Take a good, long look at this fossilized skeleton:Courtesy of Northeast Ohio University.

Now, take a look at this (more current) skeleton:Courtesy of The New Bedford Whaling Museum.

What do they have in common? They’re both whales. Separated by 50,000,000 years, these two animals are evolutionary cousins. For the next few weeks, I’d like to explore the core fundamentals of evolution by covering how whales transformed from small, hoofed, dog-like animals into the sea going behemoths we know today.

The explanation of how such transformations can occur boils down to one core tenant of evolution: Adaptive Radiation.

To answer what adaptive radiation is in less words than this sentence: nature abhors a vacuum. If a biological niche (lifestyle) is suddenly gone, you can bet money that new creatures will fill it up. There are tons of examples of this. The perennial favorite has always been Darwin’s Finches (these finches, whose lifestyles go from sipping nectar to pecking out holes in wood famously led Darwin to conclude that adaptive radiation does exist.) However, there are also the cases of Australia’s myriad of marsupials and Hawaii’s Honey Creepers.

In short, a small group of animals put into a new environment will probably diversify and evolve to fill the various niches of said environment.

So, how does our dog-like Pakicetus relate to adaptive radiation? According to various fossil dating techniques, Pakicetus came onto the scene about 10 million years after the giant, sea going reptiles (think Nessie) had vanished from the earth. Since the Cretaceous extinction, only a few sharks and crocodilians made the ocean their home.

This is the perfection environment for adaptive radiation because there is an open niche, no dangerous competitors (Nessie), and plenty of food (fish stocks rebound in the face of few predators). Pakicetus and it’s later descendants took to the water essentially because the opportunity presented itself.

How do people know that Pakicetus is a whale? It may seem a bit far-fetched to suppose a coyote like creature to be a distant ancestor of the humpbacks, especially since Pakicetus has, you know, legs. The key is to look at the skull.

Skull of Pakicetus:Courtesy of University of California, Berkeley

Skull of modern day Orca:
Courtesy of skullsunlimited.com

In addition to the similar dental plan, you may also notice that there are no holes for ears at the side of either skull. It is thought that Pakicetus had internal ears, much like today’s whale.

Last week, I talked about how cold blooded animals could grow huge in hot environments. Today, I think it would be interesting to talk a bit more about what it means to have, “cold blood.”

What does it mean to be cold blooded?
It has nothing to do with Rick James. Having cold blood basically means that the animal depends on ambient temperature to power its metabolism. Outside heat does everything from getting enzymes running to warming up muscles. While some animals do use geothermal vents for this, heat from the sun is the most common source.

What kind of animals are cold blooded?
The simple answer is most fish, and all present day reptiles and amphibians. Birds and mammals are, by design, endotherms. (There is exactly one mammal that doesn’t apply to this rule-read more about God’s mistake; the naked mole rat.)

Any exceptions?
You bet. Tuna actually produce their own body heat through working their muscles. This allows them to be fast, powerful swimmers even in colder waters. This phenomenon is called poikilothermy. Other cold blooded animals manage to keep a more or less constant body temperature simply by merit of being huge. Because of a greater mass and proportionally less surface area, animals that exhibit gigantothermy stay warm in colder areas. Everyone’s favorite gigantotherm is the Great White Shark, but bigger sea turtles, and perhaps dinosaurs had this trait too. It was unlikely that last week’s Titanoboa was a gigantotherm, because a slender, long shape has a comparatively high surface area.

Despite being cold blooded, Great Whites are capable of sustained, acrobatic activity through their size alone. Courtesy of Charles Luyt

What are the pluses of being cold blooded?
To sum it up in a sentence; being cold blooded means you don’t need to spend a lot of energy to get energy. To keep your body temperature up at a constant 98.6 degrees, which allows our enzymes, muscles, and brains in tip top shape 24/7 takes a lot of energy. We eat tons more food per year compared to a similar sized ectotherm. Even giant reptiles like Nile Crocodiles and Anacondas only need one to two big meals per year. Since less energy is being spent finding another meal, more energy can be spent on reproduction.

This guy weighs about 1200 pounds and eats about one or two 500 pound wildebeest per year. For comparison, if you weigh about 180 pounds, you eat nearly a ton of food per year. Picture courtesy of Marco Schmidt.

What are the dangers of being an ectotherm?
For one thing, cold blooded creature don’t have nearly as much stamina as warm blooded ones. This is because a fast metabolism quickly regenerates ATP and gets rid of harmful acids that build up during sustained activity. The second danger, which I went over last week, is that warming up each day can be dangerous; time spent absorbing the sun’s rays is not time spent avoiding predators.

The Economic Stimulus Package

How much is the total cost of the economic stimulus package?
Congress has voted on a package totaling 787 billion USD after several
contentious days on Capitol Hill.
Read about the package here

Who is in favor of the package?
Senate Democrats, House Democrats, the White House, and a trio of moderate
senate Republicans hailing from Maine and Pennsylvania. Polls show a slim majority of the public (53%) are in favor of the package.
More on the Moderate Republican rebellion

Who is opposed to the stimulus bill?
Senate Republicans excluding Snowe, Specter, and Collins, all House Republicans, and
many economic conservatives oppose the bill on the magnitude of money being
spent, as well as some social conservative elements debating on whether spending
money on birth control and education counts as economic stimulus
Read an economic conservative’s opinion on the package here

Where is the money going?
A variety of places. A tax cut for 400 to 800 USD is going out for all working tax payers. In addition, billions of dollars have been set aside for infrastructure and tech development, two of the stimulus package’s biggest winners.
Learn more

What role has President Obama taken with the stimulus package?
President Obama has aggressively pushed for the package since coming in to office. Despite his requests for bipartisan legislation, voting was almost completely along party lines. Some are saying his decision to cut some spending and give out tax cuts, while barely getting republican votes are signs that Obama buckled too fast with no gain.
Obama's victory called "Pyrrhic"

Giant Boa Remains Found in Columbia

Rendition of Titanoboa- Art by Jason Bourque, University of Florida

Forget the movie with J-Lo, this snake is real thing. The fossilized vertebrae of a giant (43-45 foot) serpent has been discovered in Columbia. Rightfully named Titanoboa cerrejonensis (meaning titanic boa from Cerrejon, the region where it was found), this snake lived a scant five million years after the dinosaurs made their exit. Discovered in 2007 in a Colombian coal pit, this substantial serpent’s bones are making its rounds through the scientific circles now. To answer a couple pertinent questions:


How big was this snake, really?
Enormous. If you can imagine a normal yellow school bus next to it, you would still see the snake’s head poking past the bumper. If you could bring yourself to stand next to it at its widest point, Titanoboa would come up to your waist.
As for its weight? 2,500 pounds- in today’s world, there are only 8 terrestrial species that have a higher average weight.
When compared to today’s snakes, the differences are downright disturbing. A curator at the Florida Museum of Natural History at the University of Florida, Jonathan Bloch said of a 17 foot Anaconda, “A backbone from that creature is about the size of a silver dollar, while a backbone from Titanoboa is the size of a large Florida grapefruit."

Vertebrae of Titanoboa contrasted with modern day Anaconda, courtesy of Florida Museum of Natural History

How could it get so big?
Fun answer: global warming. More specifically, something called the Paleocene-Eocene Thermal Maximum (called that because it took place at the cusp of those geological eras) happened. While no one knows for sure, many geologists think that CO2 from volcanoes helped to trigger massive global warming about 55.8 million years ago. The result? Super-sized reptiles.
Reptiles are what the science crowd likes to call “ectothermic” or cold-blooded to you and me. While the exact definition is a little hard to explain, it basically means that animals with “cold blood” need warmth to get their metabolism going. It’s why you see most reptiles basking in the sun as a start to the day, and why pet stores sell heat lamps.
This morning ritual can be dangerous. Predators will pick up a frigid snake faster than a policeman on a barfing frat boy. That’s why you don‘t see alligators in the arctic.
Now, when the world is hot enough to warm a big-boned boa quickly, less time is spent warming up, and more time and energy is spent snapping up prehistoric critters, and consequently growing huge.

Giving you another reason to think about Al Gore,
Ted Rogers

Links:
Video on Titanoboa
Huffington post story
University of Minnesota biology professor's take on the subject
More from the London Times
A quite readable explanation of the Paleocene-Eocene Thermal Maximum

Primordial Ooze

Hello, everyone.

I'm Ted. I've started this blog because...well, my professor made me. I'm not very knowledgeable when it comes to posting on the web, so I intend to use this as a learning experience.

A little about me: I'm 21. I misspent most of my youth on the charming town of Falmouth, Cape Cod. As of now, I'm a journalism student at the University of Massachusetts, Amherst. I'm currently getting a minor in both biology and history. After school is over, I'd like to write guides for museums or zoos... but in the current economic climate, I'll be happy to have a job, period.

A little about this blog: I'd like to explore the large, messy, and sometimes confusing subject of evolutionary biology. It's something that many people don't understand, and I'd wager it's because the subject seems so complex. I'm writing about it because I'm pretty sure it doesn't have to be that way. My mission is to make the subject interesting and hopefully, a little fun. You should read this blog if you're at all curious about why biological life is like it is. As for people with a grounding in evolutionary biology, you should read this too. I'm always up for learning new things.