Viruses as Planetary Forces

 
 
A couple months ago Carl Zimmer presented at the Singularity Summit. The talk, “Our Viral Future,” is now available on FORA.TV. I love learning about viruses and other pathogens, in part because their versatility, abundance and impact on our planet never cease to amaze. Zimmer gives an excellent overview of these ubiquitous life forms that have shaped the evolution of life and sundry ecosystems on earth. Below are some brief takeaways from his presentation.

– There are an estimated to be 10^31 viruses currently festering on earth (Note: not distinct strains or species). The bulk of the world’s genetic diversity is tied up in their DNA, as they shuffle genes among different hosts and species. They are a repository of life’s genetic information. It could be said that life is 99% microbiology.

– In fact about 8% of the human genome is derived from viral DNA, where a virus has inserted its genes into ours and adapted to survive. These sequences then become dormant but remain lodged as permanent fixtures in our DNA.

– There are also 10^30 bacteria particles on earth, so bacteria are of course the most abundant hosts for viruses.

– The influence of viruses on climate and ocean ecosystems are still imperfectly understood. It is believed that viruses kill off about half of the ocean’s bacteria stores every day. And to think, this profligacy of death has been going on for millions of years, escaping our attention until only recently. Every bacterium that is destroyed by a virus releases carbon into the ocean, which is already the largest repository of CO2. Scientists are currently studying how much of an impact this phenomenon has on the carbon cycle and global climate.

– Smallpox, one of the deadliest viruses in human history, has killed billions since its insertion into the human genome, including 300 million people in the 20th century alone. It has since been eradicated, thanks to the tireless efforts of virologists and epidemiologists around the world. It is the first such extirpation of a virus by proactive, scientific means.

– HIV is one of the most pernicious viruses of the past five decades. First found in chimpanzees, we can now identify the precise moments when and where HIV jumped from chimpanzees to humans, cresting at the start of the 21st century. HIV mortality rates are in decline today.

For more you can listen to the full video below.

External link: Author Carl Zimmer: Our Viral Future

Feature image via Flickr by user Laura Billings