A short break – some random Wikipedia links

I just got back from a wonderful (albeit short) break to visit Australia.  Always great to see family and friends back home.

No incredibly insightful first post for the new year sadly, I’m still enjoying the lazy feeling from a relaxing (warm!) Christmas.

So instead, here are some random Wikipedia links, inspired by visits to the beaches of Coolangatta:

A siphonophora is a colony of various organisms that then appear to be a single organism.

Siphonophores are especially scientifically interesting because they are composed of medusoid and polypoid zooids that are morphologically and functionally specialized. Each zooid is an individual, but their integration with each other is so strong that the colony attains the character of one large organism. Indeed, most of the zooids are so specialized that they lack the ability to survive on their own. Siphonophorae thus exist at the boundary between colonial and complex multicellular organisms. Also, because multicellular organisms have cells which, like zooids, are specialized and interdependent, siphonophores may provide clues regarding their evolution.

(I spotted several bluebottles on Bilinga beach)

The Portuguese Man O’ War has an air bladder (known as the pneumatophore or sail) that allows it to float on the surface of the ocean. This sail is translucent and tinged blue, purple or mauve. It may be 9 to 30 centimetres long and may extend as much as 15 centimetres above the water. The Portuguese Man O’ War secretes gas into its sail that is approximately the same in composition as the atmosphere, but may build up a high concentration of carbon dioxide (up to 90%). The sail must stay wet to ensure survival and every so often the Portuguese Man O’ War may roll slightly to wet the surface of the sail. To escape a surface attack, the sail can be deflated allowing the Man O’ War to briefly submerge.

Below the main body dangle long tentacles, which occasionally reach 50 meters (165 ft) in length below the surface, although one metre (three feet) is the average. The long tentacles “fish” continuously through the water and each tentacle bears stinging venom-filled nematocysts (coiled thread-like structures) which sting and kill small sea creatures such as small fish and shrimp. Muscles in each tentacle then contract and drag prey into range of the digestive polyps, the gastrozooids, another type of polyp that surrounds and digest the food by secreting a full range of enzymes that variously break down proteins, carbohydrates and fats. Gonozooids are responsible for reproduction.

Which then led me to the fascinating article on blanket octopi:

An unusual defense mechanism in the species has evolved: blanket octopuses are immune to the poisonous Portuguese man o’ war, whose tentacles the female rips off and uses later for defensive purposes. Also, unlike many other octopuses, the blanket octopus does not use ink to intimidate potential predators, but instead unfurls a large net-like membrane which then spreads out and billows in the water like a cape. This greatly increases the octopus’s apparent size, and is what gives the animal its name.