On a somewhat related note, as far as animals go, jelly fish are nuts. I mean they're barely animals at all. From wikipedia: "Most jellyfish do not have specialized digestive, osmoregulatory, central nervous, respiratory, or circulatory systems." and, "Jellyfish have no brain nor central nervous system". No brain? I mean come on. Jelly fish are floating piles of goo with absolutely no purpose or delight in life other than being floating piles of goo. It's made weirder by how big some of them get, "Jellyfish range from about one millimeter in bell height and diameter to nearly two meters in bell height and diameter; the tentacles and mouth parts usually extend beyond this bell dimension." Giant brainless animals roam the ocean looking to sting and absorb prey without ever really knowing they're even doing it. They're pretty much ocean zombies.
They're nuts, and are a great example of how evolution cares about nothing but survival.
> Giant brainless animals roam the ocean looking to sting
> and absorb prey without ever really knowing they're even
> doing it. They're pretty much ocean zombies.
They do lack central nervous systems, but they're not entirely brainless. There's a non-encephalized diffuse neural ring that controls effectors which is sensitive to sensors input. Eerily, some jellyfish (box jellyfish, IIRC) have corneal eyes...
So, sure, these things are super stereotyped. But so are many higher organisms, even among good ol' vertebrates.
From the wikipedia article you linked to:
Jellyfish have no brain nor central nervous system, but employ a loose network of nerves, located in the epidermis, which is called a "nerve net".
Though they are brainless, they do have enough reflexes to get by.
> They're nuts, and are a great example of how evolution cares
> about nothing but survival.
Please don't mistake evolution for natural selection. Evolution does not "care" about survival, it's just genetic change of biological populations over time, and natural selection is just one of the processes that produce evolutionary change.
Also, putting the emphasis on survival when referring to natural selection is a bit outdated. Please say "natural selection cares about nothing but differential reproduction of genotypes" instead if you don't want to sound so nineteenth-century :-) </pedantic_minutia>
from wikipedia: "Evolution is any change across successive generations in the inherited characteristics of biological populations."
from me: "Evolution(clearly biological) cares (a cute way of saying is effected by) about nothing but survival." The personification of evolution was perhaps a bit too cute, but I feel it's also a bit more inspiring than getting specific. Also, I can't see much of a difference between surviving and being naturally selected.
First, I wasn't really complaining about the use of the verb "care". I think it's OK to abbreviate like that when talking about evolution, as long as we're aware we're anthropomorphizing.
Note that the definition from Wikipedia that you quoted says nothing about "survival". Death isn't even a requirement. You just need a change in the allele frequencies of a population to call it evolution.
With that survival line you were probably referring to natural selection, which is just one of the aspects of evolution, and again not a requirement for it. You can have evolution by genetic drift, for example. But even if you were just talking about natural selection, putting the emphasis on survival (and "nothing but survival") is incomplete and misleading. Death/survival don't need to play an important role in natural selection (though there are instances when it will, of course). For example, small differences in the average number of offspring already mean natural selection.
They're nuts, and are a great example of how evolution cares about nothing but survival.
[1]https://en.wikipedia.org/wiki/Jellyfish