Tag: evolution

Mars Colonization Project

My high-school biology class is taking their exam on genetics and evolution. To make the test a little more interesting, and to point out that there may be some relevance for this knowledge in the future, I made the test a questionnaire for the new head of the Mars Colonization Project. It begins like this:

Friday, January 30th, 2054.

Dear Dr. ________________ (insert your name here):

We are excited that you have accepted our offer to head the Biomedical Division of the MCP. As we are engaged in the first ever effort to colonize another planet, we know that we will face many unique challenges. Your expertise in pluripotent stem cell research and oncology will be extremely valuable to us — even though some of us administrators still don’t know what pluripotent stem cells are.

Please fill out the questions in this document to help us with our planning for the colony and to help our Human Resources department assemble your research and medical team.

Because of the sensitivity of some of the personal information included in this document, please write out, and sign, the Honor Code below before turning the page.

Yours truly,

Board of Administrators,
Martian Colonization Project

Front page of the High Schooler's Biology exam.
Front page of the High Schooler’s Biology exam.

Then I pose all of the questions in this context. For example, to get their knowledge of vocabulary I ask them to define the scientific words and phrases (which they’ve used in their scientific publications many, many times), in terms that laymen — like the people on the board of administrators — could understand.

To get at more complex concepts, like the molecular process of gene expression and regulation, I phrased the question like this:

Medical Issues Related to Ongoing Colonization Planning

The trip to Mars will take five years, so we will be placing most of the colonists into cryogenic sleep for most of that time. We are still working out some of the bugs in the cryogenic technology, and we need your help.

To put people into cryogenic sleep, we need to stop their digestion of carbohydrates. Your predecessor, Dr. Malign, told us that we could do this using RNA interference, by injecting them with engineered microRNA that would block the production of the enzyme amalyse.

Could you draw a diagram of a cell showing how proteins are expressed from DNA, and how microRNA would interfere with protein production. Are there other methods for preventing protein expression?

We’ll see how the students do on the test, however at least one student glanced at the front page and said, “This is kinda cool,” (actually, she first asked if I’d stolen the idea from the internet somewhere), which is significant praise coming from a teenager.

Natural Selection by Alfred Russel Wallace

Everyone knows about Charles Darwin, but hardly anyone remembers Alfred Russel Wallace, who came up with the idea of natural selection at the same time as Darwin. Darwin’s publication of the On the Origin of Species was spurred on by Wallace. Flora Lichtman and Sharon Shattuck shed a little light on Wallace with this video:

Indeed, from the introduction of On the Origin of Species:

I have more especially been induced to [publish], as Mr. Wallace, who is now studying the natural history of the Malay archipelago, has arrived at almost exactly the same general conclusions that I have on the origin of species. Last year he sent to me a memoir on this subject, with a request that I would forward it to Sir Charles Lyell, who sent it to the Linnean Society, and it is published in the third volume of the Journal of that Society. Sir C. Lyell and Dr. Hooker, who both knew of my work—the latter having read my sketch of 1844—honoured me by thinking it advisable to publish, with Mr. Wallace’s excellent memoir, some brief extracts from my manuscripts.

— Darwin, 1859. On the Origin of Species.

↬ The Dish

On Evolution

Carl Segan’s Cosmos series contains a wonderful overview of the history of life.

The one possible criticism of the video is that evolution could be misconstrued as a gradual, linear process (although Segan is pretty clear that this is not the case). BouncingDodecahedrons has an interesting image showing the splitting and coiling of the process.

I prefer to illustrate evolution using the tree of life.

Phylogenetic tree of randomly selected organisms.

↬ Reddit

Choosing Extinction

We talked about the Voluntary Human Extinction Project (VHMET) in Environmental Science, when we were covering issues related to overpopulation and the need for genetic diversity. While I’ve never been quite sure just how serious VHMET is, I just came across this 2007 article by Robert Krulwich on NPR about a tribe of pygmies in the mountains bordering China and Burma that chose extinction because of all the genetic problems that were being caused by inbreeding.

Terraforming Earth

Before: Barren, Volcanic. Image by Ben Tullis via Wikimedia Commons.

Charles Darwin and colleagues attempted to vegetate the barren, volcanic Ascension Island with plants from botanical gardens around the world. Essentially, it was an experiment in transforming. And it worked. Howard Falcon-Lang has the details at the BBC.

After: An eclectic, lush mix of vegetation. Image by LordHarris via Wikimedia Commons.

Horizontal Gene Transfer: Plasmids

Peter Eisler has a somewhat scary article on the development of drug resistance in bacteria at the University of Virginia Medical Center. The bacteria were resistant to all of their antibiotics. Everything. And the bacteria were able to pass the genes that gave them their resistance to other bacteria: not just to their offspring, but horizontally to other species of bacteria by exchanging bits of DNA called plasmids.

One bacteria cell passes a piece of DNA (called a plasmid) to another. From USA Today — Image links to more complete information.

When genes are passed on from parent to offspring, or even from one microbe to another by cell splitting, it’s called vertical gene transfer. Horizontal transfer, on the other hand, involves different individual organisms passing genes from one to the other. It would be as if two people could exchange genes by shaking hands.

When the doctors began analyzing the bacteria in their first patient, who’d transferred from a hospital in Pennsylvania, they found not one, but two different strains of CRE bacteria. And as more patients turned up sick, lab tests showed that some carried yet another.

“We were really frustrated; we hadn’t seen anything like this in the literature,” says Costi Sifri, the hospital epidemiologist. “The fact that we had different bacteria told us these cases were not related, but the shoe leather epidemiology suggested to us that all these (infections) came from the same patient. … We realized we might be seeing a mobile genetic event.”

In other words, it looked like a single resistance gene was jumping among different bacteria from the Enterobacteriaceae family, creating new bugs before their eyes.

— Eisler 2012: Deadly ‘superbugs’ invade U.S. health care facilities in USA Today.

The really scary part:

There is little chance that an effective drug to kill [drug resistant] CRE bacteria will be produced in the coming years. Manufacturers have no new antibiotics in development that show promise, according to federal officials and industry experts, and there’s little financial incentive because the bacteria adapt quickly to resist new drugs.