What is the difference between a colonial animal, and us?
A colonial organism is more than just a colony of independent organisms: there is a close association of hundreds (or thousands) of tiny organisms into a superorganisms.
The superorganism, as a whole, behaves differently than any of the tiny animals that ake it up.
How is that different from us, a multicellular animal?
For us, if you pluck out individual skin or muscle cells, they die – they are not independent lifeforms. But for a colonial organism, each little piece is its own animal (or protist.)
Also, multicellular organisms create a whole organism from sperm and egg cells (or the equivalent), while colonies are made from independent animals (or protists) coming together.
What are some examples of colonial behavior?
World War Z zombie behavior: Here we see individual infected people, each obviously a separate organism, and behaving in an almost mindless fashion. But when each organism works together, they form a larger organism.
Here we see the same colonial behavior of zed (zombies) from a more distant perspective, seeing hundreds of individuals operating together like an organism.
Ant colony behavior
Emergence is the process of complex pattern formation, from more basic constituent parts or behaviors.
“I used to think ants knew what they were doing. The ones marching across my kitchen counter looked so confident, I just figured they had a plan…Turns out I was wrong. Ants aren’t clever little engineers, architects, or warriors after all—at least not as individuals. When it comes to deciding what to do next, most ants don’t have a clue. .. “Ants aren’t smart,” Gordon says. “Ant colonies are.” A colony can solve problems unthinkable for individual ants, such as finding the shortest path to the best food source, allocating workers to different tasks, or defending a territory from neighbors. As individuals, ants might be tiny dummies, but as colonies they respond quickly and effectively to their environment. They do it with something called swarm intelligence. A colony relies upon countless interactions between individual ants, each of which is following simple rules of thumb. …simple creatures following simple rules, each one acting on local information. No ant sees the big picture. No ant tells any other ant what to do… no leadership is required. “Even complex behavior may be coordinated by relatively simple interactions,” he says.”
Siphonophores appear to be like jellyfish, but they are actually colonial.
Although siphonophore appear to be a single organism, each is actually a colony composed of many individual animals. Some superficially resemble jellyfish. The best known species is the Portuguese man o’ war. Another species of siphonophore, Praya dubia, is one of the longest animals in the world, with a body length of 40–50 m (130–160 ft). The term originates from the Greek siphōn “tube” + pherein “to bear”. Here we see a praya dubia!
Portuguese Man of war – large scale
The Atlantic Portuguese man o’ war (Physalia physalis) is a marine cnidarian of the family Physaliidae. Its venomous tentacles can deliver a painful sting. It is not a common jellyfish but a siphonophore – a colony of specialized individuals called zooids. On rare occasions their stings can cause death.
Portuguese Man of war – close up
Pyrosomes are free-floating colonial lifeforms that live usually in the upper layers of the open ocean in warm seas.
They are cylindrical- or conical-shaped colonies made up of hundreds to thousands of individuals: zooids.
Colonies range in size from less than one centimeter to several metres in length.
Each zooid is only a few millimetres in size, but is embedded in a common gelatinous tunic that joins all of the individuals.
Each zooid opens both to the inside and outside of the “tube”, drawing in ocean water from the outside, to its internal filtering mesh.
Pyrosomes are planktonic: movements are largely controlled by currents, tides in the oceans. On a smaller scale each colony can move itself slowly by jet propulsion, created by the coordinated beating of cilia.
Pyrosomes are brightly bioluminescent, flashing a pale blue-green light that can be seen for many tens of metres. The name Pyrosoma comes from the Greek (pyro = “fire”, soma = “body”). Sailors on the ocean are occasionally treated to calm seas containing many pyrosomes, all luminescing on a dark night.