lastnightonIo

What is it with the number 2...

Base pairs.
A double-helix.
Cells dividing in two during mitosis.
Male and female.
Bilateral symmetry of the body.
Predators and prey.
Two states: awake & asleep.
Two states: living & dead.

Then there are the environmental quirks that have shaped human perception and culture:
Two lights in the sky of roughly equal size: sun and moon.
Two periods: night & day.

Cause & effect.


Duality seems so prevalent and incorporated in the most basic things, at least for life on Earth... anyone have some ideas on why that is?

Peez

Because two is the lowerest integer higher than 1? Surely this thread belongs elsewhere.

Peez

pz

Yes, I agree.

Doubting Didymus

The achievements of the number 2 are certainly impressive, but Just think of all the things that come in ones.

lastnightonIo

Fine, whatever, mock me.

Tell me this: why aren't there any species that require three individuals to procreate? For instance, two individuals both contributing a sex-cell to a third individual which supplies the third part?

Oh, right. Because when sex cells are produced, each comes with 1/2 the genetic code. And when other cells divide, the chromosome divides in 1/2, and the cell splits down the middle.

Isn't it possible that if the DNA molecule had originated in a different form/configuration, we might all be having threesomes to reproduce?

Yes, that was meant to be funny. But the question is serious--duality and symmetry seems to be a basic element of life on this planet (at least, once you reach a certain plateau).

Is symmetry NECESSARY for a living thing to survive in nature? Does it make it more likely? Why is that once you get to about the size of, say, a worm, everything can be cut into two evenly?

I really don't think my post was "silly" enough to warrant getting tossed down in the pile of Elsewhere among the other refuse.

orpheus last chant

Not perfect symmetry! You only have one liver, one heart, one uterus, one stomach, one aorta etc.

And scavengers, and symbiotic relationships, and parasites...

..and drunk , and comatose, and brain-dead yet functioning.

Actually, depends from what point of view you look at that.

Reminds me of the joke: Organic chemistry is the chemistry of organic compounds, and biochemistry is the study of organic compounds that crawl.

Are you serious? How on earth can you say they are of equal size? Maybe apparent equal size, but since the sun (in density) is about , oh, 1.000.000 earths, and the moon is about as big as America ...

And there are many more "lights" in the sky. Stars.

And morning and evening...oh, oh! Don't forget complete solar eclipses. Actually, I witnessed one 5 years ago... Pretty cool.



Actually, reproduction is based on two's because it's simple. It's easier to bring two mates together to propagate the species, than to need three individuals.
And it's not all based on two's. Plenty of hermaphrodites out there. Snails have both sexes, though they mate with eachother. Any other!

Some intestinal parasites, jsut detach a segment. Every segment is complete with sexual organs! These critters are basicly reproductive and eating machines.

Adn threes and more? Think about how unnecesarily hard that would be. I think any threesome based species was selected out long time ago if it ever was.

When other cells divide, they don't split their chromosomes! Think about it, for us (46 IIRC) it would in a couple of divisations, we would end up with one and then what, 0.5? No. The RNA copies the chromosome, and the new cell has a complete genome.

Well, think of it this way. We have some organs that have two's in case one malfunctions. It's practical. Evolution would favor that.

An asymetrical being on a larger scale (bigger than a worm), wouldn't have much to gain if born with one foot bigger than the other. When these things happed (and they do), the individual has few chances of passing his genes, since he's probably be caught since he cannot run, or walk to find food.

I don't exactly get this question, but one coudl cut up a worm in three evenly. It doesn't mean anything.

sweep

yes... and no.

lastnightonIo

Fine, fine, I get it.

I'm barking up a tree that's not a tree. I yield. Bad logic.




But I'm STILL not as ...misguided... as that person called Light.





Why wasn't I warned about him/her at the door? :banghead:

sweep

yur a cool dude!

lastnightonIo

"When it's ajar, Roland."