Trilobite,
Do You Bite in Threes?
When you spend a lot of time as a
child/teen/adult reading everything you can find on all those fascinating
creatures that inhabited the Earth before Humans came along, you come across a
lot of strange names. You aren’t sure what those names mean. You might have a
rough idea what that type of creature looked like, and that’s probably about
all that you know. Because, really, who cares about an extinct sea creature
that looked like some crazy kind of beetle?
So I decided to see what I could find
out about trilobites, see if there was something about them that would prove
interesting. I headed for Wikipedia to get a smattering of layman information
before I looked for more advanced info.
Wow. The first sentence in the Wikipedia
article is (basicly) “Trilobites ... are a group of extinct marine arachnomorph
arthropods that form the class Trilobita. Guess we’d better put on our thinking
caps for this one!
Extinct =
they are all dead.
Marine =
lived in the sea. Or maybe lived in water.
Arachnomorph
= ? Well, arachnid is a type of spider, scorpions and what have you. (Thanks,
dictionary.com, but why don’t you have the entire word in your list?) Morph has
more than one meaning, but the one I’m most familiar with is “to transform”.
Arthropod =
an invertebrate with a segmented body, jointed limbs and usually a hard shell
that can be molted (discarded) should the creature get too big for it.
So far, what we’ve got is a water
creature with a segmented body, limbs with joints and a hard shell. Might have
looked vaguely like a spider. What comes to mind is a lobster, but they didn’t
really look like that. The most common rendition I’ve seen for a trilobite is
an oval shape. The larger ‘end’ is a pretty solid ‘half moon’ shape, with a
‘tail’ that goes down the middle of the oval to the smaller ‘end’. Behind the
half moon head and on either side of the tail, filling up all the rest of the
oval, are lots of limbs. But other trilobites had much different shapes. Let’s
go on; what more can I find?
Trilobites ranged from 1/10 of an inch
to about 12 inches. I think that entire range is for adult specimen.
The last of the trilobites died about
252 million years ago. But before that, they were quite a successful species,
having spread all around the world and existing for over 300 million years. Scientists
believe trilobites started their long journey as much as 700 million years ago,
or possibly even further back. And if you think humans have some wildly
different lifestyles, you obviously have not met many trilobites. Some were
aggressive, and moved over the sea bed as predators, scavengers and/or filter
feeders. Others were less aggressive and swam while eating plankton. Scientists
are still debating whether or not any trilobites were parasites, while one
group of trilobites appear to have had a symbiotic relationship with
sulfur-eating bacteria.
Trilobites are thought to have
originated in what is now Siberia. But that was over half a billion years ago,
and with plate tectonics, who knows where that was actually located? Well, I’m
sure there are people who do know,
but I don’t. I’m going to have to look it up. Look for it in a later episode.
Anyway, as I said before, the
trilobites all died out. Although they seemed to excel in changing shape,
habitat and food throughout their long existence, eventually there was only one
family left, and when its habitat disappeared, so did they. But while they were
here, there were thousands of variations of trilobite. This diversity helped
them fill many niches in the cycle of life.
On the other hand, there are some very
distant relatives of the trilobites still living on Earth. Think horseshoe crab
and others of that ilk.
And that is all I found that I
understood in this 29-page article on Wikipedia. Go ahead and read it, if you
want, but I warn you, it is FULL of very long words, most of them names of
genus, family and specie, but not all. The ones that aren’t are used generously,
with no explanation what it refers to, and which may not be in your dictionary.
Have fun!
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