extremophiles

Deep ocean vent - home to the microbe Methanococcus jannaschii

Extremophiles live and thrive in severe physical environments. Heat, pressure, acidity, are all exploited by organisms looking to fill an outré environmental niche. Methanococcus jannaschii is a microbe extremophile that lives near hydrothermal vents 1.5 miles below sea level - where a submarine would be crushed by pressure and temperatures approach the boiling point of water. The variety of extremophiles inhabit all improbable niches on this planet and what astrobiologists infer about life throughout the universe (panspermia). Have to include this from wikipedia:

"Recent research carried out on extremophiles in Japan involved a variety of bacteria including Escherichia coli and Paracoccus denitrificans being subject to conditions of extreme gravity. The bacteria were cultivated while being rotated in an ultracentrifuge at high speeds corresponding to 403,627 times "g" (the normal accelaration due to gravity). Paracoccus denitrificans was one of the bacteria which displayed not only survival but also robust cellular growth under these conditions of hyperaccelaration which are usually found only in cosmic environments, such as on very massive stars or in the shock waves of supernovas. Analysis showed that the small size of prokaryotic cells is essential for successful growth under hypergravity. The research has implications on the feasibility of panspermia.^[5][6]"


I'm trying to make a metaphorical point and went farther on the limb than intended, but that's too good to exclude. Especially the bit about prokaryotes. At any excessive rate, the upper and lower limits of life are pretty broad (if not vast) and that gets translated into rules for all physical and social conditions. Dynamic equilibrium keeps the colony alive within margins - conditions change and the colony adapts, speciates, or dies. 

Suppose we have just transported here from another galaxy and are assigned to study the variety of organisms on Earth (which is known as Zkiuenvhdjfhkdei on our planet). You encounter what may be a different genus of the same species. Or they may be classified as extremophiles:

 

What do these images tell the travelers about this animal? Is it an indication of reproductive strategy / advertising, controlled estrus, social status, art adornment, disguising social pariahs, or are they completely different species? Why such extreme representations of what may be the same genetic lineage? It appears that pressures and adaptations to the environment have produced the upper and lower limit of social display/constraint (or lack of it). These females must be choosing to behave so radically different to ensure their offsprings' survival, and their environments must be diametrically opposed to produce these phenotypes.

Since females have biological imperative in determining and choosing the best mates, these clearly have adapted different strategies to ensure care and lineage of offspring. Unless by some implausible strategy, these females are not determining the course of their behavioral/mate selection, which is a violation of universal nature by all measures. Cultural, environmental, and evolutionary pressure has created the upper and lower bounds of this species customs and strategy for survival. The midpoint is where most of them reside. If the balance shifts too far in either direction, a pressure has developed favoring one side of the spectrum over another. Every action has an equal and opposite reaction, and these are extremophiles in action. Clearly, the 'middle way' represents a healthy, aware, rational alternative to such agenda-driven, obdurate constriction or reckless lack of all restrictions. To regulate or not to regulate? Easy - moderate regulation gives the flexibility to adapt to ever-changing conditions.

Another extraterrestrial explanation is that one represents an entirely different time period of evolution. One may have returned to the planet from the past or future. Or we must consider that this one-headed species is so repulsive that the females must cover themselves to attract males. (That's the most popular ET hypothesis at the moment).