Ann Jones

And what we think they were was these tiny little microbes.

Dr Emily Mitchell is assistant professor with the Department of Zoology at Cambridge, and she wasn't there either.

But she is as close as we can get to a time traveller, because she's a deep-time ecologist.

These were prokaryotes.

They didn't have a nucleus, they didn't have organelles, they were hashtag simple life all the way.

Oh, oh, they didn't have sex either.

In fact, it's about another billion years which bubbles by as a matter of microbes line the bottom of the waters of time.

Cell division seems like a pretty good system.

You're self-reliant, you can produce as and when you want to, like the empowered, independent, single amoeba that you are.

But every system has drawbacks, and this is important.

With asexual reproduction in its simplest forms, you are cloning yourself, using exactly the same genetic material every single time.

But you do accrue mutations.

And whatever things aren't working well, you 100% are going to be passing them on to your offspring.

So what is nature's solution?

Bingo!

Yes, for well over half this here planet's existence, there was no sexual reproduction at all, which is weird considering how much of your brain it takes up right now, am I right?

But it's important to note that sexual reproduction can occur without penis in vagina.

Sexual reproduction actually refers to the combining of two sets of genetic information into a new individual.

So let me summarise the too long didn't read for the first 2.9 billion years of the gradual evolution of sex.

In its simplest form, sexual reproduction arose as a way of combining with the genetics of someone else, reducing the possibility of passing your problems on to your offspring.