, birds and mammals, are there where the environment is rich enough. But as the environment shifts to the more marginal such as deserts the reptiles start gaining ground. Why? Because maintaining a reptile is cheap. Most of the energy consumed by a mammal or a bird goes straight to maintaining the body temperature. Reptiles get it for free from the sun.

But wait, you say. Birds and mammals both started (presumably) from exothermic animals. We know how diverse the animal kingdom is. Who's to say endothermy hasn't arisen from the ectothermic animals? Are there endothermic animals in the ectothermic classes?

Funny you should ask that question as I sit down to tuna maki.

Anyone who's ever ordered a tuna steak has noticed it doesn't taste like other fish meat. It is tougher. Almost like a real steak. That's because, like cattle, tuna muscle is richly filled with blood vessels, the muscles are highly oxygenated and operate at a relatively warm temperature.

Tuna are warm blooded. Literally.

Endothermy, of a sort, has been demonstrated in tuna for a while. A bluefin tuna can keep a muscle body temperature between 75-95 degrees in water that is as low as 46 degrees. They do this by creating heat via muscle exertions and then conserving that heat by a collection of mechanisms so they don't lose it to the outside water. (See here and here.) It is not endothermy as mammals practice it-- we generate heat regardless of muscle use. But it is not ectothermy as practiced by lizards and snakes.

Which, as all things inevitably must, brings us to dinosaurs. Birds are clear endotherms. Reptiles are clear ectotherms. Birds evolved from dinosaurs-- does that mean dinosaurs are endotherms? If they were endotherms of a sort, what kind were they? Dinosaurs were big, which means that if they were mammalian style endotherms they would have had problems shedding heat. But there's significant evidence they had high body temperatures.

Recently I read a paper in Nobel Intent on how to determine dinosaur temperature by analyzing their tooth structure. This is a very elegant technique based on the tendency of Carbon-13 and Oxygen-18 to preferentially clump together in the formation of the calcite in bones and teeth. This "clumping" is temperature dependent: lower temperature means more clumping. The researchers used two sauropods to derive a temperature of 96.8-100.4-- pretty much right on the dot around mammals. Low for birds but definitely higher than crocodiles.

However, there are a few limitations. 1) It says nothing of the style of temperature regulation practiced by the animals. Mammal style endothermy? Tuna style ectothermy? Lizard ectothermy? All it says is the temperature of the animals. 2) It only reflects the temperature of the head.

But we always knew dinosaurs were hot.

Friday, July 22, 2011

Citizen Science

Scientific American has listed several opportunities for non-scientists to do real science helping real research:

NestWatch: observing North American birds, nesting and behavior.
Ant School: observing and sampling ants in urban and sub-urban environments including kitchens
Rain and Snow Network: Precipitation and observation. This could become important in understanding microclimates.
Firefly Watch: Fireflies are declining. Find out why.
Monarch Health: Research to determine parasitism in monarch butterflies.
Wildlab: bird distribution research using cell phones
Valley of the Khans: Help scientists direct archeological research in Mongolia by examining satellite photos

Thursday, July 21, 2011

Okay: I'll mention Faux News and Phone Hacking Just This Once

Just in case you were wondering about the Faux News response to Rupert Murdoch's phone hacking problems, Jon Stewart will bring you up to date here.

Wednesday, July 20, 2011


People made money on the BP oil spill? There was corruption? Say it isn't so!

Saturday, July 16, 2011

Tree of Eucaryotes

Here's a terrific cladistic tree of Eucaryotes courtesy of The Ocelloid, one of Scientific American's new blogs. The link at left blows it up a bit. But to really get a good look go to the article and click on the image. It's impressive.

Friday, July 15, 2011

Reptilian Problem Solving

Here's a lizard that solves problems. Pretty cool.

Thursday, July 14, 2011

Ants Farm Meat

A very interesting discussion of some new ant research by Jerry Coyne here. Turns out there is some evidence that ants farm scale insects to eat them. There's additional evidence of something that resembles domestication.

Wednesday, July 13, 2011

Scientific American Blogs

I am often frustrated by the level of scientific illiteracy in the United States. But in this country there is also great interest in science and great availability of scientific information.

An example of this is the new blogosphere that is just become available over at Scientific American (see here.)

Go. Enlighten yourself.

Sunday, July 10, 2011

Why Evolution is Important or How I Imagine Avatar II

(Photo from here.)
I've been talking about biology and evolution for a while now without much talking about how it is important in my writing or life in general. Or, at least, I'm going to take another crack at it and see if I can get it right.

One of the principles of understanding evolutionary biology is the importance of heritage.

Mammals, reptiles, birds and amphibians belong to tetrapoda, "four feet". Each of the groups has four basic limbs and a head. Some have a tail. Some don't. Some have gills. Some have lungs. Some have both. Some have eyes. Some don't. But they all have four limbs-- even those, like whales, that don't. By that I mean that though they do not have four functioning limbs at birth they do have developmental traces that confirm their tetrapod ancestors.

We are tetrapods because our root ancestor was a tetrapod. Our heritage, from that distant root ancestor, is to be tetrapods. We're pretty much stuck with it. The complexity of creating developmental patterns means that if we change any one thing we have to change a lot of other things. Consequently, whales often have vestigial limbs and have to do funny things in development to prevent the growth of hind legs. It's also why whales move their tails up and down instead of left to right like fish or icthyosaurs. Mammalian tails evolved from animals that supported themselves on land. Consequently, the spine of mammals-- of which the tail is an extension-- are oriented to operate and support weight in a dorsal to ventral pattern. Fish, on the other hand, originated in water and never had to support such weight.

Why, you might say, do ichthyosaurs appear to be structured so that they move their body from side to side rather than up and down?

Hm. Good one, that.

While ichthyosaurs are reptiles and co-existed with dinosaurs they split from the main reptile line prior to dinosaurs. Their anatomy more resembles lizards than anything else. One of the characteristic components of lizards is the shoulder and hip joints that are splayed out rather than vertically under the body. Look at a dinosaur or a rhino. The load bearing legs are vertically under the point of attachment to the body. That means the load is transferred directly to the limb rather than at an angle. I'm guessing here but I suspect that the orientation of the limbs factored in the degrees of freedom of the tail and the body. Watch how a crocodile walks. Then, note how a crocodile swims. Heritage is everything, isn't it?

My point with this is how you do world building. For example, let's say we create a world populated by intelligent dogs. They have two eyes in the front, a nose, they walk on hind legs and have tails but hands. This means they have relatives-- there are lesser canidims (from hominims) that have smaller brains, bigger bodies and may or may not walk on their hind legs-- the moral equivalent of the great apes. This also means there are more distant relatives that run on the ground but have something like hands. And even more distant relatives that still have two eyes and four legs.

Now, it's possible that you could have competing strategies in the biosphere. We see it here. Hexalimb systems as exhibited by insects. Decalimbed systems as exhibited by shrimp (decapoda.) But in the size range of land animals, say from a pound to multiples of tons, the dominate life form is tetrapoda. Perhaps this is coincidence-- we only have a sample size of one, after all. But it should be noted that once tetrapoda managed to control this size range they kept it within the family: archeosaurs gave way to dinosaurs which gave way (briefly) to birds and then to mammals and birds together. At no time did some new n-poda creep up out of the ocean and step up. There could be a lot of reasons for this and the discussion of it would be lively and fun. However, it's not germane to this discussion. Suffice to say that, barring something drastic, once a group holds onto a role they are hard to dislodge.

Consequently, or canidims would be part of a rich pool of similar animals. No biologist would have difficulty placing canidims in the general pattern of evolution.

So, if you put that canidim as a native of a world with giant bugs it would be a biological anomaly that would require explanation.

If you have ancient intelligent fire breathing dragons in your world, you also must have tiny stupid short lived smoking dragonettes. (Which, incidentally, is one of the problems I have with Harry Potter. But that's another story.)

Which brings us to Avatar.

Let's look at the intelligent natives: tall, human like, two hands, two legs. Walk on two legs. Two eyes. Tetrapods. Vertebrates. They could be human cousins.

Let's look at the animals: six limbed. Sometimes four eyed. Clearly vertebrates but not tetrapods.

Consequently, if the Na'vi evolved on their planet they separated from the main line many, many millions of years ago.

Now, there could be an explanation for this beyond the idea that James Cameron has a foot fetish. (More is better?)

It could be that the hexalimb approach is only apparent. The extra two limbs are derivative of the original two limbs. I.e., they are all tetrapods but in the dominant form two of the limbs have split.

It could be that there were many more tetrapod forms in the past and the only remaining tetrapods are the Na'vi all others (or mostly others) being outcompeted by the hexapod forms.

It could also be (and this is my theory) that the Na'vi, while indigenous, are not native to this planet. They are also invaders-- a better, more gentle invader to the world but no more native to this world than the humans. It could even be that the Na'vi form is not their original form but one more suited to Pandora.

This last idea makes the most sense to me. Consider the differences from the main vertebrate population. The Na'vi don't just look alien to us. They look alien on Pandora. Consider that strange ability they have to connect to the nervous system of the other organisms. That ability doesn't just evolve-- there would have to be intermediate forms. And this is a common trait across many vertebrates, animals that have split off from the Na'vi line millions of years before.

There's a last idea based on the film. It could be that the world of Pandora is itself a sentient creature-- this is strongly suggested by the film. In that case, the world of Pandora is created and evolution does not apply. The Na'vi look like humans, talk like humans, have sex like humans because they were created to be like humans. Analogous to Gaea in John Varley's Gaea Trilogy.

Okay. My opinions of Avatar were based solely on the biology and appearance of the movie. It looks like there's going to be a sequel or set of sequels. We'll see how it turns out.

Saturday, July 9, 2011

Friday, July 8, 2011

BVC News

Book View Café Welcomes Linda Nagata.

Book View Café is welcoming newest member, Linda Nagata, today. She's the author of seven novels under her own name, including The Bohr Maker, winner of the Locus Award for best first novel, and the novella “Goddesses,” the first online publication to receive a Nebula award. Linda also writes under the name Trey Shiels.

To celebrate, Sue Lange is interviewing Linda at the Book View Café blog here.

And BVC is holding one of their world renowned giveaways! Send an email with “Linda Nagata ebook” in the subject line to BVC will pick five winners at random and send each a free ecopy of The Bohr Maker. This is a one day only offer, so send your email today!

Visit Linda Nagata’s bookshelf at Book View Café here.

Linda’s website and her blog.

Thursday, July 7, 2011


Jerry Coyne has linked to an article by Hans Fricke regarding a long term study of the Coelecanth.

Well worth reading but the original is behind a firewall.

Wednesday, July 6, 2011

Snail Eats Earthworm.

Here is an article and video on the earthworm-eating snaile, Powelllifanta.

Tuesday, July 5, 2011

Planet of the Apes

An interesting blog by Faye Flam is Planet of the Apes: A blog on evolution. Go enjoy.

Here is one about the recent interviews of beauty pageant victims.

Friday, July 1, 2011

Fairie Folkways

I've discovered a charming site called Fairie Folkways. Fairie Folkways explores folk tales and fairy material. The folk tales and myths are the best. I recommend The Tremors of the Buried Moon. Deceptively simple art and a wonderfully Joseph Campbell feel.

FF is authored by Jesse Rogers about whom I found nothing.

Go enjoy.