Drew Berry is one of the great movie-makers of the molecular world. He makes gorgeous computer visualizations of DNA, proteins, and the various goings-on inside the cell. Last night I spent a little time watching a new TEDx talk of his just posted online. My first thought was, “Why didn’t I get to see these movies when I was learning about biology as a kid? Life is unfair.” Compared to the flat cartoons of textbooks, or even the crude animations in documentaries of yore, Berry’s work seems to come from some advanced alien civilization.

Continue reading “Words bring life to life” →

Cancer evolves. Those two words may sound strange together. Sure, birds evolve. Bacteria evolve. But cancer? The trouble arises from the fact that cancers, unlike birds and bacteria, are not free-living organisms. They start out as cells inside a person’s body and stay there, until they’re either wiped out or the person dies.*

Yet the same forces that drive the evolution of free-living organisms can also drive cancer cells to become more aggressive and dangerous. Evolution becomes our inner foe if mutations disable a cell’s self-restraint. The cell multiplies. Sometimes a new mutation arises in its descendants. If the mutations allow the cancer to grow faster, the cells carrying it will take over the population of cancerous cells. Natural selection and other processes that drive evolution on the outside start driving it on the inside.

Continue reading “Inside Darwin’s Tumor” →

We are all sure we know what life is, but if you try to actually define it, things get tricky fast. I wrote a feature about the scientific struggle to define life in 2007 for Seed, and I’ve been keeping tabs on the evolution of this metaphysical quandary ever since. I was particularly intrigued to discover recently that one scientist thinks he can define life–and do so in just three words. I’ve written an essay about his short and sweet definition for the web magazine Txchnologist. Check it out.

Originally published January 11, 2012. Copyright 2012 Carl Zimmer.

Over on Facebook, David Hillis, an evolutionary biologist at the University of Texas, took up my question as to whether anyone can define life in three words. His short answer was no, but his long answer, which I’ve stitched together here from a series of comments he wrote, was very interesting (links are mine):

Continue reading “Life with a capital L? (Like Zimmer with a capital Z?)” →