Scanning eyes in molluscs and arthropods
Some sea snails have a linear retina. What a hopeless arrangement, to see the world through just a narrow slit! Not quite, because they have come up with a rather intriguing trick to extend their visual field - and it's a trick too good to use only once.

Light producing chemicals: how to make bioluminescence
The most remarkable luciferin in terms of its distribution is known as coelenterazine. This nitrogen-ring based molecule is found in nine separate groups, ranging from radiolarians to fish.

Cavitation: bubble formation in plants, reptiles and shrimps
The formation of bubbles in a fluid is known as cavitation. Typically this occurs at low pressures, and is perhaps best known in the xylem of plants where embolisms can be destructive to the surrounding tissues.

Why emit light? The many functions of bioluminescence
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Light producing chemicals: how to make bioluminescence
The most remarkable luciferin in terms of its distribution is known as coelenterazine. This nitrogen-ring based molecule is found in nine separate groups, ranging from radiolarians to fish.

Bioluminescence
Flying through the air on a summer's evening or sparkling in the ocean you may see magical flashes of light that signal some of nature's most enchanting creatures, those that are bioluminescent.

Myelinated nerves in vertebrates, annelids and crustaceans
Myelinated nerves are an excellent biological solution and needless to say have evolved independently in several groups other than vertebrates. In each case myelination is associated with very rapid nervous conduction and often escape reactions.

Suction feeding in fish, amphibians, reptiles and aquatic mammals
Probably everyone is familiar with the walrus, but did you know that it generates a vacuum in its mouth to suck clams out of their shells? And this is just one example of suction feeding, the feeding mode typically used by bony fish…

Independent eye movement in fish, chameleons and frogmouths
One of the most surprising convergences amongst animals is that seen between a small fish that lives in coral sands, known as the sandlance, and the lizards known as chameleons.

Compound eyes in arthropods
It is clear that amongst the arthropods as a whole the compound eye has evolved at least twice, and possibly even more times.

Scanning eyes in molluscs and arthropods
Some sea snails have a linear retina. What a hopeless arrangement, to see the world through just a narrow slit! Not quite, because they have come up with a rather intriguing trick to extend their visual field - and it's a trick too good to use only once.

Camera-like eyes in arthropods
Arthropods are famous for their compound eyes, but some groups have had a fair crack at evolving the optically superior camera eye…

Beetles: insights into convergence
The beetles are probably the most diverse animal group on earth, so it is not at all surprising that they provide many fascinating insights into convergence.

Crustaceans: insights into convergence
Whilst predominantly marine, quite a number of crustaceans have invaded freshwater habitats and even more interestingly a few demonstrate terrestrialization, effectively freeing themselves from their aquatic ancestry.

Transparent tissues: eyes, bodies and reflective surfaces
Read on if you want to know about the numerous animal equivalents to the invisible man...