leedsmuseumsI’m Joe Botting, the Assistant Curator of Natural Sciences and I look after the geology collections. Welcome to the Life on Earth gallery: this is going to be a tour of the geology part of it so we are just coming in the right hand door, next to the tiger, if you look to your left you will see a grey plinth. This is the beginning of a timeline which runs along the left hand side of the room. This timeline shows the entire history of the Earth, which is about a third of the history of the universe. Immediately to your left you will find a grey plinth which, if you walk around it, it has a strange lump of metal stuck to it.
This is a meteorite and it is the oldest thing that it is possible to touch. It’s approximately four and a half billion years old, it’s made of iron and nickel and the strange lines you that can see all over the surface are crystals of two different forms of iron-nickel. These can only form when it cools incredibly slowly – about one degree every ten million years – which means that this came from the core of a planet. The planet was destroyed by being knocked into by another asteroid and, eventually, a bit of this landed in Mexico several hundred years ago.
leedsmuseumsThe first section of a tour around the geology on display at Leeds City Museum. Curator Joe Botting takes you around the Life on Earth gallery.
leedsmuseumsThis is part five of the geology tour for the Life on Earth gallery. We are walking around the timeline and we’ve now got to the Carboniferous case. This is the age of the rocks around Leeds and all the coal mines in the Leeds area and in South Yorkshire as well, are dug into the rocks of this age. They are full of plant fossils because, finally now, we have life on land.
These are some of the earliest large forests on the planet and what we see in this case is a sample of the trunk of a gigantic clubmoss. Today clubmosses are very small plants: up to maybe twenty centimetres tall and they live on mountains and in swamps but back in the Carboniferous they reached forty or fifty metres tall and had this enormous crown with dense foliage, little leaves and cones on the end of the branches but the strange pattern that you see on the trunk is where it was covered with leaves as well. The entire surface would have been covered with little spikey leaves and the whole thing would have looked bit like a Monkey Puzzle tree today.
From evidence looking at the interior of the trunk, and how the structure of the plant worked, it now seems impossible for this to have lived for more than five years. The whole plant would have grown extremely quickly, and then fallen down. It would not have been a comfortably place to be walking!
leedsmuseumsThe fifth section of a tour around the geology on display at Leeds City Museum. Curator Joe Botting takes you around the Life on Earth gallery.
leedsmuseumsThis is part three of the geology tour for the Life on Earth gallery. We are walking around the timeline and the second case on the floor is the Cambrian. This is the point in the history of the Earth when life went a bit mad really: you had fossils all over the place because animals had started to evolve hard skeletons (things that can be fossilised) and one of the most dominant forms of life at this time were the trilobites.
There are about 50,000 species of trilobite known so far and they lived in all habitats in the sea: from the deep waters up to the beaches and the shallow shelves and also scuttled among reefs in huge abundance. They are related to things like centipedes and horseshoe crabs but there’s nothing really close to them today and, they might look like woodlice, but they’re actually quite distantly related. They died out 250 million years ago but at the time they dominated the oceans.
What you see here is one complete trilobite, sitting on a little rock in the case, and that is resting on top of a large slab which shows various trails and grooves with scratch marks all over them and these are its feeding traces. So what we see here is evidence of these animals scuttling over the floor, digging through the sand to pick out particles of food and occasionally we find evidence of one of these burrows intersecting a worm burrow. You get a huge great curfuffle in the sediment and then the trilobite carries on and the worm doesn’t. So It’s one of these very rare cases where we actually have good evidence for what these animals were eating in the distant past.
There’s a huge diversity of these things, not just in the shapes and the structures the spines on them but also in their life habits.
leedsmuseumsThe third section of a tour around the geology on display at Leeds City Museum. Curator Joe Botting takes you around the Life on Earth gallery.
leedsmuseumsThis is part four of the geology tour. We are walking along the timeline and we’ve now got to the case reading Devonian. In here we have a fossil fish. It’s not the earliest fish, there were quite a lot of fish before this, but you wouldn’t really recognise them easily. For a start they didn’t have jaws: they were strange sort of vacuum-cleaner like things that just sort of floated along the sea floor sucking up anything they could eat but by the time you get to the Devonian, this is about four hundred million years ago, suddenly we have a huge diversity of different types of fish which you would recognise. They had scales, they had teeth and jaws, they had bones and most of them weren’t armour-plated like the earlier ones had been.
There are many places, particularly in Scotland today, where we can find these fossil remains and the north of Scotland is famous for it. The one you see in here is from a place called Achanarras Quarry which is one of the most important early fish localities in the world.
leedsmuseumsThe fourth section of a tour around the geology on display at Leeds City Museum. Curator Joe Botting takes you around the Life on Earth gallery.
leedsmuseumsThis is part two of the geology tour. We’ve just been looking at the meteorite and now moving along the red line on the floor until it goes into the wall. You are going to have to walk around the room five times, come out here, and you just walked through the pre-Cambrian, almost all of that – nine tenths of the history of the Earth – was based on bacteria and microbial life.
The case on the floor in front of you now, it says pre-Cambrian, contains stromatolites. These are the most early evidence for life at this age. They’re effectively colonies of bacteria that were sort of sticky. Sediment stuck to them, sand washing over them and they built up into these strange mounds on the floor of the sea. There are very few of these alive now because mostly they are eaten by grazing animals but at this time there weren’t any so the sea was dominated by them.
leedsmuseumsThe second section of a tour around the geology on display at Leeds City Museum. Curator Joe Botting takes you around the Life on Earth gallery.
