Thursday, 12 January 2017

Using hemp fibers in anatomical sculpture

It’s always good to try new things.  This week I’ve been experimenting with using hemp fibers in sculpture.  I wanted something fibrous, and hemp string turned out to be ideal.

This is another episode in my long-running fascination with things that look abstract but aren’t (for another example, see here).  It’s the inside of a human eyeball, as seen under an electron microscope.  The round thing in the middle is the point at which the optic nerve enters the eye.  This is called the lamina cribrosa.  In reality it's about 4mm in diameter, and it's like a little sponge with nerve fibers growing through the holes.  The two large holes in the center allow a vein and an artery to enter the eye.  The lamina cribrosa is surrounded by a membrane.  Note that you cannot see the rod and cone cells, because they are underneath the membrane.  Human eyes are inside out; light has to pass through a membrane layer before it can be picked up by the rod and cone cells.


That's not an optical illusion, the whole thing is slightly concave.  It curves upward at the corners because it represents the back of an eye, as seen from the inside.


The brown parts are hemp fibers incorporated into the membrane around the lamina cribrosa, which is made from thin strips of paper rolled into small cylinders and glued together to mimic the structure of the real thing.



Lamina cribrosa, halfway through construction.


For reference, these are pictures of the real thing, as seen through an electron microscope.



Image found here.


Image found here.

You can see the tissue is very fibrous, and so I needed a fibrous sculpting material to represent it.  The hemp fiber works well and creates an interesting variety of textures.  When the sculpture is painted the hemp will be the same colour as the rest of the membrane, which will highlight the differences in texture.

Monday, 9 January 2017

Avalofractus

Happy New Year readers!  Following on from my haootia quadriformis sculpture, I've been sculpting some more Ediacaran life forms.  In this case, rangeomorphs.  These were fern-like organisms that lived on the sea bed 635-542 million years ago and were obviously very successful, because there were a lot of different species.  This one is called avalofractus



Finished sculpture showing three avalofractus specimens.


The interesting thing about rangeomorphs is that their body shape was fractally symmetrical.  Modern animals are usually bilaterally symmetrical, though some plants have fractal growth patterns.  Rangeomorphs, however, had a central column anchored to the sea bed with a round holdfast, with branches growing out on alternate sides of the column.  Each branch grew sub branches, and so on.  Every little branch or frond was a miniature version of the whole animal.


Beothukis mistakensis model og growth:
This diagram shows the rangeomorph's fractal growth pattern.  The image comes from this paper by Jennifer Hoyal Cuthill and Simon Conway Morris.

I think this is just so cool.  I say animal but in fact there's some debate as to exactly what they were, and whether they were related to modern animals at all, or whether they evolved completely separately.  Although they looked like ferns, they weren't a kind of plant.  Plants use photosynthesis, and rangeomorphs did not.  They lived at the bottom of the sea where there's no light, and probably used their fronds to absorb nutrients directly out of the water.  



These sculptures are much larger than life size.  In reality avalofractus was only about 5cm long.


As with the haootia sculpture I used a simple colour scheme where the background is painted indigo and the avalofractus figures are a lighter indigo.  Again, this is my conjecture based on the fact that there's no fossil evidence for animals with eyes at this time, and there was no light at the bottom of the sea where these things lived anyway, so why would they be colourful?  I could be wrong.  There are deep sea creatures today that are colourful, even though they live in a world without light.  However, I like the simple blue colouring.  It gives them a somewhat ghostly look against the dark background, which is appropriate for deep-sea animals.