A Public Service Announcement

[titusnowl]

1. Evolution is not a scale.  Some things have evolved further from the same origins than others, but that doesn't mean that "evolution" is a ruler with marks on it for all the different animals, and "humans" at the top as the pinnacle to which all other creatures on earth eventually want to evolve.

2. Evolution is not intelligent.  It does not choose to evolve into things.

3. Evolution is not a force that actively chooses only those things which are advantageous to the animal.  Inasmuch as you can refer to evolution as an it that chooses things at all, which really only works as a metaphor, it works by passively choosing AGAINST those things which are DISadvantageous to the animal.  Basically, if it doesn't result in death before breeding, it's going to get by.  And actually, this is natural selection, which is just a method by which evolution takes place rather than being "evolution" itself.  There's also sexual selection, which does actively choose things - but it's things that the mate finds sexy, which may or may not have anything to do with useful things at all.  (Glossy feathers on a bird might be somewhat indicative of good health, but I'm willing to bet that the hen is thinking "ooh glossy feathers" not "ooh I bet he's healthy and has good genes to pass on to my offspring.")

Comments

[emmycantbemeeko.livejournal.com]

Huzzah! So true. I hate hate hate hearing people talk about evolution casually because most people do not get it. Heck I have only the most basic grasp of the most basic aspects of the theory (and isn't it fun trying to explain to people that "theory" doesn't mean "we're uncertain it's a reality" any more than "theory of gravity" doesn't mean we're not sure there is any?).

You did leave out other mechanisms of natural selection including kin selection, which can operate to preserve a trait even in cases where the trait in question is disadvantageous to the reproduction of the individual. If the trait is disadvantageous to the reproduction of the individual but advantageous to the and reproduction their genetic kin, it may well survive through the genetically similar kin who are benefitted.

Also, what you describe as "natural vs. sexual" selection is probaly more accurately "sexual vs. environmental". Sexual selection also takes more forms than simply the female-selecting for or against particular traits in a mate- it can also take the form of intra-sex competition with no input from the opposite sex, or even at the level of sperm competition between two or more mates (which is SO NEAT and I have a really good article about it somewhere I'll have to find and send you).

And of course there's genetic drift but right about there most people's eyes start glazing over and they mutter something about how they thought it was survival of the fittest.

And now that I've babbled on, what inspired this in the first place?

[chikkiboo.livejournal.com]

Scientists discovered a previously unknown ecosystem full of new and interesting plants and animals in a cave in Israel. A photograph was posted showing an albino scorpion-like thing with no eyes. (This is on the Something Awful forums, btw.) At least seven people on the first page alone posted things like "But why would they evolve backwards into not having eyes?" or "What advantage would they get from [whatever, which isn't actually disadvantageous, simply not overtly advantageous]?" I didn't want to post this in the thread, because there are actual scientific people on the forums and I know my own grasp of the subject - though firmer than those people's - is quite loose overall, so I posted it here, where I will be corrected and learn things without getting "OMG WHAT ABOUG MONEKZY" flames.

[davew0071.livejournal.com]

But what aboug monekzy?

[chikkiboo.livejournal.com]

if ppl evloted from monekzy y r monekzyss stil hear