In 1952 Alan Turing, a british mathematician, logician, cryptanalyst, and computer scientist, wrote a paper which remains influential in computational biology today. He explained how stripes might form on a snake’s skin [and other patterns on animals], using the dispersion of two chemicals; an activator [red] and an inhibitor [yellow]. The activator causes the colouration, and the inhibitor inhibits it. Turing wrote a pair of equations which say that concentrations of the activator cause creation of more inhibitor, but that the inhibitor diffuses and spreads out more quickly than the activator. As shown in the animation, this causes the activator to form peaks with surrounding basins of inhibitor. The concentrations of the two chemicals quickly converge to a stripey pattern where the red activator is periodically in higher concentration than the yellow inhibitor. [video] [more] [code]
also ‘dove’ and ‘pigeon’
The Pinhole Eye of the Nautilus, by Marc Gosselin:
“The Nautilus is the only animal on the planet with pinhole eyes.”
The craniates are characterized by a skull; that is, a complex ensemble of skeletal elements which surrounds the brain and sensory capsules. The skull of hagfishes (top) consists of cartilaginous bars (blue), but the brain is mostly surrounded by a fibrous sheath (yellow), underlain by the notochord (green). The skull of lampreys (middle) has a more elaborate braincase and comprises a large “branchial basket” surrounding the gills. In the gnathostomes (bottom), the braincase is generally closed (after Janvier 1996b).
Biology, are you fucking serious right now? There’s an order of sharks called Carcharhiniformes, and the shark Carcharodon carcharius isn’t fucking in it?????????? UGH
<kororaa> what’s the sister group to homo sapiens?
<hilbertspcjunkie> there were several hominids 50k years ago
<hilbertspcjunkie> all very closely related
<Lando-SpacePimp> It was a huge hominid orgy back then.
i would seriously bet $50 that that “gynandromorph” cardinal is just fucking piebald
this was on one of the slides for the paleontology class i’m taking
passerine phylogeny makes me want to cry
<Chib_> what are the little boxes?
<kororaa> some molecular crap idk
<paradoxgo> respect the molecules
Replace Monera with a monophyletic group. End eukaryote privilege!
You know what pisses me off? How usually we think of amniotes as being made up of two groups: reptiles and mammals… and “reptiles” is pretty much synonymous with “diapsids”, but “mammals” isn’t synonymous with “synapsids”!
watch it in full screen hd