Hello and welcome to your Daily Fun Fact From Flora ,

WE"VE REACHED 50!! Whooooop what a milestone.

We’re back on to Wednesday’s What Was the World Doing Ages and Ages Ago

So let’s see where we are in our calendar year

We saw life begin on the 25th February.

Photosynthesis started on the 28thMarch.

Multicellular organisms appeared on the 16th August.

Sexual reproduction came about on the 17thSeptember.

Fungi starting being funky on the 15thNovember.

Now we have fish coming onto the scene on the 20thNovember.

Anyone who knows me will know just how much I love fish. So today (the 20th November I mean) is a very special day.

First things first, there is no such thing as a fish.

We usually like to define species by being able to group things together on the evolutionary family tree — kind of along the lines of “everything after THIS branch is a reptile” and “everything after THIS branch is a mammal” etc etc. But the problem with that is that we evolved from fish. So if you take that approach then we are all fish as well hmmm not so ideal.

Okay so is there another way of defining fish? Well we have to include sharks, stingrays, hagfish, sturgeon, lungfish, goldfish and tuna. Maybe they are all animals that breathe through gills (or at least they do usually sorry lungfish), have bodies covered in scales (but not sometimes like in sharks, stingrays and hagfish) and limbs in the form of fins (most of the time).

WOW what a great definition.

Now that we"ve sorted that we can have a look at what the earliest fish looked like (spoiler — they weren’t very pretty).

The earliest group of fish that we know about are called the Agnatha — or the jawless fish. Guess what. They don’t have jaws.

The only remnants of this branch of the family tree are hagfish and lampreys. They are hellish looking beings (and I"m saying that as a massive lover of all things fish).

This is a hagfish

Hagfish have a long cylindrical body and no eyes. They tend to burrow into their food face-first ,as instead of having jaws they have “rasping tooth plates” that move together and apart to snack on dead fish. That’s what you can see in the MONSTROUS GIF above. They are also capable of producing huge amounts of slime.

The slime is actually 99% seawater and acts like a really fine sieve rather than a cohesive gel. It’s a predator defence mechanism and it looks really freaking weird.

So as you can imagine it was a bit of a problem when a truck carrying about 4 tonnes of hagfish (who the fuck wanted 4 tonnes of hagfish) collided with another vehicle and chucked all of these “slime-eels” onto the US 101 highway in Oregon.

These hagfish got pretty stressed so there was a LOT of slime.

Ew.

Lampreys are similarly gross. They have a very large suction device that they use as a mouth that is very difficult to remove. This allows them to break the skin of their host and just enjoy parasitising off of them. Like the worst leech ever.

But what is kind of cool is that they have an anadromous lifecycle , meaning they can swim upriver to spawn. AND TO GET THERE they use those weird mouths to suction themselves onto waterfalls and then fling their little bodies up the waterfall.

Let’s just be glad that fish evolved jaws and stopped looking so horrendous.

Lots of love,

Flora