Camera eyes in vertebrates, cephalopods and other animals
Camera eyes are superb optical devices, so it is not surprising that they have evolved several times. But why, of all animals, in the brainless jellyfish? Or for that matter in a slow-moving snail?

Compound eyes in sabellid annelids
Compound eyes have evolved convergently in the annelids, notably amongst the sabellids, where they evidently serve as an optical alarm system.

Agriculture in marine polychaete annelids
Some polychaetes attach pieces of algae to their dwelling tube. Just for decoration? No, but for a much more substantial (and convergent) benefit...

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.

Compound eyes in sabellid annelids
Compound eyes have evolved convergently in the annelids, notably amongst the sabellids, where they evidently serve as an optical alarm system.

Camera eyes in alciopid annelids
There is a striking example in the group known as the alciopids, which are pelagic polychaetes. The similarity of their camera eye to the vertebrate eye has attracted considerable comment.

Love darts in slugs, snails and annelid worms
The curious habit of stabbing their partners with sharp calcareous (or chitinous) darts during courtship and prior to actual copulation has understandably attracted considerable attention.

Why emit light? The many functions of bioluminescence
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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.

Vibrational communication in animals
What on earth could an elephant or treehoppers have in common with a seismometer?

Pufferfish (and inflation)
Pufferfish are some of the most extraordinary fish to have evolved, especially because of their capacity to swallow water and inflate themselves to something like a football. Not only that but some representatives can be deadly to the unwary diner...

Dicyemids and chromidinids: enigmatic endoparasites
Dicyemids and chromidinids are tiny, worm-like or 'vermiform' creatures that typically live inside the kidneys ('renal organs') of cephalopod molluscs such as octopus, squid and cuttlefish.

Tetrodotoxin
Not many foods served in a restaurant can kill you, but pufferfish is the exception. Tetrodotoxin, the toxin responsible for such culinary fatalities, reveals a fascinating story of convergent evolution...

Venom and venom fangs in snakes, lizards and synapsids
Although the evolution of snake fangs itself provides us with a window on convergence, the presence of fang-like teeth in lizards, therapsids and mammals provides an even broader and more remarkable perspective.

Venom in mammals (and other synapsids)
Beware the venomous shrew! Yes, venomous. And convergent on some formidable lizards...

Vision in echinoderms
Among brittlestars and sea urchins we find visual systems that in some ways rival the arthropods in the form of compound eye-like structures.

Pinhole eyes in Nautilus and giant clam
The pinhole eye has evolved not only in the Pearly Nautilus, but also in another group of molluscs, the bivalves and specifically the giant clams (Tridacna).

Compound eyes in ark clams
Read on if you want to know more about bivalves with burglar alarms…

Zinc in teeth
On land, we find the employment of zinc to reinforce feeding structures in the fangs of spiders, and also in a variety of insect groups.

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...

Worm-like body form
Man is but a worm, but so are many other vertebrates...

Burrowing: from worms to vertebrates
Quite a few adaptations are useful for burrowing into the soil. So it is not exactly surprising that they have evolved several times...

Octopus and other cephalopods: convergence with vertebrates
What could be more different from us than the alien-like octopus? Hold on. Look it in the eye and think again.

Camera eyes in vertebrates, cephalopods and other animals
Camera eyes are superb optical devices, so it is not surprising that they have evolved several times. But why, of all animals, in the brainless jellyfish? Or for that matter in a slow-moving snail?