I love BBC documentaries. I also used to love the books of David Attenborough’s BBC documentaries (I never watched those. I know, shame on me.). They tend to have the same sense of wonder that drove me to natural science, and which is lost in a number of other documentaries I’ll refrain from naming for now.
I understand that you can’t show all the subtleties and uncertainties and bloody wars over pet hypotheses that characterise cutting-edge science in a work aimed to entertain as well as educate the public. To tell a coherent and engaging one-hour story, you must simplify.
That doesn’t mean your story has to be bullshit.
(FWIW, my first beef is with the title of the film. It’s called First Life, but it gallops through the 80% of life’s history that didn’t involve animals in like the first ten minutes of the two-hour run time. But I digress.)
You see, in the first part, we get a nice lead-up to the Cambrian explosion, starting with Snowball Earth, the origin of multicellularity, animals (enter sponges), body plans (enter Ediacaran creatures), and so on. At some point, there is some musing about how complex animals began to diversify and adapt to new lifestyles, and it’s brought down to… the increased genetic variation provided by sex.
(ETA 120121: I should clarify, because I was having a bit of a brain fart when writing the original rant. The Marinoan glaciation, where my Snowball Earth link leads, is NOT the last big glaciation before the advent of animals. That honour would probably go to the Gaskiers glaciation, which I’d completely forgot was later than the Marinoan – roughly the same age as early Ediacaran fossils, in fact. Nonetheless, Wikipedia reassures me that the Gaskiers was not as severe as hardcore snowball events like the Marinoan.)
It’s pretty clearly implied by the narration that animals began to reproduce sexually around the time they started moving about and having heads and tails and similar complexities. If you paid attention to the story they were telling you up to that point, you can come away thinking that earlier animals didn’t get it on. (Like sponges don’t???)
The only problem with this is that it’s 99.999% certainly, utterly, and obviously, wrong. Sexual reproduction is an ancestral feature of eukaryotes, that is animals, amoebae, malaria parasites, plants, algae of all sorts, fungi, slime moulds, paramecia, etc. etc. (name your favourite protist).
Animals do it in fundamentally the same way, using fundamentally the same molecular machinery as other eukaryotes. And there is every indication that they always practised it. Sponges do it. I’m willing to bet that every major animal group does it. Sure, many animals are also quite happy to reproduce by budding or falling to pieces, but most of them are at least capable of sex. Very little is known about the life of our closest non-animal relatives, but the sexy genes are there.
So, um, that exciting story you were telling us about how sex changed everything? Doesn’t work. I suspect that the whole nonsense was stuffed in so that they could show off this cool find, but can’t you talk about the earliest evidence for animal sex without making it sound like something it isn’t?
Hrm. That kind of unmade my day. Now I worry if the same level of crap gets into the other documentaries I loved so much, and I just didn’t spot it because I’m not a physicist/mathematician/historian/insert profession here. Ah, the joys of being an insufferable pedant and watching films about stuff you actually have a passing acquaintance with…