This episode is presented by eBay.

Rob, everyone loves a deal and a bargain from time to time, don't they? Absolutely, mate. And you know where you can grab a great deal? Talk to me. Where? The eBay app. Yes, you are correct. You didn't need to talk to me. I already knew it. I love eBay. When you're buying, you can discover loads of hidden gems. there's so many items where you think I would have never found that anywhere else.

Then when you're buying, you can discover loads of hidden gems. There's so many items where you think I would have never found that anywhere else. Then when you're selling, it's so simple and most

importantly, free. It's free, Rob. When it's this easy to sell for free and there's great

deals on things you love. You can't help but say when it's eBay. It excludes vehicles and business

sellers.

Hi, Steve Murski here for a scientific American science talk. Welcome back for part two of our conversation with Carl Zimmer. In part one, we discussed evolutionary research

in the urban environment. Next, we talk about Carl's latest books, as well as a study that came out last week

about toxoplasma infections

and the amazing effect that they have on rats.

You've also got a new book coming out

and another book coming out soon

that's a little bit of a departure for you.

You want to talk about those?

Yeah, so in May, I published a book called A Planet of Viruses. I write a dozen essays on a dozen

of viruses looking at different aspects of virus biology and how viruses have affected humans.

And also trying to make the point that, you know,

viruses are incredibly abundant on Earth and, in fact, are the most abundant life form on Earth.

So, well, are they a life form? I mean, I'm not even sure this question is important, but are they alive or are they almost alive? I think that they're alive.

You know, there's certainly a debate about that. I think that it's kind of an arbitrary

distinction to say that you have to be exactly like us in order to be alive. Viruses do all

sorts of things that can only be done by living things um you know they they replicate

...